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Spanish/Conditional. ../Verbs/ | ../Verb Tenses/ | ../Verbs List/ El modo potencial. These two verb tenses communicate what would happen or would have happened.

Spanish/Imperative. ../Verbs/ | ../Verb Tenses/ | ../Verbs List/ Imperativo. This form gives commands. To form the imperative mood of verbs, one normally takes the present subjunctive of the verb. The major exceptions to this rule are the second person singular and plural forms of positive command. To form a positive second person singular command, use the third person singular indicative. To form a positive second person plural command, take the stem of the verb and add: -ad if the verb is an ar verb. -id if the verb is an ir verb. -ed if the verb is an er verb. Note that when making a negative command, such as "no cantes" (don't sing), the present subjunctive is used. There are many exceptions to these rules.

Spanish/Parts of Speech. ../Grammar Index/

Vietnamese/Personal pronouns. Vietnamese is a bit different than Romance languages, in that Vietnamese doesn't just use different pronouns for casual or formal situations, but Vietnamese actually uses different pronouns depending on the relation between the speaker and his/her audience. This relation takes gender, age, and status into account. Basically, Vietnamese refer to everyone as a family member. Also, it is common to use a third person personal pronoun in the first person. Singular pronouns. In addition, there are different pronouns for each kind of relative. For a listing of those pronouns, see Family. "(More to come.)"

Spanish/Vocabulary/Emergency Room. = El Departamento de Emergencias (Emergency department) = = Equipo de primeros auxilios (First aid equipment) =

Bicycles/Degreaser. A degreaser is useful in removing greasy dirt from parts. Traditionally petroleum based products have been used. DO NOT use gasoline. Although it is an effective degreaser, its volatility (i.e. tendency to explode) make it a poor choice for shop work. If you must use a petroleum product, choose naphtha (usually available in hardware stores) or kerosene. A better choice is a modern, biodegradable water based degreaser. Specific blends for bicycle cleaning are available from bike shops and online retailers. You can probably save some money, though, by purchasing degreaser from an auto parts retailer. Whatever you use, after cleaning moving parts with a degreaser, always follow up with lubrication. All residual degreaser should be wiped off the parts before applying lubrication, as it would otherwise dilute the lubricant.

HyperText Markup Language/Textual Formatting. As with almost all programming languages and Markup Languages there are several different ways of formatting text. HTML is no exception. A popular way to format HTML is to use specific HTML tags such as , and . The World Wide Web consortium (W3C) suggest these tags may not be supported in future and that you use , and to add formatting to text on the HTML page. In practice, these methods are both fine to use, but are limited in the ways that text can be formatted. Thus, many HTML authors are shifting towards using CSS (Cascading Style Sheets) which employs "style sheets" and "inline styles" to add formatting to text. It should be noted that using CSS one can redefine the appearance of text inside all tags of a particular type. See the section on classes below for details. Inline styles. Through CSS (Cascading Style Sheets) you can reuse code using "classes" which contain "styles" (ways of formatting text). You can also put CSS styles inline, as in the following: This is a paragraph of double-size bold text results in This is a paragraph of double-size bold text Classes. Classes can be defined in two places; in style tags in HTML documents and in external files, the "style sheets" referred to in the name "Cascading Style Sheets". The term "cascading" refers to the mechanism by which the correct style is chosen when multiple style sheets are to be applied to the same document. An example style tag: An example of the contents of a style sheet file:

Heat Transfer. About this book An introductory text which should be of particular interest to students of chemical or mechanical engineering. Contents of subject /Introduction/ The basics /Heat Balances/ What goes in must come out /Conduction/ A mechanism of heat transfer /Convection/ A mechanism of heat transfer /Radiation/ A mechanism of heat transfer /Heat Transfer with Phase Change/ Different rules apply when this happens /Heat Exchangers/ Industrial devices for heating, cooling and saving energy /Appendices/ There may be something in here later /Bibliography/ Recommended for more in-depth study

The Voynich Manuscript. Welcome. The Voynich manuscript, described as "the world's most mysterious manuscript", is a work which dates to the early 15th century, possibly from northern Italy. It is named after the book dealer /Wilfrid Michael Voynich/, who purchased it in 1912. Some pages are missing, but the current version comprises about 240 pages, most with illustrations. Much of the manuscript resembles herbal manuscripts of the time period, seeming to present illustrations and information about plants and their possible uses for medical purposes. However, most of the plants do not match known species, and the manuscript's script and language remain unknown and unreadable. Possibly some form of encrypted , the Voynich manuscript has been studied by many professional and amateur cryptographers, including American and British codebreakers from both World War I and World War II. As yet, it has defied all decipherment attempts, becoming a "cause célèbre" of historical cryptology. The mystery surrounding it has excited the popular imagination, making the manuscript a subject of both fanciful theories and novels. None of the many speculative solutions proposed over the last hundred years has yet been independently verified. The Voynich manuscript was donated to Yale University's Beinecke Rare Book and Manuscript Library in 1969, where it is catalogued under call number "MS 408" and called a "Cipher Manuscript". Perhaps the appeal of Voynich research is that (a) it is truly cross-disciplinary, and (b) it rewards endeavour and persistence. This wikibook is intended to help you get started on what has already been (for some) a long road of (self-)discovery - the page you may find most useful at first is the Guide To Voynich Jargon. What we know about VMS. Source: What we know about the Voynich manuscript, by Sravana Reddy and Kevin Knight. http://www.isi.edu/natural-language/people/voynich-11.pdf Page-by-page commentary. "See: The Voynich Manuscript/Page-by-page commentary" The Voynich Manuscript has more than 200 pages, divided up into twenty quires (as per the following links). The first 7 quires are standard quires consisting of 4 nested bifolios each. Quire 8 once consisted of 5 such bifolios but only 2 remain. From quire 9 onwards, quires often consist of only one or two multiple folding bifolios. Exceptions are quires 13 (5 standard bifolios) and 20 (7 standard bifolios of which 6 remain). Further details are available at the description of each quire. The web-pages linked onwards from there are intended to summarise the debate relating to individual pages - what could they mean? To what are they similar? What interesting (visual or statistical) properties do they have? "(etc)" Cross-page commentary. This section is designed to contain commentaries on features spanning multiple pages of the VMs.

Vietnamese/Glossary/A-K. This glossary covers only the words used in this textbook. For a more complete listing of Vietnamese words and phrases, please see Wiktionary.

Bicycles/Maintenance and Repair/Tools and Supplies/Multi-tool. A multi tool combines several tools into one package.The individual tools may,for example,all fold into the handle. The is an example of a general purpose multi tool. In recent years, a number of manufacturers have produced multi tools specifically intended for bicycle repair. For example:

Latin/Lesson 4-Principal Parts. Principal Parts. All Latin verbs are identified by four principal parts. By using the four principal parts, one can obtain any and all forms of the verb, including participles, infinitives, gerunds and the like. Examples of principal parts from verbs of each conjugation: For all regular verbs, the principal parts consist of the first person singular present active indicative, the infinitive, the first person singular perfect active indicative, and the supine (or in some texts, the perfect passive participle). Some verbs lack fourth principal parts (e.g., "timeō, timēre, timuī, —"; to be afraid); others, less commonly, lack a third in addition (e.g., "fero, ferre, tuli, latum"; to bring/carry). Others, such as "sum, esse, fuī, futūrus", may use the future active participle ("futūrus") as their fourth principal part; this indicates that the verb cannot be made passive.

Vietnamese/Authors. The following people have started lessons as part of this textbook, or have made notable contributions to an existing lesson. They should be able to answer questions you may have about the Vietnamese language or Vietnamese culture: If you feel that you have made notable contributions to this textbook, please feel free to add your name to this list.

Vietnamese/Version history. This is a history of the changes that this textbook has gone through:

The Voynich Manuscript/Leo Levitov. Levitov's claim of decipherment has been thoroughly discredited. For a critique by linguistic science, by Jacques B.-M. Guy, see http://www.voynich.net/reeds/gillogly/levitov For a critique by historical analysis, by Dennis J. Stallings, see http://web.archive.org/web/20010410030648/http://www.geocities.com/ctesibos/voynich/levitov2.htm

Vietnamese/Tense. Unlike Western languages, Vietnamese doesn't change the ending of the verb (that is, verbs don't conjugate) to express when the statement occurs (the statement's tense). Instead, Vietnamese relies on context to express tense. So, where textbooks for other languages will need to spend chapters and chapters, or pages and pages, to teach you how to change tense, we'll teach you in one page! See what we mean by ? Tense words. One way to do this is to add certain words either before the verb itself, or at the end of the sentence, or both: Present tense. As in most languages, you don't have to do anything special for the present tense – no words expressing tense need to be added. Example: <ruby lang="vi"><rb>Tôi học</rb><br><rt lang="en-us">I study</rt><rb></rb></ruby> Present progressive tense. Place "đang" in front of the verb. Example: <ruby lang="vi"><rb>Tôi</rb> <rb style="font-weight: bold">đang</rb> <rb>học</rb><br><rt lang="en"> I am studying</rt></ruby> Past tense. Either place "đã" in front of the verb, or place "rồi" at the end of the sentence. You can use both, and it often sounds better when you do use both, but it's not necessary, because both words mean "already." Example: <ruby lang="vi"><rb>Anh</rb> <rb style="font-weight: bold">đã</rb> <rb>học</rb><br><rt lang="en">He already studied</rt></ruby> can also be written as: <ruby lang="vi"><rb>Anh học</rb> <rb style="font-weight: bold">rồi</rb><br><rt lang="en">He studied already</rt></ruby> Whereas many other languages have two past tenses – the preterite and imperfect past – Vietnamese has only one. Future tense. Place "sẽ" (will, shall, is about to, plans to) in front of the verb. Example: <ruby lang="vi"><rb>Anh</rb> <rb style="font-weight: bold">sẽ</rb> <rb>học</rb><br><rt lang="en">He will study</rt></ruby> Time words. There is another, more natural way of expressing tense. Just use words that express time in the sentence: Present tense. Again, you don't have to do anything special here. But sometimes it's helpful to add hôm nay (today) at the beginning or end of the sentence, just to clear things up. Present progressive tense. Place words like bây giờ (now) or phrases like ngay bây giờ (right now) at the beginning or end of the sentence. Past tense. Place words like hôm qua (yesterday) at the beginning or end of the sentence, or words like mới (recently) right before the verb. You can do both, actually. Future tense. Place words like ngày mai (tomorrow) at the beginning or end of the sentence. Context. Although other methods of expressing tense also rely on context in the sentence, another way to express tense has to do with common sense. For example, in the sentence, . . . "(More to come.)"

Physics Study Guide/Fluids. Buoyancy. Buoyancy is the force due to pressure differences on the top and bottom of an object under a fluid (gas or liquid). Net force = buoyant force - force due to gravity on the object Bernoulli's Principle. Fluid flow is a complex phenomenon. An ideal fluid may be described as: As the fluid moves through a pipe of varying cross-section and elevation, the pressure will change along the pipe. The Swiss physicist Daniel Bernoulli (1700-1782) first derived an expression relating the pressure to fluid speed and height. This result is a consequence of conservation of energy and applies to ideal fluids as described above. Consider an ideal fluid flowing in a pipe of varying cross-section. A fluid in a section of length formula_1 moves to the section of length formula_2 in time formula_3. The relation given by Bernoulli is: where: In words, the Bernoulli relation may be stated as: "As we move along a streamline the sum of the pressure (formula_4), the kinetic energy per unit volume and the potential energy per unit volume remains a constant." "(To be concluded)"

LPI Linux Certification/LPIC1 Exam 101/GNU & Unix Commands. Unix and Linux. Overview. Unix is the original Internet Operating System (NFS, TCP/IP, RPC, ...). Linux is a Unix clone written from scratch by Linus Torvalds with assistance from a world wide team of developers across the Net. Properties of both systems are: Linux aims toward POSIX compliance and supports also other standard API's such as BSD and SVR4. Linux has all the features you would expect in a modern Unix, including true multitasking/multiple-users, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management and TCP/IP networking. More and more companies and organizations are selecting Linux because of its performance, low cost, and royalty free license. Unix and Linux. Unix is the original Internet Operating System written in 1970 developed at A&T Bell Labs. Distributed freely to government and universities. Different entities did support different distributions. Most varieties of Unix carry copyright licenses. Linux was released in 1991 by Linus Torvalds. The model of Linux licence is copy left from GPL. Linux implement most of the System V and BSD Unix commands. Use the man pages to determine the version. Logging In and Out. The logging In session is the first step to access a Linux system. You need a login ID and a password to be able to start using the system. The login ID root is the super user ID that has all privileges, normally assigned to the System Administrator. When a log in session is successful it will set some environment variables and start the shell that has been assigned to the login ID account. Examples of variables set at log in time: $HOME, $SHELL, $PATH, and more. By changing the file /etc/login.defs the administrator can customize some login parameters and variables for all the users. Examples of some of them: UID_MIN 500 UID_MAX 60000 UMASK 022 ENV_PATH /usr/local/bin:/usr/bin:/bin To logout use the exit or logout command. Password. Nobody can see your password, not even the administrator. To change passwords for users or groups, use passwd. passwd [options] Common options: As a general rule a password must: User information. For every user account, there is a line defined in the file /etc/passwd. The encrypted password is stored in /etc/shadow. The format of /etc/passwd is: root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/bin/bash daemon:x:2:2:Daemon:/sbin:/bin/bash yann:x:500:100:Yann Forget:/home/yann:/bin/bash The x field is the old location for the password. The format of /etc/shadow is: root:IMXweyiV816gg:11996:0:10000:::: bin:!*:8902:0:10000:::: daemon:*:8902:0:10000:::: yann:GoIM8j1S.IuTY:11996:0:99999:7::: The * for the encrypted password means there is no password defined yet. The ! Before the encrypted password means the account is locked. Group information. For every group of users there is a line in file /etc/group. The encrypted password is stored in /etc/gshadow. The format of /etc/group is: root:x:0:root bin:x:1:root,bin,daemon daemon:x:2: video:x:33:yann The format of /etc/gshadow is: root:*:root:root bin:*:root:root daemon:*:root:root video:*:root:root,yann Passwords for group are not often implemented since you have to pass to members of a group the password. Misc. Commands. To get information on a logging In session, use id. id [options] [username] Common options: -g : Print only the group ID. -u : Print only the user ID. Example: $ id uid=0(root) gid=0(root) groups=0(root), 1(bin), 14(uucp), 15(shadow),16(dialout) To run a shell with another user ID and group ID, use su. su [options] [username] Common options: -s : Select another shell. Example: $ su toto passwd: Shell. A Shell is a command line interpreter and: There are several popular shells: Most shells let you customize your prompt and environment. For bash the prompt variable is PS1. For bash the file that can be used for the customization of the environment are: Process text streams using filters. Overview. Description: "Candidates should should be able to apply filters to text streams. Tasks include sending text files and output streams through text utility filters to modify the output, and using standard UNIX commands found in the GNU textutils package." Key files terms and utilities include:<br> cat<br> cut<br> expand<br> fmt<br> head<br> join<br> nl<br> od<br> paste<br> pr<br> sed<br> sort<br> split<br> tac<br> tail<br> tr<br> unexpand<br> uniq<br> wc<br> Pattern matching and wildcards. Wildcard is a pattern matching mechanism for filenames. The purpose of wildcard is to increase productivity: Locate files that you don't fully remember. Locate files that have something in common. Work with a group of files rather than individual. The shell interprets these special characters: The characters used for wildcard are: If you use the wildcard characters the shell will try to generate a file from them. Try the following: echo all files * Special wildcard characters ? match any one character. * Any string [abcfghz] One char set [a-z] One char in range [!x-z] Not in set ~ Home directory ~user User home directory Examples: ? One character filenames only [aA]??? Four characters, starting with a or A. ~toto pathname of toto home directory [!0-9]* All string not starting with a number. What about these commands? ls [a-z][A-Z]??.[uk] ls big* ls a???a ls ??* Shell and wildcards. A shell command line can be a simple command or more complex. ls -l [fF]* ls *.c | more ls -l [a-s]* | mail `users` The first event in the shell is to interpret wildcards. Only the shell interprets unquoted wildcards. Quoting and Comments. Quoting. Do quote to prevent the shell to interpret the special characters and to transform multiple words into one shell word. echo 'He did it, "Why?"' echo 'Because "#@&^:-)"' echo '$VAR='Me echo "What's happening?" echo "I don't know but check this $ANSWER" echo \$VAR=Me echo What\'s happening\? echo \\ Comments. You can add comments in a command line or a script. Use the character #. A white space must immediately precede #. Examples: echo $HOME # Print my Home directory echo "### PASSED ###" # Only this part is a comment echo The key h#, not g was pressed. Commands Concatenate files. To concatenate files, use cat. cat [options] [files...] tac [options] [files...] The results are displayed to the standard output. Common options: -s: never more than one single blank line. -n: number all output line. Examples: cat file # Display file to the stdout. cat chapter* # Display all chapters to stdout. cat -n -s file # Display file with line number with single blank line. To concatenate files in reverse order, use tac. View the beginning and the end of a file. To view only few lines at the beginning or at the end of a file, use head or tail. head [options] [files...] tail [options] [files...] The results are displayed to the standard output. Common options: -n: number of lines to be displayed. (head and tail) -c: number of bytes to be displayed. (head and tail) -f: append output. (tail) -s #: iteration for new data every # sec. (tail) Examples: head file # Display the first 10 lines of file. head -n 2 file # Display the first 2 lines of file. tail -c 10 file # Display the last 10 bytes of file. tail -f -s 1 /var/log/messages "Display the last 10 lines of messages, block and check for new data every second." Numbering file lines. To add the line number to a file, use nl. nl [options] [files...] The results are displayed to the standard output. Common options: -i #: increment line number by #. -b: numbering style: a: number all lines t: non empty line n: number no line -n: numbering format: rz: right justified ln: left justified. Examples: nl file # Add the line number in each line in the file. nl -b t -n rz file # Add the line number to each non-empty line with zero-completed format. Counting items in a file. To print the number of lines, words and characters of a file, use wc. wc [options] [files...] The results are displayed to the standard output. Common options: -c: the byte size. -m: the number of character. -w: the number of word. -l: the number of line. -L: length of the longest line. Examples: wc *.[ch] # Display the number of lines, words, and characters for all files .c or .h. wc -L file # Display the size of the longest line. wc -w file # Display the number of words. Cutting fields in files. To remove sections from each line of files, use cut. cut [options] [files...] The results are displayed to the standard output. Common options: -b #: Extract the byte at position #. -f #: Extract the field number #. Examples: cut -b 4 file # Extract and display the 4th byte of each line of file. cut -b 4,7 file # Extract and display the 4th and 7th byte of each line. cut -b -2,4-6, 20- file # Extract character 1 and 2, 4 to 6 and 20 to the end of the line for each line of file. cut -f 1,3 -d: /etc/passwd # Extract the username and ID of each line in /etc/passwd. The default delimiter is TAB but can be specified with -d. Characters conversion. To translate the stdin to stdout, use tr. tr [options] SET1 SET2 Common options: -d: delete character in SET1. -s: replace sequence of character in SET1 by one. Examples: tr ‘a‘ 'A' # Translate lower a with A tr ‘[A-Z]’ ‘[a-z]’ # Translate uppercase to lowercase tr -d ‘ ‘ # Delete all spaces from file To convert tabs to spaces, use expand and to convert spaces to tabs, use unexpand. expand file unexpand file Lines manipulation. To paste multiple lines of files, use paste. paste [options] [files...] Common options: -d #: delimiter: Use # for the delimiter. -s: serial: paste one file at the time. Examples: paste f1 f2 # Display line of f1 followed by f2. paste -d: file1 file2 # Use ':' for the delimiter. To join multiple lines of files, use join. join file1 file2 To remove duplicated line, use uniq. uniq [options] [files...] Common options: -d: only print duplicated lines. -u: only print unique lines. Examples: uniq -cd file # Display the number of duplicated line. Splitting files To split big files, use split. split [options] file Common options: -l #: split every # lines. -b #: split file in bytes or b for 512 bytes, k for 1Kbytes, m for 1 Mbytes. Examples: split -l 25 file # Split file into 25-line files. split -b 512 file # Split file into 512-byte files. split -b 2b file # Split file into 2*512-byte files. Formatting for printing. To format a file, use fmt. fmt [options] [files...] Common options: -w #: maximum line width. Examples: $ fmt -w 35 file # Display 35-character lines width. To format a file for a printer, use pr. pr [options] [files...] Common options: -d: double space. Examples: $ pr -d file # Format file with double-space. Sort lines of text files. To sort the lines of the names files, use sort. sort [options] file The results are displayed to the standard output. Common options: -r : Reverse -f : Ignore case -n : Numeric -o file: Redirect output to file -u : No duplicate records -t; : Use ';' as delimiter, rather than tab or space. Examples: sort file -r sort file -ro result Binary file dump. To dump a binary file, use od. od [options] file The results are displayed to the standard output and start with an offset address in octal. Common options: -c: each byte as character -x: 2-byte in hex -d: 2-byte in decimal -X: 4-byte in hex. -D: 4-byte in decimal. Examples: $ od -cx /bin/ls 0000000 177 E L F 001 001 001 \0 \0 \0 \0 \0 \0 \0 \0 \0 457f 464c 0101 0001 0000 0000 0000 0000 0000020 002 \0 003 \0 001 \0 \0 \0 224 004 \b 4 \0 \0 \0 0002 0003 0001 0000 9420 0804 0034 0000 0000040 ° ² \0 \0 \0 \0 \0 \0 4 \0 \0 006 \0 ( \0 b2b0 0000 0000 0000 0034 0020 0006 0028 0000060 032 \0 031 \0 006 \0 \0 \0 4 \0 \0 \0 4 200 004 \b 001a 0019 0006 0000 0034 0000 8034 0804 Perform basic file management. Overview. Description: "Candidates should be able to use the basic UNIX commands to copy, move, and remove files and directories. Tasks include advanced file management operations such as copying multiple files recursively, removing directories recursively, and moving files that meet a wildcard pattern. This includes using simple and advanced wildcard specifications to refer to files, as well as using find to locate and act on files based on type, size, or time." Key files terms and utilities include:<br> cp<br> find<br> mkdir<br> mv<br> ls<br> rm<br> rmdir<br> touch<br> file globbing<br> cp: Copy files and directories. ls: List directory contents. Create and Remove directories. To create a directory, use mkdir. mkdir [options] dir Common options: -m mode: set permission mode. Default use umask. -p parent: create parent directory as needed. Examples: mkdir -m 0700 bin mkdir -p bin/system/x86 To delete an empty directory, use rmdir. rmdir [options] dir Common options: -p parent: remove empty subdirectories. Examples: rmdir tmp rmdir -p bin/system/x86 Copy files and directories. To copy one file to another, or to a directory, use cp. cp [options] source target Source and target can be a file or a directory. Common options: -i interactive: prompt to overwrite -r recursive: copy the subdirectories and contents. Use -R for special files. -f force: force the overwriting The default is to silently clobber the target file. Does not alter the source. Examples: cp *.[a-z] /tmp cp readme readme.orig cp ls /bin cp -ri bin/* /bin Move & Rename files. To rename a file or directory or to move a file or directory to another location, use mv. mv [options] source target Source and target can be a file or a directory. Common options: -i interactive: prompt to overwrite -f force: force the overwriting -v verbose The default is to silently clobber the target file. Examples: mv *.[a-z] /tmp mv readme readme.orig mv ls /bin mv -fi bin/* /bin Listing filenames and information. The command to list files in the current directory is ls. ls [options] [filenames] Common options are: -l for a long format -F Append a file type character -a All files, including hidden -R Recursive listing of subtree -d Do not descend into directory The ls is equivalent to the dir command on DOS. Examples of ls output: $ ls -l /bin/ls -rwxr-xr-x 1 root root 46784 mar 23 2002 /bin/ls $ ls -ld /bin drwxr-xr-x 2 root root 2144 nov 5 11:55 /bin $ ls -a . .bash_history .bash_profile .bashrc ... $ ls -dF /etc .bashrc /bin/ls .bashrc /bin/ls* /etc/ File types. The long format means: $ ls -l /etc/hosts #List a long format of the file hosts -rw-r—r-- 1 root root 677 Jul 5 22:18 /etc/hosts File content and location Linux/Unix does not distinguish file by filename extension, like Windows. To determine the file content use file. $ file /etc .bashrc /bin/ls /dev/cdrom /etc: directory .bashrc: ASCII English text /bin/ls: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), stripped /dev/cdrom: symbolic link to /dev/hdc To determine if a command is a built-in shell command or a program, use type, and use which to find its location. $ type cp cd ls which type cp is /bin/cp cd is a shell builtin ls is aliased to `ls $LS_OPTIONS' which is aliased to `type -p' type is a shell builtin $ which cut /usr/bin/cut Creating and using filenames. Filenames can be created with: cat chapter1 chapter2 > book vi mynewfile cp file newfile netscape touch memo The valid filename may have: touch more drink touch "more drink" touch memo* Remove files or directories. To remove files or subtree directories, use rm. rm [options] files Files can be a file or a directory. Common options: -i interactive: prompt to for each removal -f force: force the overwriting -r recursive: remove subtree directories and contents There is no unremove or undelete command. Examples: rm *.[a-z] rm readme readme.orig rm ls /bin rm -rfi /bin cd; rm -rf * .* # !! this removes all files of in the home directory of the current user, as well as those in the subdirectories !! Locating files in a subtree directory. To search for a file in a subtree directory, use find. find [subtrees] [conditions] [actions] The command can take multiple conditions and will search recursively in the subtree. Some possible conditions are: -name [FNG] # Search fo the FNG name -type c # Type of file [bcdfl] -size [+-]# # Has a +- size in blocks (c:bytes,k:kilo) -user [name] # Own by user -atime [+-]# # Accessed days ago +n means not been accessed for the last n days -n means been accessed the last ndays. -mtime [+-]# # Modified days ago -perm nnn # Has permision flags nnn Some possible actions are: -print # Print the pathname -exec cmd {} \; # Execute cmd on the file -ok cmd {} \; # Same as -exec but ask first Examples find . -name '*.[ch]' -print find /var /tmp . -size +20 -print find ~ -type c -name '*sys*' -print find / -type f -size +2c -exec rm -i {} \; find / -atime -3 -print find ~jo ~toto -user chloe -exec mv {} /tmp \; To locate a binary, source file, or man pages, use whereis. Whereis [options] Common options: -b: Search only for binaries. -m: Search only for manual sections. -s: Search only for sources. Examples: $ whereis host host: /usr/bin/host /etc/host.conf /usr/share/man/man1/host.1.gz $ whereis -m host host: /usr/share/man/man1/host.1.gz To locate a file located somewhere defined by the PATH variable, use which. $ which -a ls /bin/ls The -a will look for all possible matches in PATH, not just for the first one. Use streams, pipes, and redirects. Overview. Description: "Candidates should be able to redirect streams and connect them in order to efficiently process textual data. Tasks include redirecting standard input, standard output, and standard error, piping the output of one command to the input of another command, using the output of one command as arguments to another command and sending output to both stdout and a file." Key files terms and utilities include:<br> tee<br> xargs<br> «br> «<br> ><br> »<br> Standard input and standard output. For each command executed in a terminal, there are: a standard input value 0. (default keyboard) a standard output value 1.(default terminal) and a standard output for the errors value 2. (default terminal). Each channel can also be identified by an address: &0 for input, &1 for output, And &2 for errors. Each channel [n] can be redirected. [n]< file: Default value of n is 0 and it reads standard input from file. [n]> file: Default value is 1 and it sends standard output to file, overwriting the file if it exists. (clobber) [n]»file: Default value is 1 and it appends standard output to file. «word: Read standard input until word is reached. `command`: Substitute the command name by the result. Examples: $ pwd > file # out=file in=none error=terminal. cat chap* >book # out=book in=none error=terminal. mv /etc/* . 2>error # out=terminal in=none error=error. echo end of file » book # out=book in=none error=terminal. set -o noclobber # Shell does not clobber existing files. ls > list 2>&1 # ls and errors are redirected to list. ls 2>&1 > list # Errors are redirected to standard output and ls output is redirected to list. cat `ls /etc/*.conf` > conffile 2»/tmp/errors "Concatenate all the configuration files from /etc dir in conffile and append errors in file /tmp/errors." Redirecting with pipes Pipes are an efficient way to apply multiple commandes concurrently. command1 | command2 The standard output of command1 will be piped to the standard input of command2. The standard error is not piped. Examples: ls -l /dev | more ls -l /etc/*.conf | grep user | grep 500 ls -l /bin | mail `users` To redirect the standard output to a file and to the terminal at the same time, use tee. ls -l /dev | tee file ls -l /etc | tee -a file # Append to the file Building arguments The xargs utility constructs an argument list for a command using standard input. xargs [options] [command] The xargs command creates an argument list for command from standard input. It is typically used with a pipe. Common options: -p: prompt the user before executing each command. Examples: ls f* | xargs cat # Print to standard output the content of all files starting with f. find ~ -name 'proj1*' print | xargs cat "Search in the Home directory for files starting with proj1 and send it to the standard input of cat." Use the /dev/null device file to discard output or error messages. Try the following: grep try /etc/* grep try /etc/* 2> /dev/null grep try /etc/* > /dev/null 2> /dev/null Exercises. ls *.c | xargs rm ls [aA]* | xargs cat cat `ls *.v` 2>/dev/null more `ls *.c` Create, monitor, and kill processes. Overview. Description: "Candidates should be able to manage processes. This includes knowing how to run jobs in the foreground and background, bring a job from the background to the foreground and vice versa, start a process that will run without being connected to a terminal and signal a program to continue running after logout. Tasks also include monitoring active processes, selecting and sorting processes for display, sending signals to processes, killing processes and identifying and killing X applications that did not terminate after the X session closed." Key files terms and utilities include:<br> &<br> bg<br> fg<br> jobs<br> kill<br> nohup<br> ps<br> top Create processes. A running application is a process. Every processes have: A process ID. A parent process ID. A current directory PWD. A file descriptor table. A program which it is executing. Environment variables, inherited from its parent process. Stdin, stdou, and stderr Other Bash is a program that when it is executed becomes a process. Each time you execute a command in a shell a new process is created. Except for the buil-in shell command. They run in the shell context. Use type to check if a command is a built-in shell command. Example type cp ls which type Monitor processes Once the system is up and running from a terminal it is possible to see which processes are running with the ps program. To display a long format of all the processes in the system, do: ps -Al F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 004 S 0 1 0 0 80 0 - 112 do_sel ? 00:00:04 init 004 S 0 381 1 0 80 0 - 332 do_sel ? 00:00:00 dhcpcd 006 S 0 1000 1 0 80 0 - 339 do_sel ? 00:00:00 inetd 044 R 0 1524 1222 0 79 0 - 761 - pts/3 00:00:00 ps The ps program will display all the processes running and their PID numbers and other information. To see a long format of the processes in your login session, do a: ps -l F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 000 S 500 1154 1139 0 80 0 - 724 wait4 pts/1 00:00:00 bash 002 S 500 1285 1283 0 77 0 - 24432 wait_f pts/1 00:00:00 soffice.bin 040 R 500 1442 1435 0 79 0 - 768 - pts/4 00:00:00 ps F: Process Flags 002: being created, 040: forked but didn't exec, 400: killed by a signal. S: Process States: R: runnable, S: sleeping, Z: zompbie UID: User ID, PID: Process ID, PPID: Parent Process ID, C: Scheduler, PRI: priority NI: Nice value, SZ: size of routine, WCHAN: name of routine Monitor processes. To monitor the processes in real-time, use top. top 9:20am up 2:48, 4 users, load average: 0.15, 0.13, 0.09 78 processes: 75 sleeping, 3 running, 0 zombie, 0 stopped CPU states: 15.3% user, 0.3% system, 0.0% nice, 84.2% idle Mem: 254896K av, 251204K used, 3692K free, 0K shrd, 27384K buff Swap: 514072K av, 0K used, 514072K free 120488K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 1517 rarrigon 0 0 40816 39M 17372 R 15.0 16.0 2:59 mozilla-bin 1727 rarrigon 19 0 988 988 768 R 0.3 0.3 0:00 top 1 root 20 0 220 220 188 S 0.0 0.0 0:04 init 2 root 20 0 0 0 0 SW 0.0 0.0 0:00 keventd RSS: The total amount of physical memory used by the task. SHARE: The amount of shared memory used by the task. %CPU: The task's share of the CPU time. %MEM: The task's share of the physical memory. Once top is running it is also possible to execute interactive commands: Type N to sort tasks by pid. Type A to sort tasks by age (newest first). Type P to sort tasks by CPU usage. Type M to sort tasks by memory usage. Type k to kill a process (prompted for pid). Kill processes. The ps program will display all the processes running and their PID numbers. Once the PID is known, it is possible to send signals to the process. SIGSTOP to stop a process. SIGCONT to continue a stopped process. SIGKILL to kill a process. The program to send a signal to a process is called kill. kill -SIGKILL [pid] kill -63 [pid] kill -l By default a process is started in foreground and it is the only one to receive keyboard input. Use CTRL+Z to suspend it. To start a process in background use the &. bash & xeyes & Job control In a bash process it is possible to start multiple jobs. The command to manipulate jobs are: jobs # List all the active jobs bg %job # Resume job in background fg %job # Resume job in foreground kill %job # Kill background job When bash is terminated all processes that have been started from the session will receive the SIGHUP signal. This will by default terminate the process. To prevent the termination of a process, the program can be started with the nohup command. nohup mydaemon Modify process execution priorities. Overview. Description: "Candidates should should be able to manage process execution priorities. Tasks include running a program with higher or lower priority, determining the priority of a process and changing the priority of a running process." Key files terms and utilities include:<br> nice<br> ps<br> renice<br> top Priorities. To start a command with an adjusted priority, use nice. nice -n +2 [command] nice -n -19 [command] The program nice changes the base time quantum of the scheduler. i.e. it informs the scheduler how important a process is, which is used as a guide to how much CPU time to give it. For example if you wanted to listen to music whilst ripping another CD, you could use nice -n +5 oggenc, you shouldn’t get any “hops” in the music playback, as the scheduler “knows” the oggenc process is less important. The value can go from -19 (highest priority) to +20 (lowest priority). The default value is 0. Only root can set a value below zero. To modify the priority of a running program, use renice. renice +1 -u root # Change the priority for all root processes. renice +2 -p 193 # Change the priority for PID 193 Exercises. while [ 1 ] do echo -n The date is:; date; done From the other terminal see that you can stop and continue the print out. 3) Same start as 2) but, make the print out to stop for 3[s] and to continue for 1[s] repeatedly. 4) Make a shell script to renice all process called apache to a 19 value. 5) Do a print from ps formated as: “username”, “command”, “nice value” 6) Kill all the process called “bash” and owned by user polto.. Regular Expression. Overview. Description: "Candidates should be able to manipulate files and text data using regular expressions. This objective includes creating simple regular expressions containing several notational elements. It also includes using regular expression tools to perform searches through a filesystem or file content." Key files terms and utilities include:<br> grep<br> regexp<br> sed Pattern matching. There are two kinds of pattern matching: Wildcard characters are mainly applied when they are used in the current directory or subdirectories. When wildcard characters *, ?, [ - ], ~, and ! are used in regexp they no longer generate filenames. Some of the utilities that use regexp are: Limited regexp search pattern Used by all utilities using regexp. Example: Ab[0-3]s ^Ab\^bA [01]bin$ [^zZ]oro Combinations of limited regexp Combinations used by all utilities using regexp. Examples: Ab[0-3][a-z]s ^[01]\^2 [0-9][a-z] \$ [a-zA-Z]* ^[^c-zC-Z]* ^[a-zA-Z0-9]$ Modifier patterns Replace strings matched by regexp patterns grep. To find text in a file, use grep. grep [options] [string] [files] Best to quote the string to prevent interpretation. Common options: -i: Ignore case -l: List filename only if at least one matches -c: Display only count of matched lines -n: Also display line number -v: Must not match. Examples: grep host /etc/*.conf grep -l '\<mai' /usr/include/*.h grep -n toto /etc/group grep -vc root /etc/passwd grep '^user' /etc/passwd grep '[rR].*' /etc/passwd grep '\<[rR].*' /etc/passwd sed. To apply a command on a stream, use sed. sed [address1][,address2][!]command[options] [files...] The program sed will apply a command from address1 to address2 in a file. The address1 and address2 format are regular expressions. The sed program is a noninteractive editing tool. Examples: sed '1,3s/aa/bb/g' file # Replace in file from line 1 to 3 aa by bb. sed '/here/,$d' file # Delete line from here to the end. sed '/here/d' file # Delete lines with word here. sed '1,/xxx/p' file # Print lines from 1 to xxx. sed '/ll/,/ff/!s/maison/house/g' file # In file replace words maison by house excluding lines from ll to ff. Perform basic file editing using vi. Overview. Description: "Candidates should be able to edit text files using vi. This objective includes vi navigation, basic vi nodes, inserting, editing, deleting, copying, and finding text." Key files terms and utilities include:<br> vi<br> /, ?<br> h,j,k,l<br> G, H, L<br> i, c, d, dd, p, o, a<br> ZZ, :w!, :q!, :e!<br> vi. When using X-Windows, you can use mouse-oriented editors such as xedit. In a cross-development environment, users use their favorite editor. On a non-windowing system, you only need a keyboard editor such as vi. The vi editor on Linux is the same as on any Unix systems. vi has two modes: Transition from one mode to another Command mode to Input mode: i, I, a, A, o, O keys Input mode to Command mode: ESC key The default starting mode is the Command mode The file configuration .exrc can be created in your HOME directory to set up some vi behavior. set ignorecase # No case-sensitive set tabs=3 # 3 space for tab character Perform basic file editing using vi Enter Input mode Delete Move cursor

