Citizendia
Your Ad Here

For other uses, see Code (disambiguation).

In communications, a code is a rule for converting a piece of information (for example, a letter, word, or phrase) into another form or representation, not necessarily of the same type. Communication is the process of conveying information from a sender to a receiver with the use of a medium in which the communicated information is understood the same way In Mathematics, an operator is a function which operates on (or modifies another function Information as a concept has a diversity of meanings from everyday usage to technical settings A letter is an element in an Alphabetic system of writing such as the Greek alphabet and its descendants A word is a unit of Language that carries meaning and consists of one or more Morphemes which are linked more or less tightly together and has a Phonetic In Grammar, a phrase is a group of Words that functions as a single unit in the Syntax of a sentence. In communications and information processing, encoding is the process by which information from a source is converted into symbols to be communicated. Information processing is the change (processing of Information in any manner detectable by an observer. A source or sender is one of the basic concepts of Communication and Information processing. Decoding is the reverse process, converting these code symbols back into information understandable by a receiver.

One reason for coding is to enable communication in places where ordinary spoken or written language is difficult or impossible. For example, a cable code replaces words (e. g. , ship or invoice) into shorter words, allowing the same information to be sent with fewer characters, more quickly, and most important, less expensively. For other uses see Character. In Computer and machine-based Telecommunications terminology a character is a unit of Another example is the use of semaphore, where the configuration of flags held by a signaller or the arms of a semaphore tower encodes parts of the message, typically individual letters and numbers. Flag semaphore is a system for conveying information at a distance by means of visual signals with hand-held flags rods disks paddles or occasionally bare or gloved hands A semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, or Napoleonic semaphore is a system Another person standing a great distance away can interpret the flags and reproduce the words sent.

In the history of cryptography, codes were once common for ensuring the confidentiality of communications, although ciphers are now used instead. The history of Cryptography begins thousands of years ago Until recent decades it has been the story of what might be called classic cryptography — that is of In Cryptography, a cipher (or cypher) is an Algorithm for performing Encryption and Decryption &mdash a series of well-defined steps See code (cryptography). In Cryptography, a code is a method used to transform a Message into an obscured form preventing those who do not possess special information or key

Contents

Codes in communication used for brevity

Code can be used for brevity. When telegraph messages were the state of the art in rapid long distance communication, elaborate commercial codes which encoded complete phrases into single words (commonly five-letter groups) were developed, so that telegraphers became conversant with such "words" as BYOXO ("Are you trying to weasel out of our deal?"), LIOUY ("Why do you not answer my question?"), or AYYLU ("Not clearly coded, repeat more clearly. "). Code words were chosen for various reasons: length, pronounceability, etc. In Telecommunication, a code word is an element of a Code. Each code word is a Sequence of symbols assembled in accordance with the specific rules of Length is the long Dimension of any object The length of a thing is the distance between its ends its linear extent as measured from end to end Meanings were chosen to fit perceived needs: commercial negotiations, military terms for military codes, diplomatic terms for diplomatic codes, any and all of the preceding for espionage codes. Codebooks and codebook publishers proliferated, including one run as a front for the American Black Chamber run by Herbert Yardley between WWI and WWII. The Black Chamber, otherwise known as MI-8 or Cipher Bureau, was America 's first peacetime Cryptanalytic organization and a forerunner Herbert Osborne Yardley ( 13 April 1889 - 7 August 1958) was an American Cryptologist best known for his book The American Black The purpose of most of these codes was to save on cable costs. The use of data coding for data compression predates the computer era; an early example is the telegraph Morse code where more frequently-used characters have shorter representations. Morse code is a Character encoding for transmitting telegraphic information using standardized sequences of short and long elements to represent the letters numerals Techniques such as Huffman coding are now used by computer-based algorithms to compress large data files into a more compact form for storage or transmission. History In 1951 David A Huffman and his MIT information theory classmates were given In Mathematics, Computing, Linguistics and related subjects an algorithm is a sequence of finite instructions often used for Calculation

An example: the ASCII code

Probably the most widely known data communications code (aka character representation) in use today is ASCII. American Standard Code for Information Interchange ( ASCII) In one or another (somewhat compatible) version, it is used by nearly all personal computers, terminals, printers, and other communication equipment. A computer is a Machine that manipulates data according to a list of instructions. A computer terminal is an electronic or electromechanical hardware device that is used for entering data into and displaying data from a Computer or a Computing It represents 128 characters with seven-bit binary numbers—that is, as a string of seven 1s and 0s. For other uses see Character. In Computer and machine-based Telecommunications terminology a character is a unit of The binary numeral system, or base-2 number system, is a Numeral system that represents numeric values using two symbols usually 0 and 1. In ASCII a lowercase "a" is always 1100001, an uppercase "A" always 1000001, and so on. Successors to ASCII have included 8-bit characters (for letters of European languages and such things as card suit symbols), and in fullest flowering have included characters from essentially all of the world's writing systems (see Unicode and UTF-8). In Computing, Unicode is an Industry standard allowing Computers to consistently represent and manipulate text expressed in most of the world's UTF-8 (8- Bit UCS / Unicode Transformation Format) is a variable-length Character encoding for Unicode.

Codes to detect or correct errors

Codes may also be used to represent data in a way more resistant to errors in transmission or storage. Such a "code" is called an error-correcting code, and works by including carefully crafted redundancy with the stored (or transmitted) data. In Mathematics, Computer science, Telecommunication, and Information theory, error detection and correction has great practical importance in Examples include Hamming codes, Reed–Solomon, Reed–Muller, Bose–Chaudhuri–Hochquenghem, Turbo, Golay, Goppa, low-density parity-check codes, and space–time codes. In Telecommunication, a Hamming code is a linear Error-correcting code named after its inventor Richard Hamming. Reed-Solomon error correction is an Error-correcting code that works by Oversampling a Polynomial constructed from the data Reed-Muller codes are a family of linear Error-correcting codes used in communications In Electrical engineering and Digital communications, turbo codes (originally in French Turbocodes) are a class of high-performance error correction Golay code may refer to Binary Golay code Ternary Golay code SpecialShortpages In Mathematics, an algebraic geometric code (AG-code, otherwise known as a Goppa code, is a general type of Linear code constructed by using an Algebraic In Information theory, a low-density parity-check code (LDPC code is an Error correcting code, a method of transmitting a message over a noisy transmission A space&ndashtime code (STC is a method employed to improve the reliability of data transmission in wireless communication systems using multiple transmit antennas Error detecting codes can be optimised to detect burst errors, or random errors.

Codes and acronyms

Acronyms and abbreviations can be considered codes, and in a sense all languages and writing systems are codes for human thought. Acronyms, initialisms, and alphabetisms are Abbreviations that are formed using the initial components in a phrase or name A language is a dynamic set of visual auditory or tactile Symbols of Communication and the elements used to manipulate them Occasionally a code word achieves an independent existence (and meaning) while the original equivalent phrase