LPI Linux Certification/LPIC1 Exam 101/Linux Filesystems. Create partitions and filesystems. Overview. Description: "Candidates should be able to configure disk partitions and then create filesystems on media such as hard disks. This objective includes using various mkfs commands to set up partitions to various filesystems, including ext2, ext3, reiserfs, vfat, and xfs." Key files terms and utilities include:<br> fdisk<br> mkfs Partitions. Media can be divided into partitions. Partitions are usually created at installation time but can also be created with the fdisk program or other utilities. This will divide the media in partitions and different filesystems can be built and different operating systems can be installed. IDE is recognized as follows: SCSI is recognized as follows: USB and FireWire disks are recognized as SCSI disks. Once it is partitioned it is possible to build a filesystem on every partition. Filesystems. Filesystems exist to allow you to store, retrieve and manipulate data on a media. Filesystems maintain an internal data structure (meta-data) that keeps all you data organized and accessible. The structure of this meta-data gives the characteristic of the filesystem. A filesystem is accessed by a driver through the organized meta-data structure. When Linux boots it reads in /etc/fstab all the filesystems that needs to be mounted and checks if they are in an usable state. When a power failure occurs Linux won't be able to unmout the filesystem properly and some data in the cache won't be synchronized on the media. The meta-data may be corrupted. Once you reboot the system, it will detect this and do a fsck to the full meta-data structure for a consistency check. This can take a very long time. Few minutes to few hours in proportion of the media size. Journaling a filesystem is adding a new data structure called a journal. This journal is on-disk and before each modification to the meta-data is made by the driver it is first written into the journal. Before each meta-data modification the journal maintains a log of the next operation. Now, when a power failure occurs there is only the need to check the journal. A journaling filesystem recovery is very fast. It just needs to go through the logs and fix the latest operation. Journaling filesystem recovery can take only few seconds. On a cluster systems, journaling allows to quickly recover a shared partition of a node that went down. Filesystem tree. A Linux file system has one top directory called root (/) where all sub directories of the entire system is stored. The sub directories can be another partition, a remote directory, or a remote partition accessible through the network with NFS protocol. Create filesystems. To create a file system on a partition, use mkfs. mkfs [options] -t [fstype] device [blocksize] Common options: The full partition will be erased and organized to the type of filesystem requested. There is no undo command. The fstype possible are: msdos, ext2, ext3, reiserfs,minix,xfs The blocksize allows to customize the block size for your filesystem. Examples: mkfs -t msdos /dev/fd0 mkfs -t reiserfs /dev/hdd1 4096 Create extended filesystems. To create an extended (ext2, ext3) filesystem on an partition, use mke2fs. mke2fs [options] device [blocksize] Common options: With mke2fs it is possible to store the super-block the journal information on another device. Examples: mkefs -b 2048 /dev/fd0 -L floppy mkfs -V mke2fs 1.26 (3-Feb-2002) Using EXT2FS Library version 1.263 Monitoring disk usage. To print the disk usage, use du. du [options] [files...] Common options: Examples: $ du -ch Documents 112k Documents/Cours/LPI101 4.0k Documents/Cours/LPI102 4.0k Documents/Cours/LPI201 4.0k Documents/Cours/LPI202 124k total du -sk ~ # Sums up your total disk usage in kilobytes du -ak ~ | sort -n more # Display every file and its disk space in numerical order. Filesystem disk space. A filesystem is composed of a meta-data structure plus a list of blocks. To print the filesystem disk space usage, use df. df [options] [files...] Common options: Examples: $ df -t reiserfs -h F 1k-blocks Used Available Use% Mounted on /dev/hda3 28771528 3121536 25649992 11% / $ df -t ext2 -h Filesystem Size Used Avail Use% Mounted on /dev/hda1 15M 3.8M 10M 27% /boot Maintain the integrity of filesystems. Overview. Description: "Candidates should be able to verify the integrity of filesystems, monitor free space and inodes, and repair simple filesystem problems. This objective includes the commands required to maintain a standard filesystem, as well as the extra data associated with a journaling filesystem." Key files terms and utilities include:<br> du<br> df<br> fsck<br> e2fsck<br> mke2fs<br> debugfs<br> dumpe2fs<br> tune2fs Checking filesystems. To check filesystems consistency, use fsck. fsck [options] -t [fstype] device [fsck-options] Common options: Common fsck-options: Examples: fsck -t msdos /dev/fd0 -a fsck -t reiserfs /dev/hda2 -r Checking extended filesystems. To check extended filesystems consistency, use e2fsck. e2fsck [options] device Common options: Examples: e2fsck -ay /dev/fd0 e2fsck -f /dev/hda2 Debugging extended filesystems. The debugfs program is an interactive file system debugger. It can be used to examine and change the state of an ext2 file system. debugfs device Common commands: Example: stat haut.gif Inode: 14 Type: regular Mode: 0644 Flags: 0x0 Generation: 67558 User: 0 Group: 0 Size: 3786 File ACL: 0 Directory ACL: 0 Links: 1 Blockcount: 8 Fragment: Address: 0 Number: 0 Size: 0 ctime: 0x3ddf3840 -- Sat Nov 23 09:11:44 2002 atime: 0x3ddf3840 -- Sat Nov 23 09:11:44 2002 mtime: 0x3ddf3840 -- Sat Nov 23 09:11:44 2002 BLOCKS: (0-3):55-58 TOTAL: 4 Dumping extended filesystems info. To print the super block and blocks group information of an extended filesystem, use dumpe2fs. dumpe2fs [options] device Common options: Example: dumpe2fs -h /dev/fd0 dumpe2fs 1.26 (3-Feb-2002) Filesystem volume name: floppy Last mounted on: <not available> Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 184 Block count: 1440 Reserved block count: 72 Free blocks: 1258 Free inodes: 168 First block: 1 Block size: 1024 First inode: 11 Inode size: 128 Tuning extended filesystems. To tune an extended filesystem, use tune2fs. tune2fs [options] device Common options: Examples: tune2fs -L floppy /dev/fd0 tune2fs -l /dev/fd0 (Same output as dumpe2fs -h /dev/fd0) tune2fs 1.26 (3-Feb-2002) Filesystem volume name: floppy Block count: 1440 Reserved block count: 72 Free blocks: 1258 Free inodes: 168 First block: 1 Block size: 1024 First inode: 11 Inode size: 128 Attach and detach filesystems. Overview. Description: "Candidates should be able to configure the mounting of a filesystem. This objective includes the ability to manually mount and unmount filesystems, configure filesystem mounting on bootup, and configure user mountable removable filesystems such as tape drives, floppies, and CDs." Key files terms and utilities include:<br> /etc/fstab<br> mount<br> umount Attach a filesystem. The mount command serves to attach the file system found on some device to the big file tree. mount [options] mount [options] [-t vfstype] [-o options] device dir If the device or directory is listed in /etc/fstab you can use the following: mount [options] [-o options [...]] device | dir Normally only root has the privilege to mount devices unless it is specified in the /etc/fstab file. Examples: # Print all the mounted filesystems (/etc/mtab). mount # Mount devices or dirs listed in /etc/fstab. mount -a # Mount /dev/hdc partition in read only mode without updating /etc/mtab. mount -n -o ro /dev/hdc /mnt # Allow a user to mount the CDROM if the following line is in /etc/fstab: # /dev/cdrom /media/cdrom iso9660 ro,user,noauto,unhide mount /media/cdrom mount /dev/cdrom # Sync in realtime mount -o sync /dev/sdb1 /mnt/usb Detach a filesystem. To detach a filesystem from the file tree, use umount. umount [options] umount [options] [-o options [...]] device | dir A busy filesystem cannot be unmounted. Examples: umount -a # Unmount devices or dirs listed in /etc/fstab. umount /mnt # Unmount the filesystem attached to /mnt. umount /media/cdrom # Allow a user to unmount the CDROM if the following line is in /etc/fstab: /dev/cdrom /media/cdrom iso9660 ro,user,noauto,unhide File system information. The file /etc/fstab contains all the file systems and related information that will be used when doing a mount -a. (Boot time) The file /etc/mtab is maintained by the kernel and keeps track on what is or isn't mounted. The /etc/fstab format is: #Device Mount point Fs type Options 1 2 /dev/hda3 / reiserfs defaults 1 2 /dev/hda1 /boot ext2 defaults 1 2 /dev/cdrom /media/cdrom auto ro,noauto,user,exec 0 0 usbdevfs /proc/bus/usb usbdevfs noauto 0 0 /dev/hda2 swap swap pri=42 0 0 Common options: Managing disk quota. Overview. Description: "Candidates should be able to manage disk quotas for users. This objective includes setting up a disk quota for a filesystem, editing, checking, and generating user quota reports." Key files terms and utilities include:<br> quota<br> edquota<br> repquota<br> quotaon<br> Quotas. On a system, root can manage the usage of disk space per user and per filsystems. The two limits that can be setup are: The soft limit (soft =) specifies the maximum amount of disk usage a quota user is allowed to have. The hard limit (hard =) specifies the absolute limit on the disk usage a quota user can't go beyond it. There is also the possibility to setup a grace period that will enforce the soft limit only after an amount of time specified. Setting up quotas for users. 1) The keyword usrquota or/and grpquota must be added in file /etc/fstab for the partition interested. /dev/fd0 /home/yann/mnt auto rw,noauto,user,usrquota 0 0 /dev/hda5 /home ext2 defaults,usrquota,grpquota 1 2 2) Add in each root filesystems the file user.quota or/and group.quota. touch /mnt/aquota.user touch /home/aquota.user touch /home/aquota.group chmod 600 /mnt/aquota.user chmod 600 /home/aquota.user chmod 600 /home/aquota.group Only root can do the quota administration and once the empty files have been created some disk quota can be set such as: Setting up quotas for users. 3) Check the setting quotacheck -v mnt quotacheck: Scanning /dev/fd0 [/home/yann/mnt] done quotacheck: Checked 6 directories and 1 files 4) Enable quota on the disk quotaon -av /dev/fd0 [/home/yann/mnt]: user quotas turned on 5) Customize the disk quota limits: $ edquota -u yann Disk quotas for user yann (uid 500): Filesystem locks soft hard inodes soft hard /dev/fd0 15 0 0 4 0 0 $ edquota -g yann $ edquota -t Grace period before enforcing soft limits for users: Time units may be: days, hours, minutes, or seconds Filesystem Block grace period Inode grace period /dev/fd0 7days 7days List quotas. To list quotas for a user or group, use quota. quota [options] [user|group] Common options: Example: quota -u yann Display a quota report. To display a quota report, use repquota. repquota [options] [user|group] Common options: Example: $ repquota /dev/fd0 *** Report for user quotas on device /dev/fd0 Block grace time: 7days; Inode grace time: 7days Block limits File limits User used soft hard grace used soft hard grace root -- 8 0 0 2 0 0 yann -- 15 0 0 4 0 0 File Permissions and Security. Overview. Unix File Security File and Directory Permissions Default Permissions Changing File Permissions Changing File Owner and Group More Privileges Unix file security The biggest security problem may be you. You own any directory or files you created. You are responsible for accessibility of your files. You decide who can access which files and directories. In your home directory you will be able to grant different levels of permission to yourself, users in your group and the all other users. File and Directory Permissions. The permission of a file or of a directory can be viewed with ls -l. File permissions. Examples of file permissions: ls -l readme -rwxrw---- 1 toto users 14 Jul 5 10:00 readme This means read,write, and execution permissions for user toto, read and write permissions for members of group users. No permissions for others. (0760) ls -l /etc/hosts -rw-r--r-- 1 root root 14 Jul 5 10:00 /etc/hosts This means read and write permissions for user root, read permissions for members of group root and all others. (0644) Examples of directory permissions: ls -ld /bin drwxr-xr-x 2 root root 4096 Jul 5 10:00 /bin This means read,write, and execution permissions for user root, read and execution permissions for members of group root and others. (0755) ls -l /home/toto drwxr-xr-x 10 toto users 4096 Jul 5 1:00 /home/toto This means read, write, and execution permissions for user toto, read and execution permissions for members of group users and others. (0755) Default permissions. The default permissions when creating a file are 0666 and when creating a directory are 0777. Most of the systems overwrite this at boot time with the program umask. Generally the mask value is 022. It means the write for group and other will be blocked. To check or change the mask value, do: umask umask 066 Examples for file: default: rw- rw- rw- (0666) umask: 0 2 2 (0022) Block result: rw- r-- r-- (0644) Examples for directory: default: rwx rwx rwx (0777) umask: 0 2 2 (0022) Block result: rwx r-x r-x (0755) Changing file permissions. To change permissions on a file or directory, use chmod. To overwrite the existing permissions, do: chmod 0755 /tmp #rwx for user, rx for group and others To change add or cancel some permissions without overwriting all the existing permissions, do: chmod u+w readme # Add write permission for user chmod +r readme # Add read permission for everybody chmod -r readme # Remove read permission for everybody chmod u+x,g=r readme # Add execution for user and set read for group chmod u=rwx,go=rx readme # Set read write and execution for user, read and execution for group and others To change in recursive mode, use the -R option. chmod -R +x /sbin/* Manage file ownership. Overview. Description: "Candidates should be able to control user and group ownership of files. This objective includes the ability to change the user and group owner of a file as well as the default group owner for new files." Key files terms and utilities include:<br> chmod<br> chown<br> chgrp Changing file owner and group. To change the owner of a file or directory, use chown. chown yann mon_fichier.txt To change the group of a file or directory, use chgrp. chgrp dialout caller The programs gpasswd and yast2 allow you to administrate groups. gpasswd [-A user...] [-M user...] group Group administrators can add or delete members of the group gpasswd -d toto users gpasswd -a toto users Group administrators can set or remove the password for the group. gpasswd users gpasswd -r users More privileges. It is possible to give more privileges to a user when it executes a particular script or program by setting the uid or gid bit of the file. If the bit is set, the process will inherit the permissions of the owner of the file not the permissions of the user. To set the effective uid or gid, use chmod. chmod 2640 [file] # (2) gid is inheritable for group. chmod 4640 [file] # (4) uid is inheritable for user. Example of such program is /bin/passwd. The sticky bit can also be set and can make the program text segment resident in RAM. chmod 1640 [file] (1) The file program stays in RAM. Exercises. 1) Write the command line by using letters with chmod to set the following permissions: rwxrwxr-x : rwxr--r-- : r--r----- : rwxr-xr-x : rwxr-xr-x : r-x--x--x : -w-r----x : -----xrwx : 2) Write the command line by using octal numbers with chmod to set the following permissions: rwxrwxrwx : --x--x--x : r---w---x : -w------- : rw-r----- : rwx--x--x : 3) With the following umask values what would be the files and directories creation permissions? umask = 0027 File permissions: Directory permissions: umask = 0011 File permissions: Directory permissions: umask = 0541 File permissions: Directory permissions: umask = 0777 File permissions: Directory permissions: 4) Create two user accounts Logging in id: tst1, group users, with bash shell, home directory /home/tst1 Logging in id: tst2, group public, with bash shell, home directory /home/tst2 For the two accounts set a password. Logging in as tst1 and copy /bin/ls into tst1 home directory as myls. Change the owner of myls to tst1 and the permissions to 0710. What does this permission value mean? Logging in as tst2 and try to use /home/tst1/myls to list your current directory. Does it work ? Create in /etc/group and /etc/gshadow a new group labo with tst1 and tst2. Change the owner group of myls to labo. Try again from tst2 account to execute /home/tst1/myls to list your current directory. Does it work?. Hard and symbolic links. Overview. Description: "Candidates should be able to create and manage hard and symbolic links to a file. This objective includes the ability to create and identify links, copy files through links, and use linked files to support system administration tasks." Key files terms and utilities include:<br> ln Links. Use link when: You want to create a pathname to a file. Set a shorter or fixed pathname to a file. To link one file to another, use ln: ln [options] filename linkname ln [options] filename linkdirectory Common options: The default links are hard links (ln without an option). On Windows they're called shortcuts. A hard link can only be created to an existing file on the same physical device, after creation no visible association can be displayed between a link name and a file name. A symbolic link can be created on a file that doesn’t exist yet, the association between the link name and the file name can be viewed with the ls command. Linking to a file. The symbolic and hard link can be displayed with ls -l. Symbolic link are indicated with an arrow: link_name->real_filename. $ ls -l /dev/midi lrwxrwxrwx 1 root root 6 Jul 4 21:50 /dev/midi -> midi00 Hard links are indicated with the number of links counter (3-1=2 in this case). $ ls -l readme -rwxrwxrwx 3 yann users 677 Jul 4 21:50 readme When removing a link name, use rm. Only the link will be removed not the linked file.

LPI Linux Certification/LPIC1 Exam 101/The X Window System. Install & Configure XFree86. Overview. X is a windowing system that provides the basic graphic functions of Linux. It's designed to provide a GUI to any other systems operating across a network, regardless of OS. X operates on a client/server model. X is not part of the operating system. It is an application. The standard Linux X server is Xfree86. The XFree86 log file is located at /var/log/XFree86.0.log. Configuration. type "XFree86 -configure", it will scan your hardware and auto. generate a configuration file matching to your hardware. However, FOR PS/2 MOUSE, I usually need to modify this config file manually from ""Device" "/dev/mouse" to "Device" "/dev/psaux"" Starting and stopping X. To start X you can use:<br> "startx" - terminal command used at level 3;<br> "edit /etc/inittab" to run default at level 5;<br> "xinit" - when there is no .xinitrc file;<br> "init 5" - to change manually runlevel to 5 (and run display manager);<br> "xdm" - (X Display Manager) - graphical login manager, which run automatically at boot process when starting Linux at level 5 (there are also external graphical login managers ex. kdm, gdm).<br> To stop X you can use: <CTRL>+<ALT>+<BACKSPACE>;<br> "init 3" - at lower level than 5 Linux will stop X Window;<br> kill the XFree process. Configuring X To configure X on a system use XF86Setup. The program will generate a configuration file that will be used by the XFree86 server. To tune the screen under X use Xfine2. Under X, the user can configure every conceivable aspect of graphic display. Screen font size, styles Pointer behaviour Screen colors Window manager The tunning can be done on a system-wide or per-user. .xinitrc contains the default window manager and style information to be used by the "startx" command. This file is usually located under /home/username when defined on a per-user basis. .Xdefaults used to setup pointer behaviour, colors, fonts, etc... Setup a display manager. Overview. X needs window managers to manipulate all the graphic applications. Move, size. Open and close. Maximize, minimize, iconize. Title bars The look and feel is implemented in the window manager. Provide virtual desktops. Linux distributions contain many window managers: The desktops bring on top of X Window managers more facilities: Networked X. Overview. X works in a client-server relationship where the application is the client and the server is the application that knows how to provide the services. On a single system, both applications reside on the same system. On a networked system the user can run an X application which is installed on a remote system and do the display on a local system. The advantage of having a X application server is: No local applications installation is needed. No need to have performant local system. No local access to data. Networked X. Exporting a simple application : In order to do so do: startx on the serverhost. xhost + Enable lack of identification on the server host. telnet serverhost from the clienthost and set the DISPLAY variable to the clienthost. Export DISPLAY=clienthost:0.0 Exporting the window manager : In order to do so do: Activate xdmcp with gdmsetup on the server Use Xnest to connect the client on the server in broadcast Exercises. 1)Logging In your system with the failsafe display manager. Execute kde or gdm. Exit kde and logout from failsafe. 2)After logging into your system try to type the following key combinations. CTRL-ALT-F1, CTRL-ALT-F2, CTRL-ALT-F7 What is happening? 3)When you use startx, what is the file where you define the default window manager?

LPI Linux Certification/LPIC1 Exam 101/Detailed Objectives. The following material is directly from the Linux Professional Institute at Objectives 101 reprinted with their permission. Note that their inclusion in this book in no way signifies endorsement on the part of LPI. This is a required exam for LPI certification Level 1. It covers basic system administration skills that are common across all distributions of Linux. Each objective is assigned a weighting value. The weights range roughly from 1 to 10, and indicate the relative importance of each objective. Objectives with higher weights will be covered in the exam with more questions. Topic 101: Hardware & Architecture. 1.101.1 Configure Fundamental BIOS Settings. Description: "Candidates should be able to configure fundamental system hardware by making the correct settings in the system BIOS. This objective includes a proper understanding of BIOS configuration issues such as the use of LBA on IDE hard disks larger than 1024 cylinders, enabling or disabling integrated peripherals, as well as configuring systems with (or without) external peripherals such as keyboards. It also includes the correct setting for IRQ, DMA and I/O addresses for all BIOS administrated ports and settings for error handling." Key files terms and utilities include:<br> /proc/ioports<br> /proc/interrupts<br> /proc/dma<br> /proc/pci<br> 1.101.3 Configure Modem and Sound cards. Description: "Ensure devices meet compatibility requirements (particularly that the modem is NOT a win-modem), verify that both the modem and sound card are using unique and correct IRQ's, I/O, and DMA addresses, if the sound card is PnP install and run sndconfig and isapnp, configure modem for outbound dial-up, configure modem for outbound PPP | SLIP | CSLIP connection, set serial port for 115.2 Kbps." 1.101.4 Setup SCSI Devices. Description: "Candidates should be able to configure SCSI devices using the SCSI BIOS as well as the necessary Linux tools. They also should be able to differentiate between the various types of SCSI. This objective includes manipulating the SCSI BIOS to detect used and available SCSI IDs and setting the correct ID number for different devices especially the boot device. It also includes managing the settings in the computer's BIOS to determine the desired boot sequence if both SCSI and IDE drives are used." Key files terms and utilities include:<br> SCSI ID<br> /proc/scsi/<br> scsi_info<br> 1.101.5 Setup different PC expansion cards. Description: "Candidates should be able to configure various cards for the various expansion slots. They should know the differences between ISA and PCI cards with respect to configuration issues. This objective includes the correct settings of IRQs, DMAs and I/O Ports of the cards, especially to avoid conflicts between devices. It also includes using isapnp if the card is an ISA PnP device." Key files terms and utilities include:<br> /proc/dma<br> /proc/interrupts<br> /proc/ioports<br> /proc/pci<br> pnpdump(8)<br> isapnp(8)<br> lspci(8)<br> 1.101.6 Configure Communication Devices. Description: "Candidates should be able to install and configure different internal and external communication devices like modems, ISDN adapters, and DSL switches. This objective includes verification of compatibility requirements (especially important if that modem is a winmodem), necessary hardware settings for internal devices (IRQs, DMAs, I/O ports), and loading and configuring suitable device drivers. It also includes communication device and interface configuration requirements, such as the right serial port for 115.2 Kbps, and the correct modem settings for outbound PPP connection(s)." Key files terms and utilities include:<br> /proc/dma<br> /proc/interrupts<br> /proc/ioports<br> setserial(8)<br> 1.101.7 Configure USB devices. Description: "Candidates should be able to activate USB support, use and configure different USB devices. This objective includes the correct selection of the USB chipset and the corresponding module. It also includes the knowledge of the basic architecture of the layer model of USB as well as the different modules used in the different layers.." Key files terms and utilities include:<br> lspci(8)<br> usb-uhci.o<br> usb-ohci.o<br> /etc/usbmgr/<br> usbmodules<br> /etc/hotplug<br> Topic 102: Linux Installation & Package Management. 1.102.1 Design hard disk layout. Description: "Candidates should be able to design a disk partitioning scheme for a Linux system. This objective includes allocating filesystems or swap space to separate partitions or disks, and tailoring the design to the intended use of the system. It also includes placing /boot on a partition that conforms with the BIOS' requirements for booting." Key files terms and utilities include:<br> / (root) filesystem<br> /var filesystem<br> /home filesystem<br> swap space<br> mount points<br> partitions<br> cylinder 1024<br> 1.102.2 Install a boot manager. Description: "Candidate should be able to select, install, and configure a boot manager. This objective includes providing alternative boot locations and backup boot options (for example, using a boot floppy)." Key files terms and utilities include:<br> /etc/lilo.conf<br> /boot/grub/grub.conf<br> lilo<br> grub-install<br> MBR<br> superblock<br> first stage boot loader<br> 1.102.3 Make and install programs from source. Description: "Candidates should be able to build and install an executable program from source. This objective includes being able to unpack a file of sources. Candidates should be able to make simple customizations to the Makefile, for example changing paths or adding extra include directories." Key files terms and utilities include:<br> gunzip<br> gzip<br> bzip2<br> tar<br> configure<br> make<br> 1.102.4 Manage shared libraries. Description: "Candidates should be able to determine the shared libraries that executable programs depend on and install them when necessary. Candidates should be able to state where system libraries are kept." Key files terms and utilities include:<br> ldd<br> ldconfig<br> /etc/ld.so.conf<br> LD_LIBRARY_PATH<br> 1.102.5 Use Debian package management. Description: "Candidates should be able to perform package management skills using the Debian package manager. This objective includes being able to use command-line and interactive tools to install, upgrade, or uninstall packages, as well as find packages containing specific files or software (such packages might or might not be installed). This objective also includes being able to obtain package information like version, content, dependencies, package integrity and installation status (whether or not the package is installed)." Key files terms and utilities include:<br> unpack<br> configure<br> /etc/dpkg/dpkg.cfg<br> /var/lib/dpkg/*<br> /etc/apt/apt.conf<br> /etc/apt/sources.list<br> dpkg<br> dselect<br> dpkg-reconfigure<br> apt-get<br> alien<br> 1.102.6 Use Red Hat Package Manager (RPM). Description: "Candidates should be able to perform package management under Linux distributions that use RPMs for package distribution. This objective includes being able to install, re-install, upgrade, and remove packages, as well as obtain status and version information on packages. This objective also includes obtaining package information such as version, status, dependencies, integrity, and signatures. Candidates should be able to determine what files a package provides, as well as find which package a specific file comes from." Key files terms and utilities include:<br> /etc/rpmrc<br> /usr/lib/rpm/*<br> rpm<br> grep<br> Topic: 103 GNU & Unix Commands. 1.103.1 Work on the command line. Description: "Candidates should be able to Interact with shells and commands using the command line. This includes typing valid commands and command sequences, defining, referencing and exporting environment variables, using command history and editing facilities, invoking commands in the path and outside the path, using command substitution, applying commands recursively through a directory tree and using man to find out about commands." Key files terms and utilities include:<br> .<br> bash<br> echo<br> env<br> exec<br> export<br> man<br> pwd<br> set<br> unset<br> ~/.bash_history<br> ~/.profile<br> 1.103.2 Process text streams using filters. Description: "Candidates should should be able to apply filters to text streams. Tasks include sending text files and output streams through text utility filters to modify the output, and using standard UNIX commands found in the GNU textutils package." Key files terms and utilities include:<br> cat<br> cut<br> expand<br> fmt<br> head<br> join<br> nl<br> od<br> paste<br> pr<br> sed<br> sort<br> split<br> tac<br> tail<br> tr<br> unexpand<br> uniq<br> wc<br> 1.103.3 Perform basic file management. Description: "Candidates should be able to use the basic UNIX commands to copy, move, and remove files and directories. Tasks include advanced file management operations such as copying multiple files recursively, removing directories recursively, and moving files that meet a wildcard pattern. This includes using simple and advanced wildcard specifications to refer to files, as well as using find to locate and act on files based on type, size, or time." Key files terms and utilities include:<br> cp<br> find<br> mkdir<br> mv<br> ls<br> rm<br> rmdir<br> touch<br> file globbing<br> 1.103.4 Use streams, pipes, and redirects. Description: "Candidates should be able to redirect streams and connect them in order to efficiently process textual data. Tasks include redirecting standard input, standard output, and standard error, piping the output of one command to the input of another command, using the output of one command as arguments to another command and sending output to both stdout and a file." Key files terms and utilities include:<br> tee<br> xargs<br> «br> «<br> ><br> »<br> ` `<br> 1.103.5 Create, monitor, and kill processes. Description: "Candidates should be able to manage processes. This includes knowing how to run jobs in the foreground and background, bring a job from the background to the foreground and vice versa, start a process that will run without being connected to a terminal and signal a program to continue running after logout. Tasks also include monitoring active processes, selecting and sorting processes for display, sending signals to processes, killing processes and identifying and killing X applications that did not terminate after the X session closed." Key files terms and utilities include:<br> &<br> bg<br> fg<br> jobs<br> kill<br> nohup<br> ps<br> top<br> 1.103.6 Modify process execution priorities. Description: "Candidates should should be able to manage process execution priorities. Tasks include running a program with higher or lower priority, determining the priority of a process and changing the priority of a running process." Key files terms and utilities include:<br> nice<br> ps<br> renice<br> top<br> 1.103.7 Search text files using regular expressions. Description: "Candidates should be able to manipulate files and text data using regular expressions. This objective includes creating simple regular expressions containing several notational elements. It also includes using regular expression tools to perform searches through a filesystem or file content." Key files terms and utilities include:<br> grep<br> regexp<br> sed<br> 1.103.8 Perform basic file editing operations using vi. Description: "Candidates should be able to edit text files using vi. This objective includes vi navigation, basic vi nodes, inserting, editing, deleting, copying, and finding text." Key files terms and utilities include:<br> vi<br> /, ?<br> h,j,k,l<br> G, H, L<br> i, c, d, dd, p, o, a<br> ZZ, :w!, :q!, :e!<br> Topic 104: Devices, Linux Filesystems, Filesystem Hierarchy Standard. 1.104.1 Create partitions and filesystems. Description: "Candidates should be able to configure disk partitions and then create filesystems on media such as hard disks. This objective includes using various mkfs commands to set up partitions to various filesystems, including ext2, ext3, reiserfs, vfat, and xfs." Key files terms and utilities include:<br> fdisk<br> mkfs<br> 1.104.2 Maintain the integrity of filesystems. Description: "Candidates should be able to verify the integrity of filesystems, monitor free space and inodes, and repair simple filesystem problems. This objective includes the commands required to maintain a standard filesystem, as well as the extra data associated with a journaling filesystem." Key files terms and utilities include:<br> du<br> df<br> fsck<br> e2fsck<br> mke2fs<br> debugfs<br> dumpe2fs<br> tune2fs<br> 1.104.3 Control mounting and unmounting filesystems. Description: "Candidates should be able to configure the mounting of a filesystem. This objective includes the ability to manually mount and unmount filesystems, configure filesystem mounting on bootup, and configure user mountable removeable filesystems such as tape drives, floppies, and CDs." Key files terms and utilities include:<br> /etc/fstab<br> mount<br> umount<br> 1.104.4 Managing disk quota. Description: "Candidates should be able to manage disk quotas for users. This objective includes setting up a disk quota for a filesystem, editing, checking, and generating user quota reports." Key files terms and utilities include:<br> quota<br> edquota<br> repquota<br> quotaon<br> 1.104.5 Use file permissions to control access to files. Description: "Candidates should be able to control file access through permissions. This objective includes access permissions on regular and special files as well as directories. Also included are access modes such as suid, sgid, and the sticky bit, the use of the group field to grant file access to workgroups, the immutable flag, and the default file creation mode." Key files terms and utilities include:<br> chmod<br> umask<br> chattr<br> 1.104.6 Manage file ownership. Description: "Candidates should be able to control user and group ownership of files. This objective includes the ability to change the user and group owner of a file as well as the default group owner for new files." Key files terms and utilities include:<br> chmod<br> chown<br> chgrp<br> 1.104.7 Create and change hard and symbolic links. Description: "Candidates should be able to create and manage hard and symbolic links to a file. This objective includes the ability to create and identify links, copy files through links, and use linked files to support system administration tasks." Key files terms and utilities include:<br> ln<br> 1.104.8 Find system files and place files in the correct location. Description: "Candidates should be thoroughly familiar with the Filesystem Hierarchy Standard, including typical file locations and directory classifications. This objective includes the ability to find files and commands on a Linux system." Key files terms and utilities include:<br> find<br> locate<br> slocate<br> updatedb<br> whereis<br> which<br> /etc/updatedb.conf<br> Topic 110: The X Window System. 1.110.1 Install & Configure XFree86. Description: "Candidate should be able to configure and install X and an X font server. This objective includes verifying that the video card and monitor are supported by an X server, as well as customizing and tuning X for the videocard and monitor. It also includes installing an X font server, installing fonts, and configuring X to use the font server (may require a manual edit of /etc/X11/XF86Config in the "Files" section)." Key files terms and utilities include:<br> XF86Setup<br> xf86config<br> xvidtune<br> /etc/X11/XF86Config<br> .Xresources</br><br> 1.110.2 Setup a display manager. Description: "Candidate should be able setup and customize a Display manager. This objective includes turning the display manager on or off and changing the display manager greeting. This objective includes changing default bitplanes for the display manager. It also includes configuring display managers for use by X-stations. This objective covers the display managers XDM (X Display Manger), GDM (Gnome Display Manager) and KDM (KDE Display Manager)." Key files terms and utilities include:<br> /etc/inittab<br> /etc/X11/xdm/*<br> /etc/X11/kdm/*<br> /etc/X11/gdm/*<br> 1.110.4 Install & Customize a Window Manager Environment. Description: "Candidate should be able to customize a system-wide desktop environment and/or window manager, to demonstrate an understanding of customization procedures for window manager menus and/or desktop panel menus. This objective includes selecting and configuring the desired x-terminal (xterm, rxvt, aterm etc.), verifying and resolving library dependency issues for X applications, exporting X-display to a client workstation." Key files terms and utilities include:<br> .xinitrc<br> .Xdefaults<br> xhost<br> DISPLAY environment variable<br>

Chinese (Mandarin)/Greetings. Chinese, like all languages, has its own set of unique greetings which may be seemingly strange to learners of the language (this is particularly true if the two cultures are vastly different). Below, you will find commonly-used Mandarin greetings and farewells, along with corresponding pinyin pronunciations.

Spanish/Vocabulary/Love. = El amor =

Chinese (Mandarin)/Lesson 2. =Lesson 2: 今天你忙不忙？= Lesson 2 contains a dialogue of two students discussing their classes for the day. Dialogues. Dialogue 1 Dialogue 2 Vocabulary. Note: Visit this lesson's Stroke Order subpage to see images and animations detailing how to write the following characters. Audio files of the words are linked from the pīnyīn when available. Problems listening? See . Grammar. The adverb Hěn [很]. <br> 1. 我很忙。 Le [了] as emphasizer. <br> 1. 太多了。 2. 太少了。 Affirmative-negative questions. <br> <br><br> Example:<br> Q: 他是不是东尼？ A: 是的。（是，他是/嗯，他是。）or 不是。 （不，他不是。） <br> <br><br> Example: <br> Q:艾美今天忙不忙？/艾美今天忙不？ A: 她很忙。or 她不忙。 Sentences using yǒu [有]. <br> <br><br> Example: <br> 我有三门课。 <br> <br><br> Example: <br> 今天，他们没有课。 <br> <br><br> Example: <br> 今天，他们一门课都没有。

Chinese (Mandarin)/Lesson 3. = Lesson 3: 助詞 = The Chinese language employs heavy usage of particles to modify the meaning of characters and sentences. Since Chinese has neither inflections nor tense, the mastery of particles is an absolute must if one is to fully comprehend both written and spoken Chinese. Below, you will find some of the most common particles in everyday Chinese. The De {的} particle. Example: 她 的 名字 是 金妮。 Tā de míngzi shì Jīnní. Her name is Ginny. Example 她是一个美丽的姑娘 Tā shì yīge měilì de gū’niang. She is a beautiful girl. where "美丽" "beautiful" is an adjective, and Example 研究是一个科学的过程 Yánjīu shì yígè kēxué dè guòchéng Researching is a scientific process. and where "科学" is a noun in Chinese and is turned into adjective using "的". The Le {了} / Liăo {了} particle. Perfective Aspect Particle Example: 他 走 了。 Tā zŏu le. He has gone. ※The "le" here is used to modify 走 (zŏu, "to go") into an action which has already been completed. Example: 別 再 打扰 我 了! 別 再 打擾 我 了! Bié zài dărăo wŏ le! Do not bother me again! ※In this instance, le is used in conjunction with bié ("do not") to form an imperative. "Note": most imperatives are not formed using this construction. Example: 我 实在 吃 不 了 了。 我 實在 吃 不 了 了。 Wŏ shízài chī bù liăo le. I cannot possibly eat any more. At first glance, this sentence may seem a bit daunting as it includes two instances of the le particle, paired side-by-side. However, the first le is understood to be liăo given its placement (bù + le is a nonsensical pairing). Therefore, liăo serves to indicate the capability of eating any further and le "emphasizes" this assertion. The Zhe [着] particle showing continuation. 1. 他睡着觉时有人敲门。 The Zháo [着] particle indicating accomplishment. 1. 我终于把东西买着了! (我終於把東西買著了!) And another word, dào [到], can be seen as a substitution for 着, in most cases they are interchangeable. 2. 他在行窃时被当场抓到。 The 把 + N + V + 着(到)了 construction is particularly useful and should be studied. The De [得] particle indicating degree. 1. 我说得很好. This construct often requires a context to gain its full meaning. If you wish to speak more specifically about an action, the two constructs below demonstrate the use of 得 with a direct object. 2. 我说中文说得很好. Note the dual-use of the verb. 3. 中文我说得很好. This construct emphasizes the object (here being "Chinese"). 4. 我中文说得很好. This expression is the simplification of the 2nd expression by eliminating the 1st verb. This form is even more frequently used than the 2nd expression above. Vocabulary. Note: Visit this lesson's Stroke Order subpage to see images and animations detailing how to write the following characters. Audio files of the words are linked from the pīnyīn when available. Problems listening? See .

Lucid Dreaming. Synopsis. This book attempts to teach the skills that can help you to have lucid dreams — dreams in which you know that you are dreaming. For the skeptical, lucid dreams have been scientifically demonstrated to exist. The ability to lucid dream will open your mind to a world of infinite possibilities as you become adept at taking control of your dreams. We will start by explaining how lucid dreaming works biologically. Next, the book will prepare you for lucid dreaming by helping you to remember more of your dreams (dream recall). You will then learn a variety of ways of becoming, and staying, lucid. Finally, you will find suggested activities to try while in the dream world. Contents. Before each target there is an image with a subjective indication of how complete that target is:

Chinese (Mandarin)/Lesson 4. <br><br> =Lesson 4: Word order and Verbs= Basic Word Order. Subject-Verb-Object. The order of most Chinese sentences, like in English, is S-V-O, that is Subject-Verb-Object. Word order in Chinese is more rigid than in English. However, sometimes you may find sentences that seem to defy normal word order. For example, 我住在中国。wǒ zhù zài zhōngguó. The English translation does this too: I live in China. The reason for this is that "in China" is a preposition (prepositions indicate place or time) that is tacked on to the main sentence—"I live." More examples: As in English, a preposition can also appear after a subject. When using both a preposition for time and a preposition for place, put the preposition for time first. Note the variation in word order. You can also place a preposition for place, but not for time, at the end of a sentence. Topic-Comment. Another structure for Chinese sentences is topic-comment. That is, the first thing mentioned is the topic of discussion and then the speaker will add a comment following that. It is used to emphasize a certain part of the sentence. In the following example, the speaker wants to emphasize that he is going to read the particular book being discussed. Zhè běn shū, wǒ míngtiān zài wǒ jiā kàn.

How to Write an Essay/AP/Introduction. Content needed. AP (Advanced Placement) courses allow high school students to take and get credit for college-level classes. To get credit for a course, a student must pass the AP test. Unfortunately, not all colleges and universities in the US accept AP tests, and some may have their own independent exams. The AP is prepared by Collegeboard and their buddies at ETS (I think), also the writers of such tests as the SAT and PSAT. Courses cover a wide range of subjects, including Spanish, Calculus, English, Chemistry, and History. 1. Agree or Disagree<br> 2. Author's attitude, tone, or point of view<br> 3. Analyze effect<br> 4. Author's purpose<br> 5. General statement about society or human nature<br> 6. Comparison/Contrast<br>

Botany/Mycology. Chapter 10 Chapter 10. Mycology ~ The Fungi Introduction. The Fungi (singular is "fungus") are a large group of organisms treated within the science of Botany, but not really "plants" in the usual sense of the term. The Fungi are ranked as a kingdom within the Domain . That is, they have eukaryotic cells with distinct nuclei, although in some species divisions between nucleated "cells" are sparse. However, they all lack chlorophyll, and the species are saprophytic, parasitic or mycorrhizal. Included within the Fungi are the well known mushrooms, but the group also includes many microscopic forms, and fungi inhabit every environment on earth, perhaps second only to the bacteria (Chapter 7) in distribution.

Lucid Dreaming/Induction Techniques. This page describes a number of lucid dream induction techniques. It is recommended that you be able to recall "at least" one dream per night in order to maximize the effectiveness of these methods. Preliminary Knowledge. Certain elements are common to many of the lucidity-inducing techniques discussed later in this chapter. To better understand these techniques, these common components will be discussed first. Sleep Interruption. An element shared by many of the techniques is sleep interruption. Sleep interruption is the process of purposefully awakening during your normal sleep period and falling asleep a short time later (10–60 minutes). This can be easily done by using a relatively quiet alarm clock to bring you to consciousness without fully waking you. If you find yourself resetting the clock in your sleep, it can be placed on the other side of the room, forcing you to get out of bed to turn it off. Other biorhythm-based options involve drinking lots of fluid (particularly water or tea, a known diuretic) prior to sleep, forcing one to get up to urinate. Sleep interruption is a natural part of the MILD technique (described below) which trains you to arise immediately after your dreams end. Sleep Continuity. If you have trouble initially falling asleep, avoid drinking water for about an hour before going to bed. Otherwise, you may find yourself running to the bathroom, disrupting any attempts at lucidity. Also, try to avoid caffeine and sugar before bed. However, depending on your sensitivity, caffeine may only stimulate your mind as opposed to your body. This extra grip on consciousness could be helpful in inducing lucid dreams. Exercising during the day is an excellent way of preparing your body for sleep. However, be sure to not exercise inside the three hours before bedtime, as your body will be stimulated for a short time afterwards. The morning or afternoon is the best time for this. If you still have difficulty getting to sleep, try reading about lucid dreaming just before going to sleep. Your subconscious will likely absorb this information, increasing your chances of experiencing a lucid dream. If you "do" decide to read before going to sleep, keep a lamp next to your bed as physically getting up to turn off the lights may reawaken your body. Reality checks. A reality check is a test you can perform to see if you're dreaming or awake. It might seem odd to test reality when you are sure that you're awake, but making a habit out of one or more of these reality checks will hugely increase your chances of having a lucid dream. If, say, you hold your nose and try to breathe in through it several times throughout the day then you're very likely to dream about doing it. And when you dream about performing a reality check, then of course the results should come out differently, in this case you'll find that you are somehow breathing in through your closed nostrils. You'll know that you're dreaming, and be able to take lucid control! So here are some reality checks. You should be familiar with the entire list even if you only use a few. Choose a few reality checks which you will do regularly. Take them seriously, do not assume you are awake (even when you know you are). If you practice performing these checks very thoroughly while awake, then you're more likely to perform them thoroughly while dreaming. You should always carry out more than one reality check. If you find that it is not a dream, look around you and think of what would be different if it were a dream. If you do this it will make it more likely that you will do a reality check in a dream. Apart from doing reality checks throughout the day, you also need to do a reality check immediately after you wake up. This helps you become lucid in false awakenings, when you dream that you have woken up but in fact are still dozing. Using a digital alarm clock or mobile phone display to do a Reading check, every single time you wake up, is a quick and reliable way to catch false awakenings. If you have trouble bringing reality checks into your dreams then before going to bed imagine yourself in a dream, noticing odd details and doing a reality check. Then do a reality check in real life. If you do this a few times before bed you will find that you will do it more often in dreams. If you are in a situation where you cannot do a reality check, such as at a public speaking, try to do one as soon as possible. You can do some reality checks very inconspicuously, such as looking at some text on a sign. If you start to say “well, I can't do a reality check now” you should not be surprised when you make this mistake in a dream! Which reality checks are best? When selecting reality checks, the most important properties of a reality check are "reliability", "speed", and "inconspicuousness". On the table above, these are scored out of 5. I have trouble remembering to do reality checks throughout the day. What reminders can I use? You are lucky to have an interesting day and forget about lucid dreaming! You can tag your mind to remember dreaming when you think of certain things, like your friend or your homework. It isn't advisable to explicitly write “reality check” or “lucid” on your hand, as this could create an over dependence on this reminder, which may not exist in a dream. However, you might want to just draw a dot or small circle on your hand. This should be enough to remind you to do a reality check. Try putting a little label on your clock, mobile phone, or watch, reminding yourself to do a reality check. (Some weird colors will make it more noticeable and it will take longer for you to get used to it and ignore it.) If you check these regularly during the course of your waking day, you will be doing lots of reality checks. A simple coffee mug with a reminder such as "Are you dreaming?" printed on it or random alarms can also serve well, but try not to become too dependent on them. You can find examples of these at LD4All. Another technique is to write down three things you do regularly in a day. Examples include hearing your name, going through a doorway, turning on a TV, beginning to read a book, or seeing a stranger. In the morning, choose three such events and intend to do a reality check whenever they happen in the following day. I did a reality check in a dream but it said that I was not dreaming. What went wrong? Some reality checks work perfectly for some people and awfully for others. These are mostly the light switches one and the hands one. If you find that the light switch works or that your hands are perfectly normal, you need to change to a different technique. I did a reality check in a dream but I did not quite realize I was dreaming. What went wrong? An example of this is looking into a mirror and seeing some huge boils or a gray mist on your reflection and not realizing that you are dreaming. This is rare if you actually intended to look into the mirror as a reality check. You need to be more careful when doing your reality checks in real life or pick more reliable reality checks which show more obviously that you are dreaming. Also try to pick reality checks that are easy to do. For example, don't rely the Time Reality Check if you never wear a watch, and don't pick the Mirror Reality Check if you rarely look in the mirror during the day or you know that you won't find a mirror in your dream. Another good remedy for this problem (and a good practice in general) is to perform two or three reality checks at a time. The Time Reality Check, for example, can be easily combined with attempting to push one hand through another. Or, for those with glasses, testing your ability to read text fits naturally with checking for "perfect eyesight w/o glasses". Threads about reality checks on ld4all.com: The BIG Reality Check topic I II | RCs that prove you are awake while dreaming | New RC? | Today's Lucid Tip: Dream Characters Suck | The RC List! | Failed Reality Checks | Funny dream cue / RC experience | The Automatization Technique | Reality Check Failure | Need a better reality check for Christ's sake!!!!!! | WHY?!?!?! Failed Reality Check! Threads about reality checks at The Lucidity Institute: Reality Testing September 2000 June 2001 August 2001 December 2001 Latest top<br> Techniques. When you read through these techniques, remember that different techniques work for different people. There is no “best technique” and most techniques could be used to have 2–5 lucid dreams every night! You could have several lucid dreams in a night, but you will not know it unless you remember them! However, you will probably want some advice as to which technique you should try first. Consider whether you want to use a method which starts from a dream or a method which starts from being awake.* If you master a technique which starts from being awake, you will eventually be able to have lucid dreams on demand when you sleep. For other techniques, you have to rely on your luck to give you lucid dreams after you have done your technique. Here are some advantages and disadvantages for specific techniques: WBTB. WBTB stands for “Wake-Back-To-Bed”. Wake yourself up after 4 to 6 hours of sleep, get out of bed and stay up for anywhere between a few minutes to an hour before going back to bed. It is preferable that you do something related to lucid dreaming during this time (such as reading about lucid dreaming), but it is not required. This is best combined with other techniques; many people have amazing results with a MILD/WBTB combination. The WBTB technique significantly increases your chances of a lucid dream, and using MILD (see below) in conjunction increases your success rate if you are planning to sleep an hour or more after your WBTB session. However, you might need plenty of sleep time and therefore you may only be able to use it on weekends. If you are sleeping too deeply to become lucid, then you can modify this technique. Try returning to sleep somewhere different than where you usually sleep, e.g. on a couch, a different bed, or even on the floor. If you are unable to do this, try changing the way you sleep, e.g. try sleeping with a lighter blanket or reversing the orientation of your body while in the bed (that is, swapping head and feet). Do this in order to teach your body that these different surroundings mean you want to have a more conscious sleep rather than a deeper sleep. In the beginning, different surroundings will also make you more alert, which can heighten your level of consciousness during sleep. I am sometimes awake for very short times, but cannot pull myself together enough to get up and out of bed. What can I do? Put a bright piece of paper on the wall or ceiling so that you will see it when you wake up. Other stimuli could be a hot water bottle, a light turned on under your bed, or an alarm clock. A good technique is to place an alarm clock out of arm's reach so that you are compelled to physically get up from bed and turn it off. If this is still insufficient to restore consciousness, try making a note of your intentions to remain awake and place the note on your alarm clock. After you get a lucid dream with this method, you'll find it easier and easier to get out of bed because you'll have more motivation. Threads about the WBTB technique at ld4all.com: The BIG WBTB topic Auto-suggestion. This technique describes how to use auto-suggestion to have lucid dreams. It can be especially effective for people who are highly susceptible to hypnosis or understand meditation, but for most people, MILD will probably be more effective. As you are falling asleep, suggest to yourself that you will have a lucid dream either that night or in the near future. You can use a mantra (such as “I will recognize that I'm dreaming”) if you want, but make sure you don't try too hard to get a lucid dream. Instead of putting intentional effort into the suggestion, try to genuinely expect to have a lucid dream. Let yourself think expectantly about the lucid dream you are about to have, but be patient if you don't get one right away. You may also use auto-suggestion to improve dream recall. Just use the technique as described above, but instead of suggesting that you'll have a lucid dream, suggest that you'll remember your dreams when you wake up. You could also use a mantra with this, such as “When I wake up, I will remember what I dreamt”. Just be careful not to put too much intentional effort into the mantra — try to genuinely expect to remember your dreams instead. MILD. MILD stands for “Mnemonic Induction of Lucid Dreams", or sometimes, “Mnemonically Induced Lucid Dream". The MILD technique was developed by Stephen LaBerge, and is described fully in his book "Exploring the World of Lucid Dreaming". With the MILD technique, as you are falling asleep, you concentrate on your intention to "remember" to recognize that you are dreaming. Repeat a short mantra in your head, such as “Next time I'm dreaming, I will remember I'm dreaming”. Think about what this means (i.e., that you want to remember that you are dreaming—in the same way you might go to a grocery store and suddenly remember that you need bread), and imagine that you are back in a dream you've had recently, but this time you recognize that you are dreaming. For example, if you recently dreamed of flying, imagine realizing that it is a dream because you are flying. Keep repeating and visualizing the mantra until you are sure that your intention is set in your mind or you fall asleep. If you stop repeating and visualizing the mantra, then still try to make sure the last thing in your mind before falling asleep is your intention to remember to recognize that you are dreaming. In general, the MILD technique can be practiced when you first go to bed at night, or after you have awakened from a dream during the night. If you practice the MILD technique after you have awakened from a dream, you should first run through the dream to ensure that you remember it. Some people find it helpful to jot down a few notes about their dream in their dream journal. Once you have committed the dream to memory, go back to sleep and follow the steps above. But this time, visualize the dream you just had. Move through the dream in your mind until you encounter a dream-sign you originally missed. Now, instead of missing the dream-sign, imagine yourself recognizing it and becoming “lucid”. Repeat this until you have fallen asleep. You "will" re-enter the dream, and you "will" recognize the dream-sign and finally, become lucid. Threads about the MILD technique at ld4all.com: The BIG MILD topic I II | MILD at Midnight? | MILD Mantras archive.org threads about the MILD technique from www.dreamviews.com (offline): Mnemonic Induction of Lucid Dreams (MILD) | Getting more help with MILD from your subconscious WILD. WILD stands for “Wake-Initiated Lucid Dream”, or “Wake-Initiation of Lucid Dreams” to refer to any technique that involves falling asleep consciously. These techniques are similar to self-hypnosis. Some people believe that WILDs are not actual dreams, but are instead astral projection. Various detailed resources are available under that moniker. For most people, they are far easier to induce in the early morning after waking up or in afternoon naps, as the sleep cycle will continue with a REM period. Once you are experienced with inducing WILDs, you can try to induce them at other times. For WILDs to occur, it is best for your body to be completely relaxed. When you go back to bed, lie down comfortably. Now tense and relax your body, starting from your shoulders and working downwards, then back up to the face. This (or similar relaxation, meditation, or trance techniques) should make your body feel slightly heavy and relaxed. There are many different ways to induce WILDs, but they all involve simultaneously attempting to keep the mind aware, while attempting to have the body fall asleep. A few techniques are detailed below. One of the common ways used to induct oneself into a concious sleep, is using an anchor. Anchors can be anything in your environment that you can focus on. These can be either internal, external, or both. An external anchor could be your breathing, white noise, quiet music, the sound of your fan, the ambiance of your room, any external stimuli that you can't control. An internal anchor is a feeling, sensation, or motion that doesn't really exist. These could be an image behind your eyes, moving the hands or fingers of your "dream/spirit body", or going through the motions of falling asleep. These anchors are meant to keep your mind awake, while you fall asleep, and should not be something that will keep you awake. If you pay attention to your physical body while using these techniques, then you will likely enter sleep paralysis (which usually happens after you are already asleep) without losing conscious awareness of your body. You will get a tingling and buzzing sensation (this might be unpleasant). These sensations might be so strong that you feel that you will die (e.g., you might feel a choking sensation), but don't worry, this is perfectly safe! In fact, this process happens to you every time you sleep, you are just not conscious during it. Sometimes you can simply wait until you fall asleep straight into a lucid dream. However, if you do not fall asleep, and you become completely paralyzed (with the exception of your eyes), do not try to move. Imagine your dream hand (or spirit hand if you prefer) going up and leaving your physical hand behind. Now you should have two separate bodies, a dream one and a real one. Control your dream body only — if you control your real one, you will wake up. Now you can try to roll out of bed into your dream world (alternatively, you can get up and walk through a mirror, or sink into your bed). There is a possibility that after waking up from a dream that you initiated using this technique, you may still be paralyzed. If this phenomenon occurs, it may be accompanied by hallucinations. For example, you may wake up from a lucid dream that you started using one of the WILD techniques, and you will still be paralyzed, this is a state of Sleep paralysis. If you have the experience then you have been given an example of what your mind can do, even without your direction. Before the phenomena was understood, as Sleep paralysis also occurs outside of Lucid Dream experiments it had been given a general negative outlook, while the experience is truly unique (partial awareness, unable to move, and multi-sense hallucinations) it is often linked to cultural fears, nightmares and other night terrors, Americans call it Old Hag, Japanese people call it kanashibari, Korean people call it kawi nullida (being pressed by a pair of scissors), Turkish people call it "karabasan" and in old French it was called "Cauquemare", which was later transformed into the term "cauchemar". In any case as soon as you rationalize what is happening you should lose any fear by the temporary loss of muscular control and contextualize any hallucination. Chakra Technique. Using Chakra ("third eye") meditation is one way to achieve WILDs. Basically, one has to focus solely on his third eye and breathing to achieve a lucid dream. This is a technique over 5000 years old, taught to Parvati by Shiva. He is quoted as saying:With intangible breath in center of forehead, as this reaches heart at the moment of sleep, have direction over dreams and over death itself. Eyelid Patterns. This has been found to be very effective in many cases. However, it may lead to strange after effects, such as up to 15 dreams in one night, but otherwise, nothing harmful. This technique is as follows: When you go to sleep, ensure the room is completely dark. Then, with eyes closed, try to focus on the little dots that should appear to be moving on your eyelids. You will find that you can change their color at will. Continue focusing on these dots; make them dance around and form patterns and change colors, and eventually you should enter a Lucid Dream. This may take a little practice, but is usually very effective for summoning Lucid Dreams at will. Works better in conjunction with WBTB and other techniques mentioned above, but is still extraordinarily effective on its own. Hypnagogic Imagery. Stimulate your thinking patterns by constantly switching your attention. After doing this long enough, the images and sounds should begin to take a momentum on their own (this is called hypnagogic imagery), and may they get very strange and illogical. You should enter a dream at this point and quickly become lucid. Otherwise, you will eventually realize you have entered sleep paralysis consciously (see above). Because hypnagogic sleep paralysis involves full consciousness, dreaming can sometimes be frighteningly real. There is often a feeling of being flipped upside down, spun, or being tugged upon by an outside force. Hypnagogic hallucinations may also include strange auditory hallucinations, dark beings and flying. It is possible to observe waking reality while in a hypnagogic state, but this is limited to the sensations of your physical body. Most hypnagogic sleep paralysis states occur when sleeping face up. There is evidence that the tendency toward experiencing Hypnagogic sleep paralysis may be hereditary. Counting. Another technique is to count up to 100 in your head, optionally adding (for example) an “I'm dreaming” between each number. Alternatively, you can imagine stepping down stairs and reading each floor number, from 100 to 0. Try to make this image as vivid as possible — include not only what you see, but also what you hear, feel (touch the banister), and smell. At some point this image should continue into a dream or you will begin to get sleep paralysis as described above. It is easy to lose count, especially with counting up to 100 with an 'I'm dreaming' with each number. But stay focused: you are not going to sleep; your body is, and you must concentrate fully. Sound Technique. This method is for people, who can hear the "tinnitus". The idea is pretty much the same as the other WILD methods, which is to remain conscious while entering the dream state. In order to use this method, you must sleep in a perfectly quiet place. You need to hear the inner buzzing sound inside your ears. Lay your body down and relax as much as possible while trying to hear the sound. If you are too tired, you will fall asleep too fast and it will be difficult to remain conscious - in this case you should combine it with WBTB. By time you realize that the buzzing sound will increase in intensity. This might frighten newcomers, but be assured - nothing bad is going to happen. No, you will not be deaf when you wake up, it’s perfectly safe! *It is just an effect caused by your brain is trying to change mode, from listening to the ambient sound, to listening to the sound of dreamland, which is not real sound but just electrical charge inputed to the part of the brain to create a sensation of hearing. By that time, you will enter the hypnagogic state. All you need to do is concentrate, do not be afraid or think of anything, just be still, and in time your dream body will float, separating from your physical body, and there you go, you arrive in the dreamworld. Note: These sounds can be heard when you concentrate, even throughout the day - when you pay attention to them, but they shouldn't be heard much aloud if you are not in silence and concentrating on it - *as author said. The formula to hear it is quite simple: come into complete silence close your eyes and listen: is there only absolute silence or is there - something else? some...? do not create some sound just concentrate - :-) The best thing on this tech is - you can do it when you want. Slight Physical Discomfort. For the purpose of helping to retain your conscious awareness, slight physical discomfort is useful while performing any WILD technique. This prevents you from just drifting off to sleep. If you are lying down on your bed to do WILD and you are totally comfortable then your chances of going to sleep instead of remaining conscious are very high. The WILD technique relies on a form of deep trance induction, and many people who induce trances for other reasons rely on slight physical discomfort — for example the lotus position, or sitting in a hard-backed chair. Depending on your own preferences and your requirements of discomfort for success, you could choose from the following methods, arranged in ascending order of discomfort: Threads about the WILD technique at ld4all.com: The BIG WILD topic I II III IV V VI VII VIII IX X XI XII XIII XIV| Strange colored dots?!? ULTIMATE WILD method | Threads about the WILD technique at dreamviews.com: Wake-Initiated Lucid Dream (WILD) | Five Stages of WILD | WILD induction. help, only 3 hours til sleep time | Lotus-Flame WILD technique Incubating Dreams. To incubate a dream about a specific topic, you should first think of a phrase that summarizes that topic (e.g., “I want to go to Atlantis.”). It may help to write the phrase down. If there is something you want to do in the dream, think of a phrase to summarize that too (e.g., “I want to watch Atlantis sink into the ocean.”). If you want to become lucid in the dream, then you should probably write something like “When I dream of [the topic], I will remember that I'm dreaming.” beneath your topic phrase. Immediately go to sleep and focus on your topic phrase. Visualize yourself dreaming about the topic and (if you want to become lucid) realizing that you are dreaming. If there is something specific you want to do in the dream, visualize yourself doing it once you become lucid (not very likely to work if you don't become lucid in the dream). Think about your phrase and topic (and intention to become lucid) as you fall asleep. Make sure that the last thing in your mind before falling asleep is your intention to (lucidly) dream about the topic you want to dream about. You might want to wake yourself up when the dream starts to fade so that you remember more of the dream; you can do this by ignoring your perception of the dream environment — the opposite of dream stabilization techniques (just make sure you do a reality check when you wake up to make sure you are really awake). Chaining Dreams. Dream-chaining or “chaining dreams” is a method to re-enter your dream "after you've woken up". It can work for lucid and non-lucid dreams, but you will probably want to enter your dream lucidly. Once you wake up from a dream (if you don't think you were dreaming before you woke up, it may not work well) you should stay still and keep your eyes closed. Small movements are okay, but the less movement, sensory stimulation, and less time awake, the better. Ideally, it should feel less like you've woken up, and more like you've taken a 30 second break from dreaming. Once you are prepared to go back to sleep, close your eyes and either visualize yourself back in your dream, or use the “spinning technique” given in the next chapter to imagine yourself spinning back “into” your dream. Spinning is a little faster than visualization. Be sure to maintain the fact that you are dreaming (unless you don't want to be lucid), or you may lose your lucidity while falling asleep. Once in the dream, stimulate your senses as early as possible (see the next chapter). VILD. VILD stands for “Visual Induction of Lucid Dreams”, or sometimes, “Visually Incubated Lucid Dream”. This technique has been perfected by Peter Harrison, known as Pedro on the forums at ld4all.com. You may wish to read the main thread about the technique. The version described here has been adapted slightly. First, make sure you are relaxed. You can use the relaxing technique mentioned in the description of the WILD technique. You can also imagine your brain emptying out and becoming sleepier. If you have a hard time falling asleep quickly, it should help to read a book (preferably about lucid dreaming) for a while before you go to sleep, until you feel very sleepy. Now, you need to visualize a dream which you had prepared earlier. Here is an example of a prepared dream: Make sure you know exactly what the dream would be like, such as which friend, the exact words they say, and which reality checks you do. Reality checks that require no props, such as books or clocks, are recommended. Visualize this dream slowly three times, to make sure that you know every detail. Then, start going full-on and visualize the dream over and over. You should visualize the dream as though you are looking through your own eyes, not from a third-person perspective. If you find your thoughts drifting, ignore them and continue to visualize the dream continuously. You will need patience for this — don't just give up if you think it won't work. When you actually dream this, you will not notice the difference — until you do your reality checks! Continue with the dream as you incubated it (e.g., remember to thank your friend!) before continuing through the door. I tried to visualize the dream until I fell asleep, but I just stayed awake. What went wrong? If visualizing keeps you awake, the VILD technique is not the technique for you! You should use a different technique. Threads about VILD at ld4all.com: I can LD at will!!!! I II III | VILD...Visually Incubated Lucid Dream Topics about VILD at The Lucidity Institute: The VILD Technique There is an appendix on VILD. LILD. LILD stands for “Lucid Induction of Lucid Dreams”, or sometimes, “Lucidly Induced Lucid Dream”. To use this technique, you need to have a lucid dream in the first place, but it can help you to get more later. The idea is to do something in your dream that will help you to become lucid the next time you are dreaming. For example, you could ask a dream character for help — ask them to meet you the next night and tell you that you are dreaming. If it works out the way it should, then the next time you are dreaming, the dream character will walk up to you and tell you that you are dreaming, and so you'll (hopefully) become lucid. There are many variations on this technique; you could set up signs in your dreamworld that remind you to do a reality check or eat lucid pills instead! This technique is not likely to be very effective, but it "can" work; it relies on the chance that you'll subconsciously induce the reminder (i.e., the dream character or sign or whatever you used) during some later dream, and become lucid because of it. Note that LILD is best used in conjunction with dream-signs and auto-suggested non-lucid dreams. The basic idea as explained above is to have something in your dream that triggers the transition from normal dream state to lucid dreaming. To simply tell a character to tell you that you are dreaming the next time you fall asleep is usually not enough. There is no guarantee that you will dream about that character and there is no guarantee that your subconscious will believe the character enough to make you snap into lucidity (make you realize that you are in fact dreaming). Now as this technique suggests, you must have some previous alternate means of having a lucid dream. Whatever technique you employ to get into this initial lucid dream state is not really important, but you should try to remember to use this technique (LILD) once you do get into a lucid dream state. Thinking of this before falling asleep (MILD) sometimes helps and usually takes many lucid dreams before finally remembering. Once you are in a lucid dream, make up a dream-sign. It can be anything. It can be an object. It can be food or a drink (that doesn't taste like anything). It is usually best to pick something that isn't quite right. Something that on the surface would appear normal in the real world, but that upon closer inspection is not quite right. Food or drinks are good as they can have no taste or not be refreshing in a dream. But try and pick something that you dream about a lot so that there is a better chance of you dreaming about this dream-sign later on. Now pick something else that only appears or happens in your lucid dream. It can be anything. If there is nothing in your current lucid dream, create something really strange. Something that could never be confused with the real world. Now mentally associate the dream-sign (food) with this unusual item or event that could never happen in the real world. But at the same time, this unusual item or event should equate to "lucid dreaming". When you see the unusual item, it should only make you think of when you have a lucid dream as this should be the only time you encountered it. So we have a 3 item associative link. Do all of the above while in a lucid dream. The next time you dream about your dream-sign, your subconscious will think of the unusual item or event. The unusual item or event will make you think of lucid dreaming. The two combined impossibilities (1. dream-sign that cannot exist in the real world 2. item or event that only appears in lucid dreams) will make your unconscious try to make a decision on all this. This will make your conscious mind come to the surface and hopefully you will come to the conclusion that you are dreaming. Many times, you will not want to deal with it because you are too tired (that is why you are sleeping, no?) and fall back into a normal dream state. This is why it can take a few tries. Eventually, your subconscious will start putting clear signs in your dreams like billboards that spell out "YOU ARE DREAMING". But once it triggers, it is quite the realization that an instant before, you had no real control over your actions and now you can do whatever you want. Another note... if it failed, you will usually know why. So next time, you can choose another dream-sign or slightly different technique or something more shocking. Once you get this working once, it is relatively easy to use over and over as the hard part just described is over with. Sometimes disassociative techniques are needed if used too much. To sum up, this technique is a way to force a reality check while in a normal dream state where your subconscious has no choice but to come to the conclusion that you are in fact dreaming. Once your mind knows that you are dreaming, there will be no other conclusion than your conscious mind taking over. And this is what lucid dreaming is all about. CAT. For detailed information on the Cycle Adjustment Technique, see the appendix on CAT. Topics about CAT at The Lucidity Institute: **CAT method** New Lucid dream induction technique There is an appendix on CAT. Tibetan methods. Tibetan Buddhists practice what is known as Tibetan dream yoga. Probably the most time consuming way of inducing lucid dreams, it is also, according to the practitioners, the most rewarding. The basic practice is "awareness". Awareness should be practiced while sleeping just as well as while being awake. Meditating on the question “who is aware?” might catapult you into a higher degree of awareness according to Buddhist beliefs. Keeping this level of awareness is another matter. The Tibetans have developed many yogic exercises and disciplines to be practiced. Maybe the most interesting difference between Tibetan dream yoga and modern western methods of lucid dream induction is the Tibetan claim of the possibility to be aware during deep sleep, not only in the REM periods of sleep. For the reader who is interested in these methods a good start is to begin to regard all experience as a dream. After all, from the countless multitude of matter and radiation reaching our senses the nervous system tunes in only to a small fraction of this chaos. For members of the phalanx that believes we, more or less, create our own reality in the above sense this practice should feel natural. In general though, it is recommended to gain instruction from a teacher in the flesh rather than from books (like this one!). The Tibetan Methods are not "time consuming" if the goal is to go into deeper than Lucid states. From a Raja Yoga stand point, from a Daoist standpoint, and from a Tibetan Yoga standpoint the goal is not to "play" in Lucid Dreams, but to dispel the delusional nature of what we call "reality." Also, to heal and to develop super-learning, and to increase the "energy" you find most attractive: innovative, creative, joyous, blissful, love, power, wisdom, mirth. Are you Ambitious-Worldly or Ambitious-Spiritual? All these factors play into it. These techniques are very easy to learn and are rooted in a deeper science than the WILD, VILD, LILD -- one that does not use auto-suggestion or forced recall. In conclusion, the Tibetan methods are advanced yogic techniques that only an accomplished practitioner can fully teach. If one does not have access to a Tibetan dream yogi, one should probably concentrate on techniques that are more mundane from a Western point of view. Other techniques. Many of these are combinations of other techniques with some addition or modification. Other methods. Food and drink. There are various foods and drinks that you can consume which seem to have some effect on sleeping and dreaming. Note that for most of these there is no explanation or scientific study of how they work, and some may simply be placebos. Don't go overboard with the consumption of any of these, as overdosing could have nasty effects (well, milk should be safe unless you are allergic). Don't experiment without accumulating enough knowledge first. The authors in no way encourage the use of legal or illegal drugs. Some people who practice Lucid dream (LD) or Out of body experience (OBE) use Galantamine to increase their odds to achieve LD or OBE. By taking small amount of Galantamine (around 4 to 8 mg) after 5 to 6 hours of deep sleep and practice the induction technique such as meditation, MILD or WILD many people report more success with Galantamine. There also report that taking Galantamine without proper induction technique will not lead to LD or OBE but will result in only a vivid dream instead. It should also be noted that due to a long half life Galantamine will stay in the body for a period of up to and over 48 hours, as such it is advisable to space out the use of Galantamine over a period of three days so that the body does not build a resistance to the drug ruining its effectiveness. Some people report mixing Galantamine with other Nootropic can enhance the degree of lucidity but this is still controversial since some mixtures may work for some people, but lead to failure for others. Plants: For an in-depth guide to using supplements for lucid dreaming, see the book Advanced Lucid Dreaming - The Power of Supplements. Drugs. Dissociatives and hallucinogens can be used to create a (more or less) lucid dream-like state, though whether or not these help with lucid dreaming is debatable. The authors do not recommend use of these substances for induction of lucid dreams, nor do they condone the breaking of any applicable laws. Some dissociatives and hallucinogens are: For more info, see Erowid Vaults Gadgets. There are various gadgets you can use to become lucid easily. They generally detect when you are in the REM state and then provide a light and/or sound signal. This signal is supposed to be adjusted so that it doesn't wake you up but does enter your dream. The signal is then recognized as showing that you are dreaming, and you become lucid. The most well-known device is the NovaDreamer from the Lucidity Institute. However, this product is no longer produced. Be sure to check for recommendations for devices from lucid dreaming forums. A similar device is the DreamMaker. The DreamMaker works very similarly to the NovaDreamer but without the Dream Alarm feature, which worked to wake the dreamer in the middle of the REM state. This device comes with a mask, a circuit board with adjustable controls, the batteries needed to operate it, a short owner's manual, a lucid dreaming workbook, and the Stephen LaBerge book "Exploring the World of Lucid Dreaming". The circuit board is supplied completely ready to use, but you have to insert the batteries and put the circuit board into the mask yourself. An alternative is the Kvasar. The Kvasar costs about $20 in raw materials, but needs to be constructed by somebody skilled in electronics as it is not sold commercially. It can also be hard to operate. Another do-it-yourself alternative to commercial dreaming masks is Nate True's Lucid Dream Mask, which does not bother with difficult-to-calibrate sensors and just uses a timer for flashing lights, and has (ostensibly) competitive results with all of the former gadgets. The owners of Wellness Tools, who makes the DreamMaker, and Kvasar have not had friendly relations; see DreamViews.com. Software. There are many programs for your computer that can assist with lucid dreaming. These can give out verbal cues while you sleep, or assist in doing your reality checks: There is also a list of programs available at LD4all.com, under the “How” section. Hypnosis. The techniques commonly referred to as hypnosis is based in a set of hypnotic suggestions are commonly composed of a series of instructions and ideas that may be delivered by a hypnotist in the presence of the subject, or they may be self-administered ("self-suggestion" or "autosuggestion"), even in a conscious state. Hypnosis is not a science. In fact, it has in almost every aspect eluded scientific analysis, as it is extremely hard to generalize (each individual responds differently and at different levels) and the methodology is so diverse and based on yet to be completely understood mental/biological phenomena, most related with faith or the placebo effect. For the phenomena to work, whom in aggregate we define as hypnosis, the mind has to be able to turn the suggestions into reality. All hypnosis is ultimately self hypnosis. If you, for instance, take into consideration the problems that faith beliefs have caused to the human race, or even the problems in the field of psychology, you can appreciate the problem of scientifically studying hypnotic phenomena, as they are extremely open to individual interpretation and to one's ability to be open to suggestibility (self-induced or otherwise). The Wikibook's work on Hypnosis will covers the subject in greater detail. It will also offer support material, or reference it, such as methods to induce, or reinforce specific mental states (or states of mind) and any attitudes and beliefs that impact the phenomena. Including information on techniques or procedures for hypnotic induction and hypnotic suggestion. References. top

Bicycles/Maintenance and Repair/Tools and Supplies/Cable Cutter. Brake and derailleur cables are extremely difficult to cut with a standard pair of wire cutters (sometimes called side or diagonal cutters); when it is finally accomplished, this process usually leaves a frayed mess of the inner cable, which is impossible to slip through the cable housing or the hole in a fastening bolt. In addition, the jaws of these cutters are made for cutting copper electrical wire, and will become notched when cutting steel bicycle cables. Cable cutters specifically designed for steel cable, on bicycles or elsewhere, are available at prices low enough to eliminate this nuisance. They are generally similar to regular cutters or scissors, but have extra-hard jaws, each of which carries a v-shaped notch. When cutting a cable, the notches overlap, trapping the cable in a diamond shaped hole with sharp edges, which becomes smaller as the handle is compressed, thereby cutting the cable easily without fraying and with no damage to the tool. They are also useful for cutting the cable housing, although they often close the inner sleeve, and it needs to be re-opened with a piece of cable or other means. Sometimes their use leaves a small burr on the housing which may need to be filed off.

Cryptography. Welcome to Cryptography, the study of obfuscating data to unintended recipients. Part I: Introducing Cryptography Part II: Designing Crypto-systems Part III: Cryptanalysis Part IV: Using Cryptosystems Part V: Cryptography and Society Part VI: Miscellaneous Pages to be merged into the text. Cryptography/Prime Curve/Affine Coordinates Cryptography/Prime Curve/Chudnovsky Coordinates Cryptography/Prime Curve/Jacobian Coordinates Cryptography/Prime Curve/Standard Projective Coordinates Cryptography/Notes

Canadian History/Confederation. Canada's Obligation. By the 1860s, Great Britain became really concerned that Canada was more of a shining star than an asset to the Empire. British politicians did not like the expense of providing for the defence of the North American colonies from real or perceived threats from the Americans. The American Civil War only heightened fears in Canada of a potential invasion. Americans, on the other hand, always seemed to have a group of people willing to go to war with Britain and invade British North America, often in high places (for example, Lincoln's Secretary of State, Seward). Britain's trade with the United States at this time had simply become too valuable to jeopardize by maintaining a colonial system in British North America, so prominent British politicians began the process of pushing Canada "out of the nest," so to speak. However, the process was not simple. British North America consisted of no less than seven colonies, and the vast territory of Rupert's Land owned and run by Hudson's Bay Company. Uniting this area would prove to be difficult. --- The following passage is inaccurate -- Confederation was achieved for many reasons. Canada West and Canada East felt that uniting the colonies would help make all of the colonies stronger, more economically stable, and would make the government system more fair. The maritimes, who were having a boom period, were disinclined to join confederation. They wanted to join together the maritime colonies and have a separate country for only them, however, the Americans had just finished the Civil War, and had about as many soldiers as all the colonies that were thinking about confederation did combined, and posed a real threat to the colonies. The maritimes thought about it, and with the help of a conference with John A. Macdonald decided to join confederation. The only maritime colonies that didn't join were Newfoundland and Prince Edward Island, which would join later on. At the Quebec conference, representatives from all the participating colonies came together and constructed the 72 Resolutions which outlined all of the laws that the new country Canada would have.

Lucid Dreaming/Using. Dream stabilization. Once you are able to dream lucidly, you may find that it is difficult to stay in the dream; for example, you may wake instantly or the dream may start “fading” which is characterized by loss or degradation of any of the senses, especially vision. Alternatively, a new lucid dreamer could easily forget that they are in a dream, as a result of the shock of the sensation. Don't worry if you wake immediately after becoming lucid. As you gain more experience of becoming lucid, it will come as less of a shock and you’ll be less likely to wake up. Make sure you do a reality check to be sure you’re not still dreaming. As you gain more experience, you will have an easier time identifying when and remembering that you are dreaming. You can avoid more gradual fadings by stimulating your senses. This means listening for sounds, feeling around with your hands, and paying attention to what you see and smell. The idea here is to load your senses with stimulation from the dream so that your senses cannot shift to the real world. If you close your eyes, you are removing a great deal of sensory information and might wake up. Staring at a single point can cause effectively the same problem if you stop seeing everything else in your peripheral vision, or don't see enough movement. If you hear something loud in real life and are hearing nothing in the dream, your senses may shift to the real world, causing you to wake up. Ideally you should be able to use the techniques below to stabilize your dream "before" it starts to fade (or “black out”). As always, prevention is better than treatment - and the more stable and vivid your dreams are, the more enjoyable they will be. However, if that doesn't work you may be able to use stabilization techniques to stop the fading; the spinning technique is probably the most effective in this case. If you still can’t stabilize your dream, you may decide to try and wake up with the aim of remembering your dream as accurately as possible while its still fresh in your mind. Hand Touching. Rub your hands together and concentrate on the rubbing. You should feel the friction and the heat of your hands. If you can concentrate on the feelings that this action generates, your dream is likely to stabilize and become more vivid and detailed. You can also keep one hand on your arm while exploring the dream for a constant sense of stimulation. This technique is most effective when used in conjunction with the “Slowing it down” technique, by staring at your hands while rubbing them together. Spinning. You spin around in your dream much as you would if you suddenly want to feel dizzy in real life. The sensation of movement is the key here to stabilizing the dream. Many people report success with this technique, but it also tends to cause a complete change of your dream scene (see Changing the dream environment below). If the dream scene disappears completely (e.g., becomes black), it is necessary to visualize the dreamscape to return to the dream. Slowing it down. Some people like to stabilize the dream by “stopping to smell the roses” and slowly staring at a dream object until it becomes clear. The dreamer would then look around elsewhere, noticing how detailed everything is, thereby stimulating the visual portion of the dream. "However, others find this can cause their lucid dream to end." If you focus on one object for too long to the exclusion of everything else, you will likely wake up or lose the dream. It works best to pay attention to everything in your vision, including your peripheral vision, not just the center of the object you're staring at. If staring at a single object doesn't work for you, try to let your eyes wander around instead. Touching your dream. If you feel that your dream is too abstract and fear that it might be fading, you can prevent this by grabbing hold of a solid object in your dream and focus on how real the sensation is. A good tip is to find something you know is stuck, for instance a table nailed to the ground, and pull it with all your muscular power (no "supernatural" powers!), and you should feel how solid it is. The idea is that you convince yourself that the dream is solid and real — through tactile stimulation — and nothing abstract. Regaining waking memory or skills. This is also likely to enhance your degree of lucidity. Try to remember facts from your waking life, such as your phone number, address, etc., or do some simple math. Or, start reciting the lyrics to your favorite song. Or perhaps try some sports practice you know well — this all depends on which senses / methods of thought process you tend to rely on most in your waking life. Dream Guide. Summon a DC (Dream character) that you expect to Guide you through the dream. Summoning is easier if you always expect this Guide to be there in a dream. The Guide is useful for escaping scary or unpredicted environments ("whooshing" you away, killing or unsummoning the threat, reminding you that you are in control.). Imagine this Guide as powerful, knowledgeable, and protective over you. Guides can also walk you through summoning, flying, shapeshifting, etc. and be useful for learning and controlling your dreams. False awakening. A couple of the users on the ld4all.com forums have had success with creating a false awakening to stabilize a dream. If the above techniques are failing and you find your dream still fading, "and you really want to continue your lucid dream", do the following: You will either have a false awakening, reality check, and then end up with an even more vivid lucid dream, or will really wake up, perform a reality check, and realize that you just woke up (bad luck!). The most important part of this is the reality check. This is what will continue your lucid dream. You should be performing reality checks when you wake up. If you plan to induce false awakenings in order to stabilize a dream, the reality check that you perform as you wake up is as important as the one that got you lucid, if not more. Perform every check in the book until you are positively, absolutely, and completely sure that you aren’t dreaming. A series of 10 reality checks is more likely to produce dream results in a dream, especially if you are expecting dream results. This technique is for those who are desperate! "If you have had a good experience with this technique, please go to the talk page and post your experiences, as there have not been many anecdotes of it working yet." top Recovering from lost visuals. There are a few things you can try to do if you lose your vision. Most of these are less likely to help prolong your dream than the above techniques. You can also try these if you have just woken up and are lying in your bed. You may be able to return to your dream. Autosuggestion. You can repeat over and over a phrase similar to “I can see my dream,” or otherwise enforce in your mind that you can see a dreamscape. (See Autosuggestion) Visualising. You can visualise the scene as it would be if you could see it. You could take this as an opportunity to change the dreamscape by visualising a different environment from the previous one in the dream. This can be made easier by spinning as you visualize. (See Changing the dream environment below) Altering the dream. Changing the dream environment. You can change the dreamscape by simply visualizing a different environment. Stephen LaBerge, author of "Exploring the World of Lucid Dreaming", suggests closing your eyes, spinning around, and visualizing a new location. Alan Worsley, a famous lucid dreamer, describes another technique of summoning a television and remote to switched dreamscapes. By simply “changing the channel” on the remote, imagine your surroundings switching to your desired location, as though you were switching through various television programs. In both of these methods, details are key. The more details you provide for your next dreamscape, the easier it will be to get there. For example, if you wanted go to the Superbowl in your dreams, you might simply state: But this statement could be improved by adding details: Summoning objects into your dream. At some point in your lucid dreaming experience, you'll probably want to handle various objects, or talk with certain people. Both of these needs can be fulfilled by using your mind, and the power of suggestion. There is no set way to "make" things in the dream world; in fact, many lucid dreamers devise their own methods through experimentation. However, here are some of the more common "summoning" techniques: Remember, in the dream world, your expectations shape your surroundings. If you think a big, scary monster is going to step out of the shadows and attack you...well, a big, scary monster probably "is" going to step out of the shadows and attack you. So, don't be a victim; take control of your thoughts and use them to your advantage. top What you can do. This final section should see you off with a few ideas of what to do in a dream. It is advised to have a "clear purpose" for your lucid dreams whenever you go to sleep. In other words, every night you consider what you want to do when you have a lucid dream, and select one thing, or perhaps two or three if you are skilled. Avoid this: You will either end up doing none of these things in your dream or getting overexcited and waking up. Now that that’s clear, here’s a list of possible things you could do, ordered in difficulty. Remember that you might find some things unusually hard (or easy) compared to most lucid dreamers, this is perfectly normal! This is a very rough guide — if you’ve managed something in the Easy section, don't be scared to try for something from the Medium section. Hard. top Conclusion. With all the techniques in this book, you may feel overwhelmed and uncertain of what to do next. Don't worry — just choose a few techniques to “map your way to lucidity”, decide on a few things you will want to do from this page, and start! If you are still unsure of what to do, don’t worry — you might happen to have a lucid dream tonight! If you are beginning to feel a compulsive thirst for "more" information about dreams, head over to the Further Reading section for the sites to satisfy your cravings. Remember to come back occasionally and help make the wikibook grow! top

Vietnamese/History. It seems likely that in the distant past Vietnamese shared more characteristics common to other languages in the Austroasiatic family, such as an inflectional morphology and a richer set of w:consonant clusters, which have subsequently disappeared from the language. However, Vietnamese appears to have been heavily influenced by its location in the Southeast Asian sprachbund—with the result that it has acquired or converged toward characteristics such as isolating morphology and w:tonogenesis. These characteristics, which may or may not have been part of proto-Austroasiatic, nonetheless have become part of many of the philologically unrelated languages of Southeast Asia—for example, Thai (one of the w:Tai-Kadai languages), Tsat (a member of the Malayo-Polynesian language group within Austronesian), and Vietnamese each developed tones as a phonemic feature, although their respective ancestral languages were not originally tonal. The Vietnamese language has similarities with Cantonese in regard to the specific intonations and unreleased plosive consonant endings, a legacy of archaic Chinese that can also be found in Korean. The ancestor of the Vietnamese language was originally based in the area of the Red River in what is now northern Vietnam, and during the subsequent expansion of the Vietnamese language and people into what is now central and southern Vietnam (through conquest of the ancient nation of Champa and the Khmer of the Mekong delta in the vicinity of present-day Ho Chi Minh City), Vietnamese was linguistically influenced primarily by Indic and Malayo-Polynesian languages at first, until Chinese came to politically predominate the Vietnamese area toward the middle of the first millennium AD. With the rise of Chinese political dominance came a radical importation of Chinese vocabulary and grammatical influence. As Chinese was, for a prolonged period, the only medium of literature and government, as well as the primary language of the ruling class in Vietnam, much of the lexicon of Vietnamese in all realms consists of Hán Việt (Sino-Vietnamese) words. In fact, as the vernacular language of Vietnam gradually grew in prestige toward the beginning of the second millennium, the Vietnamese language was written using Chinese characters (see Chữ nôm) adapted to write Vietnamese, in a similar pattern as used in Japan (see "kanji"), Korea and other countries in the Chinese cultural sphere. The Nôm writing reached its zenith in the 18th century when many Vietnamese writers and poets composed their works in Chữ Nôm, most notably Nguyễn Du and Hồ Xuân Hương (dubbed "the Queen of Nôm poetry"). As contact with the West grew, the Quốc Ngữ system of Romanized writing was developed in the 17th century by Portuguese and other Europeans involved in proselytizing and trade in Vietnam. When France invaded Vietnam in the late 19th century, French gradually replaced Chinese as the official language in education and government. Vietnamese adopted many French terms, such as đầm (dame, from "madame"), ga (train station, from "gare"), and va-li (valise). In addition, many Sino-Vietnamese terms were devised for Western ideas imported through the French. However, the Romanized script did not come to predominate until the beginning of the 20th century, when education became widespread and a simpler writing system was found more expedient for teaching and communication with the general population.

Cryptography/Introduction. Cryptography is the study of information hiding and verification. It includes the protocols, algorithms and strategies to securely and consistently prevent or delay unauthorized access to sensitive information and enable verifiability of every component in a communication. Cryptography is derived from the Greek words: kryptós, "hidden", and gráphein, "to write" - or "hidden writing". People who study and develop cryptography are called cryptographers. The study of how to "circumvent" the use of cryptography for unintended recipients is called cryptanalysis, or codebreaking. Cryptography and cryptanalysis are sometimes grouped together under the umbrella term cryptology, encompassing the entire subject. In practice, "cryptography" is also often used to refer to the field as a whole, especially as an applied science. At the dawn of the 21 century in an ever more interconnected and technological world cryptography started to be ubiquitous as well as the reliance on the benefits it brings, especially the increased security and verifiability. Cryptography is an interdisciplinary subject, drawing from several fields. Before the time of computers, it was closely related to linguistics. Nowadays the emphasis has shifted, and cryptography makes extensive use of technical areas of mathematics, especially those areas collectively known as discrete mathematics. This includes topics from number theory, information theory, computational complexity, statistics and combinatorics. It is also a branch of engineering, but an unusual one as it must deal with active, intelligent and malevolent opposition. An example of the sub-fields of cryptography is steganography — the study of hiding the very "existence" of a message, and not necessarily the "contents" of the message itself (for example, microdots, or invisible ink) — and traffic analysis, which is the analysis of patterns of communication in order to learn secret information. When information is transformed from a "useful form" of understanding to an "opaque form" of understanding, this is called encryption. When the information is restored to a useful form, it is called decryption. Intended recipients or authorized use of the information is determined by whether the user has a certain piece of secret knowledge. "Only" users with the secret knowledge can transform the opaque information back into its useful form. The secret knowledge is commonly called the key, though the secret knowledge may include the "entire process" or algorithm that is used in the encryption/decryption. The information in its useful form is called plaintext (or cleartext); in its encrypted form it is called ciphertext. The algorithm used for encryption and decryption is called a cipher (or cypher). Common goals in cryptography. In essence, cryptography concerns four main goals. They are: Not all cryptographic systems achieve all of the above goals. Some applications of cryptography have "different" goals; for example some situations require repudiation where a participant can plausibly deny that they are a sender or receiver of a message, or extend this goals to include variations like: Common forms of cryptography. Cryptography involves all legitimate users of information having the keys required to access that information. Other: Poorly designed, or poorly implemented, crypto systems achieve them only by accident or bluff or lack of interest on the part of the opposition. Users can, and regularly do, find weaknesses in even well-designed cryptographic schemes from those of high reputation. Even with well designed, well implemented, and properly used crypto systems, some goals aren't practical (or desirable) in some contexts. For example, the sender of the message may wish to be anonymous, and would therefore deliberately choose not to bother with non-repudiation. Alternatively, the system may be intended for an environment with limited computing resources, or message confidentiality might not be an issue. In classical cryptography, messages are typically enciphered and transmitted from one person or group to some other person or group. In modern cryptography, there are many possible options for "sender" or "recipient". Some examples, for real crypto systems in the modern world, include: When confusion on these points is present (e.g., at the design stage, during implementation, by a user after installation, or ...), failures in reaching each of the stated goals can occur quite easily—often without notice to any human involved, and even given a perfect cryptosystem. Such failures are most often due to extra-cryptographic issues; each such failure demonstrates that good algorithms, good protocols, good system design, and good implementation do not alone, nor even in combination, provide 'security'. Instead, careful thought is required regarding the entire crypto system design and its use in actual production by real people on actual equipment running 'production' system software (e.g., operating systems) -- too often, this is absent or insufficient in practice with real-world crypto systems. Although cryptography has a long and complex history, it wasn't until the 19th century that it developed anything more than ad hoc approaches to either encryption or cryptanalysis (the science of finding weaknesses in crypto systems). Examples of the latter include Charles Babbage's Crimean War era work on mathematical cryptanalysis of polyalphabetic ciphers, repeated publicly rather later by the Prussian Kasiski. During this time, there was little theoretical foundation for cryptography; rather, understanding of cryptography generally consisted of hard-won fragments of knowledge and rules of thumb; see, for example, Auguste Kerckhoffs' crypto writings in the latter nineteenth century. An increasingly mathematical trend accelerated up to World War II (notably in William F. Friedman's application of statistical techniques to cryptography and in Marian Rejewski's initial break into the German Army's version of the Enigma system). Both cryptography and cryptanalysis have become far more mathematical since WWII. Even then, it has taken the wide availability of computers, and the Internet as a communications medium, to bring effective cryptography into common use by anyone other than national governments or similarly large enterprise. External links

Cryptography/History. Classical Cryptography. The earliest known use of cryptography is found in non-standard hieroglyphs carved into monuments from Egypt's Old Kingdom (ca 4500 years ago). These are not thought to be serious attempts at secret communications, however, but rather to have been attempts at mystery, intrigue, or even amusement for literate onlookers. These are examples of still another use of cryptography, or of something that looks (impressively if misleadingly) like it. Later, Hebrew scholars made use of simple Substitution ciphers (such as the Atbash cipher) beginning perhaps around 500 to 600 BCE. Cryptography has a long tradition in religious writing likely to offend the dominant culture or political authorities. The Greeks of Classical times are said to have known of ciphers (e.g., the scytale transposition cypher claimed to have been used by the Spartan military). Herodutus tells us of secret messages physically concealed beneath wax on wooden tablets or as a tattoo on a slave's head concealed by regrown hair (these are not properly examples of cryptography per se; see secret writing). The Romans certainly did (e.g., the Caesar cipher and its variations). There is ancient mention of a book about Roman military cryptography (especially Julius Caesar's); it has been, unfortunately, lost. In India, cryptography was apparently well known. It is recommended in the Kama Sutra as a technique by which lovers can communicate without being discovered. This may imply that cryptanalytic techniques were less than well developed in India ca 500 CE. Cryptography became (secretly) important still later as a consequence of political competition and religious analysis. For instance, in Europe during and after the Renaissance, citizens of the various Italian states, including the Papacy, were responsible for substantial improvements in cryptographic practice (e.g., polyalphabetic ciphers invented by Leon Alberti ca 1465). And in the Arab world, religiously motivated textual analysis of the Koran led to the invention of the frequency analysis technique for breaking monoalphabetic substitution cyphers sometime around 1000 CE. Cryptography, cryptanalysis, and secret agent betrayal featured in the Babington plot during the reign of Queen Elizabeth I which led to the execution of Mary, Queen of Scots. And an encrypted message from the time of the Man in the Iron Mask (decrypted around 1900 by Étienne Bazeries) has shed some, regrettably non-definitive, light on the identity of that legendary, and unfortunate, prisoner. Cryptography, and its misuse, was involved in the plotting which led to the execution of Mata Hari and even more reprehensibly, if possible, in the travesty which led to Dreyfus' conviction and imprisonment, both in the early 20th century. Fortunately, cryptographers were also involved in setting Dreyfus free; Mata Hari, in contrast, was shot. Mathematical cryptography leapt ahead (also secretly) after World War I. Marian Rejewski, in Poland, attacked and 'broke' the early German Army Enigma system (an electromechanical rotor cypher machine) using theoretical mathematics in 1932. The break continued up to '39, when changes in the way the German Army's Enigma machines were used required more resources than the Poles could deploy. His work was extended by Alan Turing, Gordon Welchman, and others at Bletchley Park beginning in 1939, leading to sustained breaks into several other of the Enigma variants and the assorted networks for which they were used. US Navy cryptographers (with cooperation from British and Dutch cryptographers after 1940) broke into several Japanese Navy crypto systems. The break into one of them famously led to the US victory in the Battle of Midway. A US Army group, the SIS, managed to break the highest security Japanese diplomatic cipher system (an electromechanical 'stepping switch' machine called Purple by the Americans) even before WWII began. The Americans referred to the intelligence resulting from cryptanalysis, perhaps especially that from the Purple machine, as 'Magic'. The British eventually settled on 'Ultra' for intelligence resulting from cryptanalysis, particularly that from message traffic enciphered by the various Enigmas. An earlier British term for Ultra had been 'Boniface'. World War II Cryptography. By World War II mechanical and electromechanical cryptographic cipher machines were in wide use, but they were impractical manual systems. Great advances were made in both practical and mathematical cryptography in this period, all in secrecy. Information about this period has begun to be declassified in recent years as the official 50-year (British) secrecy period has come to an end, as the relevant US archives have slowly opened, and as assorted memoirs and articles have been published. The Germans made heavy use (in several variants) of an electromechanical rotor based cypher system known as Enigma. The German military also deployed several mechanical attempts at a one-time pad. Bletchley Park called them the Fish cyphers, and Max Newman and colleagues designed and deployed the world's first programmable digital electronic computer, the Colossus, to help with their cryptanalysis. The German Foreign Office began to use the one-time pad in 1919; some of this traffic was read in WWII partly as the result of recovery of some key material in South America that was insufficiently carefully discarded by a German courier. The Japanese Foreign Office used a locally developed electrical stepping switch based system (called Purple by the US), and also used several similar machines for attaches in some Japanese embassies. One of these was called the 'M-machine' by the US, another was referred to as 'Red'. All were broken, to one degree or another by the Allies. Other cipher machines used in WWII included the British Typex and the American SIGABA; both were electromechanical rotor designs similar in spirit to the Enigma. Modern Cryptography. The era of modern cryptography really begins with Claude Shannon, arguably the father of mathematical cryptography. In 1949 he published the paper Communication Theory of Secrecy Systems in the Bell System Technical Journal, and a little later the book "Mathematical Theory of Communication" with Warren Weaver. These, in addition to his other works on information and communication theory established a solid theoretical basis for cryptography and for cryptanalysis. And with that, cryptography more or less disappeared into secret government communications organizations such as the NSA. Very little work was again made public until the mid '70s, when everything changed. 1969 saw two major public (i.e., non-secret) advances. First was the DES (Data Encryption Standard) submitted by IBM, at the invitation of the National Bureau of Standards (now NIST), in an effort to develop secure electronic communication facilities for businesses such as banks and other large financial organizations. After 'advice' and modification by the NSA, it was adopted and published as a FIPS Publication (Federal Information Processing Standard) in 1977 (currently at FIPS 46-3). It has been made effectively obsolete by the adoption in 2001 of the Advanced Encryption Standard, also a NIST competition, as FIPS 197. DES was the first publicly accessible cypher algorithm to be 'blessed' by a national crypto agency such as NSA. The release of its design details by NBS stimulated an explosion of public and academic interest in cryptography. DES, and more secure variants of it (such as 3DES or TDES; see FIPS 46-3), are still used today, although DES was officially supplanted by AES (Advanced Encryption Standard) in 2001 when NIST announced the selection of Rijndael, by two Belgian cryptographers. DES remains in wide use nonetheless, having been incorporated into many national and organizational standards. However, its 56-bit key-size has been shown to be insufficient to guard against brute-force attacks (one such attack, undertaken by cyber civil-rights group The Electronic Frontier Foundation, succeeded in 56 hours—the story is in "Cracking DES", published by O'Reilly and Associates). As a result, use of straight DES encryption is now without doubt insecure for use in new crypto system designs, and messages protected by older crypto systems using DES should also be regarded as insecure. The DES key size (56-bits) was thought to be too small by some even in 1976, perhaps most publicly Whitfield Diffie. There was suspicion that government organizations even then had sufficient computing power to break DES messages and that there may be a back door due to the lack of randomness in the 'S' boxes. Second was the publication of the paper New Directions in Cryptography by Whitfield Diffie and Martin Hellman. This paper introduced a radically new method of distributing cryptographic keys, which went far toward solving one of the fundamental problems of cryptography, key distribution. It has become known as Diffie-Hellman key exchange. The article also stimulated the almost immediate public development of a new class of enciphering algorithms, the asymmetric key algorithms. Prior to that time, all useful modern encryption algorithms had been symmetric key algorithms, in which the same cryptographic key is used with the underlying algorithm by both the sender and the recipient who must both keep it secret. All of the electromechanical machines used in WWII were of this logical class, as were the Caesar and Atbash cyphers and essentially all cypher and code systems throughout history. The 'key' for a code is, of course, the codebook, which must likewise be distributed and kept secret. Of necessity, the key in every such system had to be exchanged between the communicating parties in some secure way prior to any use of the system (the term usually used is 'via a secure channel') such as a trustworthy courier with a briefcase handcuffed to a wrist, or face-to-face contact, or a loyal carrier pigeon. This requirement rapidly becomes unmanageable when the number of participants increases beyond some (very!) small number, or when (really) secure channels aren't available for key exchange, or when, as is sensible crypto practice keys are changed frequently. In particular, a separate key is required for each communicating pair if no third party is to be able to decrypt their messages. A system of this kind is also known as a private key, secret key, or conventional key cryptosystem. D-H key exchange (and succeeding improvements) made operation of these systems much easier, and more secure, than had ever been possible before. In contrast, with asymmetric key encryption, there is a pair of mathematically related keys for the algorithm, one of which is used for encryption and the other for decryption. Some, but not all, of these algorithms have the additional property that one of the keys may be made public since the other cannot be (by any currently known method) deduced from the 'public' key. The other key in these systems is kept secret and is usually called, somewhat confusingly, the 'private' key. An algorithm of this kind is known as a public key / private key algorithm, although the term asymmetric key cryptography is preferred by those who wish to avoid the ambiguity of using that term for all such algorithms, and to stress that there are two distinct keys with different secrecy requirements. As a result, for those using such algorithms, only one key pair is now needed per recipient (regardless of the number of senders) as possession of a recipient's public key (by anyone whomsoever) does not compromise the 'security' of messages so long as the corresponding private key is not known to any attacker (effectively, this means not known to anyone except the recipient). This unanticipated, and quite surprising, property of some of these algorithms made possible, and made practical, widespread deployment of high quality crypto systems which could be used by anyone at all. Which in turn gave government crypto organizations worldwide a severe case of heartburn; for the first time ever, those outside that "fraternity" had access to cryptography that wasn't readily breakable by the 'snooper' side of those organizations. Considerable controversy, and conflict, began immediately. It has not yet subsided. In the US, for example, exporting "strong" cryptography remains illegal; cryptographic methods and techniques are classified as munitions. Until 2001 'strong' crypto was defined as anything using keys longer than 40 bits—the definition was relaxed thereafter. (See S Levy's "Crypto" for a journalistic account of the policy controversy in the US). Note, however, that it has NOT been proven impossible, for any of the good public/private asymmetric key algorithms, that a private key (regardless of length) can be deduced from a public key (or vice versa). Informed observers believe it to be currently impossible (and perhaps forever impossible) for the 'good' asymmetric algorithms; no workable 'companion key deduction' techniques have been publicly shown for any of them. Note also that some asymmetric key algorithms have been quite thoroughly broken, just as many symmetric key algorithms have. There is no special magic attached to using algorithms which require two keys. In fact, some of the well respected, and most widely used, public key / private key algorithms can be broken by one or another cryptanalytic attack and so, like other encryption algorithms, the protocols within which they are used must be chosen and implemented carefully to block such attacks. Indeed, "all" can be broken if the key length used is short enough to permit practical brute force key search; this is inherently true of all encryption algorithms using keys, including both symmetric and asymmetric algorithms. This is an example of the most fundamental problem for those who wish to keep their communications secure; they must choose a crypto system (algorithms + protocols + operation) that resists all attack from any attacker. There being no way to know who those attackers might be, nor what resources they might be able to deploy, nor what advances in cryptanalysis (or its associated mathematics) might in future occur, users may ONLY do the best they know how, and then hope. In practice, for well designed / implemented / used crypto systems, this is believed by informed observers to be enough, and possibly even enough for all(?) future attackers. Distinguishing between well designed / implemented / used crypto systems and crypto trash is another, quite difficult, problem for those who are not themselves expert cryptographers. It is even quite difficult for those who are. Revision of modern history. In recent years public disclosure of secret documents held by the UK government has shown that asymmetric key cryptography, D-H key exchange, and the best known of the public key / private key algorithms (i.e., what is usually called the RSA algorithm), all seem to have been developed at a UK intelligence agency before the public announcement by Diffie and Hellman in '76. GCHQ has released documents claiming that they had developed public key cryptography before the publication of Diffie and Hellman's paper. Various classified papers were written at GCHQ during the 1960s and 1970s which eventually led to schemes essentially identical to RSA encryption and to Diffie-Hellman key exchange in 1973 and 1974. Some of these have now been published, and the inventors (James Ellis, Clifford Cocks, and Malcolm Williamson) have made public (some of) their work.

Cryptography/Transposition ciphers. A transposition cipher encodes a message by reordering the plaintext in some definite way. Mathematically, it can be described as applying some sort of bijective function. The receiver decodes the message using the reordering in the opposite way, setting the ordering right again. Mathematically this means using the inverse function of the original encoding function. For example, to encrypt the sentence "A simple kind of transposition cipher writes the message into a rectangle by rows and reads it out by columns," we could use the following rectangle: Asimplekin doftranspo sitionciph erwritesth emessagein toarectang lebyrowsan dreadsitou tbycolumns Then the encrypted text would be "Adsee tldts oirmo erbif tweab eymti rsrya cproi serdo lanta cosle ncegt wiuks iseas tmipp tinao nnohh ngnus." This cipher is often complicated by permuting the rows and columns, as in columnar transposition. Columnar transposition. The standard columnar transposition consists of writing the key out as column headers, then writing the message out in successive rows beneath these headers (filling in any spare spaces with nulls), finally, the message is read off in columns, in alphabetical order of the headers. For example suppose we have a key of 'ZEBRAS' and a message of 'WE ARE DISCOVERED. FLEE AT ONCE'. We start with: Then read it off as: EVLNE ACDTK ESEAQ ROFOJ DEECU WIREE To decipher it, the recipient has to work out the column lengths by dividing the message length by the key length. Then he can write the message out in columns again, then re-order the columns by reforming the key word. Double transposition. A single columnar transposition could be attacked by guessing possible column lengths, writing the message out in its columns (but in the wrong order, as the key is not yet known), and then looking for possible anagrams. Thus to make it stronger, a double transposition was often used. This is simply a columnar transposition applied twice, with two different keys of different (preferably relatively prime) length. Double transposition was generally regarded as the most complicated cipher that an agent could operate reliably under difficult field conditions. It was in actual use at least as late as World War II (e.g. poem code). Grille. Another type of transpositional cipher uses a grille. This is a square piece of cardboard with holes in it such that each cell in the square appears in no more than one position when the grille is rotated to each of its four positions. Only grilles with an even number of character positions in the square can satisfy this requirement. As much message as will fit in the grille is written, then it is turned to another position and more message is written. Removing the cardboard reveals the cyphertext. The following diagram shows the message "JIM ATTACKS AT DAWN" encoded using a 4x4 grille. The top row shows the cardboard grille and the bottom row shows the paper underneath the grille at five stages of encoding: After the letters in the message have all been written out, the ciphertext can be read from the paper: "JKDT STAA AIWM NCAT". The sender and receiver must agree on the initial orientation of the grille, the direction to rotate the grille, the order in which to use the spaces on the grille, and the order in which to read the ciphertext characters from the paper.

Cryptography/Caesar cipher. A Caesar cipher (also known as a shift cipher) is a substitution cipher in which the cipher alphabet is merely the plain alphabet rotated left or right by some number of positions. For instance, here is a Caesar cipher using a right rotation of three places: Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ Cipher: XYZABCDEFGHIJKLMNOPQRSTUVW To encipher a message, simply look up each letter of the message in the "plain" line and write down the corresponding letter in the "cipher" line. To decipher, do the reverse. Because this cipher is a group, multiple encryptions and decryptions provide NO additional security against any attack, including brute-force. The Caesar cipher is named for Julius Caesar, who allegedly used it to protect messages of military significance. It was secure at the time because Caesar's enemies could often not even read plaintext, let alone ciphertext. But since it can be very easily broken even by hand, it has not been adequate for secure communication for at least a thousand years since the Arabs discovered frequency analysis and so made all simple substitution cyphers almost trivially breakable. An ancient book on cryptography, now lost, is said to have discussed the use of such cyphers at considerable length. Our knowledge is due to side comments by other writers, such as Suetonius. Indeed, the Caesar cypher is much weaker than the (competently done) random substitution ciphers used in newspaper cryptogram puzzles. The most common places Caesar ciphers are found today are in children's toys such as secret decoder rings and in the ROT13 cipher on Usenet (which, of course, is meant to be trivial to decrypt)...

Cryptography/Frequency analysis. In the field of cryptanalysis, frequency analysis is a methodology for "breaking" simple substitution ciphers, not just the Caesar cipher but all monoalphabetic substitution ciphers. These ciphers replace one letter of the plaintext with another to produce the cyphertext, and any particular letter in the plaintext will always, in the simplest and most easily breakable of these cyphers, turn into the same letter in the cypher. For instance, all E's will turn into X's. Frequency analysis is based on the fact that certain letters, and combinations of letters, appear with characteristic frequency in essentially all texts in a particular language. For instance, in the English language E is very common, while X is not. Likewise, ST, NG, TH, and QU are common combinations, while XT, NZ, and QJ are exceedingly uncommon, or "impossible". Given our example of all E's turning into X's, a cyphertext message containing lots of X's already seems to suggest one pair in the substitution mapping. In practice the use of frequency analysis consists of first counting the frequency of cypher text letters and then assigning "guessed" plaintext letters to them. Many letters will occur with roughly the same frequency, so a cypher with X's may indeed map X onto R, but could also map X onto G or M. But some letters in every language using letters will occur more frequently; if there are more X's in the cyphertext than anything else, it's a good guess for English plaintext that X stands for E. But T and A are also very common in English text, so X might be either of them. It's very unlikely to be a Z or Q which aren't common in English. Thus the cryptanalyst may need to try several combinations of mappings between cyphertext and plaintext letters. Once the common letters are 'solved', the technique typically moves on to pairs and other patterns. These often have the advantage of linking less commonly used letters in many cases, filling in the gaps in the candidate mapping table being built. For instance, Q and U nearly always travel together in that order in English, but Q is rare. Frequency analysis is extremely effective against the simpler substitution cyphers and will break astonishingly short ciphertexts with ease. This fact was the basis of Edgar Allan Poe's claim, in his famous newspaper cryptanalysis demonstrations in the middle 1800's, that no cypher devised by man could defeat him. Poe was overconfident in his proclamation, however, for polyalphabetic substitution cyphers (invented by Alberti around 1467) defy simple frequency analysis attacks. The electro-mechanical cypher machines of the first half of the 20th century (e.g., the Hebern? machine, the Enigma, the Japanese Purple machine, the SIGABA, the Typex, ...) were, if properly used, essentially immune to straightforward frequency analysis attack, being fundamentally polyalphabetic cyphers. They were broken using other attacks. Frequency analysis was first discovered in the Arab world, and is known to have been in use by about 1000 CE. It is thought that close textual study of the Koran first brought to light that Arabic has a characteristic letter frequency which can be used in cryptoanalysis. Its use spread, and was so widely used by European states by the Renaissance that several schemes were invented by cryptographers to defeat it. These included use of several alternatives to the most common letters in otherwise monoalphabetic substitution cyphers (i.e., for English, both X and Y cyphertext might mean plaintext E), use of several alphabets—chosen in assorted, more or less, devious ways (Leon Alberti seems to have been the first to propose this), culminating in such schemes as using only pairs or triplets of plaintext letters as the 'mapping index' to cyphertext letters (e.g., the Playfair cipher invented by Charles Wheatstone in the mid 1800s). The disadvantage of all these attempts to defeat frequency counting attacks is that it increases complication of both encyphering and decyphering, leading to mistakes. Famously, a British Foreign Secretary is said to have rejected the Playfair cipher because, even if school boys could learn it as Wheatstone and Playfair had shown, 'our attaches could never learn it!'. Frequency analysis requires a basic understanding of the language of the plaintext, as well as tenacity, some problem solving skills, and considerable tolerance for extensive letter bookkeeping. Neat handwriting also helps. During WWII, both the British and Americans recruited codebreakers by placing crossword puzzles in major newspapers and running contests for who could solve them the fastest. Several of the cyphers used by the Axis were breakable using frequency analysis (e.g., the 'consular' cyphers used by the Japanese). Mechanical methods of letter counting and statistical analysis (generally IBM card machinery) were first used in WWII. Today, the hard work of letter counting and analysis has been replaced by the tireless speed of the computer, which can carry out this analysis in seconds. No mere substitution cypher can be thought credibly safe in modern times. The frequency analysis method is neither necessary nor sufficient to solve ciphers. Historically, cryptanalysts solved substitution ciphers using a variety of other analysis methods long before and after the frequency analysis method became well known. Some people even question why the frequency analysis method was considered useful for such a long time. However, modern cyphers are not simple substitution cyphers in any guise. They are much more complex than WWII cyphers, and are immune to simple frequency analysis, and even to advanced statistical methods. The best of them must be attacked using fundamental mathematical methods not based on the peculiarities of the underlying plaintext language. See Cryptography/Differential cryptanalysis or Cryptography/Linear cryptanalysis as examples of such techniques.

Bourne Shell Scripting/Running Commands. Before we can start any kind of examination of the abilities of the Bourne Shell and how you can tap into its power, we have to cover some basic ground first: we have to discuss how to enter commands into the shell for execution by that shell. The easy way: the interactive session. Taking another look at what you've probably already seen. If you have access to a Unix-based machine (or an emulator on another operating system), you've probably been using the Bourne Shell -- or one of its descendants -- already, possibly without realising. Surprise: you've been doing shell scripting for a while already! In your Unix environment, go to a terminal; either a textual logon terminal, or a terminal-in-a-window if you're using the X Window System (look for something called "xterm" or "rxvt" or just "terminal", if you have actually not ever done this yet). You'll probably end up looking at a screen looking something like this: Ben_Tels:Local_Machine:~>_ or The admin says: everybody, STOP TRYING TO CRASH THE SYSTEM Have a lot of fun! bzt:Another_Machine:~>_ or even something as simple as $_ That's it. That's your shell: your direct access to everything the system has to offer. Using the shell in interactive mode. Specifically, the program you accessed a moment ago is your shell, running in "interactive mode": the shell is running in such a way that it displays a prompt and a cursor (the little, blinking line) and is waiting for you to enter a command for it to execute. You execute commands in interactive mode by typing them in, followed by a press of the Enter key. The shell then translates your command to something the operating system understands and passes off control to the operating system so that it can actually carry out the task you have sent it. You'll notice that your cursor will disappear momentarily while the command is being carried out, and you cannot type anymore (at this point, the Bourne Shell program is no longer in control of your terminal -- the other program that you started by executing your command is). At some point the operating system will be finished working on your command and the shell will bring up a new prompt and the cursor as well and will then start waiting again for you to enter another command. Give it a try: type the command After a short time, you'll see a list of files in the working directory (the directory that your shell considers the "current" directory), a new prompt and the cursor. This is the simplest way of executing shell commands: typing them in one at a time and waiting for each to complete in order. The shell is used in this way very often, both to execute commands that belong to the Bourne Shell programming language and simply to start running other programs (like the ls program from the example above). A useful tidbit. Before we move on, we'll mention two useful key combinations when using the shell: the command to interrupt running programs and shell commands and the command to quit the shell (although, why you would ever want to "stop" using the shell is beyond me...). To interrupt a running program or shell command, hit the Control and C keys at the same time. We'll get back to what this does exactly in a later chapter, but for now just remember this is the way to interrupt things. To quit the shell session, hit Control+d. This key combination produces the Unix end-of-file character -- we'll talk more later about why this also terminates your shell session. Some modern shells have disabled the use of Control+d in favor of the "exit" command (shame on them). If you're using such a shell, just type the word "exit" (like with any other command) and press Enter (from here on in, I'll leave the "Enter" out of examples). The only slightly less easy way: the script. As we saw in the last section, you can very easily execute shell commands for all purposes by starting an interactive shell session and typing your commands in at the prompt. However, sometimes you have a set of commands that you have to repeat regularly, even at different times and in different shell sessions. Of course, in the programming-centric environment of a Unix system, you can write a program to get the same result (in the C language for instance). But wouldn't it be a lot easier to have the convenience of the shell for this same task? Wouldn't it be more convenient to have a way to replay a set of commands? And to be able to compose that set as easily as you can write the single commands that you type into the shell's interactive sessions? The shell script. Fortunately, there "is" such a way: the Bourne Shell's "non-interactive" mode. In this mode, the shell doesn't have a prompt or wait for your commands. Instead, the shell reads commands from a text file (which tells the shell what to do, kind of like an actor gets commands from a script -- hence, shell script). This file contains a sequence of commands, just as you would enter them into the interactive session at the prompt. The file is read by the shell from top to bottom and commands are executed in that order. A shell script is very easy to write; you can use any text-editor you like (or even any wordprocessor or other editor, as long as you remember to save your script in plain text format). You write commands just as you would in the interactive shell. And you can run your script the moment you have saved it; no need to compile it or anything. Running a shell script. To run a shell script (to have the shell read it and execute all the commands in the script), you enter a command at an interactive shell prompt as you would when doing anything else (if you're using a graphical user interface, you can probably also execute your scripts with a click of the mouse). In this case, the program you want to start is the shell program itself. For instance, to run a script called "MyScript", you'd enter this command in the interactive shell (assuming the script is in your working directory): Starting the shell program from inside the shell program may sound weird at first, but it makes perfect sense if you think about it. After all, you're typing commands in an "interactive mode" shell session. To run a script, you want to start a shell in "non-interactive mode". That's what's happening in the above command. You'll note that the Bourne Shell executable takes a single parameter in the example above: the name of the script to execute. If you happen to be using a POSIX 1003.1-compliant shell, you can also execute a single command in this new, non-interactive session. You have to use the -c command-line switch to tell the shell you're passing in a command instead of the name of a script: We'll get to why you would want to do this (rather than simply enter your command directly into the interactive shell) a little further down. There is also another way to run a script from the interactive shell: you type the execute command (a single period) followed by the name of the script: The difference between that and using the "sh" command is that the "sh" command starts a new process and the execute command does not. We'll look into this (and its importance) in the next section. By the way, this notation with the period is commonly referred to as "sourcing" a script. Running a shell script the other way. There is also another way to execute a shell script, by making more direct use of a feature of the Unix operating system: the executable mode. In Unix, each and every file has three different permissions (read, write and execute) that can be set for three different entities: the user who owns the file, the group that the file belongs to and "the world" (everybody else). Give the command in the interactive shell to see the permissions for all files in the working directory (the column with up to nine letters, r, w and x for read write and execute, the first three for the user, the middle ones for the group, the right ones for the world). Whenever one of those entities has the "execute" permission, that entity can simply run the file as a program. To make your scripts executable by everybody, use the command as in You can then execute the script with a simple command like so (assuming it is in a directory that is in your PATH, the directories that the shell looks in for programs when you don't tell it exactly where to find the program): If this fails then the current directory is probably not in your PATH. You can force the execution of the script using At this command, the operating system examines the file, places it in memory and allows it to run like any other program. Of course, not every file makes "sense" as a program; a binary file is not necessarily a set of commands that the computer will recognize and a text file cannot be read by a computer at all. So to make our scripts run like this, we have to do something extra. As we mentioned before, the Unix operating system starts by examining the program. If the program is a text file rather than a binary one (and cannot simply be executed), the operating system expects the first line of the file to name the interpreter that the operating system should start to interpret the rest of the file. The line the Unix operating system expects to find looks like this: In our case, the following line should work pretty much everywhere: The Bourne Shell executable, to be found in the bin directory, which is right under the top of the filesystem tree. For example: Executing shell scripts like this has several advantages. First it's less cumbersome than the other notations (it requires less typing). Second, it's an extra safety if you're going to pass your scripts around to others. Instead of relying on them to have the right shell, you can simply specify which shell they should use. If Bourne Shell is enough, that's what you ask for. If you absolutely need "ksh" or "bash", you specify that instead (mind you, it's not foolproof — other people can ignore your interpreter specification by running your script with one of the other commands that we discussed above, even if the script probably won't work if they do that). Just as a sidenote, Unix doesn't limit this trick to shell scripts. Any script interpreter that expects its scripts to be plain-text can be specified in this way. You can use this same trick to make directly executable Perl scripts or Python, Ruby, etc. scripts as well as Bourne Shell scripts. Note also that with the distributions using bash as their default shell, you can use the #!/bin/sh shebang and have typical bash syntax in your script. It will work. But for the same script to work with a distribution not using bash as its default shell (as example Debian), you will have to modify the script or to change its shebang to #!/bin/bash. A little bit about Unix and multiprocessing. Why you want to know about multiprocessing. While this is not directly a book about Unix, there are some aspects of the Unix operating system that we must cover to fully understand why the Bourne Shell works the way it does from time to time. One of the most important aspects of the Unix operating system – in fact, the main aspect that sets it apart from all other main-stream operating systems – is that the Unix Operating System is and always has been a multi-user, multi-processing operating system (this in contrast with other operating systems like MacOS and Microsoft's DOS/Windows operating systems). The Unix OS was always meant to run machines that would be used simultaneously by several users, who would all want to run at least one but possibly several programs at the same time. The ability of an operating system to divide the time of a machine's processor among several programs so that it seems to the user that they are all running at the same time is called "multiprocessing". The Unix Operating System was designed from the core up with this possibility in mind and it has an effect on the way your shell sessions behave. Whenever you start a new process (by running a program, for instance) on your Unix machine, the operating system provides that process with its very own operating environment. That environment includes some memory for the process to play in and it can also include certain predefined settings for all processes. Whenever you run the shell program, it is running in its own environment. Whenever you start a new process from another process (for instance by issuing a command to your shell program in interactive mode), the new process becomes what is called a "child process" of the first process (the ls program runs as a child process of your shell, for instance). This is where it becomes important to know about multiprocessing and process interaction: a child process always starts with a "copy" of the environment of the parent process. This means two things: What does what. We have seen several ways of running a shell command or script. With respect to multiprocessing, they run in the following way: A useful thing to know: background processes. With the above, it may seem like multiprocessing is just a pain when doing shell scripting. But if that were so, we wouldn't "have" multiprocessing—Unix doesn't tend to keep things that aren't useful. Multiprocessing is a valuable tool in interacting with the rest of the system and one that you can use to work more efficiently. There are many books available on the benefits of multiprocessing in program development, but from the point of view of the Bourne Shell user and scripter the main one is the ability to hand off control of a process to the operating system "and still keep on working while that child process is running". The way to do this is to run your process as a "background process". Running a process as a background process means telling the operating system that you want to start a process, but that it should not attach itself to any of the interactive devices (keyboard, screen, etc.) that its parent process is using. And more than that, it also tells the operating system that the request to start this child process should return immediately and that the parent process should then be allowed to continue working without having to wait for its child process to end. This sounds complicated, but you have to keep in mind that this ability is completely ingrained in the Unix operating system and that the Bourne Shell was intended as an easy interface to the power of Unix. In other words: the Bourne Shell includes the ability to start a child process as a simple command of its own. Let's demonstrate how to do this and how useful the ability is at the same time, with an example. Give the following (rather pointless but still time consuming) command at the prompt: We'll get into what this says in later chapters; for now, it's enough to know that this command asks the system for the date and time and writes the result to a file named "scriptout". Since it then repeats this process 10000 times, it may take a little time to complete. Now give the following command: You'll notice that you can immediately resume using the shell (if you don't see this happening, hit Control+C and check that you have the extra ampersand at the end). After a while the background process will be finished and the scriptout file will contain another 10000 time reads. The way to start a background process in Bourne Shell is to append an ampersand (&) to your command. Remarks. Actually, you can force a child process here as well -- we'll see how when we talk about command grouping

Bicycles/Maintenance and Repair/Tools and Supplies/Truing Jig. A truing jig, aka a wheel truing stand, facilitates the precise truing or building of a wheel. It consists of fork, similar to a bicycle's front fork, and callipers which allow precise measurement of the position of the rim. It is possible to make your own truing jib. Start by getting an old bicycle fork and finding a way of supporting it. The easiest way is to find a sturdy box, and drilling a hole big enough to accommodate the fork column. The hole should be tight enough to firmly hold the fork and the wheel which will be supported. The fork is now upside down. It is possible to fashion some kind of true indicator or caliper using a nail or pencil attached on one leg of the fork. A metal strap that can be attached with a screw as a pencil or nail holder works best. I try to avoid using tape, string or rubber band since they have a tendency to move which could affect an accurate reading of the wheel's straightness. Straight wheels tend to turn smoothly without deviation when viewed from the front. I start by bringing the nail as closely as possible to the wheel rim. Turning the wheel by hand, warped wheels will occasionally touch the rim or show a large gap. Wheel spokes work by providing enough pull or release on both sides of the rim so that the rim remains straight. By loosening one spoke, the tension is strengthened on the other side and vice-versa. Ideally the spokes on both sides should be even to maintain optimum rim straightness. A sequence of tightening and loosening both sides of the spokes where necessary is the key to rim straightness.

Cryptography/Brute force attack. A brute force attack against a cipher consists of breaking a cipher by trying all possible keys. Statistically, if the keys were originally chosen randomly, the plaintext will become available after about half of the possible keys are tried. As we discuss in ../Basic Design Principles/, the underlying assumption is, of course, that the cipher is known. Since A. Kerckhoffs first published it, a fundamental maxim of cryptography has been that security must reside only in the key. As Claude E. Shannon said a few decades later, 'the enemy knows the system'. In practice, it has been excellent advice. As of the year 2002, symmetric ciphers with keys 64 bits or fewer are vulnerable to brute force attacks. DES, a well respected symmetric algorithm which uses 56-bit keys, was broken by an EFF project in the late 1990s. They even wrote a book about their exploit—"Cracking DES", O'Reilly and Assoc. The EFF is a non-profit cyberspace civil rights group; many people feel that well-funded organisations like the NSA can successfully attack a symmetric key cipher with a 64-bit key using brute force. This is surely true, as it has been done publicly. Many observers suggest a minimum key length for symmetric key algorithms of 128 bits, and even then it is important to select a secure algorithm. For instance, many algorithms can be reduced in effective keylength until it is computationally feasible to launch a brute force attack. AES is recommended for use until at least 2030. The situation with regard to asymmetric algorithms is much more complicated and depends on the individual algorithm. Thus the currently breakable key length for the RSA algorithm is at least 768 bits (broken publicly since 2009), but for most elliptic curve asymmetric algorithms, the largest currently breakable key length is believed to be rather shorter, perhaps as little as 128 bits or so. A message encrypted with a 109 bit key by an elliptic curve encryption algorithm was publicly broken by brute force key search in early 2003. As of 2015, a minimum key length of 224 bits is recommended for elliptic curve algorithms, and 2048 bits for such other asymmetric key algorithms as RSA (asymmetric key algorithms that rely on complex mathematical problems for their security always will need much larger keyspaces as there are short-cuts to cracking them, as opposed to direct brute-force). Common Brute Force Attacks. The term "brute force attacks" is really an umbrella term for all attacks that exhaustively search through all possible (or likely) combinations, or any derivative thereof. Dictionary Attack. A dictionary attack is a common password cracking technique, relying largely on the weak passwords selected by average computer users. For instance, if an attacker had somehow accessed the hashed password files through various malicious database manipulations and educated searching on an online store, he would then write a program to hash one at a time all words in a dictionary (of, for example any or all languages and common derivative passwords), and compare these hashes to the real password hashes he had obtained. If the hashes match, he has obtained a password. Pre-Computation Dictionary Attack. The simple dictionary attack method quickly becomes far too time-consuming with any large number of password hashes, such as an online database would yield. Thus, attackers developed the method of pre-computation. In this attack, the attacker has already hashed his entire suite of dictionaries, and all he need do is compare the hashes. Additionally, his task is made easier by the fact that many users will select the same passwords. To prevent this attack, a database administrator must attach unique 32-bit salts to the users passwords before hashing, thus rendering precompution useless. The ../Breaking Hash Algorithms/ chapter of this books goes into more detail on attacks that specifically apply to hashed password files. Responses to Brute Force Attacks. There are a number of ways to mitigate brute force attacks. For example: The ../Secure Passwords/ chapter of this book goes into more detail on mitigations and other responses that specifically apply to hashed password files.

Cryptography/DES. The Data Encryption Standard (DES) was a widely-used algorithm for encrypting data. It was developed by IBM under the name Lucifer, and was submitted to NBS in response to a 1973 solicitation for better cryptosystems. The US National Institute of Standards and Technology with help from the National Security Agency took IBM's design and made some changes; DES was adopted as a standard in January 1977. DES is a product block encryption algorithm (a cipher) in which 16 iterations, or rounds, of the substitution and transposition (permutation) process are cascaded. The block size is 64 bits, so that a 64-bit block of data (plaintext) can be encrypted into a 64-bit ciphertext. The key, which controls the transformation, also consists of 64 bits. Only 56 of these, however, are at the user's disposal; the remaining eight bits are employed for checking parity. The actual key length is therefore 56 bits. Subsets of the key bits are designated K1, K2, etc., with the subscript indicating the number of the round. The cipher function (substitution and transposition) that is used with the key bits in each round is labeled f. At each intermediate stage of the transformation process, the cipher output from the preceding stage is partitioned into the 32 leftmost bits, Li, and the 32 rightmost bits, Ri. Ri is transposed to become the left-hand part of the next higher intermediate cipher, Li+1. The right-hand half of the next cipher, Ri+1, however, is a complex function of the key and of the entire preceding intermediate cipher. The essential feature to the security of the DES is that f involves a very special nonlinear substitution—i.e., f(A) + f(B) does not equal f(A + B)--specified by the Bureau of Standards? in tabulated functions known as S-boxes. This operation results in a 32-bit number, which is logically added to Ri to produce the left-hand half of the new intermediate cipher. This process is repeated, 16 times in all. To decrypt a cipher, the process is carried out in reverse order, with the 16th round being first. The DES algorithm lends itself to integrated-chip implementation. By 1984 the Bureau of Standards had certified over 35 LSI- and VLSI-chip implementations of the DES, most on single 40-pin chips, some of which operate at speeds of several million bits per second. When the cipher was first released, the design criteria for the S-boxes was not released. With the National Security Agency's involvement in the design of the S-boxes, most security researchers were wary of DES, and there was the widespread fear that the modifications of the NSA were intended to weaken the cipher. In 1990 with the independent discovery and open publication by Biham and Shamir of differential cryptanalysis, it turned out that at least some of the wariness was uncalled for. After the publication of this paper, the IBM personnel involved in the designed publically stated that the main factor in the design was to strengthen them against differential cryptanalysis. The secrecy behind the design criteria at the time appears to have been due to the fact that the technique was not known to the public at the time. Notably, DES is theoretically vulnerable to a technique discovered later by Matsui, linear cryptanalysis. It is unknown whether the NSA was aware of linear cryptanalysis at the time DES was finalized, but most knowledgeable observers think not. Don Coppersmith, one of DES's designers at IBM, has stated that IBM itself was not aware of linear cryptanalysis at that time. Because the key length is only 56 bits, DES can be, and has been, broken by the brute force attack method of running through all possible keys. It is believed that one of the reasons this reduced key length was chosen was that NSA in the mid-'70s possessed enough computer power to brute force break keys of this length. In the years since, computer hardware progress has been such that most anyone now can have sufficient computational capacity. The EFF, a cyberspace civil rights group (with neither much funding nor personnel), did it in a little more than 2 days' search at about the same time at least one attorney from the US Justice Department was publicly announcing that DES was and would remain unbreakable. The most obvious way of improving the security of DES is to encrypt the data multiple times with different keys. Double encrypting data with DES does not add much security as it is vulnerable to meet in the middle attacks. Going one step about this, many former DES users now use Triple DES (3DES) which was described and analyzed by one of DES's patentees (see FIPS 46-3); it involves DES encryption of each data block three times with different keys. 3DES is widely regarded as adequately secure for now, though it is quite slow. Note, however, that there are several ways to use DES three times; only one of those is Tuchman's 3DES. After another, long delayed competition, (NIST) has selected a new cipher, the Advanced Encryption Standard (AES) to replace DES (fall -'01). AES was submitted by its designers under the name Rijndael. Implementations: http://www.codeproject.com/KB/cs/NET_Encrypt_Decrypt.aspx (C#, Xinwen Cheng) <br> http://frank.anemaet.nl/crypto/DES/ (Java implementation, Frank Anemaet) <br> http://www.tero.co.uk/des/ (Javascript implementation, Paul Tero)

Chinese (Mandarin)/Contributors. The Chinese Wikibook was started 2003 December 13. Below is a list of users who have contributed greatly to the authoring of this Wikibook. Please add your username if you have made substantial additions and/or revisions to this textbook. Use * to add a name. , and all made substantial contributions to the on , which are used in our lessons. , also of Wikicommons, contributed the first audio samples used in this Wikibook. In addition, the authors would like to thank the development team in relation with the Wikimedia Foundation and its affiliates, without whom our text could not be so accessible.

XML - Managing Data Exchange/Preface. Goals. Book. The goal of this book is to provide a comprehensive coverage of eXtensible Markup Language (XML) in a textbook format. This book is written and edited by students for students. Each student who uses the book should improve its quality by correcting errors, adding exercises, adding examples, starting new chapters and so forth. Chapters 2 through 6 take the perspective that an XML schema is a representation of a data model, and thus these chapters deal with mapping the complete range of relationships that occur between entities. As you learn how to convert each type of relationship into a schema, other aspects of XML are introduced. For example, stylesheets are initially introduced in Chapter 2 and progressively more stylesheet features are added in Chapters 3 through 6. Consolidation chapters (e.g., Chapter 7 "Data schemas") bring together the material covered across previous chapters; in this case, Chapters 2 through 6. This means students see key skills twice: once in the context of gradually developing their broad understanding of XML and then again in the specific context of one dimension of XML. Application chapters cover particular uses of XML (e.g., SVG for scalable vector graphics) to give the reader examples of the use of XML to solve particular types of problems. This part of the book is expected to grow as the use of XML extends. Project. Professors typically throw away their students’ projects at the end of the term. This is a massive waste of intellectual resources that can be harnessed for the betterment of many by creating an appropriate infrastructure. In our case, we use wiki technology as the infrastructure to create a free open content textbook. University students are an immense untapped global resource. They can be engaged in creating open textbooks if the right infrastructure is in place to sustain renewable student projects. This book is an example of how waste can be avoided. Software. To complete the exercises in the book and view the slides, you will need access to the following software (or a suitable alternative):

Io Programming. __NOEDITSECTION__ About This Wiki. This work is disjointly licensed under the GNU FDL, the CC BY SA, and Io's license. The authors of this tutorial are: And many others who wish to remain anonymous. Hello world. When learning to program, the first thing usually learned is how to write a program that prints "Hello, world!" to the console. It gives programmers a feel of how simple programs are structured. Io has many ways to write things to the console, so at times it can be confusing about which one to use. The one that's most often used is the write function. Enter the Io's interactive interpreter (by typing codice_1 at the console) and type the following: write("Hello, world!\n") With the interactive interpreter, this should look like: user@computer:~$ io Io> write("Hello, world!\n") Hello, world! ==> nil Another way would be: "Hello, world!\n" print Some of this makes sense. It looks like codice_2 is telling Io to write something to the console, specifically the stuff after it. The stuff after it is in quotes so it's some text, and it's what's going to be printed. But why are those parentheses there, what's with that codice_3 at the end of it, and why was there an arrow with the quoted text after it? The parentheses are telling codice_2 to use the thing within the parentheses, which is called an "argument". codice_2 is called a "function" (remember functions in math?). There might be multiple arguments within the parentheses separated by commas in a single function. The first and only argument for codice_2, namely codice_7, is a "string" (because it's a string of letters). The codice_3 at the end of the string is an "escape sequence". You can tell that because it begins with a backslash. This particular escape sequence signals a newline, the equivalent of pressing enter. If you just pressed enter in the middle of the string (or at least this type of string -- we'll get to that later), it would confuse Io. The thing where there's an arrow and then the string that was the argument of the codice_2 function is the value that codice_2 "return"ed. Every function returns a value. With some functions, it makes sense to return something (such as a function to add two numbers), but with other functions, it just returns something simple done with the arguments. In this case, codice_2 returns the special value codice_12, indicating it has nothing to return. Concatenate Strings. Use the double dot operator to concatenate strings. Or, you can use string interpolation, as shown below. Let's say codice_13 is a codice_14 instance, and it has both a first name and a last name: Io> olle ==> Object_0080B818 do( appendProto(Object_00806B58) lastname := "Jonsson" title := "Developer" firstname := "Olle" We want a method to show first and last name with a space in-between: Io> olle fullname := method(firstname .. " " .. lastname) ==> method(firstname ..(" ") ..(lastname)) or, using string interpolation: Io> olle fullname := method("#{firstname} #{lastname}" interpolate) ==> method("#{firstname} #{lastname}" interpolate) Now, calling codice_15 will yield codice_16. Looking at the returned method object, we can see how the Io interpreter creates regular message calls (the parentheses) for the method codice_17. So, this is the new codice_13 instance: Io> olle ==> Object_0080B818 do( appendProto(Object_00806B58) fullname := Block_007B5030 lastname := "Jonsson" title := "Developer" firstname := "Olle" Simple arithmetic. In Io, you can use arithmetic expressions and they will work correctly. Arithmetic in Io is just like functions, except it uses objects to help. Objects make it so that instead of typing something like +(1, 2), you can type 1+2. More about objects later. + is still a function, though, so it returns a value. This is very useful; it makes it so you can use Io as a simple calculator. Notes about what it's doing are put after two slashes (like this: //). Io> 1+2 //addition ==> 3 Io> 4-5 //subtraction ==> -1 Io> 7*3 //multiplication ==> 21 Io> 3/6 //division ==> 0.50000 Io> 2**3 //exponents ==> 8 Io> 7%2 //remainder of 7/2 (technically, 7 mod 2) ==> 1 This follows normal order of operations (called "precedence") and parentheses can be used. As you'd expect, you can use codice_2 on numbers, but the newline isn't included. You have to use multiple arguments with codice_2 to print multiple things and then it returns all of those things put together. So to print codice_27, you would write: write((1/3)**2, "\n") As you would expect, this prints 0.11111. It returns the string "0.11111\n" because with the codice_2 function, multiple arguments are converted to strings and joined together. Then that value is printed and returned. Variables. A "variable" is basically a word that stands for a value. They are somewhat like variables in mathematics, except in mathematics, variables could only be numbers and they were one letter long. In programming, functions, objects, strings, and numbers are all types of variables, but we haven't defined any yet. Many variables, such as write, 3, and "Hello, world!" can already be used, but only some of them can be changed. You can make your own variables using = and :=. Below are some examples of making and using variables: x := 3 line := "\n" write(x, line) Can you tell what's happening? The variable x is being set to 3 and the variable line is being set to "\n", which is equivalent to a newline. Then, the contents x and line are being written to the console. Since x is 3 and line is a newline, this prints 3 and then goes to the next line on the console. The function returns "3\n". In Io, there is a difference between creating and changing the value of variables. If a variable doesn't exist yet, you have to use :=, but if you've already given it an initial value using :=, you can use = for subsequent definitions. Here's an example: x := 1 incrementor := 2 write("x is ", x, "\n") x = x + incrementor write("but when we added ", incrementor, " to it, it became ", x, "\n") It may be confusing that sometimes we use := and other times we use =, but you'll get used to it. If you want to, you can always use :=, but when we get into objects later, it will become very inconvenient to keep using :=, so you should probably start using = whenever appropriate. Programs. Until now, you've been simply been going to Io's interactive interpreter. This prevents you from making larger applications or writing things for others. If you want to write code to be reused, simply put it in a text file and run it with codice_29, where <filename> is the name of the file you use. Here's an example of using a file on Linux to store a program: user@computer:~$ cat > incrementor.io x := 1 incrementor := 2 writeln("x is ", x) x = x + incrementor writeln("but when we added ", incrementor, " to it, it became ", x) user@computer:~$ io incrementor.io x is 1 but when we added 2 to it, it became 3 user@computer:~$ That was the last example we just did. If you noticed, I used a .io file extension. This is in no way mandated, it is merely a convention. Something happened differently this time then when we did it from a file, if you noticed. Unlike before, we didn't see what each function returned. Instead, we only saw what was explicitly output by codice_2. If you're on Linux or a similar system (such as Unix, Mac OS X, or Cygwin), you can make it so that your file can be run simply by typing codice_31 (where yourProgram.io is the name of your program), without needing to precede it with codice_1. This can be accomplished by putting a line of code at the beginning of your program and then giving it executable permissions. On Linux, that code is: #! /usr/bin/env io It may differ for other systems. To give it executable permissions, simply type the following: chmod +x yourProgram.io Again, this may be different on different systems. Once you do this, nothing will change about the actual execution of the code, but you can, for example, just double click on a source code file in a GUI and it will run. Writing functions. As I said before, functions are just another type of variable, so you can create them using := and change them using =. Functions themselves are created with a function called codice_33. Here's an example of a function: add := method(a, b, //function to add 2 numbers a + b writeln(add(1, 2)) //writes 3 x := 1 writeln(add(3, x)) //writes 4 x = add(4, 5) //9 writeln(x) //writes 9 x = add(x, 1) //in effect increment x by 1 writeln(x) //writes 10 The function add takes two arguments, a and b, and then returns a + b. It would do exactly the same thing if, instead of a and b, we used the variable names 'this' and 'that', everywhere that a and b were used. In that case, the function would be written as: add := method(this, that, this + that What a function really does is take a list of arguments; then it assigns the arguments to "local variable"s, which are specified when you make the function. Local variables stay in the function you're working in and you can't get to them outside of the function. In the most recent case, those local variables are 'this' and 'that', so the variable 'this' will take the first argument, and the variable 'that' will take the second argument. Then it executes the rest of the function and returns the result. The function can have multiple lines of code and the last line will be the value returned. Here's an example: examineArgs := method(this, that, writeln("This is ", this, ".") writeln("That is ", that, ".") // usage: examineArgs(3, 5) /* writes: This is 3. That is 5. */ x := examineArgs("hi", "bye") /* writes: This is hi. That is bye. */ write(x) /* writes: That is bye. */ Why was x set to "That is bye.\n"? Because that's what examineArgs returned. It returned the value of the last line, the value of write("That is ", that, ".\n"). That was set to "bye", so it printed the string "That is bye.\n" and returned the same string. If you want to return something before the function ends, you can use the return function. Unlike most functions, you don't need to put parentheses around the argument to call the return function. Here is an example of its usage: returning := method(this, that, writeln(this) return this writeln(that) x := returning(1, 2) //writes "1\n" write(x) //writes 1 with no newline As you can see, the code after return isn't used at all. Right now, this doesn't seem very useful, but later, when we get into flow control, it will be used very often. Conditionals. Conditionals in Io are made using the if function: if(a == 1) then( writeln("a is one") ) else( writeln("a is not one") However, the preferred way to write this (without the need for then() and else() messages, so it is faster):

Cryptography/Breaking Caesar cipher. Breaking the Caesar cipher is trivial as it is vulnerable to most forms of attack. The system is so easily broken that it is often faster to perform a brute force attack to discover if this cipher is in use or not. An easy way for humans to decipher it is to examine the letter frequencies of the cipher text and see where they match those found in the underlying language. Frequency analysis. By graphing the frequencies of letters in the ciphertext and those in the original language of the plaintext, a human can spot the value of the key by looking at the displacement of particular features of the graph. For example in the English language the frequencies of the letters Q,R,S,T have a particularly distinctive pattern. Computers can also do this trivially by means of an auto-correlation function. Brute force. As the system only has 25 non-trivial keys it is easy even for a human to cycle through all the possible keys until they find one which allows the ciphertext to be converted into plaintext. Known plaintext attack. If you have a message in both ciphertext and in plaintext it is trivial to find the key by calculating the difference between them.

Computer Programming/Highlevel. Computer languages come in many flavors. Generally there are high-level and low-level languages. The term "language level" is an attempt to convey information about how close the programming language is to the machine language of the particular hardware. Low-level languages are closer to the machine language, and high-level languages are further away from machine language, and close to natural languages (e.g., English). An extreme example of a low-level language is the machine language which consists of ones and zeros. It is extremely rare (difficult, and error prone), however, for people to write programs in machine language. The closest programming language to machine language is assembly language, which normally has one instruction, or statement, for each machine language instruction. An example of the kind of instruction that exists in assembly language is to copy the contents of a particular memory address into a machine register. One example of a high-level computer language might be , where the language is programmed by the user with specific words which can be found in the English dictionary. Any language (computer or natural) still must have certain structures, though. English sentences are made of English words which are combined to respect the grammar (i.e., the structure) of English. We understand a sentence if the grammar is (more or less) correct. However, just because a high-level language uses some words which seem to be natural English does not mean that the computer can directly understand English sentences as we would speak them to a person. A program must be written to respect the structure (grammar) of the computer language used, if the computer is to understand. Typically the grammar of a computer language is more rigid than the grammar of a natural language.

Engineering Thermodynamics. This book deals with Engineering Thermodynamics, where concepts of thermodynamics are used to solve engineering problems. Engineers use thermodynamics to calculate the fuel efficiency of engines, and to find ways to make more efficient systems, be they rockets, refineries, or nuclear reactors. One aspect of "engineering" in the title is that a lot of the data used is empirical ("e.g." steam tables), since you won't find clean algebraic equations of state for many common working substances. Thermodynamics is the science that deals with transfer of heat and work. Engineering thermodynamics develops the theory and techniques required to use empirical thermodynamic data effectively. This course forms the foundation for the Heat Transfer course, where the "rate" and mechanisms of transmission of energy in the form of heat is studied. The concepts can be used in further study including internal combustion engines, refrigeration and air conditioning, and turbomachines to name a few. Rigorous treatment of the molecular basis will be omitted, in favor of formulations most useful for developing intuition and understanding common technologies. Students of physics will want to pair this text with one on Statistical Mechanics.

How to Find a Book. How to Find a Book depends on how much information you have about the book and whether you want to buy it or simply read it. Acquiring information about the book. Normally, title and name of the author of a book is enough to locate more information about it. You can then use online bookstores or online library catalogs to identify publisher, publication date, edition and ISBN; these items are sometimes required by libraries or bookstores to order the book. Occasionally, the author's name is misspelled, especially with foreign authors. In this case try searching for the title alone, until you find the proper spelling of the name. If you only have the book's ISBN, you should be aware of the fact that different editions as well as hardcover and soft-cover versions of a book have different ISBNs. It is possible that the version of the book with your ISBN is already out of print, while another version is still available. It is therefore best to use an online service to get the author and title information, and then proceed with that information. Locating a book is much more difficult if you want to educate yourself about a topic but don't have a particular author or title in mind. Library shelves are organized by subject; learn the system used by your library, go to the relevant shelve and browse the books about your topic. Some of this can also be done online: library catalogs allow subject and keyword searches and the Library of Congress permits browsing by call number, which can often locate closely related materials. For an effective subject search, you need to know which subject words are being used; this is contained in the "Library of Congress Subject Headings", a red five-volume work that many libraries have but can not be found online (most library subjects can be searched and browsed on ISBNdb.com's subject search). Most topics have one or two "standard references", the generally acknowledged best treatments of the subject. To find these, you need to talk to a specialist in the field. A Usenet posting to a relevant newsgroup, asking about good books, also often yields excellent results. Closely reading the user-supplied book reviews on amazon.com will also often point you to standard references: they are often only identified by author and everyone seems to know them. Acquiring the book. You have to decide whether you want to buy the book or just read it. If you want to buy it, you have to decide whether to buy it new or used (the only option if no version of it is in print, unless you can find a new after-market copy or a remaindered book). To buy used books, you can try a local used book store. These can also often help you buy books that they don't have. You may also go to a professional book finder with connections in the used-book markets. These used-book markets are now open to everyone with a web browser and a credit or debit card, and books can also be found via auction websites. The three best sites for used-books, which between them cover countless thousands of sellers are: Abebooks, eBay and Amazon (on an Amazon book entry look for the link to "new and used books", which takes one to many sellers of used books). A book in print can be ordered at any bookstore and can also be ordered online; several price comparison services exist. By ordering online, you typically save sales tax but you have to pay shipping and handling costs. Depending on what you need, you may be able to find a book at a public library or a good local college or university library. These can be used by non-students for free or for a small fee. If your reading interest is general, or if you want to read a popular novel, a public library is the place to go. Membership is usually free. If you cannot find the book on your own, you should visit an information desk because many libraries offer the ability to place "holds" on materials so you can get them when you return. At college and university libraries, Research librarians can help you locate books and journal articles of academic interest quickly. On campus, you can often use expensive databases such as LexisNexis for free. Libraries are connected by an Inter Library Loan network: if the book exists, and is held by a library willing to loan it, you will have it in as little as a week or so. Most libraries also offer an Inter-library loan service. This means that items that do not appear in their catalog can be requested from libraries elsewhere. Depending on the library and how far the book has to travel, there may be charges for this service. Libraries use WorldCat at OCLC in order to find books at other libraries. It is by far the most extensive database of library holdings. Some libraries allow access by their patrons; ask your librarian how to access WorldCat. Unsuccessful ABEbooks searches are directed to WorldCat as unsuccessful WorldCat searches are to ABEbooks. WorldCat attempts to restrict use of its data but such terms are not legally valid under US copyright law, since only the specific and creative original expression, if any, can be protected by copyright and the right to use public domain works cannot be restricted by contract (see Feist v. Rural and Assessment Technologies v. WIREdata) External links. Digital libraries. There are also digital libraries, where you can find books in electronic form (mostly scanned paper books). The most famous digital library is Project Gutenberg.

General Chemistry/Introduction. Chemistry is Everywhere. The modern human experience places a large emphasis upon the material world. From the day of our birth to the day we die, we are frequently preoccupied with the world around us. Whether struggling to feed ourselves, occupying ourselves with modern inventions, interacting with other people or animals, or simply meditating on the air we breathe, our attention is focused on different aspects of the material world. In fact only a handful of disciplines—certain subsets of religion, philosophy, and abstract math—can be considered completely unrelated to the material world. Everything else is somehow related to chemistry, the scientific discipline which studies the properties, composition, and transformation of matter. Branches of Chemistry. Chemistry itself has a number of branches: Chemistry as a discipline is based on a number of other fields. Because it is a measurement-based science, math plays an important role in its study and usage. A proficiency in high-school level algebra should be all that is needed in this text, and can be obtained from a number of sources. Chemistry itself is determined by the rules and principles of physics. Basic principles from physics may be introduced in this text when necessary. Why Study Chemistry? There are many reasons to study chemistry. It is one pillar of the natural sciences necessary for detailed studies in the physical sciences or engineering. The principles of biology and psychology are rooted in the biochemistry of the animal world, in ways that are only now beginning to be understood. Modern medicine is firmly rooted in the chemical nature of the human body. Even students without long-term aspirations in science find beauty in the infinite possibilities that originate from the small set of rules found in chemistry. Chemistry has the power to explain everything in this world, from the ordinary to the bizarre. Why does iron rust? What makes propane such an efficient, clean burning fuel? How can soot and diamond be so different in appearance, yet so similar chemically? Chemistry has the answer to these questions, and so many more. Understanding chemistry is the key to understanding the world as we know it. This Book: General Chemistry. An introduction to the chemical world is set forth in this text. The units of study are organized as follows. « Begin Your Study of General Chemistry! »

MIPS Assembly. The MIPS microprocessor paradigm was created in 1981 from work done by J. L. Hennessy at Stanford University. Since that time, the MIPS paradigm has been so influential that nearly every modern-day processor family makes some use of the concepts derived from that original research. This book will discuss the MIPS architecture and (perhaps more importantly) MIPS assembly programming. Resources and Licensing. __NOEDITSECTION__

Puzzles/Easy Sequence 4/Solution. alternate subtracting and adding numbers starting with 1 and increasing by 1 each time. 3,2,4,1,5,0,6,-1,7...

Puzzles/Easy Sequence 5/Solution. < Problem 3 2 4 1 4 ? Solution Alternate subtracting and multiplying, starting with 1 and increasing by 1 each time. 3,2,4,1,4,-1,-6...

General Chemistry/Physical Change. General Chemistry Physical changes in chemistry include phase changes and anything else that changes the way that matter is arranged in space. Examples of physical changes are: Phase changes. The three basic phases of matter are solid, liquid, and gas. (Under certain unusual conditions matter can transform into a phase called plasma) A phase change is a change from one phase to another. The most common example is liquid water freezing into ice or evaporating into a gas. Phase changes result in different properties for the substance changing phases but the chemical identity of the material does not change. In the case of water, its molecules are always composed of two hydrogen atoms bonded to one oxygen atom. However, in frozen water the molecules are frozen into place in relation to each other in a structure called a crystal; in liquid water the molecules flow relative to each other; and water molecules in the gas phase are flying freely in space and seldom even contact each other. Phase changes are controlled by temperature and pressure. By lowering the temperature of a gas it can be condensed into a liquid and then even into a solid. Heating a solid melts it into a liquid and then, with further heat, into a gas.

Dutch/Appendix 3. Appendix 3 - Voornaamwoorden ~ "pronouns". Like English, Dutch has pronouns. These can mark number, case, gender,politeness and emphasis. Pronouns can function either as substantives (nouns) or as adjectives. There is also a number of related adverbs that will be treated here. Adverbs are typically not considered pronouns in grammatical analysis, but they deserve mention when discussing the Dutch language because pronouns are often "replaced" by pronominal adverbs. Persoonlijke voornaamwoorden ~ "Personal pronouns". In this table personal pronouns are given in nominative, accusative and dative case. These cases signify the role the pronouns have in the sentence. For example: In "I am hitting you", "I" is nominative (subject) and "you" is accusative (object). Also words with a preposition are in accusative case ("you" in "I am looking at you"). Dative case is special and tells us something is indirect object, as "me" in "He gave me that" or "He built me a snowman" or, with a preposition, "He gave it to me". Remarks: Bezittelijke voornaamwoorden ~ "Possessive pronouns". Pssessive pronouns are essentially the adjectival forms of the personal pronouns. Remarks: Personal Adverb - "er". Dutch has a somewhat curious personal locative adverb er that replaces "het" and "ze" particularly in inanimate cases (i.e. for things more so than for persons). It occurs as the locative part of many pronominal adverbs, such as :erin, erdoor, ervan etc. but it can also be used independently: Notice that "er" is not considered the subject of these sentences ("koffie" and "mensen" are the subject resp.) Aanwijzende voornaamwoorden -- Demonstrative pronouns. Demonstrative pronouns are typically used as adjectives: they can also be used independently: They are more and more used to replace inanimate personal pronouns. Aanwijzende bijwoorden - demonstrative adverbs. Dutch has three demonstrative adverbs of time: One modal demonstrative adverb is common: Occasionally a more proximate one "zus" is used for contrast Two locative adverbs are in common use: Both of them are used as the locative part of demonstrative pronominal adverbs like: hierdoor, daarvan etc. A third adverb is less common: Betrekkelijke voornaamwoorden -- Relative pronouns. Zelfstandig- substantive. Without "antecedent": With inclusion of antecedent. There are a number of archaic forms that can be used with prepositions: As in English the genitives wiens and wier (whose) can be used in relative clauses referring to persons: In inanimate cases the relative pronominal adverb waarvan is virtually mandatory. Bijwoordelijk - adverbial. waar - where "Waar" is also used to form the relative pronominal adverbs like waarvan, waarvoor etc. that frequently replace relative pronouns.

Vietnamese/Numbers. Powers of ten:

Vietnamese/Colors. The list below is partial list of colours/colors described in Vietnamese: Examples:

Dutch/Lesson 3. Gesprek 3-1. Mam teaches her toddler, Jeroen to count: Leren 3 ~ Tellen van 1 tot 12. In Dutch, as in English, there are both ordinal and cardinal numbers, and number formation is similar in that the first twelve numbers are unique. Above twelve, numbers are formed by combination. For example, 15 is "vijftien" and 16 is "zestien". Other numbers will be the subject of more advanced lessons. Note in the table how ordinals are formed from the cardinals in Dutch by adding -de. 'Ten' becomes 'tenth' in English; tien become tiende in Dutch. As in English, there are several variants: "eerste", "derde", and "achtste". Remark: een is used both as an indefinite article ("a" or "an") and a number ("one"). One often puts accents on the e's when "one" is meant in case of ambiguity: één. In Dutch spelling such accents are allowed but only if otherwise ambiguity would arise. There is also a difference in pronunciation: /ən/ (-n) for the article and /e:n/ (ayn) for the number. Eerst en laatst. The ordinals are a special kind of adjectives. They always have the inflection -e. So, words like *zesd do not exist. The only exception is "eerst". As in English, it can be used as an adverb: Its opposite (antonym) is "laatst" as adverb and "laatste" as adjective: Grammatica 3-1 ~ Telling time (hours). Knowing the numbers from 1 to 12, you can now begin asking and telling time in Dutch. Gesprek 3-2. Asking for the time is accomplished by the sentence: The answer is: Half en kwart. The half hours are indicated differently in Dutch: The quarter hours are similar For more on time telling, have look at the practice lesson 3A. Syntax 3-1 ~ Some more word order: inversion. We have seen that inversion of subject and verb is used to create a question: However, recall from the conversation that inversion happens for other reasons. These are not questions, still there is inversion. The reason is that the adverb "daarna" or the adverbial expression "op een middag" was put before the "subject" + "verb" part for emphasis. This causes inversion. We could also have said: Notice that the verb loses final -t when using the informal second person jij or je in such cases as it does in questions: Grammatica 3-3 ~ Introduction to "naamwoorden". Dutch grammar uses the word "naamwoord" ("lit." name-word) that does not translate well into English. "Naamwoorden" indicates a rather broad class of words, both independently used (like nouns) or used to specify another word (like adjectives). Dutch grammar is therefore structured a bit differently from the English one. Besides "naamwoorden" there are two other large classes of words in Dutch: "werkwoorden" (verbs) and "bijwoorden" (adverbs). A is a fundamental part of speech, occurring in sentences in two different ways: as subjects (performers of action), or objects (recipients of action). As a generality, a noun is the name of a "person, place, thing or concept". Nouns are classified into The latter group is often considered a separate class of words. They stand in for (pro-, voor-) nouns. Words like "hij" - "he" are known as personal pronouns ("persoonlijke voornaamwoorden") Dutch has its own grammatical nomenclature and to use dictionaries and grammars it is useful to know it. Noun is rendered as "zelfstandig naamwoord" ('nameword that stands on itself'). An adjective is called "bijvoeglijk naamwoord" (nameword that can be added). "Naamwoord" is more general than noun. It derives from the Latin term "nomen": nomen substantivum (zelfstandig naamwoord) and nomen adiectivum (bijvoeglijk naamwoord). Adjectives are usually added to nouns to further determine them: Some pronouns, e.g. possessive pronouns ("bezittelijk voornaamwoord") are used as adjectives: A special class of adjectives is formed by the articles ("lidwoorden"): Gender of Nouns. We have seen evidence of word gender in the pronouns we have been encountering; notably 'he', 'she', and 'it' in English and hij, zij, and het in Dutch. We also saw that adjectives depend on gender in Dutch. There are a few rules that help to determine a noun's gender, but mostly it must be learned as children do: word by word. Noun gender is also reflected in the "definite article" It should always be learned as "part of the noun", as this is a good way to memorize gender. Definite Articles. Definite articles are equivalent to an English 'the', and the two basic gender forms in Dutch are as follows: Animate nouns. Much like in English there are three genders for animate nouns (people, pets etc.) and this shows up clearly in their personal pronouns: "hij, zij and het" (he, she and it) and their possessive pronouns "zijn, haar and zijn" (his, her, its): However, "zijn" is not used much anymore to refer to a neuter word and we will see a different way of expressing "its" later. In the plural the gender distinctions are absent: "de mannen, de vrouwen, de kalveren" are all referred to by "zij" (they) and "hun" (their). As you see the definite article is the same for masculine and feminine, but it is not just definite articles, but also adjectives and pronouns that must match the gender of the noun they are related to. Inanimate nouns. In the Netherlands (the North) the distinction between masculine and feminine was lost for "inanimate" nouns (things, concepts etc.) in the 17th century. The feminine and the masculine have merged into a "common" gender north of "de grote riveren" (the Great Rivers: the Meuse, the Rhine and its branches) almost entirely. Someone learning the language therefore best considers Dutch a two-gender language for anything but persons: This does not hold for the South, where a "de klok" may still be referred to as "zij" (she), but it is acceptable standard Dutch to disregard the masculine-feminine distinction. By contrast, the twofold split common-neuter is still very much alive in Dutch and this must be mastered by any beginner to learn the language well. Therefore, it is important when learning Dutch nouns to always learn them together with their correct definite article. That is: This is by far the most important thing you should do right now. The fine distinctions between the varieties of the language can wait. Referring to inanimate common gender. As we saw above the personal pronouns (hij,zij,het) still show the three-gender distinction that Dutch inherited from its Indoeuropean ancestry. That makes it hard to use personal pronouns for an inanimate common gender word. In the South "de klok" may still be called a "she", but Northerners avoid such references and so should you. Strictly speaking it would be correct for Northerners to call a clock a "he", but they often avoid that as well. Nowadays "hij" and "zij" are pretty much restricted to people or their pets, so they indicate "natural" rather than "grammatical" gender, certainly in the North. Notice that Northerners cannot resort to "het" (it) as done in English, because "de klok" is not neuter... This leaves roughly two thirds of all inanimate nouns without a personal pronoun to refer them by. For possessive pronouns (his, her, its) a similar problem exists. We shall see three common ways that speakers use to avoid inanimate hij/zij references: These three aspects of the language have come to play a more prominent role in Dutch than they do in English. One could say that the merger of m/f into common gender has triggered a number of shifts in the language, that for example German or English do not have and must be mastered to speak Dutch well. Rules for gender. There are a few general (and helpful) rules for gender: Another helpful fact is that all genders behave the same in the plural, all use "de", "die", "zij" etc. Apart from these general rules, nouns should be memorized together with their definite article. So, learn "de klok", not just "klok" and "het paard" not just "paard" Double gender. There is an interesting group of words for which the natural gender is in conflict with the grammatical gender, e.g. diminutives of people: Grammatically they are neuter and their articles, adjectives and demonstratives follow the neuter pattern. However the personal and possessive pronouns follow the natural gender: Woordenlijst 3. <br clear="all"> Also included in the vocabulary for Lesson 3 are the ordinal and cardinal numbers 1 through 12 from the table at the beginning of this lesson. Quizlet. You can practice your vocabulary at Quizlet (44 terms) Progress made. If you have studies this lesson well, you should Cumulative term count:

Dutch/Gesprek 1-1. To make your first encounter with Dutch as easy as possible, the first conversation is given here in several versions: Dutch version. Gesprek 1-1 ~ Vrienden<br> Jan komt Karel op straat tegen. Ze zijn vrienden. Translated into English. Gesprek 1-1 ~ Vrienden<br> Jan meets Karel in the street. They are friends. Glossed version. Gesprek 1-1 ~ Vrienden conversation 1-1 ~ Friends Jan komt Karel op straat tegen. Ze zijn vrienden. Jan comes Karel on street across. They are friends. Jan: Goeden-dag, Karel. Hoe gaat het met je? Jan: Good-day, Karel. How goes it with you? Karel: Goeden-dag. Dank je, met mij gaat het goed. En met jou? Karel: Good-day. Thank you, with me goes it good. And with you? Jan: Dank je, met mij gaat het goed. Tot ziens. Jan: Thank you, with me goes it good. Until seeing. Karel: Tot ziens, Jan! Karel: Until seeing, Jan! Pronunciation: English (more or less). (Note: The G is pronounced loud "from the back of the throat", the same way Spanish-speakers pronounce the "j")<br> Guh-SPREK 1-1 ~ VREEN-duh<br> Yahn comt KAA-rul op straat TAY-Gun. Zuh zian VREEN-duh.

Vietnamese/Comparison. Vietnamese creates comparatives and superlatives out of adjectives and adverbs simply by adding a word to the end. First of all, what are and ? Comparatives are demonstrated in the following sentences: They simply express a comparison between two items. Superlatives are demonstrated in the following sentences: They express the outcome of a comparison between more than two items. (All of the items being compared, except for "she," are implied in the second sentence.) Comparatives. In Vietnamese, comparatives are formed by placing "hơn" after the adjective or adverb. For example: "(More to come.)"

Calculus/Complex analysis. Complex analysis is the study of functions of complex variables. Complex analysis is a widely used and powerful tool in certain areas of electrical engineering, and others. Before we begin, you may want to review Complex numbers Complex Numbers. Complex Numbers Complex Functions. A function of a complex variable is a function that can take on complex values, as well as strictly real ones. For example, suppose f(z) = z2. This function sets up a correspondence between the complex number z and its square, z2, just like a function of a real variable, but with complex numbers. Note that, for f(z) = z2, f(z) will be strictly real if z is strictly real. Generally we can write a function f(z) in the form f(z) = f(x+iy) = a(x,y) + ib(x,y), where a and b are real-valued functions. Limits and continuity. As with real-valued functions, we have concepts of limits and continuity with complex-valued functions also – our usual delta-epsilon limit definition: Note that ε and δ are real values. This is implicit in the use of inequalities: only real values are "greater than zero". One difference between this definition of limit and the definition for real-valued functions is the meaning of the absolute value. Here we mean the complex absolute value instead of the real-valued one. Another difference is that of how "z" approaches "w". For real-valued functions, we would only be concerned about "z" approaching "w" from the left, or from the right. In a complex setting, "z" can approach "w" from any direction in the two-dimensional complex plane: along any line passing through "w", along a spiral centered at "w", etc. For example, let formula_7. Suppose we want to show that the formula_8. We can write "z" as formula_9 where we think of "γ" being a small complex quantity. Note then that formula_10. Then, with "L" in our definition being -1, and "w" being i, we have By the triangle inequality, this last expression is less than In order for this to be less than ε, we can require that Thus, for any formula_14, if formula_15, and formula_16, then formula_17. Hence, the limit of formula_7 as "z" approaches i is -1. Differentiation and Holomorphic Functions. Since we have limits defined, we can go ahead to define the "derivative" of a complex function, in the usual way: provided that the limit is the same no matter how Δ"z" approaches zero (since we are working now in the complex plane, we have more freedom!). If such a limit exists for some value "z", or some set of values - a "region", we call the function "holomorphic" at that point or region. Continuity and being single-valued are necessary for being analytic; however, continuity and being single-valued are not sufficient for being analytic. Many elementary functions of complex values have the same derivatives as those for real functions: for example D "z"2 = 2"z". Problem set. Given the above, answer the following questions. Answers. 1. formula_20 2. formula_21 Cauchy-Riemann Equations. We might wonder which sorts of complex functions are in fact differentiable. It would appear that the criterion for holomorphicity is much stricter than that of differentiability for real functions, and this is indeed the case. Suppose we have a complex function where "u" and "v" are real functions. Assume furthermore that "u" and "v" are differentiable functions in the real sense. Then we can let formula_23 in the definition of differentiability approach 0 by varying only "x" or only "y". Therefore "f" can only be differentiable in the complex sense if In fact, if "u" and "v" are differentiable in the real sense and satisfy these two equations, then "f" is holomorphic. These two equations are known as the Cauchy-Riemann equations. Integration. In single variable Calculus, integrals are typically evaluated between two real numbers On the real line, there is one way to get from formula_26 to formula_27. In the complex plane, however, there are infinitely many different paths which can be taken between two points, formula_28 and formula_29. For this reason, complex integration is always done over a path, rather than between two points. Let formula_30 be a path in the complex plane parametrized by formula_31, and let formula_32 be a complex-valued function. Then the contour integral is defined analogously to the line integral from multivariable calculus: Example Let formula_34, and let formula_30 be a line from 0 to 1+i. This curve can be parametrized by formula_36, with formula_37 ranging from 0 to 1. Now we can compute Note that we also have This indicates that complex antiderivatives can be used to simplify the evaluation of integrals, just as real antiderivatives are used to evaluate real integrals. Cauchy's Theorem. Cauchy's theorem states that if a function formula_40 is holomorphic in the closure of an open set formula_41, and formula_30 is a simple closed curve in formula_41, then This can be understood in terms of Green's theorem, though this does not readily lead to a proof, since Green's theorem only applies under the assumption that f has continuous first partial derivatives... Contour Integration. Cauchy's theorem allows for the evaluation of many improper real integrals (improper here means that one of the limits of integration is infinite). As an example, consider Since we consider We now integrate over the indented semicircle contour, pictured above. We parametrize each segment of the contour as follows By Cauchy's Theorem, the integral over the whole contour is zero. So, We now handle each of these integrals separately. Recalling the definition of the sine of a complex number, Now we evaluate the other two integrals As formula_61, the integrand approaches one, so The fourth integral is equal to zero, but this is somewhat more difficult to show. Its form is similar to that of the third segment: This integrand is more difficult, since it need not approach zero everywhere. This difficulty can be overcome by splitting up the integral, but here we simply assume it to be zero. Combining everything, we now have Hence, Cauchy's Integral Formula. Cauchy's integral formula characterizes the behavior of holomorphics functions on a set based on their behavior on the boundary of that set. If formula_41 is an open set with a piecewise smooth boundary and formula_40 is holomorphic in formula_68, then This is a remarkable fact which has no counterpart in multivariable calculus. It says that if we know the values of a holomorphic function along a closed curve, then we know its values everywhere in the interior of the curve. Because formula_70, an open set, it follows that formula_71 for all formula_72. Hence the integrand in Cauchy's integral formula is infinitely differentiable with respect to z, and by repeatedly taking derivatives of both sides, we get This result shows that holomorphicity is a much stronger requirement than differentiability. In the complex plane, if a function has just a single derivative in an open set, then it has infinitely many derivatives in that set. Corollaries of Cauchy's Theorem. Cauchy's Theorem and integral formula have a number of powerful corollaries:

Organic Chemistry/Introduction to reactions/Alkyne hydrogenation. Alkynes are hydrogenated in generally the same way as alkenes. However, standard catalysts like Pd/C will not allow hydrogenation to stop before the alkane stage. A "poisoned catalyst" will permit the reduction of a triple bond to a double bond by "syn" addition, but no further. A common poisoned catalyst is Lindlar's catalyst: Pd/CaCO3 treated with quinoline and lead acetate. "Anti" addition of hydrogen atoms can be achieved with a dissolving metal reduction. Dissolving Metal Reduction. The dissolving metal reaction takes place in a solution of sodium or lithium metal dissolved in liquid ammonia. An alkali metal is dissolved in liquid ammonia and forms a solution containing solvated electrons. Once an alkyne is added to the solution, the electrons add to the antibonding π molecular orbital and produce a radical-anion intermediate. This intermediate has one unpaired electron and has a negative charge. The radical anion then reacts with a proton source (generally ethanol or tertiary-butyl alcohol which is added to the ammonia) to yield a vinyl radical. The radical then accepts another electron and forms a carbanion. The alkene is formed when the vinyl carbanion is protonated. Protonation normally occurs from the side of the double bond that is least sterically hindered, so a trans-alkene is produced.

Organic Chemistry/Introduction to reactions/Halogenation. There are several ways to halogenate Alkenes. The simplest is by adding appropriate hydrogen halides, where the reaction follows Markovnikov's rule. This rule states that the halogen will become bonded to the more highly substituted carbon. This is a result of greater carbocation stability of more highly substituted carbon atoms, which have more ability to distribute the positive charge to the attached alkyl groups. When both carbon atoms have the same number of substituents, a mixture of products will often result.

Haskell. Haskell is a functional programming language. It is distinct in a few ways: Haskell is enjoyable to use because dealing with pure functions makes code much easier to reason about, and the advanced type system helps catch silly and profound mistakes. Our aim in this book is to introduce you to the Haskell programming language — from the very basics to advanced features — and to computer programming in general. We urge seasoned programmers to be especially patient with this process. The languages you are familiar with are likely to differ greatly from Haskell, and the habits acquired from those languages might make it difficult to understand how things work — Haskell is simple, but different. Learning to see the world through the warped mindset of a functional programmer is an adventure in a brave new world, which brings knowledge valuable far beyond the boundaries of any language. Overview. The book is divided into three sections: a Beginner's Track, an Advanced Track, and a section called "Haskell in Practice". The last section, which covers practical use cases, depends only on the Beginner's Track. Seasoned programmers may read the overview to quickly evaluate what makes Haskell unique and different from other languages. Beginner's Track. This section introduces you to Haskell basics and some commonly used libraries. At the end of this track, you should be able to write simple Haskell programs. Most chapters include exercises, with solutions, for your practice. Advanced Track. This section introduces wider functional programming concepts such as different data structures and type theory. It will also cover more practical topics like concurrency. Haskell in Practice. Day-to-day issues of working with Haskell include items such as knowing the standard libraries, building graphical interfaces, and working with databases. You should be able to jump directly to this section from the beginner's track. Tutorials that have been incorporated into the Haskell Wikibook. The following may be read independently, but their content has been imported and adapted already into the Wikibook here

Chinese (Mandarin)/Lesson 7. = Lesson 7: 这是什么? What's this? = Text 1. "You can check out the translations here." Vocabulary. Stroke orders. "More will be added if it's helpful." Grammar. Chinese Names. <br> In this lesson, we learn how to say "something is something" in Chinese. The first thing you need to know is that the sentence structure of Chinese is very similar to that of English in that they both follow the pattern of Subject-Verb-Object (SVO). But unlike many Western languages, verbs in Chinese aren't conjugated and noun and adjective endings don't change. They are never affected by things such as time or person. 这(/那)是什么？. This sentence means "What's this/that?": The sentences, if broken down literally, shows that the ordering of words differs in English and Chinese: The order of the sentences may seem a little bit tricky, but don't worry about that, we will discuss this later. A　是　B. This sentence means "A is B." "是" (shì), the equational verb "to be", can be used as the English "is" or "equals". When used in a simple Subject-Verb-Object sentence, the subject defines the object. Since Chinese verbs never change, no other forms for shì exist such as "was" or "am" in English. Also, articles like "a" and "the" are absent in Chinese. They are not translated. For example: A　不是　B. This sentence means "A is not B." in which shì is negated when preceded by "不" (bu). "不" literally means "no", "not". For example: Now, we come back to the "what's this/that?" questions. We already see that the order is a bit tricky comparing to the English question order. But comparing to the latter pattern "A　是　B", we find the similarity: their orders are identically the same. In fact, like particles, question words make statements into questions without changing the order of the sentence. To make one, simply substitute the QW in where the subject would be in the answer. Comparison: 吗. "吗"(ma) is a final interrogative particle used to form a question sentence. Adding this character at the end of a statement transforms the sentence into a question. Example 1: Example 2: 是/不. "是" (shì) can be used to answer a simple yes/no question. In this case, "是" means "yes", whilst "不" (bú) or "不是" (bú shì) means "no" (literally, "not is"). How to answer yes/no questions correctly in Chinese? Usually, it's the same as in English, but pay attention if the questions are negative, like "Isn't this a book?". In Chinese, you answer to the questions, not the fact. If the question itself is a negative answer, use "不是" or simply "不", vice versa. For example: A asks if that's a book in a negative way. If the object is not a book, you should nevertheless approve A's saying first. So we use "是" to acknowledge that A is correct, and then say "this is not (a) book" to emphasis A is right; In the case of that is a book, you should deny A's saying first, using "不" (no) to point out A is wrong, then make a new statement by noting that "这是书" (this "is" (a) book). One more example: 的. Character "的" (de) indicates that the previous word has possession of the next one. In English it functions like "'s" or like the word "of" but with the position of possessor and possessee switched. For example: Further reading. Read the following article, and then answer the questions in Chinese. Questions:

Engineering Thermodynamics/First Law. Energy. Energy as described on Wikipedia is "the property that must be transferred to an object in order to perform work on, or to heat, the object". Energy is a conserved quantity, the Law of Conservation of Energy on Wikipedia states that "energy can be converted in form, but not created or destroyed". Common forms of energy in physics are potential and kinetic energy. The potential energy is usually the energy due to matter having certain position (configuration) in a field, commonly the gravitational field of Earth. Kinetic energy is the energy due to motion relative to a frame of reference. In thermodynamics, we deal with mainly work and heat, which are different manifestations of the energy in the universe. Work. Work is said to be done by a system if the effect on the surroundings can be reduced solely to that of lifting a weight. Work is only ever done at the boundary of a system. Again, we use the intuitive definition of work, and this will be complete only with the statement of the second law of thermodynamics. Consider a piston-cylinder arrangement as found in automobile engines. When the gas in the cylinder expands, pushing the piston outwards, it does work on the surroundings. In this case work done is mechanical. But how about other forms of energy like heat? The answer is that heat cannot be completely converted into work, with no other change, due to the second law of thermodynamics. In the case of the piston-cylinder system, the work done during a cycle is given by "W", where "W = −∫ F dx = −∫ p dV", where "F = p A", and "p" is the pressure on the inside of the piston (note the minus sign in this relationship). In other words, the work done is the area under the "p-V" diagram. Here, "F" is the external opposing force, which is equal and opposite to that exerted by the system. A corollary of the above statement is that a system undergoing free expansion does no work. The above definition of work will only hold for the quasi-static case, when the work done is reversible work. A consequence of the above statement is that work done is not a state function, since it depends on the path (which curve you consider for integration from state 1 to 2). For a system in a cycle which has states 1 and 2, the work done depends on the path taken during the cycle. If, in the cycle, the movement from 1 to 2 is along "A" and the return is along "C", then the work done is the lightly shaded area. However, if the system returns to 1 via the path "B", then the work done is larger, and is equal to the sum of the two areas. The above image shows a typical indicator diagram as output by an automobile engine. The shaded region is proportional to the work done by the engine, and the volume "V" in the "x"-axis is obtained from the piston displacement, while the "y"-axis is from the pressure inside the cylinder. The work done in a cycle is given by "W", where formula_1 Work done by the system is negative, and work done on the system is positive, by the convention used in this book. Flow Energy. So far we have looked at the work done to compress fluid in a system. Suppose we have to introduce some amount of fluid into the system at a pressure "p". Remember from the definition of the system that matter can enter or leave an open system. Consider a small amount of fluid of mass "dm" with volume "dV" entering the system. Suppose the area of cross section at the entrance is "A". Then the distance the force "pA" has to push is "dx = dV/A". Thus, the work done to introduce a small amount of fluid is given by "pdV", and the work done per unit mass is "pv", where "v = dV/dm" is the specific volume. This value of "pv" is called the "flow energy". Examples of Work. The amount of work done in a process depends on the irreversibilities present. A complete discussion of the irreversibilities is only possible after the discussion of the second law. The equations given above will give the values of work for quasi-static processes, and many real world processes can be approximated by this process. However, note that work is only done if there is an opposing force in the boundary, and that a volume change is not strictly required. Work in a Polytropic Process. Consider a polytropic process "pVn=C", where "C" is a constant. If the system changes its states from 1 to 2, the work done is given by formula_2 And additionally, if n=1 formula_3 Heat. Before thermodynamics was an established science, the popular theory was that heat was a fluid, called "caloric", that was stored in a body. Thus, it was thought that a hot body transferred heat to a cold body by transferring some of this fluid to it. However, this was soon disproved by showing that heat was generated when drilling bores of guns, where both the drill and the barrel were initially cold. Heat is the energy exchanged due to a temperature difference. As with work, heat is defined at the boundary of a system and is a path function. Heat rejected by the system is negative, while the heat absorbed by the system is positive. Specific Heat. The "specific heat" of a substance is the amount of heat required for a unit rise in the temperature in a unit mass of the material. If this quantity is to be of any use, the amount of heat transferred should be a linear function of temperature. This is certainly true for ideal gases. This is also true for many metals and also for real gases under certain conditions. In general, we can only talk about the average specific heat, "cav = Q/mΔT". Since it was customary to give the specific heat as a property in describing a material, methods of analysis came to rely on it for routine calculations. However, since it is only constant for some materials, older calculations became very convoluted for newer materials. For instance, for finding the amount of heat transferred, it would have been simple to give a chart of "Q(ΔT)" for that material. However, following convention, the tables of "cav(ΔT)" were given, so that a double iterative solution over "cav" and "T" was required. Calculating specific heat requires us to specify what we do with Volume and Pressure when we change temperature. When Volume is fixed, it is called specific heat at constant volume (Cv). When Pressure is fixed, it is called specific heat at constant pressure (Cp). Latent Heat. It can be seen that the specific heat as defined above will be infinitely large for a phase change, where heat is transferred without any change in temperature. Thus, it is much more useful to define a quantity called "latent heat", which is the amount of energy required to change the phase of a unit mass of a substance at the phase change temperature. Adiabatic Process. An "adiabatic" process is defined as one in which there is no heat transfer with the surroundings, that is, the change in amount of energy dQ=0 A gas contained in an insulated vessel undergoes an adiabatic process. Adiabatic processes also take place even if the vessel is not insulated if the process is fast enough that there is not enough time for heat to escape ("e.g." the transmission of sound through air). Adiabatic processes are also ideal approximations for many real processes, like expansion of a vapor in a turbine, where the heat loss is much smaller than the work done. First Law of Thermodynamics. Joule Experiments. It is well known that heat and work both change the energy of a system. Joule conducted a series of experiments which showed the relationship between heat and work in a thermodynamic cycle for a system. He used a paddle to stir an insulated vessel filled with fluid. The amount of work done on the paddle was noted (the work was done by lowering a weight, so that work done = "mgz"). Later, this vessel was placed in a bath and cooled. The energy involved in increasing the temperature of the bath was shown to be equal to that supplied by the lowered weight. Joule also performed experiments where electrical work was converted to heat using a coil and obtained the same result. Statement of the First Law for a Closed System. The first law states that "when heat and work interactions take place between a closed system and the environment, the algebraic sum of the heat and work interactions for a cycle is zero". Mathematically, this is equivalent to dQ + dW = 0 for any cycle closed to mass flow Q is the heat transferred, and W is the work done on or by the system. Since these are the only ways energy can be transferred, this implies that the total energy of the system in the cycle is a constant. One consequence of the statement is that the total energy of the system is a property of the system. This leads us to the concept of internal energy. Internal Energy. In thermodynamics, the "internal energy" is the energy of a system due to its temperature. The statement of first law refers to thermodynamic cycles. Using the concept of internal energy it is possible to state the first law for a non-cyclic process. Since the first law is another way of stating the conservation of energy, the energy of the system is the sum of the heat and work input, "i.e.", "ΔE = Q + W". Here "E" represents the internal energy (U) of the system along with the kinetic energy (KE) and the potential energy (PE) and is called the "total energy" of the system. This is the statement of the first law for non-cyclic processes, as long as they are still closed to the flow of mass ("E = U + KE + PE"). The KE and PE terms are relative to an external reference point i.e. the system is the gas within a ball, the ball travels in a trajectory that varies in height H and velocity V and subsequently KE and PE with time, but this has no affect upon the energy of the gas molecules within the ball, which is dictated only by the internal energy of the system (U). Thermodynamics does not define the nature of the internal energy, but it can be rationalised using other theories (i.e. the gas kinetic theory), but in this case is due to the KE and PE of the gas molecules within the ball, not to be mistaken with the KE and PE of the ball itself. For gases, the value of "KE" and "PE" is quite small, so the important term is the internal energy function "U". In particular, since for an ideal gas the state can be specified using two variables, the state variable "u" is given by "u(v, T)", where "v" is the specific volume and "T" is the temperature. Introducing this temperature dependence explicitly is important in many calculations. For this purpose, the constant-volume heat capacity is defined as follows: "cv = (∂u/∂t)v", where "cv" is the specific heat at constant volume. A constant-pressure heat capacity will be defined later, and it is important to keep them straight. The important point here is that the other variable that U depends on "naturally" is v, so to isolate the temperature dependence of U you want to take the derivative at constant v. Internal Energy for an Ideal Gas. In the previous section, the internal energy of an ideal gas was shown to be a function of both the volume and temperature. Joule performed an experiment where a gas at high pressure inside a bath at the same temperature was allowed to expand into a larger volume. In the above image, two vessels, labeled A and B, are immersed in an insulated tank containing water. A thermometer is used to measure the temperature of the water in the tank. The two vessels A and B are connected by a tube, the flow through which is controlled by a stop. Initially, A contains gas at high pressure, while B is nearly empty. The stop is removed so that the vessels are connected and the final temperature of the bath is noted. The temperature of the bath was unchanged at the end of the process, showing that the internal energy of an ideal gas was the function of temperature alone. Thus "Joule's law" is stated as "(∂u/∂v)t = 0". Enthalpy. According to the first law, "dQ + dW = dE" If all the work is pressure volume work, then we have "dW = − p dV" ⇒ "dQ = dU + pdV = d(U + pV) - Vdp" ⇒ "d(U + pV) = dQ + Vdp" We define "H ≡ U + pV" as the "enthalpy" of the system, and "h = u + pv" is the specific enthalpy. In particular, for a constant pressure process, "ΔQ = ΔH" With arguments similar to that for "cv", "cp = (∂h/∂t)p". Since "h", "p", and "t" are state variables, "cp" is a state variable. As a corollary, for ideal gases, "cp = cv + R", and for incompressible fluids, "cp = cv" Throttling. "Throttling" is the process in which a fluid passing through a restriction loses pressure. It usually occurs when fluid passes through small orifices like porous plugs. The original throttling experiments were conducted by Joule and Thompson. As seen in the previous section, in adiabatic throttling the enthalpy is constant. What is significant is that for ideal gases, the enthalpy depends only on temperature, so that there is no temperature change, as there is no work done or heat supplied. However, for real gases, below a certain temperature, called the "inversion point", the temperature drops with a drop in pressure, so that throttling causes cooling, "i.e.", "p1 < p2 ⇒ T1 < T2." The amount of cooling produced is quantified by the Joule-Thomson coefficient "μJT = (∂T/∂p)h". For instance, the inversion temperature for air is about 400 °C.

Botany/Leaves (forms). Leaves (forms) Chapter 3. Plant Cells and Tissues<br>Leaves (forms) Leaf Shapes, Margins, Apices, and Bases. Simple, Angiosperm Leaves. This page presents the terminology used to describe the shapes and forms of leaves. The following examples are all simple leaves. All are from flowering plants (angiosperms). Descriptive terms are given for the lamina shape (that is, its overall shape in outline), the lamina margin, the form or shape of both the apex (tip) and the base (lamina junction with petiole) of the leaf, and (in some cases) other qualities evident in the example picture presented. Compound, Angiosperm Leaves. These examples are all compound leaves. In these leaves, it is not always very instructive to describe the "leaf outline" and better to describe the number (or range) of leaflets. If the number is odd, there will be an unpaired leaflet at the tip. The shape terminology can be applied to the individual leaflets. <BR> <HR> Links. Botanical Terms

UK Constitution and Government. __NOEDITSECTION__ Presentation. UK Constitution and Government

UK Constitution and Government/Normans. William I. The course of English political, legal and cultural history was changed in 1066, when William, Duke of Normandy (also called William the Conqueror) successfully invaded the nation and displaced the Saxon king, Harold II. In 1066 King Edward, also called St Edward the Confessor, died. His cousin, the Duke of Normandy, claimed that the childless King had named him heir during a visit to France, and that the other claimant to the throne, Harold Godwinson, had pledged to support William when he was shipwrecked in Normandy. The veracity of this tale, however, is doubtful, and Harold took the crown upon King Edward's death. William, however, invaded England in September, and defeated (and killed) Harold at the famous Battle of Hastings in October. William II. In 1087, King William I died, and divided his lands and riches between his three sons. The eldest, Robert, became Duke of Normandy; the second, William, became King of England; the youngest, Henry, received silver. Henry, however, eventually came to possess all of his father's dominions. William II died without children, so Henry became King. Henry later invaded Normandy, imprisoned his brother, and took over the Duchy of Normandy. Henry I, Stephen and Matilda. Henry, whose sons had predeceased him, took an unprecedented step: naming a woman as his heir. He declared that his daughter Matilda would be the next Queen. However, Matilda's claim was disputed by Stephen, a grandson of William I in the female line. After Henry I died in 1135, Stephen usurped the throne, but he was defeated and imprisoned by Matilda in 1141. Later, however, Matilda was defeated, and Stephen took the throne. Matilda, however, was not completely defeated. She escaped from Stephen's army, and her own son, Henry Plantagenet, led a military expedition against Stephen. Stephen was forced to agree to name Henry as his heir, and when Stephen died in 1154, Henry took the throne, commencing the Plantagenet dynasty.

UK Constitution and Government/Plantagenets. Henry II. With the death of King Stephen, Henry Plantagenet took the throne as King Henry II. He already had control over the duchy of Normandy; he had also inherited Anjou from his father Geoffrey. Furthermore, he acquired many territories from his wife, Eleanor of Aquitaine. Henry thus had a vast territory when he came to the throne; as King of England, he took over Ireland. Henry II made other remarkable achievements in England. He established courts throughout England and introduced trial by jury. Furthermore, he reduced the power of ecclesiastical courts. The Archbishop of Canterbury and Lord High Chancellor, Thomas à Becket, opposed the King's attempt to take power from the Church. At a confrontation between the two in 1170, Henry II famously said, "Who will rid me of this turbulent priest?" Four of his knights took him literally, and in December murdered Becket. Henry, however, did not have good relations with his sons. In 1170, his eldest son Henry was crowned, and is known as Henry the Young King. In 1173, the Young King and his brothers revolted against Henry II, planning to dethrone him and leave the Young King as the sole ruler in England. In 1174, the revolt failed, and all of the brothers surrendered. Later, in 1189, Henry II's third son, Richard, attacked and defeated him. Henry II died days after his defeat, and Richard, nicknamed "the Lionheart," became King. Richard I. Richard the Lionheart is often portrayed as a hero, but he did not do much for England. In fact, he spent almost all of his time outside the nation, and did not even find it necessary to learn English. He is most famous for his fighting in the Crusades, a holy war seeking to assert Christian dominance over Jerusalem. John. Richard's successor was his brother, John Allin. Henry II had granted John the lands of Ireland, so when John came to the throne, the titles Lord of Ireland and King of England were united. However, though Ireland became a dominion of the Crown, several lands on the Continent, including most of Normandy, were lost during John's reign. King John was very unpopular with the nation's magnates, the barons, whom he taxed. A particularly resented tax was the scutage, a penalty paid by barons who failed to supply the King with military resources. In 1215, after John had been defeated in France, several barons rebelled. Later in that year, John compromised and signed the "Magna Carta", or Great Charter. It guaranteed political liberties and provided for a church free from domination by the monarchy. These liberties and privileges, however, were not extended to the common man; rather, they were granted to the barons. Nonetheless, the document is immensely significant in English constitutional history as it is a major indication of a limitation on the power of the Crown. King John, however, broke the provisions of the Charter later, claiming that he agreed to it under duress. In the next year, when he was retreating from a French invasion, John lost England's most valuable treasures - the Crown Jewels - in a marsh known as The Wash. His mental and physical health deteriorated, and he later died from dysentery. Henry III. John was succeeded by his son, Henry, who was only nine years old. Henry III, despite a reign that lasted over half a century, is not a particularly memorable or noteworthy monarch. Nonetheless, a very significant political development occurred during Henry III's reign. In 1258, one of Henry's opponents, Simon de Montfort, called a Parliament, the forerunner of the modern institution. It, however, bears little resemblance to the modern body, as it had little power. Simon de Montfort, who was married to Henry III's sister, defeated and imprisoned his brother-in-law in 1264. He was originally supported by Henry's son Edward, but the latter later returned to his father's side. Edward defeated de Montfort in 1265 at the Battle of Evesham and restored Henry III. In 1270, the ageing Henry gave up most of power to his son; two years later, he died, and Edward succeeded to the throne. Edward I. Edward I was the monarch who brought the entire British Isles under English domination. In order to raise money in the war against the rebellious Wales, Edward instituted a tax on Jewish moneylenders. The tax, however, was too high for the moneylenders, who eventually became too poor to pay. Edward accused them of disloyalty and abolished the right of Jews to lend money. He also ordered that all Jews wear a yellow star on their clothing; that idea was later adopted by Adolf Hitler in Germany. Edward also executed hundreds of Jews, and in 1290 banished all of them from England. In 1291, the Scottish nobility agreed to submit to Edward. When Queen Margaret I died, the nobles allowed Edward to choose between the rival claimants to the throne. Edward installed the weak John Balliol as monarch, and easily dominated Scotland. The Scots, however, rebelled. Edward I executed the chief dissenter, William Wallace, further antagonising Scotland. Edward II. When Edward I died in 1307, his son Edward became King. Edward II abandoned his father's ambitions to conquer Scotland. Furthermore, he recalled several men his father had banished. The barons, however, rebelled against Edward. In 1312, Edward agreed to hand over power to a committee of barons known as "ordainers." These ordainers removed the power of representatives of commoners to advise the monarch on new laws, and concentrated all power in the nobility. Meanwhile, Robert the Bruce was slowly reconquering Scotland. In 1314, Robert's forces defeated England's in battle, and Robert gained control over most of Scotland. In 1321, the ordainers banished a baron allied with the King, Hugh le Despencer, along with his son. In 1322, Edward reacted by recalling them and attacking the barons. He executed the leader of the ordainers, the Earl of Lancaster, and permitted the Despencers to rule England. The Despencers declared that all statutes created by the ordainers were invalid, and that thereafter, no law would be valid unless it had received the assent of the Commons, representatives of the commoners of England. However, the Despencers became corrupt, causing them to be very unpopular, even with Edward's own wife, Isabella. In 1325, Isabella went to France, and in 1326, she returned, allied with Roger Mortimer, one of the barons Edward had defeated. The two killed the Despencers and forced Edward to resign his crown to his son, also named Edward. Edward II was imprisoned and later killed. Edward III. Since Edward III was a child, Isabella and Roger Mortimer ruled England in his stead. When Edward III became eighteen, however, he had Mortimer executed and banished his mother from court. In 1328, when Charles IV, Isabella's father and King of France, died, Edward claimed France, suggesting that the kingdom should pass to him through his mother. His claim was opposed by Philip VI, who claimed that the throne could only pass in the male line. Edward declared war on Philip, setting off the Hundred Years' War. The British claim to the French throne was not abandoned until the nineteenth century. Richard II. Richard II succeeded his grandfather, Edward III, in 1377. Richard II was only about ten years old when coming to the throne. Even as an adult, Richard II was a rather weak king. In 1399, he was deposed by his cousin, Henry of Bolingbroke, and probably murdered the next year.

XML - Managing Data Exchange/Author guidelines. Editing Chapters. You simply click on the "edit this page" tab at the top of any page you want to edit. You can also just edit a section or subsection - any place you see a little 'edit' to the far right above a line, click on it to edit that section. The thoughts behind the editing process of the chapters will be documented in the "discussion" tab of each chapter - go there to record your intentions for your assigned chapter. If you would like to make any suggestions to the editorial board, we welcome them. At the top of the XML: Managing Data Exchange contents page is a tab to "discussion" follow that link and edit the page with your comments, be sure to follow the directions for entries. Consistency guidelines. - developed to create a consistent look and feel to the book Layout. The bottom of each chapter should include a chapter summary highlighting the key points of the chapter. Follow the formatting guideline detailed later on this page. As new concepts and terminology are introduced in each chapter, make sure that they are defined first before using them; so that the reader understands what the words and ideas represent. Bold the first occurrence of the word (or preceding the definition). Capitalize the first letter of a title and allow the rest of the letters to be lower case, as in this title. For consistency, label all tables, figures (e.g. charts and photos), and code examples as "exhibits." Place the label for exhibits at the top of the exhibit, flush left, and enumerate the exhibits, followed by a brief caption. Examples: "Exhibit 1: XML data types" and "Exhibit 2: Schema code example" Think of your chapter as a data model or a large steak. A useful data model is broken down into its smallest attributes that require recording and maintaining for future analysis. A large steak is best eaten in bite size pieces to prevent choking and promote good digestion. As you revise your chapter consider the basic elements of your topic; break your topic down and present each element in a section - so that it is easy for the reader to follow and understand each part. Feel free to use bullets to represent lists. To continue with the steak analogy, it is also good to eat slowly, taking breaths between each bite. Allow for spaces between each subsection and greater spaces between each section. This opens up the text so that it does not appear to dense and compact - and therefore intimidating. Scroll down the contents page to "Appendices". You will see a link to the chapter "Using an XML editor". When you open this link - go to the edit this page tab and insert a link under the NetBeans heading with the name of your chapter. This is the format for the link: After you save your edit, the XML Editor page will contain a link to your new NetBeans page. It will appear red because no information has been posted to that page yet. Click on the link and paste all the NetBeans information from your chapter into the edit box. In your assigned chapter, at the places where there were NetBeans information (that you just cut and paste into the XML editor page) - put a link to the XML editor - your Chapter page. This help page also has a link to a "sandbox." This is a blank page that allows you to experiment with wiki without affecting a real page. Code examples. If you run into trouble while inserting code, one of the two tags mentioned above might be able to get you out. Exercises & Answers. Create two links at the bottom of your chapter, one to an Exercises page and one to the Answers page already made (you can find this answer page link at the bottom of the contents page). In the Exercises page, cut and paste your chapter exercises into a new page. An easy way to create a new page is simply to go to your main chapter page, type "exercises" at the end of the URL, and hit enter. If the page does not exist, Wikipedia will ask you to create the page by going to "edit this page." At the top and bottom of the Exercises page, provide a link to the chapter and the Answers page—and vice versa with the Answers page. Elements of Style - Principles of Composition. taken from "the Elements of Style" - by William Strunk and E.B. White Source code. For inserting source code (e.g., XML or Java) into the book, use the following format: Use the following wiki code: Section summary. Section summaries should appear in the following format: Use the following wiki code: Story. Stories/case studies should appear in the following format: Use the following wiki code:

Puzzles/Easy Sequence 8/Solution. This series is represented by the months. If the month has 31 days, it gets a one. If not, it gets a zero. Alternatively, it can be described as the remainder after dividing by 2 of the length of each month in a common year (as opposed to a leap year).

High School Mathematics Extensions/Counting and Generating Functions. Before we begin: This chapter assumes knowledge of Some Counting Problems. "..more to come" Generating functions. "..some motivation to be written" To understand this section you need to see why this is true: For a more detailed discussion of the above, head to Infinity and infinite processes. Generating functions, otherwise known as Formal Power Series, are useful for solving problems like: where how many unique solutions are there if formula_4? Before we tackle that problem, let's consider the infinite polynomial: We want to obtain a "closed form" of this infinite polynomial. The "closed form" is simply a way of expressing the polynomial so that it involves only a finite number of operations. To find the "closed form " we starting with our function: formula_6 We multiply both sides of the function by x to get: formula_7 Next we subtract S-xS to get S - xS = 1 + x + x^2 + x^3 ... - x - x^2 - x^3 ... Grouping like terms we get Which simplifies to (1 - x)S = 1 Dividing both sides by formula_8 we get formula_9 So the closed form of is For convenience we can write, although this isn't true for any particular value of "x". info - Infinite sums. The two expressions are not "equal". It's just that for certain values of "x" (-1 < x < 1), we can approximate the right hand side "as closely as possible" by adding up a large number of terms on the left hand side. For example, suppose "x" = 1/2, RHS = 2; we approximate the LHS using only 5 terms we get LHS equals 1 + 1/2 + 1/4 + 1/8 + 1/16 = 1.9375, which is close to 2, as you can imagine by adding more and more terms, we will get closer and closer to 2. Anyway we really only care about its nice algebraic properties, not its numerical value. From now on we will omit the condition for equality to be true when writing out generating functions. Consider a more general case: where "A" and "B" are constants. We can derive the "closed-form" as follows: The following identity as derived above is worth investing time and effort memorising. Exercises. 1. Find the closed-form: 2. Given the closed-form, find a function f(n) for the coefficients of xn: Method of Substitution. We are given that: and we can obtain many other generating functions by substitution. For example: letting z = x2 we have: Similarly is obtained by letting z = Bx then multiplying the whole expression by A. Exercises. 1. What are the coefficients of the powers of x: 2. What are the coefficients of the powers of x (Hint: take out a factor of 1/2): Linear Recurrence Relations. The Fibonacci series where each and every number, except the first two, is the sum of the two preceding numbers. We say the numbers are "related" if the value a number takes depends on the values that come before it in the sequence. The Fibonacci sequence is an example of a recurrence relation, it is expressed as: where xn is the ("n"+ 1)th number in the sequence. Note that the first number in the sequence is denoted x0. Given this recurrence relation, the question we want to ask is "can we find a formula for the ("n"+1)th number in the sequence?". The answer is yes, but before we come to that, let's look at some examples. Example 1. The expressions define a recurrence relation. The sequence is: 1, 1, 5, 13, 41, 121, 365... Find a formula for the ("n"+1)th number in the sequence. Solution Let G(z) be generating function of the sequence, meaning the coefficient of each power (in ascending order) is the corresponding number in the sequence. So the generating functions looks like this Now, by a series of algebraic manipulations, we can find the closed form of the generating function and from that the formula for each coefficient by definition xn - 2xn - 1 - 3xn - 2 = 0 by the method of partial fractions we get: each part of the sum is in a recognisable closed-form. We can conclude that: the reader can easily check the accuracy of the formula. Example 2. Find a non-recurrent formula for xn. Solution Let G(z) be the generating function of the sequence described above. Therefore xn = 1, for all n. Example 3. A linear recurrence relation is defined by: Find the general formula for xn. Solution Let G(z) be the generating function of the recurrence relation. Therefore Exercises. 1. Derive the formula for the ("n+1")th numbers in the sequence defined by the linear recurrence relations: 2. Derive the formula for the ("n+1")th numbers in the sequence defined by the linear recurrence relations: 3. (Optional) Derive the formula for the ("n+1")th Fibonacci numbers. Further Counting. Consider the equation For a fixed positive integer n, how many solutions are there? We can count the number of solutions: As you can see there are (n + 1) solutions. Another way to solve the problem is to consider the generating function Let H(z) = G(z)G(z), i.e. I claim that the coefficient of zn in H(z) is the number of solutions to a + b = n, a, b > 0. The reason why lies in the fact that "when multiplying like terms, indices add". Consider Let it follows Now the coefficient of zn (for n ≥ 0) is clearly the number of solutions to a + b = n (a, b > 0). We are ready now to derive a very important result: let tk be the number solutions to a + b = n (a, b > 0). Then the generating function for the sequence tk is i.e. Counting Solutions to a1 + a2 + ... + am = n. Consider the number of solutions to the following equation: where ai ≥ 0; i = 1, 2, ... m. By applying the method discussed previously. If tk is the number of solutions to the above equation when n = k. The generating function for tk is but what is tk? Unless you have learnt calculus, it's hard to derive a formula just by looking at the equation of T(z). Without assuming knowledge of calculus, we consider the following counting problem. "You have three sisters, and you have n (n ≥ 3) lollies. You decide to give each of your sisters at least one lolly. In how many ways can this be done?" One way to solve the problem is to put all the lollies on the table in a straight line. Since there are "n" lollies there are ("n" - 1) gaps between them (just as you have 5 fingers on each hand and 4 gaps between them). Now get 2 dividers, from the ("n" - 1) gaps available, "choose" 2 and put a divider in each of the gaps you have chosen! There you have it, you have divided the "n" lollies into three parts, one for each sister. There are formula_50 ways to do it! If you have 4 sisters, then there are formula_51 ways to do it. If you have m sisters there are formula_52 ways to do it. Now consider: "You have three sisters, and you have n lollies. You decide to give each of your sisters some lollies (with no restriction as to how much you give to each sister). In how many ways can this be done?" Please note that you are just solving: where ai ≥ 0; i = 1, 2, 3. You can solve the problem by putting n + 3 lollies on the table in a straight line. Get two dividers and "choose" 2 gaps from the n + 2 gaps available. Now that you have divided n + 3 lollies into 3 parts, with each part having 1 or more lollies. Now take back 1 lollies from each part, and you have solved the problem! So the number of solutions is formula_53. More generally, if you have m sisters and n lollies the number of ways to share the lollies is Now to the important result, as discussed above the number of solutions to where ai ≥ 0; i = 1, 2, 3 ... m is i.e. Example 1. The closed form of a generating function T(z) is and tk in the coefficient of zk is T(z). Find an explicit formula for tk. Solution Therefore tk = k Example 2. Find the number of solutions to: for all positive integers n (including zero) with the restriction a, b, c ,d ≥ 0. Solution By the formula so More Counting. We turn to a slightly harder problem of the same kind. Suppose we are to count the number of solutions to: for some integer formula_61, with "a", "b", also "c" greater than or equal zero. We can write down the closed form straight away, we note the coefficient of "x""n" of: is the required solution. This is due to, again, the fact that when multiplying powers, indices add. To obtain the number of solutions, we break the expression into recognisable closed-forms by method of partial fraction. Example 1. Let sk be the number of solutions to the following equation: Find the generating function for sk, then find an explicit formula for sn in terms of "n". Solution Let T(z) be the generating functions of tk It's not hard to see that Example 2. Let tk be the number of solutions to the following equation: Find the generating function for tk, then find an explicit formula for tn in terms of "n". Solution Let T(z) be the generating functions of tk Exercises. 1. Let be the generating functions for tk (k = 0, 1, 2 ...). Find an explicit formula for tk in terms of "k". 2. How many solutions are there the following equations if "m" is a given constant where a, b and c ≥ 0 Problem Set. 1. A new Company has borrowed $250,000 initial capital. The monthly interest is 3%. The company plans to repay $"x" before the end of each month. Interest is added to the debt on the last day of the month (compounded monthly). Let Dn be the remaining debt after "n" months. a) Define Dn recursively. b) Find the minimum values of "x". c) Find out the general formula for Dn. d) Hence, determine how many months are need to repay the debt if "x" = 12,000. 2. A partion of "n" is a sequence of positive integers (λ1,λ1..,λr) such that λ1 ≥ λ2 ≥ .. ≥ λr and λ1 + λ2 + .. + λr = n. For example, let "n" = 5, then (5), (4,1), (3,2), (3,1,1), (2,2,1), (2,1,1,1), (1,1,1,1,1) are all the partions of 5. So we say the number of partions of 5 is 7. Derive a formula for the number of partions of a general "n". 3. A binary tree is a tree where each node can have up to two child nodes. The figure below is an example of a binary tree. a) Let cn be the number of unique arrangements of a binary tree with totally n nodes. Let C(z) be a generating function of cn. b) Let formula_73 be a power series. Hint: Instead of doing recursion of finding the change in cn when adding nodes at the bottom, try to think in the opposite way, and direction.(And no, not deleting nodes) Project - Exponential generating function. This project assumes knowledge of differentiation. (Optional)0. 1. Consider formula_75 (Optional)2. 3. The function E(x) is the most fundamental and important exponential generating function, it is similar to the ordinary generating function, but with some difference, most obviously having a fractorial fraction attached to each term. 4. Apart from A(x) defined in question 2, let formula_78 Notes: Question with *** are difficult questions, although you're not expected to be able to answer those, feel free to try your best.

Dutch/Lesson 4. Grammatica 4-1 ~ The indefinite articles "een" en "geen". In the previous lesson you were introduced to the definite articles—'the' in English and het or de in Dutch. Indefinite articles precede nouns in the same way that definite articles do, but convey a general or indefinite sense. These are 'a' or 'an' in English. Thus, 'the book' or "het boek" refers to a definite or specific book, whereas 'a book' or "een boek" is indefinite about which book is referred to. If your mother tongue does not have articles (such as Russian, Polish etc.) try this. Dutch indefinite articles only come in one form ("een"), so they don't display gender. The use of definite and indefinite articles is virtually the same as in English. The few deviations are best learned when listening to the language or speaking it. Please note (see also previous lesson) that the indefinite article has the same form as the numeral one ("één"). One could argue that one is a clitic form of the other. To denote the difference, one could place accents on the numeral. Also, there is a difference in pronunciation. The numeral "één" (one) is pronounced /e:n/, the article "een" (a) with a much weaker /ən/. Occasionally Dutch has one and English the other: Notice that "one" is used here in the meaning of "a certain", not say in contrast to two or three. There is an inflected form "ene" that is used independently: Negation. In English a negative of an indefinite article is simply formed by adding not: Alternatively one can drop the article and say: In Dutch there is a special negative of een: "Geen" is used both with singular and with plural indefinite nouns Relation to "niet". The combination niet + een is only used in contrasting things: With definite nouns negation involves adding "niet", usually at end: Notice also that Dutch does not use the auxiliary verb "to do" for negations: Relation to "wel". When a negative is negated Dutch uses the adverb "wel" to express that. English has to use a construction involving the verb "to do": This adverb is also used for contrasting: Notice that the second part of the Dutch sentence does not even have a verb. Dutch is quite an 'adverbial' language. If the adverb expresses the meaning sufficiently, why bother with superfluous things like verbs? A game of "Yes, you do" - "No, I don't" sounds like "Welles!" - "Nietes!" in Dutch Much like in French, there are two words for "yes". A simple confirmation is "ja" (French: "oui"); a negation of a negative is "jawel" (French: "si") Grammatica 4-2 ~ More pronouns. Possessives. Recall the following from Gesprek 3-1: Which translates as: The sentence demonstrates one of the possessive pronouns. In the singular these are The neuter "zijn" for "its" is not used very much in Dutch, as we shall see in lesson 8 it often gets replaced by "ervan". The above pronouns like "jouw" often turn into a weak (clitic) form je that is used when the emphasis is on something else, such as the motorcycle in this case. In the spoken language this holds for all the ones shown in the table, but in the written language "je" is the most generally accepted clitic. When written they are: Dutch does not have a possessive case as English does. In English one could say "this house of mine", where mine (and yours, hers, his, ours, yours, theirs) is possessive case. Dutch uses objective case for this: "dit huis van mij" as if 'van' ("of") is a preposition. However, for a sentence like "is this yours or his?" Dutch would use nominalized pronouns (pronouns turned into nouns) with an inflection -e usually accompanied by a definite pronoun "de" or "het": The possessive for the polite 2nd person pronoun "u" is "uw" and in the south this same word is used to refer to the "gij" pronoun (but no formal usage is implied). "Uw" does not have a clitic form and the same can be said about the possessives of the plural. Uw does have an inflected form "uwe" used for nominalization. For the third person plural the possessive is "hun" and it follows the same pattern: For the first person plural Dutch has "ons". This is the only one that follows the rules for inflection of the adjectives. I.e. its inflected form is used for de-words but not for het-words: The inflected form is once again also used for nominalization: For the second person plural the possessive is "jullie" which cannot be inflected and cannot be used as a noun, which necessitates a construction involving "van": See Dutch/Appendix 3 for a table of the possessive pronouns. Quizlet. Practice the possessive pronouns at Quizlet (24 term, includes demonstrative and reciprocal pronouns) Demonstratives. In English, this is used as demonstrative pronoun to indicate something in proximity. "That" indicates greater distance. In Dutch a similar distinction exists, but gender plays a role: So, one replaces 'de' by deze and 'het' by dit. At a greater distance: Notice that often when English has th, Dutch will have d: A third, even more distant pronoun exists (gene, gindse), but it is about as common as its English equivalent "yon", "yonder". Again, the two languages betray their kinship. In some words, a g in Dutch corresponds to a y in English.. Compare: Using demonstrative pronouns instead of personal pronouns. Recall: As we have seen Dutch is on its way to a two-gender system. For inanimate nouns, this makes demonstrative pronouns a more attractive choice to refer things by than personal pronouns. Compare: As you see demonstratives do not distinguish whether a word is feminine or masculine and follow the same common-neuter pattern as the articles. Compare: Note: because "de auto" is not neuter, it is not correct to say: "Het" is duur. But saying "hij" is duur or "zij" is duur makes the word specifically masculine or feminine. Using die avoids the issue, because die follows the "common gender" pattern of the definite article. Increasingly, personal pronouns are reserved for reference to persons (natural gender as in English). To refer to things people resort to substituting the demonstratives. Reflexive and Reciprocal pronouns. In English reflexive pronouns always carry the ending -self -selves: myself, themselves etc. In Dutch that is not always so. In fact, for a verb that is "always" reflexive, like "zich vergissen" (to be mistaken) the ending "cannot be used": In other words the reflexive pronoun is identical to the clitic object form of the personal pronoun, except in the third person where it is zich. The pronoun u was originally a third person (It stems from U.E. uwe edele, something like: your nobility, your honor) which explains the zich for this pronoun. Vergissen can only be used with zich, but some verbs can be used with or without a reflexive pronoun. In that case -zelf may be added: Ik was me/mij/mezelf/mijzelf. - I wash myself. This topic is revisited in Lesson 16 The most important reciprocal pronoun is elkaar - each other Grammatica 4-3 Plural of nouns. We already have seen some things about the plural above: Forming the plural of the noun itself is a bit more complicated. In English it is basically always done with -s, but in Dutch that is different Recall: "...tafels en stoelen..." With few exceptions like "ox - oxen" pretty much all words simply get an -s in English. Dutch however has two main ways to form a plural: by adding -s and by adding -en. The latter is pronounced /-ən/, /-ə/ or even as a syllabic /-n/ depending on the region. Which plural applies is best learned case by case as gender is, although we can attempt a general rule: The ones in -a, -o, -i and -y get an apostrophe before the -s Unfortunately there are lots of exceptions. Many recent (latinate) loans from English or French and all diminutives get a -s. Words in -te and -aar usually get -s: Amongst the many words that get -en are the ones in -ing: Vowel changes. Most monosyllabic words have -en in the plural: In the latter case, notice that one of the a's is dropped in the spelling of the plural. This difficulty is related to the fact that most Dutch vowels occur in two varieties, a closed one and an open one. Dutch spelling has a rather ingenious and systematic way of denoting which one is intended. It involves the doubling of either vowels or consonants. Compare: In this case the vowels remain the same in the plural, but notice the doubling: It is customary to call the first sound [ɔ] a 'short o' and the second [o] a 'long o', but this terminology can be rather confusing. There are languages like Czech or Gàidhlig where vowels are indeed distinguished purely on their length. In Dutch, however, the difference in length ("quantity") is actually pretty negligible, but the difference in vowel sound ("quality") is not. This presents a problem for speakers of the many languages with a five-vowel system, like Italian, Russian, Arabic or isiXhosa whose ears are not accustomed to this kind of difference. Anglophones usually do quite well. The following five vowels possess open ('long') and covered ('short') varieties: Vowel changes. For non-native speakers a complication arises in those cases where the actual vowel changes ('lengthens') in the plural, compare: The vowel /ɑ/ in pad and padden is approximately as in father. Paden has a vowel /a/ like in broad American 'Oh, my God' (In Dutch the spelling would be: Gaad). Also, notice the gender difference of the two words. Vowel change is systematic in the plural of the past of certain strong verbs (class 4 and 5; see 6). A few words show vowel changes other than between the open and closed variety of the same vowel: Words ending in -heid get -heden: -eren. There are about a dozen plurals in Dutch that end in -eren: The ending -eren is essentially a double plural. It derives from a plural in -er and in some compounds that is still visible: -ën. Some words in -ie have an -en plural that requires a diaeresis ("trema" in Dutch). The spelling depends on where the stress falls: Notice that in Dutch orthography the stress of a word cán be indicated with an acute accent, but this is only permitted if otherwise ambiguity might arise. A "trema" (diaeresis) is also used after -ee: Changes of consonants. If the root of the word ends in a -z of -v this is both written and pronounced as -s and -f in the singular, but the voiced consonant returns in a plural on -en: Such words typically have a 'long' vowel ("aa" in this case) or diphthong. With "short" vowel the consonant typically remains voiceless and is doubled in the plural Lieden, lui. Some compounds of -man have a plural involving "lieden" or "lui" (people) Classical plurals. Occasionally a Latin or Greek plural is preserved in Dutch: Woordenlijst 4. <br clear="all"> Quizlet. The vocabulary or this lesson can be practiced at Quizlet (28 terms) Progress made. Cumulative count <br clear="all"> Quizlet. The vocabulary or this lesson can be practiced at Quizlet (28 terms) Progress made. If you have thoroughly studied the above lesson you should Cumulative vocabulary count <br clear="all">

German/Lesson 6. Lektion 6 "Die Wohnung" ~ The Apartment Gespräch 6-1 ~ Ein Bruder besucht Markus. This incomplete story and conversation introduces terms for items around the house (or apartment). Vokabeln 6-1. der Bruder brother die Eltern parents die Küche kitchen das Schlafzimmer bedroom die Vorlesung class, instruction (at a university) die Wohnung apartment, flat das Wohnzimmer living room das Zimmer, die Zimmer room(s) es gibt there is gegen Abend towards evening gern haben like (i.e., "to gladly have") Herein! Come in! sich umsehen look around zeigen show besuchen visit, attend (classes) grüßen greet mieten rent sein his (a possessive adjective) Grammatik 6.1 ~ Introduction to verb conjugations. In German, every grammatical person has, or potentially has, its own unique verb form. Describing the various verb forms is called verb conjugation. This variation in verb form is certainly one of the things that makes German grammar somewhat difficult for English speakers to learn. In English, only the 3rd person singular might differ from the verb form used with all of the other persons (see Grammatik 1-3) and that difference is made by adding an ending of 's' or 'es'. For example: I/you/we/they 'go', but he/she/it 'goes'. Let us have a closer look at German verbs. Usually, the infinitive form of a verb in German ends with -en—for examples, consider these verbs you have already learned: "gehen ('go'), "haben ('have'), and "studieren" ('study'). In order to "build" the different verb forms (that is, conjugate a verb), first cut off the '-en' ending from the infinitive. Then append a new ending according to the grammatical person. For regular verbs it works essentially as follows: As you see in this example using the verb "gehen", the singular 1st person ends with -e, the 2nd person with -st and 3rd person (no matter what gender) ends with -t. As for the plural forms, note that 1st and 3rd person in plural number (see Grammatik 1-3) are built the same way as the infinitive. Again note that, in English, only the verb form for the 3rd person singular is "unique". An easy way to remember the regular verb endings is the following mnemonic "Elephants standing together enjoy trumpeting endlessly". Seems simple enough. However, realize we are discussing here only the regular verb forms in the present tense ("Präsens"). You will learn quite soon that, unfortunately, there are many exceptions from these simple rules. An important one is the irregular verb "sein" ('to be') which is irregular in English as well (I am, you are, he is...). At least 1st and 3rd person plural are the same. Another important verb is "haben" ('to have'): You see, it's not too irregular—only the 2nd and 3rd person singular constitute a small exception since the 'b' has vanished. English is somewhat curious in this respect as well: 'I have', but 'he has'. Future lessons will introduce you to the many irregular verbs in German. But you should now recognize what is happening to the verbs in German sentences. They are reflecting the person and number of their nominative case subjects. Recall these sentences from past lessons (verbs underlined here): "Danke, es geht mir gut" Thanks, it goes well with me (verb is "gehen") "Ich habe viel Arbeit" I have much work (verb is "haben") "Ist er zu Besuch?" Is he visiting? (verb is "sein") "Du bist ein Schwein!" You are a pig! (verb is "sein") "Wie heißen Sie?" What are you called? (verb is "heißen", and pronoun is formal) "Wir spielen eine Stunde lang!" We play for one hour! (verb is "spielen") "Sie liegt am Ausfluss des Zürichsees." It lies at the outlet of Lake Zurich (verb is "liegen") Grammatik 6.2 ~ Case in German nouns. Through our discussions on the personal pronouns, you have learned how pronouns have case. Nouns also have case—and in German, noun case can be expressed by the definite article ("der"). Recall this table from Lektion 3: These "der"-words reflect noun gender in the nominative case—appropriate whenever a noun is used as the subject of a sentence. For other cases, the "der" words change. Expanding the table to present nominative (NOM.), accusative (ACC.), dative (DAT.), and genitive (GEN.) cases: Note, there are also "der"-word forms to be used for plural nouns. Fortunately, these are the same, no matter what the gender of the singular noun. For future reference, you can find the "der"-words summarized in Anhänge Drei. The following examples demonstrate the use of the definitive article in various parts of speech: "Du hast die Wurst und den Käse." You have the sausage and the cheese. (accusative case) "Die Geschäftsleute verstehen die Arbeit" The business associates understand the work. (nominative and accusative cases) "Sie liegt am Ausfluss des Zürichsees." It lies at the outlet of (the) Lake Zurich. (genitive case) "Zürich ist die größte Stadt der Schweiz." Zurich is the largest city in (of the) Switzerland. (nominative and genitive cases) In the last example, remember that in both English and German, the noun (or pronoun) that follows the verb 'to be' is a predicate noun, for which the correct case is the nominative. That is why, in English, 'It is I' is grammatically correct and 'It is me' is incorrect. So consider the following (and note that case of each definite article is the same as in the last example above): "Zürich ist der Kanton der gleichnamigen Stadt." Zurich is the canton of the same named city. Grammatik 6.3 ~ Commands. "Ruf sie an, bitte!" Call her, please. or "Ruf sie bitte an!" "Gehen Sie nach Hause!" Go home (formal). "Kommt mit!" Come with (plural)! "Gib es mir!" Give me it! Notice that in these sentences there are no subjects (except for #2). In German, as in English, there is a "commandative form", a way to demand something using an understood you. In English, there is only one you-form and one command form. In German, since there are three you's, there are three ways to command. If the subject is singular ("du"), then the verb has no ending. If it is irregular, it takes the du-form, such as in essen (Iss!) or lesen (Lies!). If there is a plural subject ("ihr"), then the verb takes the ihr-form. Nothing else is changed. Most of the time, ihr-commands are used with children, but that is not always the case. In both of these sentences, the du or ihr is omitted. Formal is normal. The "Sie" stays (after the verb) and the verb is in its formal form. Although it is worded like a question, in written or spoken form, it is easy to tell the difference.

General Chemistry/Measurement. Moles. The mole is a unit used to measure the number of particles in a substance (where particles can be atoms, molecules, electrons, ions etc.). One mole of substance contains 6.02205 × 1023 particles. This rather large quantity is a constant called "Avogadro's Number", which is abbreviated as "NA". It simply refers to the number of particles in one mole. formula_1 For example, one mole of helium gas contains 6.022×1023 atoms; 2 moles of oxygen gas contains 1.204×1024 molecules. Moles and Mass. It would be useful to be able to convert between the number of moles and the mass of a substance. The "molar mass" is the mass of one mole of a substance, measured in grams per mole or formula_2. Not by coincidence, the "molar mass" is the same as the "atomic weight" of a substance (this is how the concept of moles was originally defined). For example, the molar mass (and atomic weight) of carbon-12 is 12 g·mol−1, so 1 mole of carbon-12 weighs 12 grams. Similarly, chlorine has a molar mass of 35.45 g·mol−1, so one mole of chlorine atoms weighs 35.45 g. There are two chlorine atoms in one molecule of Cl2 gas, so one mole of Cl2 gas weighs 70.90 g. Measurement and Quantities. "See the Units Appendix for tables of SI fundamental and derived units."

LPI Linux Certification/Use Debian Package Management. Detailed Objective. (LPIC-1 Version 5.0 Weight: 3 Description: <br> Candidates should be able to perform package management using the Debian package tools. Key knowledge areas: The following is a partial list of the used files, terms and utilities: Package Structure. In order to understand how to use Debian's package management system, it would be useful to first have an understanding of how a Debian package is named. For example, the package ncftp_3.1.3-1_i386.deb has 5 major parts: Note that there is special significance to the use of underscores(_) and hyphens(-); an underscore shall separate the name of the program and its version, a hyphen shall separate a version number and the revision number, and an underscore shall separate the revision number and the architecture. dpkg. dpkg is the "grandaddy" or "back-end" of the Debian Package Management System. Features present in the more advanced tools are not available to dpkg but it is nevertheless a useful tool. Some notes: Some of the more common functions used by administrators by dpkg are:<br> Adding, Removing, and Configuring Packages Querying Package Information Updating Package Information dpkg-reconfigure. dpkg-reconfigure reconfigures packages after they have already been installed. Dselect. The utility that allows you on Debian to easily add/remove packages is dselect. There is on dselect an interactive menu that will allow you to install/remove packages. Care must be taken with this utility. You can damage your system. Dselect menu example: Debian `dselect' package handling frontend. 0. [A]ccess Choose the access method to use. 1. [U]pdate Update list of available packages, if possible. 2. [S]elect Request which packages you want on your system. 3. [I]nstall Install and upgrade wanted packages. 4. [C]onfig Configure any packages that are unconfigured. 5. [R]emove Remove unwanted software. 6. [Q]uit Quit dselect. $ dselect - list of access methods Abbrev. Descriptio cdrom Install from a CD-ROM. * multi_cd Install from a CD-ROM set. nfs Install from an NFS server (not yet mounted). multi_nfs Install from an NFS server (using the CD-ROM set) (not yet mounted). harddisk Install from a hard disk partition (not yet mounted). mounted Install from a filesystem which is already mounted. multi_mount Install from a mounted partition with changing contents. floppy Install from a pile of floppy disks. apt APT Acquisition [file,http,ftp] apt-get. If you know the name of a package you want to install, use apt-get. You must configure the sources.list file. This same file is used when you choose the apt access method of dselect. The location is /etc/apt. Apt-cache. To find the name of a package that you want to install use apt-cache. apt-cache main options are : user@host:~$ apt-cache search gimp babygimp - An icon editor in Perl-Tk blackbook - GTK+ Address Book Applet cupsys-driver-gimpprint - Gimp-Print printer drivers for CUPS escputil - A maintenance utility for Epson Stylus printers filmgimp - A motion picture editing and retouching tool Resources. APT HOWTO<br> http://www.debian.org/doc/manuals/apt-howto/index.en.html<br> dselect Documentation for Beginners<br> http://www.debian.org/doc/manuals/dselect-beginner/<br>

Trigonometry/Law of Sines. For any triangle with vertices formula_1 corresponding angles formula_1 and corresponding opposite side lengths formula_3 , the Law of Sines states that Each of these expressions is also equal to the diameter of the triangle's circumcircle (the circle that passes through the points formula_1). The law can also be written in terms of the reciprocals: Proof. Dropping a perpendicular formula_7 from vertex formula_8 to intersect formula_9 (or formula_9 extended) at formula_11 splits this triangle into two right-angled triangles formula_12 and formula_13 . We can calculate the length formula_14 of the altitude formula_7 in two different ways: By using the other two perpendiculars the full law of sines can be proved. QED. Application. This formula can be used to find the other two sides of a triangle when one side and the three angles are known. (If two angles are known, the third is easily found since the sum of the angles is formula_21 .) See Solving Triangles Given ASA. It can also be used to find an angle when two sides and the angle opposite one side are known. Area of a triangle. The area of a triangle may be found in various ways. If all three sides are known, use Heron's theorem. If two sides and the included angle are known, consider the second diagram above. Let the sides formula_22 and formula_23 , and the angle between them formula_24 be known. The terms /alpha and /gamma are variables represented by Greek alphabet letters, and these are commonly used interchangeably in trigonometry just like English variables x, y, z, a, b, c, etc. From triangle formula_25 , the altitude formula_26 is formula_27 so the area is formula_28 . If two angles and the included side are known, again consider the second diagram above. Let the side formula_23 and the angles formula_24 and formula_31 be known. Let formula_32 . Then Thus

Trigonometry/Law of Cosines. Law of Cosines. The Pythagorean theorem is a special case of the more general theorem relating the lengths of sides in any triangle, the law of cosines: where formula_2 is the angle between sides formula_3 and formula_4 . Does the formula make sense? This formula had better agree with the Pythagorean Theorem when formula_5 . So try it... When formula_5 , formula_7 The formula_8 and the formula reduces to the usual Pythagorean theorem. Permutations. For any triangle with angles formula_9 and corresponding opposite side lengths formula_10 , the Law of Cosines states that Proof. Dropping a perpendicular formula_14 from vertex formula_15 to intersect formula_16 (or formula_16 extended) at formula_18 splits this triangle into two right-angled triangles formula_19 and formula_20 , with altitude formula_21 from side formula_22 . First we will find the lengths of the other two sides of triangle formula_19 in terms of known quantities, using triangle formula_20 . Side formula_22 is split into two segments, with total length formula_22 . Now we can use the Pythagorean Theorem to find formula_4 , since formula_33 . The corresponding expressions for formula_3 and formula_22 can be proved similarly. The formula can be rearranged: and similarly for formula_37 and formula_38 . Applications. This formula can be used to find the third side of a triangle if the other two sides and the angle between them are known. The rearranged formula can be used to find the angles of a triangle if all three sides are known. See Solving Triangles Given SAS.

Computer Programming/Database Programming. Database Programming. Introduction. A database is a repository of information managed by a database engine which ensures integrity of data and fast access to the data. A very common implementation of a database is a Relational Database Management System (RDBM). To users, the information in a database can be accessed by using Structured Query Language (SQL) a database language common to most databases. However, SQL only provides commands to access and manipulate the data in the database. For any complex application, there commonly is a need for conditions, branching, and loops. None of these are a part of the SQL language. In order to fill this gap, many common programming languages allow integration with SQL through a common library such as Open Data Base Connectivity (ODBC), Object Linking and Embedding (OLE), and sometimes with application programming interfaces or libraries supplied with the database. In addition, most databases now have a simple language of their own which allows simple control for applications which do not need the full power of standard languages like C++ and Pascal. These simple languages are used to write stored procedures and are proprietary to each database. An alternate approach taken by other languages like is to have a data model that includes persistent variables that are shared among multiple processes. This approach hides the database operations within the programming language instead of hiding the language within the database.

LPI Linux Certification/LPI Permission. Date: Fri, 16 Jan 2004 14:33:06 -0500<br> From: "Wilma Silbermann" <[email protected]><br> To: "m strawser" <[email protected]><br> Subject: Re: reprinting of exam objectives<br> Hi there Mark, We are pleased that you are creating more training material for the LPI exams and would have no problem approving your request to reprint the objectives as long as you ensure you show that LPI does not approve or endorse your book in any way. You may use the logo in the same manner - please read the logo license; https://www.lpi.org/en/logo.html Please give me a call if you have any further concerns or questions on this or any other matter. Thanks again for your support of LPI. Wilma

Java Swings/Overview. Swing is a tool kit in Java which provides a way to build cross platform user interfaces. It is built on top of and designed as a replacement for AWT, the other UI toolkit built into Java. SWT is a third toolkit you may hear about. SWT is an open source toolkit and is a full topic in of itself, see SWT's Homepage for more information. Overview. Swing provides many controls and widgets to build user interfaces with. Swing class names typically begin with a J such as codice_1, codice_2, codice_3. This is mainly to differentiate them from their AWT counterparts and in general are one-to-one replacements. Swing is built on the concept of "Lightweight components" vs AWT and SWT's concept of "Heavyweight components". The difference between the two is that the Lightweight components are rendered (drawn) using purely Java code, such as drawLine and drawImage, whereas Heavyweight components use the native operating system to render the components. Some components in Swing are actually heavyweight components. The top-level classes and any derived from them are heavyweight as they extend the AWT versions. This is needed because at the root of the UI, the parent windows need to be provided by the OS. These top-level classes include codice_4, codice_3, codice_6 and codice_7. All Swing components to be rendered to the screen must be able to trace their way to a root window or one of those classes. So what does using Swing get you? So far we've only talked about components and rendering. Well, to start with you get the following.

UK Constitution and Government/Parliament. Parliament. Parliament is the supreme law-making body in the United Kingdom. It is made up of two "Houses of Parliament", namely the "House of Commons" and the "House of Lords", as well as the Sovereign. The Sovereign's involvement in the life and working of Parliament is purely formal. In constitutional theory, Parliament in its strictest sense is sometimes referred to as the "Queen-in-Parliament"; this contrasts with the more ordinary use of the term "Parliament", meaning just the two Houses of Parliament. Within the British constitutional framework, the Queen-in-Parliament is supreme ("sovereign"), able to make, alter, or repeal any law at will. Both Houses of Parliament meet at the "Palace of Westminster". Parliaments and Sessions. As with most legislatures, Parliament does not continue in perpetual existence. Typically, the "life" of a Parliament is around four years. Parliament is initially "summoned" by the Sovereign. This now always occurs after there has been a general election. Once assembled, and a Speaker has been chosen by the House of Commons, Parliament is formally "opened" by the Sovereign. The business of the two Houses is arranged into "sessions", which usually last a year (running from around October or November each calendar year). However, there is usually a long "recess" during the summer months, when business is temporarily suspended. The opening of each parliamentary session is conducted in accordance with a great deal of traditional ceremony. The Sovereign takes his or her seat on the throne situated in the chamber of the House of Lords, and the Gentleman Usher of the Black Rod (one of that House's officers) is commanded to summon the House of Commons. When Black Rod reaches the door of the Commons, it is slammed shut in his face, to symbolise the right of the Commons to debate without royal interference. Black Rod then solemnly knocks on the door with his staff of office; on the third knock, the door is opened, and he is permitted to enter and deliver his message. MPs then proceed from the Commons to the House of Lords, to hear the "Speech from the Throne", more commonly known as the "Queen's Speech". The Speech outlines the Government's legislative proposals for the session; while worded as if it's the Sovereign's own policy, the Speech is in fact entirely drafted by Government ministers. Each session is ended by a "prorogation". The Commons are formally summoned to the House of Lords, where another formal Speech is read out, summing up the work of the two Houses of Parliament over the course of the session. In practice the Sovereign no longer attends for the prorogation; "Lords Commissioners" are appointed to perform the task, and one of their number also reads out the Speech. By law, each Parliament must come to an end no later than five years from its commencement; this is known as "dissolution". Because a dissolution is necessary in order to trigger a general election, the Prime Minister was effectively able to choose to hold elections at a time that seems the most advantageous to his or her political party. After the 2010 General Election the Liberal Democrat party made the introduction of a law on fixed term parliaments a requirement for forming a coalition government with the Conservative party. A coalition was necessary as the result of the election meant no party had an overall majority of seats. The main opposition party from the previous parliament, the Conservative party, gained the most seats and under parliamentary protocol had the first opportunity to try and form a government. They concluded a formal deal with the Liberal Democrats to govern together. The Liberal Democrats had insisted on fixing the term of parliaments to reduce the inherent advantage the governing party had in being able to choose the moment to hold an election. There are provisions in the Fixed Term Parliaments Act to allow an early election with the consent of Parliament. These provisions were used in 2017. Although the duration of Parliament has been restricted to five years since 1911, legislation was passed during both World Wars to extend the life of the existing Parliament; this meant that the Parliament summoned in 1935 eventually continued in existence for around ten years, until 1945. House of Commons. Composition. While sometimes described as the "lower house", the House of Commons is by far the most important of the two Houses of Parliament. Members of the House of Commons are known as "Members of Parliament", or "MPs". The entire United Kingdom is subdivided into "constituencies", each of which returns one MP to sit in the House of Commons. There are presently 650 constituencies, however the exact number fluctuates over time as the boundaries of constituencies are periodically reviewed by Boundaries Commissions set up for each part of the UK. Constituencies are intended to have roughly equal numbers of voters, but in practice the smallest and largest constituencies can have a significant difference in size. At each "general election" all seats in the House of Commons become vacant. If a seat becomes vacant during the life of a Parliament (i.e. between general elections), then a "by-election" is held for that constituency. The election for each constituency is by secret ballot conducted according to the "First-Past-the-Post" system: the candidate with the most votes is "returned" as MP. Qualifications of voters. A person must be aged at least eighteen in order to vote. The following nationalities are entitled to vote at parliamentary elections: Irish and Commonwealth citizens must have been resident in the United Kingdom. British citizens who are resident abroad are only able to vote if they had been resident in the United Kingdom within the previous 15 years. Certain categories of people are unable to vote: By convention, close relatives of the Sovereign also do not vote. Qualifications of MPs. Anyone who is not disqualified to vote is also qualified to be an MP, except the following: Resignation as an MP. Since the 17th century, the House of Commons has asserted that MPs may not resign. However, in practice members are able to resign by the legal fiction of appointment as "Crown Steward and Bailiff of the three Chiltern Hundreds of Stoke, Desborough, and Burnham", or as "Crown Steward and Bailiff of the Manor of Northstead". Neither of these offices carries any duties, but have been preserved in force so that those appointed to them automatically lose their seats in the House of Commons as having accepted an "office of profit under the Crown". Speakership and procedure. The House of Commons is presided over by the "Speaker". There are also three Deputy Speakers, with the titles of "Chairman of Ways and Means", "First Deputy Chairman of Ways and Means", and "Second Chairman of Ways and Means". The Speaker and his or her deputies are elected at the commencement of a Parliament, and serve until its dissolution. Following a general election, the "Father of the House" (the member with the longest unbroken service in the House, who is not also a Minister of the Crown) takes the chair. If the Speaker from the previous Parliament has been returned as a member of the new Parliament, and intends to continue in office, then the House votes on a motion that the member take the chair as Speaker. Otherwise, or if the motion for his or her re-election fails, then members vote by secret ballot in several rounds; after each round, the candidate with the fewest votes is eliminated. The election ends when one member secures a majority of votes in a particular round. Thereafter, the Speaker-elect leads the House of Commons to the House of Lords, where the Lords Commissioners (five Lords representing the Sovereign) officially declare the Royal Approbation (approval) of the Speaker, who immediately takes office. The Speaker traditionally lays claim to all of the House's privileges, including freedom of speech in debate, which the Lords Commissioners then confirm on behalf of the Sovereign. If a Speaker should choose to resign from his post during the course of Parliament, then he must preside over the election of his successor. The new election is otherwise conducted in the same manner as at the beginning of a Parliament. The new Speaker-elect receives the Royal Approbation from Lords Commissioners; however, the ceremonial assertion of the rights of the Commons is not repeated. The Speaker is expected to act impartially. He or she is an important figure within the House of Commons, controlling the flow of debate by selecting which members get to speak in debates, and by ensuring that the customs and procedures of the House are complied with. The Speaker and his deputies do not generally speak during debates, nor vote at divisions. The Speaker also exercises disciplinary powers. He or she may order any member to resume his or her seat if they consistently contribute irrelevant or repetitive remarks during a debate. An individual who has disregarded the Speaker's call to sit down may be requested to leave the House; if the request is declined, then the Speaker may "name" the member. The House then votes on whether to suspend the member in question for a certain number of days, or even, in the case of repeated breaches, for the remainder of the session. In the most serious cases, the House may vote to expel a member. In the case of grave disorder, the Speaker may adjourn the House without a vote. The House votes on all questions by voice first. The Speaker asks all those in favour of the proposition to say "Aye," and those opposed to say "No". The Speaker then assesses the result, saying "I think the Ayes have it" or "I think the Noes have it", as appropriate. Only if a member challenges the Speaker's opinion is a "division", or formal count, called. During a division, members file into two separate lobbies on either side of the Commons chamber. As they exit each lobby, clerks and tellers count the votes and record the names. The result is then announced by the Speaker. In the event of a tied vote, the Speaker (or other occupant of the Chair) has a "casting vote"; however, conventions exist that the Speaker would cast a vote to maintain the "status quo." In effect moving bills on to further scrutiny, but not pass a bill into law. House of Lords. Composition. Generally speaking, membership of the House of Lords is by appointment for life. However, up until 1999, hereditary peers were also members of the Lords; when this right was abolished, a compromise measure allowed them to elect ninety of their number to continue as members. Certain office-holders are also ex officio members of the House of Lords: The Earl Marshal and Lord Great Chamberlain are mostly ceremonial offices. In addition to the three ex officio bishops, the 21 longest-serving diocesan bishops also sit in the Lords. The general qualifications for sitting and voting in the Lords are: Speakership and procedure. The "Lord Speaker" is elected by the House. Until recently his or her duties were carried out by the Lord Chancellor, a Minister of the Crown. In contrast with the Speaker of the House of Commons, the Lord Speaker has a relatively minor role, since the House of Lords is generally self-governing: the House itself decides upon points of order and other such matters. The seat used by the Lord Speaker is known as "the Woolsack". Similar to the House of Commons, the Lords also vote by voice first. The Lord Speaker (or whoever else is presiding) puts the question, with those in favour saying "Content," and those opposed saying "Not-Content." If the Lord Speaker's assessment of the result is challenged, a division follows, with members voting in the appropriate lobby just as is done in the Commons. The officer presiding may vote from his or her place in the chamber rather than from a lobby. In the case of a tie, the result depends on what type of motion is before the House. A motion that a bill be advanced to the next stage or passed is always decided in the positive, while amendments to bills or other motions are decided in the negative, if there is an equality of votes. Acts of Parliament. Legislation passed by Parliament is in the form of an "Act of Parliament". A draft law is known as a "Bill". A bill passes into law provided that it has either been passed by both Houses of Parliament, or the provisions of the Parliament Acts have been complied with; and provided it has received the Royal Assent. A bill must pass through several stages in both of the two Houses. A bill is "read" three times in each House. The First Reading for Public Bills is almost always a formality. The Second Reading is a debate on the merits of the general principles behind the bill. Next follow the Committee and Report stages. The Third Reading is a vote upon the bill as a whole, as amended during the Committee and Report stages. Once the House into which the bill was first introduced has finished with it, the bill is then introduced into the other House. Any amendments by the second House then have to be agreed to by the first before the bill can proceed. Bills are classified as either "Government Bills" or as "Private Members' Bills". Ministers of the Crown introduce Government Bills; private members introduce Private Members' Bills. Bills are also classified as "Public", "Private", "Personal" or "Hybrid". Public bills create laws applied generally (for instance, reforming the nation's electoral system). Private bills affect a specific named company, person or other entity (for instance, authorising major constructions on specific named public lands). Personal bills are private bills that confer specific rights to specific named individuals (for example by granting the right to marry a person one would not normally be allowed to wed). Hybrid bills are public bills that directly and specially affect private interests. Public Bills. A Public Bill's First Reading is usually a mere formality, allowing its title to be entered in the Journals and for its text to be printed by the House's authority. After two weeks, one of the bill's supporters moves "that the bill be now read a second time". At the second reading debate, the bill's general characteristics and underlying principles, rather than the particulars, are discussed. If the vote on the Second Reading fails, the bill dies. It is, however, very rare for a Government bill to be defeated at the Second Reading; such a defeat signifies a major loss. In the House of Commons, following the Second Reading, various procedural resolutions may need to be passed. If the bill seeks to levy or increase a tax or charge, then a "Ways and Means Resolution" has to be passed. If it involves significant expenditure of public funds, then a "Money Resolution" is necessary. Finally, the government may proceed with a "Programme Motion" or an "Allocation of Time Motion". A Programme Motion outlines a timetable for further debate on the bill and is normally passed without debate. An Allocation of Time Motion, commonly called the "Guillotine", limits time available for debate. Normally, a Programme motion is agreed to by both parties while an Allocation of Time Motion becomes necessary if the Opposition does not wish to cooperate with the Government. In the House of Lords, there are no Guillotines or other motions that limit the time available for debate. Next, the bill can be committed to a committee. In the House of Commons, the bill may be sent to the "Committee of the Whole House", a "Standing Committee", a "Special Standing Committee" or a "Select Committee." The Committee of the Whole House is a committee that includes all members of the House and meets in the regular chamber. The Speaker is normally not present during the meetings; a Deputy Speaker normally takes the chair. The procedure is used for parts of the annual Finance Bill and for bills of major constitutional importance. More often, the bill is committed to a Standing Committee. Though the name may suggest otherwise, the membership of Standing Committees is temporary. There can be from sixteen to fifty members; the strength of parties in the committee is proportional to their strengths in the whole House. It is possible for a bill to go to a Special Standing Committee, which is like a Standing Committee except that it may take evidence and conduct hearings; the procedure has not been used in several years. Finally, the bill may be sent to a Select Committee. Select Committees are permanent bodies charged with the oversight of a particular Government department. This last procedure is rarely used; the quinquennial Armed Forces Bill, however, is always referred to the Defence Select Committee. In the House of Lords, the Bill is committed to the "Committee of the Whole House", a "Public Bill Committee", a "Special Public Bill Committee", a "Select Committee" or a "Grand Committee". The most common committee used is the Committee of the Whole House. Sometimes, the bill is sent to a Public Bill Committee of twelve to sixteen members (plus the Chairman of Committees) or to a Special Public Bill Committee of nine or ten members. These committees correspond in function to the Commons Standing and Special Standing Committees, but are less often utilised. Select Committees may also be used, like in the Commons, though it is rare for this to be done. The Grand Committee procedure is the only one unique to the House of Lords. The procedure is reserved for non-controversial bills that must be passed quickly; a proposal to amend the bill is defeated if a single member votes against it. In both Houses, the committee used considers the bill clause-by-clause and may make amendments. Thereafter, the bill proceeds to the "Consideration" or "Report Stage". This stage occurs on the Floor of the House and offers it an opportunity to further amend the bill. While the committee is bound to consider every single clause of the bill, the House need only debate those clauses which members seek to amend. Following the Report Stage, the motion "that the bill be now read a third time" is considered. In the House of Commons, there is a short debate followed by a vote; no further amendments are permitted. If the motion passes, then the Bill is considered passed. In the Lords, however, amendments may be moved. Following the vote on the third reading, there must be a separate vote on passage. After one House has passed a bill, it is sent to the other for its consideration. Assuming both Houses have passed a bill, differences between their separate versions must be reconciled. Each House may accept or reject amendments made by the other House, or offer other amendments in lieu. If one House has rejected an amendment, the other House may nevertheless insist upon it. If a House insists upon an amendment that the other rejects, then the bill is lost unless the procedure set out in the Parliament Acts is complied with. Once a bill has passed by both Houses, or has been certified by the Speaker of the Commons as having passed the House of Commons in conformity with the Parliament Acts, the bill is finally submitted to the Sovereign for "Royal Assent". Since 1708, no Sovereign has failed to grant Royal Assent to a bill. Assent may be given by the Sovereign in person, but is usually given in the form of letters patent read out in each of the Houses; in the House of Lords the Clerk announces the Norman French formula "La Reyne le Veult", and the Bill thereupon becomes an Act of Parliament. In 1708 the formula used for the Scottish Militia Bill was "La Reyne s'avisera" (however, this was on ministerial advice). In theory the Sovereign has the right to either "withhold" or "reserve" the assent, however this right is not exercised. If assent were withheld, then the bill would fail. If assent were reserved, then formally a final decision on the bill has been put off until a later time; if Assent were not given before prorogation of the session, then the bill would fail. Private, Personal and Hybrid Bills. In the nineteenth century several hundred private Acts were passed each year, dealing with such matters as the alteration of local authority powers, the setting up or alteration of turnpike trusts, etc. A series of reforms has eliminated the necessity for much of this legislation, meaning that only a handful of private Acts are now passed each year. A private bill is initiated when an individual petitions Parliament for its passage. After the petition is received, it is officially gazetted so that other interested parties may support or contest it. Counter-petitions objecting to the passage of the bill may also be received. To be able to file such a petition, the bill must "directly and specially" affect the individual. If those supporting the bill disagree that such an effect exist, then the matter is resolved by the "Court of Referees", a group of senior Members of Parliament. The bill then proceeds through the same stages as public bills. Generally, no debate is held on the Floor during the Second Reading unless a Member of Parliament files a "blocking motion". It is possible for a party whose petition was denied by the Court of Referees to instead lobby a Member to object to the bill on the Floor. After the bill is read a second time, it is sent to one of two committees: the "Opposed Bill Committee" if there are petitions against the bill, or the "Unopposed Bill Committee" if there aren't. After taking evidence, the committee may return a finding of "Case Proved" or "Case Not Proved". In the latter case, the bill is considered rejected, but in the former case, amendments to the bill may be considered. After consideration, third reading and passage, the bill is sent to the other House, which follows the same procedure. If necessary, the bill may have to face two different Opposed Bill Committees. After differences between the Houses are resolved, the bill is submitted for Royal Assent. Personal bills relate to the "estate, property, status, or style" or other personal affairs of an individual. By convention, these bills are brought first in the House of Lords, where it is referred to a Personal Bill Committee before being read a "first" time. The Committee may make amendments or even reject the bill outright. If the bill is reported to the House, then it follows the same procedure as any other private bill, including going through an Unopposed or Opposed Bill Committee in both Houses. A special case involves bills that seek to enable marriages between those who are within a "prohibited degree of affinity or cosanguinity". In those cases, the bill is not discussed on the Floor and is sent at the committee stage to a Select Committee that includes the Chairman of Committees, a bishop and two lay members. Hybrid bills are public bills that have a special effect on a private interest. Prior to the second reading of any public bill, it must be submitted to the Clerk, who determines if any of the House's rules have been violated. If the Clerk finds that the bill does have such an effect on a private interest, then it is sent to the "Examiners", a body which then may report to the House that the bill does or does not affect private interests. If the latter, then it proceeds just like a public bill, but if the former, then it is treated as hybrid. The first and second readings are just as for public bills, but at the committee stage, if petitions have been filed against the bill, it is sent to a Select Committee, but the Committee does not have the same powers of rejection as Private Bill Committees. After the Committee reports, the bill is recommitted to another committee as if it were a public bill. Thereafter, the stages are the same as for a public bill, though, in the other chamber, the bill may have to be considered once more by a Select Committee. Supremacy of the House of Commons. Under the Parliament Acts of 1911 and 1949, the House of Commons is essentially the pre-eminent chamber in Parliament. If the Lords fail to pass a bill (by rejecting it outright, insisting on amendments disagreed to by the Commons, or by failing to vote on it), and the bill has been passed by the Commons in two consecutive sessions, then the bill may be presented for Royal Assent unless the House of Commons otherwise directs, and provided that the bill was introduced in the Lords at least one month before the end of each session. However, twelve months must have passed between the Second Reading in the first session, and the final vote on passage in the second one. Also, the bill passed by the Commons in each session must be identical, except to take into account the passage of time since the bill was first proposed. The effect of the procedure set out in the Parliament Acts is that the House of Lords may delay a bill for at least thirteen months, but would ultimately be unable to overturn the concerted will of the House of Commons. However, this procedure does not apply in the case of private or personal bills, nor to bills seeking to extend the life of Parliament beyond five years. Under the Parliament Acts, a special procedure applies to "money bills". A bill is considered a money bill if the Speaker certifies that it relates solely to national taxation or to the expenditure of public funds. The Speaker's decision is final and cannot be overturned. Following passage by the House of Commons, the bill can be considered by the House of Lords for not longer than one month. If the Lords have not passed the bill within that time, it is submitted for Royal Assent regardless. Any amendments made by the House of Lords are ignored unless accepted by the House of Commons. In addition to the Parliament Acts, tradition and conventions limit the House of Lords. It is the privilege of the House of Commons to levy taxes and authorise expenditure of public funds. The House of Lords cannot introduce bills to do either; furthermore, they are barred from amending supply bills (bills appropriating money to expenditure). In some cases, however, the House of Lords can circumvent the rule by inserting a "Privilege Amendment" into a bill they have originated. The Amendment reads: The House of Commons then amend the bill by removing the above clause. Therefore, the privilege of the Commons is not violated as they, not the Lords, have approved the tax or public expenditure. Delegated legislation. Many Acts of Parliament authorise the use of Statutory Instruments (SIs) as a more flexible method of setting out and amending the precise details for new arrangements, such as rules and regulations. This delegated power is given either to the Queen in Council, a Minister of the Crown, or to other named office holders. An Act may empower the Government to make a Statutory Instrument and lay it before both Houses, the SI to take legal effect if approved by a simple vote in each House; or in other cases, if neither House objects within a set time. In theory, Parliament does not lose control over such statutory instruments when delegating the power to make them, while being saved the necessity to debate and vote upon even quite trivial changes, unless members wish to raise objections. English Votes For English Laws. During the creation of the Devolved Administrations of Scotland and Wales, the idea of an English Parliament or Regional Assemblies were discussed but ultimately not implemented. This created an issue where the UK Parliament is acting as a "de facto" English Parliament on matters devolved to the national assemblies. MPs from all regions were free to debate and vote on issues which did not effect their constituencies or constituents. The Conservative Government of 2015 decided to address the issue in a controversial manner. Instead of bringing a bill to the Parliament, they proposed changes to the Statutory Instruments (SIs). Any bill brought before the Commons which is adjudged by the Speaker to only effect English Constituencies (or in some limited cases England and Wales) can have a ”double majority” rule imposed. In short, all MPs are allowed to debate and vote, but for a vote to be won both a count of votes of all MPs and a vote for English only MPs must be won. Privilege. Each House has a body of rights that it asserts, or which are conferred by statute, with the aim of being allowed to carry out its duties without interference. For example, members of both Houses have freedom of speech during parliamentary debates; what they have said cannot be questioned in any place outside Parliament, and so a speech made in Parliament cannot constitute slander. These rights are collectively referred to as "Parliamentary Privilege". Both Houses claim to determine their own privileges, and are acknowledged by the courts as having the authority to control their own proceedings, as well as to discipline members abusing the rules. Furthermore, each House is the sole judge of the qualifications of its members. Collectively, each House has the right of access to the Sovereign. Individually, members must be left free to attend Parliament. Therefore, the police are regularly ordered to maintain free access in the neighbouring streets, and members cannot be called on to serve on a jury or be subpoenaed as a witness while Parliament is in session. (Arrest for crime is still possible, but the relevant House must be notified of the same.) Parliament has the power to punish "contempt of Parliament", that is, violation of the privileges and rules of a House. Any decisions made in this regard are final and are cannot be appealed to any court. The usual modern penalty for contempt is a reprimand, or brief imprisonment in the precincts of the House, but historically large fines have been imposed.

Haskell/Overview. Haskell is a standardized functional programming language with non-strict semantics. Haskell features include support for recursive functions, datatypes, pattern matching, and list comprehensions. By combining these features, functions that would be difficult to write in a procedural programming language are almost trivial to implement in Haskell. The language is, as of 2011, the functional language on and in which the most research is being performed. The examples below give a taste of Haskell, oriented toward those familiar with other programming languages. Examples. The classic definition of the function: fac 0 = 1 fac n = n * fac (n - 1) A cute definition using Haskell's built-in list notation and the standard codice_1 function: fac n = product [1..n] Both definitions above should compile into the "same" efficient code via a smart compiler using equational reasoning. A naive implementation of a function which returns the nth number in the Fibonacci sequence: fib 0 = 0 fib 1 = 1 fib n = fib (n - 2) + fib (n - 1) A function which returns a list of the Fibonacci numbers in linear time: fibs = 0 : 1 : zipWith (+) fibs (tail fibs) The previous function defines an infinite list, which is possible because of lazy evaluation. One could implement codice_2 as: fib n = fibs !! n (codice_3 is an operator which gets the nth element of a list). The Quicksort algorithm can be expressed in Haskell concisely as: qsort [] = [] qsort (x:xs) = qsort [y | y<-xs, y < x ] ++ [x] ++ qsort [y | y<-xs, y >= x] Non-skipping stable merge sort is mgsort less [] = [] mgsort less xs = head $ until (null.tail) pairs [[x] | x <- xs] where pairs (x:y:xs) = merge x y : pairs xs pairs xs = xs merge (x:xs) (y:ys) | less y x = y : merge (x:xs) ys | True = x : merge xs (y:ys) merge xs ys = xs ++ ys where codice_4 is the function composition operator codice_5, codice_6 is a lambda expression (a nameless function), and the predefined function  codice_7  repeatedly applies a function "fun"  until a condition "cond"  is met; with codice_8 keyword introducing the local definitions showcasing the use of patterns (with codice_9 matching a non-empty list with the head codice_10 and tail codice_11) and guards. The Hamming numbers sequence is just hamm = 1 : map (2*) hamm `union` (map (3*) hamm `union` map (5*) hamm) -- a union of two ordered lists: union (x:xs) (y:ys) = case (compare x y) of LT -> x : union xs (y:ys) EQ -> x : union xs ys GT -> y : union (x:xs) ys using sections (partially applied operators) and the built-in function codice_12 working with lists, whether finite or not, due to lazy (i.e. "by-need" ) evaluation. Also, enclosing function's name into back-quotes turns it into infix operator so that sub-expressions are automatically formed as if by placing parentheses appropriately, forming a nested expression, as in 2+3+5 --> ((2+3)+5) ; and a comment line is introduced by two dashes. Finally, the infinite list of prime numbers by trial division is primes = 2 : sieve [3..] primes -- 2 : _Y ((3:) . sieve [5,7..]) where sieve xs (p:ps) | (h,t) <- span (< p*p) xs = h ++ sieve [n | n <- t, rem n p > 0] ps or as unbounded incremental Sieve of Eratosthenes with ordered lists, import Data.List.Ordered primes = 2 : _Y ((3:) . minus [5,7..] -- ps = [2..] \\ [[p*p, p*p+p..] | p <- ps] . unionAll . map (\p -> [p*p, p*p+2*p..])) _Y g = g (_Y g) -- = g (g (g (g (g ... )))) defining primes corecursively as natural numbers which are not multiples of primes. Or with arrays, import Data.Array import Data.List (tails, inits) ps = 2 : [n | (r:q:_, px) <- (zip . tails . (2:) . map (^2)) ps (inits ps), (n,True) <- assocs ( accumArray (\_ _ -> False) True (r+1,q-1) [(m,()) | p <- px, let s = div (r+p) p * p, m <- [s,s+p..q-1]] )] It's not just for quicksort! Haskell is also used to build "real world" programs, including [[../GUI/|graphical]] or web user interfaces. To get a taste of Haskell in the real world, check out web frameworks in Haskell and Haskell in industry articles on the Haskell wiki, or darcs, an advanced revision control system written in Haskell. Notes. [[/Not in book]]

Biochemistry/Proteins. Proteins are a primary constituent of living things and one of the chief classes of molecules studied in biochemistry. Proteins provide most of the molecular machinery of cells. Many are enzymes or subunits of enzymes. Other proteins play structural or mechanical roles, such as those that form the struts and joints of the cytoskeleton. Each protein is linear polymers built of amino acids. Proteins are also nutrient sources for organisms that do not produce their own energy from sunlight and/or are unable to fix nitrogen. Proteins can interact with one another and with others molecules to form complexes. Index of chapters and main sections

Gothic/Old. = Phonology = Examples. Feminine A=Stems (so is the fem. definite article) Weak Declensions. Weak nouns decline differently than strong nouns (hence the different name) and sometimes are more simple. Examples. But the Weak declensions are not all the same there exists a few irregulars. First the masculine irregulars: NEXT TO COME: FEMININE WEAK NOUNS, NEUTER AND FEMININE STRONG A-STEM VOCABULARY ALSO. = Links = Gothic language on the web

German/Lesson 5. Lektion 5 Wiederholung. Lesson 5 is a review ("Wiederholung") lesson to summarize the German language lessons presented in Lessons 1 through 4. You should, then, return to Lektion 1 and review (that is, reread) each of the four lessons back up to this point. For a more advanced course, you might now incorporate each of the advanced lessons into this "review" process. That is: review Lesson 1, then do Lesson 1A, review Lesson 2, then do Lesson 2A, etc. Parts of Speech and Word Order. Sentences are composed of parts that perform specific functions. You have been introduced to most (but not all) the major parts of speech: pronouns/nouns, verbs, and adjectives; and how these are expressed in German compared with English. Consider the following: Ich brauche Wurst und Käse Haben sie zu viel Arbeit? Word order in a simple sentence follows that used in English. Subject and verb are reversed to form a question. In English, but not in German, the question sentence could also be stated (and, in fact, occurs more often in the US) as 'Do they have too much work?' Nouns. Nouns are words that typically occur in sentences as either subjects (performers of some action) or objects (recipients of some action). Most nouns are the name of either a "person, place, or thing" and, in German, are always capitalized. Every noun in German has an "assigned" gender (masculine, feminine, neuter), and we learn each noun with its nominative case, definite article ("der", "die", "das", respectively) in order to also learn that gender. Thus, a "Vokabeln" section for nouns is presented thusly: der Anhang, die Anhänge appendix, appendices (singular and plural) die Brücke bridge der Freund, die Freunde friend, friends (singular and plural) das Gespräch, die Gespräche conversation, conversations die Grammatik grammar (note irregular stress) die Lektion lesson (note irregular stress) die Straße street

Gothic/Phonology. « Gothic Strong Nouns This is the strong noun A-Stem section, there are other kinds of strong nouns but we will deal with those later. Masculine A-Stem Nouns Gothic has strong and weak nouns (along with strong and weak adjectives!). There are many stems or different declensions within each class of nouns. Here I will show you a-stem nouns. There are three genders in Gothic: masculine, feminine, neuter. These are not always sex-based as in English. Now onto the masculine article (definite). Gothic has no indefinite article (a, an) but only a definite (the) which has masculine, feminine, and neuter forms. For a while here I'm going to be basically throwing you a lot of tables. But here I'll explain the cases: <br>Nominative: marks the subject of the sentence <br>Accusative: marks the direct object of the sentence <br>Genitive: marks possession <br>Dative: marks the indirect object of a sentence.

Genealogy. Genealogy is the research of one's family history (or someone else's). What is included in "family history" varies depending on the individual researcher. There's a table of contents on every page that will help you navigate the pages. If you want to skip to a certain page, look below. Table of contents. Area-specific. /Authors/ Genealogy sites. __NOEDITSECTION__

Gothic/Masculine. Strong Nouns This is the strong noun A-Stem section, there are other kinds of strong nouns but we will deal with those later. Masculine A-Stem Nouns Gothic has strong and weak nouns (along with strong and weak adjectives!). There are many stems or different declensions within each class of nouns. Here I will show you a-stem nouns. There are three genders in Gothic: masculine, feminine, neuter. These are not always sex-based as in English. Now onto the masculine article (definite). Gothic has no indefinite article (a, an) but only a definite (the) which has masculine, feminine, and neuter forms. For a while here I'm going to be basically throwing you a lot of tables. But here I'll explain the cases: <br>Nominative: marks the subject of the sentence <br>Accusative: marks the direct object of the sentence <br>Genitive: marks possession <br>Dative: marks the indirect object of a sentence.

Genealogy/Authors. This book initiated on 02/14/04 by .<BR> Getting Started material by Diana Grzelak Needham. is also working on this project.<BR> from http://bob.fornal.org is also working on this project.

Genealogy/Locating the previous overseas residence. Finding your family village name: You must find your ancestor’s community's name before you will be able to locate ancestral records that were recorded in the "old country." This will usually require beginning research in the U.S., or whatever your home country, to determine the correct community. First, begin with yourself. Gather everything you know about your own origins: where you were born, what religion you were raised in, your own civil and religious records. Then go back one generation at a time, looking for all of the available information you have. Where did your parents live? Where were they born? Gather their records. Sometimes even the smallest detail can lead you on the path to discovery. At times, you will not be able to locate a particular record for a parent or grandparent. If that is the case, look for records of their siblings. Often those will have the information you seek. =Records to Search= Family documents. Get out those old shoe boxes, start reading and really look at the details. Old letters often contain family connections, dates, locations and hints to lead you in the right direction. The same applies to old photographs which may have names and dates, or the photograpy studio or photographer’s name. Address books, postcards and, of course, family Bibles contain information and clues. Deeds, marriage certificates, naturalization papers, social security papers, Wills, and even insurance policies can be sources for information. I found one great-great grandmother’s address in Poland in an old personal address book which was about to be thrown out when her granddaughter passed on. Contact your relatives. Many families are large, and an aunt, great-uncle, or distant cousin may have family documents you were not even aware existed. Begin with the one who was closest to your ancestor or cared for them before they died. Often those relatives end up with the ancestor’s documents. An important note about family Bibles: in most of the older Bibles, the family information is listed about 2/3 to 3/4 of the way toward the back of the book (unlike modern Bibles where this information is listed in the first few pages). Public Records. Public records in general present some problems. Families changed their names; names were misspelled due to language barriers; phonetic spellings were used by clerks; different pronunciation of letters from one language to the next, typographical errors and poor penmanship created transcription errors, among others. Some records are missing due to misfiling, or were destroyed by fire and flood. This is as true in the U.S. as it is in other countries; the 1890 Federal Census being a prime example. Vital records. Birth, marriage and death records are generally located in the county seat in which the event happened (in the USA, other arrangements apply in the rest of the world). The cost of those records vary from county to county, and often depend upon whether you ask for a certified copy of the record or just a genealogical copy (generally cost less). Most U.S. counties can be accessed on the web as follows: www.co.”countyname”.”state two letter abbreviation”.us/ (omit the quotation marks in your search. If that doesn’t work, just do a web search with your favorite search engine. The information for obtaining the records should be on the county site. In the U.S. this information can be found on the USGenWeb site: http://www.usgenweb.org/. There is also a World GenWeb site that may help for researching in other countries: http://www.worldgenweb.org/. Another source to find vital records by state in the U.S. can be found at http://www.cdc.gov/nchs/howto/w2w/w2welcom.htm. Some of these state sites give the year in which the state began to maintain the records, the locations to find earlier records, and refer to databases which are also searchable on the web. SSDI. The Social Security Death Index is available free on line at http://ssdi.rootsweb.com/ Scroll down a bit and just put the name in the search box, and a list of persons with that name will come up. The Social Security Death Index is generally updated every three months. When a person is found, the name, date of birth, date of death, last residence, the state in which the number was issued, and the number itself is shown. If you wish to obtain a copy of the original Social Security Application, you can click on the SS-5 letter link. The following information was requested on the application: Name, current address, birthdate, birthplace (generally City and State, place of employment and business address (if applicable) and names of parents (mother’s full maiden name). Social Security is constantly updating this file. If the person for whom you are looking recently died, they probably won't be here. Give it a few months before you check again. Obituaries. Published obituaries can be a valuable source of information. Often parents’ names, spouses, children and surviving siblings are shown. This is especially valuable if you are unable to locate information on your ancestor and don’t have the female siblings’ married names. Generally, if listed at all, it is with their then present married name, giving you another piece of information to allow you to continue your search. Obituaries may be found in the “morgue” of the local newspapers, historical libraries in various cities and counties, and some public libraries have film or online databases for obituaries, marriages and death notices. Alien Registration. Alien registration was required beginning in 1940 for resident aliens in the USA. The records can be obtained for the years 1940-1944 from the Immigration and Naturalization Service. http://www.bcis.gov/graphics/aboutus/history/ImmRecs/AREG.htm Voter Registration. Most U.S. counties and states keep voter registration records. The states’ records are generally kept in the office of the Secretary of State. You can check with the county or state departments for information. Additionally, the LDS has filmed numerous voter registration indexes for various areas of the United States. You can check their Family History Library Catalog on line to see if your location has been filmed. http://www.familysearch.org/eng/Library/FHLC/frameset_fhlc.asp WWI Draft Registration. In 1917 and 1918 males old enough to serve in the military were required to register for the draft, whether citizen or alien. See more detailed information on Ancestry WWI Draft Information at Ancestry.com The LDS has compiled the WWI Draft Registration on microfiche arranged by state of residence, and you can contact your local Family History Center to view the registration records. Information is available at WWII Draft Info at FamilySearch.org United States Census. The U.S. census is an excellent source of information, although it won’t usually give you the town of origin, it will give the country and occasionally the Province, such as “Prussian Posen” or “Russian Warsawa”. Keep in mind that the reference to “Posen” and “Warsawa” in these records generally refer to the Province and not the city. Remember that these records are organized by family group. You will generally find parents and children, but sometime will also find grandparents and even great-grandparents living with their descendants. This information is also valuable because it provides a fairly accurate view of where the family (including siblings) were located when the individual census was taken - given several, this can show how the family members came and went in a household. Census films may be obtained at your local Family History Center of the LDS (see the Family History Library search page listed under voter registration above) or through the National Archives and Records Administration (NARA) http://www.archives.gov/research_room/genealogy/research_topics/census_records.html. These records are also available on line through the paid genealogical subscription sites, www.Ancestry.com and www.Genealogy.com. Immigration records. There are a number of sources for ship manifests, and their availability varies with the time and port to which your ancestor immigrated. The most well-known is the Ellis Island database on line, and if your ancestors immigrated between 1892 and 1924 to the port of New York, you may find that information free online: http://www.ellisisland.org/sign/index.asp?ACT=LL&login_targ=none. You must register to use the site, but it is without charge.  There have been some problems with the Ellis Island database indexing and linking, and the usual problems with misspellings and transcription errors. Another site which can help with such problems is the Stephen P. Morse website which gives search options not available from the Ellis Island site, and a way in which to find “missing manifests.” http://stevemorse.org/ For more information on Ellis Island records, go to the Jewish GenWeb site: http://www.jewishgen.org/infofiles/eidbfaq.html The LDS has filmed numerous passengers records for many ports, and have some ports indexed so that you can find your ancestor’s name and arrival date before you order the actual manifest. Again, you can check what records they hold at http://www.familysearch.org/eng/Library/FHLC/frameset_fhlc.asp NARA also has many manifests for U.S. ports: http://www.archives.gov/research_room/genealogy/immigrant_arrivals/passenger_records.html Additional passenger arrival information can be found on the following sites:  Immigration and Ships Passenger Lists Research Guide http://home.att.net/~arnielang/ship04.html#whatrec Polish Genealogical Society of America http://www.pgsa.org/ships.htm An extensive reference for immigration to Australia, Canada, Europe, the U.S. and other parts of the world is found on Mary’s Genealogy Treasures at: http://www.telusplanet.net/public/mtoll/immigr.htm. Declarations of Intent or Citizenship Applications are generally found in the local county court of residence prior to the Federal government taking over the naturalization process. A guide to finding these records is found at: http://www.germanroots.com/naturalizationrecords.html There are some free and paid searchable naturalization databases on the web for the U.S. and Canada at: http://www.germanroots.com/naturalization.html Land records. These are often harder to obtain and study than other documents, but they may hold clues, if not outright references to former residence. Probate records. Again, these may hold clues, if not outright references to former residence. Religious records. Baptismal records and marriage applications kept by the churches often have parents’ names and place of birth. If you cannot find your ancestor’s batismal certificate, you may have be able to find a sibling’s record and locate the information indirectly. Catholic records are generally kept in the parish in which the ceremony was performed. If a parish has closed, the records may have been sent to the Diocese or Archdiocese archives, or to the nearest church still in existence. Many local parishes are now on line in the U.S. To locate a specific church by town or city and even by foreign Language masses, this site is very helpful: http://www.masstimes.org/ASP/ . There is even a scrollable map so you can find a parish nearest your ancestors’ home. There is no set web address for the Archidiocese in the U.S., but a web search for “catholic archdiocese” and the city or state will generally get you good results. For a Diocese, you can use a similar search. Many have information about how to obtain genealogical records. The Evangelical(Lutheran) church of the U.S. has genealogical assistance. Their website is: http://www.elca.org/os/archives/index.html. Genealogical information is at the top right. Additionally, the Lutheran World Federation has information and links to their member churches throughout the world. Just click on “member churches” and scroll down to the area in which you are searching: http://www.elca.org/os/archives/index.html. Jewish records: Jewish Temples did not (and do not) keep records as did the Christian churches. These are family records, and were kept in the family papers. Some of the mohels who performed the bris mila kept records, but they were his personal records and would be with his family documents. Of course, many of these were lost through war and the holocaust, but there are still many ways one can search for their Jewish ancestors. Jewis GenWeb has an excellent guide to searching for family and ancestors: http://www.jewishgen.org .

Genealogy/Recording your research. Research success is more than knowing where to look. In addition to data about your family, you'll want to have maps, background information about places, material about resources and how to use them. It won't take long for you to gather so much information that you can't keep track of it all. A systematic method for handling data is crucial. A good system has these qualities: Decide how you will store irreplaceable materials (original documents, photos). Always copy or scan originals and store the originals in a secure location (safety deposit box, safe, firesafe box, etc.) Label each newly acquired document with a source description and an ID. You may find it easiest to just number each document sequentially. It becomes almost impossible to know in advance how to organize an ID system that handles all future acquisitions. Refer to this document ID when extracting data from the document into your research system (binders, software, etc.) Most genealogy software allows you to keep a list of sources. Use this ID to file the documents, or enter you own ID as part of each source notation. Unless you can always bring a notebook computer to every research site, you should use a binder to display the current state of your research for reference. You'll need to know what you already know as you look for new information. A new option for those that use computers for recording their research, you can use a USB thumb drive/flashdrive/memory stick and load the entire Personal Ancestral File (PAF) program on the drive along with your database and access it at any computer that has USB capabilities. Other computer programs may be able to do the same thing, but I am not sure. PAF is a free computer download from www.familysearch.org that has documentation and multimedia abilities. The PAF program is a windows based program, but can be run on a MAC if a pc-emulator is used.

Genealogy/Establish goals. When starting genealogy, you should ask yourself what you want to accomplish with your research. Are you primarily curious about your ancestors and want to see what information is easily available? Do you want to devote your life to uncovering and preserving the past? What parts of your family do you wish to research? Some people prefer to focus on a few lines and mostly ignore the lines that marry in. Some people collect every person that can be tied in, including every umpteenth cousin many times removed. What about adoptions? Which line do you research? If you have a surname to research that isn't very common, will you research anyone with that name, whether there is any known connection to you or not ("one-name study")? As time goes on, your scope may change. But try to determine at the beginning what you wish to research in order to avoid re-doing previous work.

Genealogy/Work backwards. Working backwards from yourself to your most distant ancestors is a critical method in tracing one's own ancestry. Although it requires discipline, it is extremely important to systematically work backwards in time through the record trail, exhausting all record sources for each person, before working on their parents and grandparents. Without working systematically backwards, it becomes more and more easy to miss a crucial piece of evidence, or to rely on a hypothesis or guess as the foundation for later efforts. Use of a checklist for every person you are researching can make this methodical task easier. In order to properly work backwards, one should use evidence in one generation regarding the previous generation as your foundation. Birth, marriage, and death certificates, both civil and ecclesiastic, often name, or even describe the occupation of, the bride or groom's father and mother. Many times the certificate's subject's place of birth is given, and sometimes the place of the parents' birth as well. For example, old civil birth records (1865–1910) in New York City, found at the Municipal Archives, have a field for Father, Father's Place of Birth, Mother (with maiden name), and Mother's Place of Birth. Similarly, old ecclesiastic records from the villages around Kaiserslautern in southern Germany often describe the fathers of both groom and bride, the fathers' residences, and occupations. Less often in the oldest records, the mother is named. However, using either record, one would certainly establish a solid footing for looking into the previous generation. However, a single record, such as a birth, is not enough if further records are available. If one readily finds the civil birth record, it can serve as a guide for the location of the same person's ecclesiastic baptismal, christening, or circumcision records, which may confirm, conflict, or expand upon the information in the civil record. Further research should be conducted upon your subject, however. Marriage and death certificates and records, both civil and church, land records, coroner's reports, voter rolls, census returns, and numerous other pieces can add to your understanding of a person's parents and their history. In many cases, you will find information about several different generations at the same time.

Discrete Mathematics/Recursion. In this section we will look at certain mathematical processes which deal with the fundamental property of recursion at its core. What is Recursion? Recursion, simply put, is the process of describing an action in terms of itself. This may seem a bit strange to understand, but once it "clicks" it can be an extremely powerful way of expressing certain ideas. Let's look at some examples to make things clearer. Exponents. When we calculate an exponent, say "x"3, we multiply "x" by itself three times. If we have "x"5, we multiply "x" by itself five times. However, if we want a recursive definition of exponents, we need to define the action of taking exponents in terms of itself. So we note that "x"4 for example, is the same as "x"3 × "x". But what is "x"3? "x"3 is the same as "x"2 × "x". We can continue in this fashion up to "x"0=1. What can we say in general then? Recursively, with the fact that We need the second fact because the definitions fail to make sense if we continue with negative exponents, and we would continue indefinitely! Recursive definitions. Reducing the problem into same problem by smaller inputs. for example a power n 2 power 4 the recursion(smaller inputs) of this function is = 2.2.2.2.1 for this we declare some recursive definitions a=2 n=4 f(0)=1 f(1)=2 f(2)=2 f(3)=2 f(4)=2 for this recursion we form a formula f(n)= a.f(n-1) by putting these smaller values we get the same answer. Recurrence relations. In mathematics, we can create recursive "functions", which depend on its previous values to create new ones. We often call these "recurrence relations". For example, we can have the function :"f"("x")=2"f"("x"-1), with "f"(1)=1 If we calculate some of "f"'s values, we get However, this sequence of numbers "should" look familiar to you! These values are the same as the function 2"x", with x = 0, 1, and so on. What we have done is found a "non-recursive" function with the same values as the "recursive" function. We call this "solving" also know as x'to sup with value 0 and so on. Linear recurrence relations. We will look especially at a certain kind of recurrence relation, known as "linear". Here is an example of a linear recurrence relation: Instead of writing "f"("x"), we often use the notation "a"n to represent "a"("n"), but these notations are completely interchangeable. Note that a linear recurrence relation should always have stopping cases, otherwise we would not be able to calculate "f"(2), for example, since what would "f"(1) be if we did not define it? These stopping cases when we talk about linear recurrence relations are known as "initial conditions". In general, a linear recurrence relation is in the form The number "j" is important, and it is known as the "order" of the linear recurrence relation. Note we always need at least "j" initial conditions for the recurrence relation to make sense. Recall in the previous section we saw that we can find a nonrecursive function (a "solution") that will take on the same values as the recurrence relation itself. Let's see how we can solve some linear recurrence relations - we can do so in a very systematic way, but we need to establish a few theorems first. Solving linear recurrence relations. Sum of solutions. This theorem says that: This is true, since if we rearrange the recurrence to have "a""n"-"Aa""n"-1-"Ba""n"-2=0 And we know that "f"("n") and "g"("n") are solutions, so we have, on substituting into the recurrence If we substitute the sum "f"("n")+"g"("n") into the recurrence, we obtain On expanding out, we have But using the two facts we established first, this is the same as So "f"("n")+"g"("n") is indeed a solution to the recurrence. General solution. The next theorem states that: <BR>Then γ"r""n" is a solution to the recurrence, where "r" is a solution of the quadratic equation which we call the "characteristic equation". <br>We guess (it doesn't matter why, accept it for now) that γ"r""n" may be a solution. We can prove that this is a solution IF (and only if) it solves the characteristic equation ;<br> We substitute γ"r""n" ("r" not zero) into the recurrence to get then factor out by γ"r""n"-2, the term farthest on the right and we know that "r" isn't zero, so "r""n"-2 can never be zero. So "r"2-"Ar"-"B" must be zero, and so γ"r""n", with "r" a solution of "r"2-"Ar"-"B"=0, will indeed be a solution of the linear recurrence. Please note that we can easily generalize this fact to higher order linear recurrence relations. <br> Where did this come from? Why does it work (beyond a rote proof)? Here's a more intuitive (but less mathematically rigorous) explanation. <br> Solving the "characteristic equation" finds a function that satisfies the linear recurrence relation, and conveniently doesn't require the summation of all "n" terms to find the "n"th one.<br> We want : a function F("n") such that F("n") = "A" * F("n"-1) + "B" * F("n"-2) <br> We solve : "x"2 = "A"* "x" + "B", and call the solution(s) "r". There can be more than one value of "r", like in the example below! <br> We get : a function F("n") = "r""n" that satisfies F("n") = "A" * F("n"-1) + "B" * F("n"-2)<br> Let's check: Does "r""n" = "A"*"r""n"-1 + "B"*"r""n"-2 ? Divide both sides by "r""n"-2 and you get "r"2 = "A"*"r" + "B", which must be true because "r" is a solution to "x"2 = "A"* "x" + "B" <br> <br> Why does γ*"r""n" also satisfy the recurrence relation? If F("n")="r""n" is a solution, that is, "r""n"-"A"*"r""n"-1-"B"*"r""n"-2=0, then certainly F("n")=γ"r""n" is a solution since γ"r""n"-"A"*γ"r""n"-1-"B"*γ"r""n"-2=γ("r""n"-"A"*"r""n"-1-"B"*"r""n"-2)=0. <br><br> Because we have a second order recurrence, the general solution is the sum of two solutions, corresponding to the two roots of the characteristic equation. Say these are r and s. The general solution is C(rn)+D(sn) where C,D are some constants. We find them using the two (there must be two so that we can find C and D) starting values of the relation. Substituting these into the general solution will give two equations which we can (hopefully) solve. Example. Let's work through an example to see how we can use the above theorems to solve linear recurrence relations. Examine the function "a"("n") given here The characteristic equation of this recurrence relation is i.e. ("r"-2)("r"+1)=0 which has roots 2, -1. So the general solution is C(2n)+D(-1)n. To find C and D for this specific case, we need two starting values, let's say "a"("1") = 0 and "a"("2") = 2. These give a system of two equations<br> 0 = C(21)+D(-1)1 <br> 2 = C(22)+D(-1)2 <br> Solving these two equations yields: C = 1/3 , D = 2/3, so the solution is 1/3*(2n)+2/3*(-1)n.

Lucid Dreaming/Reality Checks/Breathing. Presentation. With the breathing reality check, you check if you can breathe underwater or with your fingers tightly sealing your nose. Always remember to concentrate on the act. When you seal your nose, don't release the air pressure when you're done with the test. As well as doing this regularly, you could also do it every time you go swimming. That being said, if you feel at all uncomfortable, unplug your nose! You don't want to risk suffocating yourself. NOTE: I have had personal experience with the breathing technique. I have used it numerous times. Only until recently it has worked perfectly fine for inducing lucid dreams; however, within the last two weeks, every time I try to plug my nose and breathe in, it doesn't work even in the dream world! It may be because I do the test so often that my expectation of the result carries into the dream world, therefore giving me the result I expect no matter if I'm dreaming or not. But, I do not see why this would happen since I constantly question the reality of the world around me hoping and expecting to be in a dream. My advice is to have a variety of techniques down in your mind and test two or three of them. Sometimes, my breathing AND hand checks don't work any more! I have found that text and digital clocks are the only solid way to know for sure since I seem to have exhausted the ability to use the techniques relating to my body.

Lucid Dreaming/Reality Checks/Jumping. Presentation. Also called the flying reality check; with the jumping reality check, you jump up and see if you float back down. Also try these techniques: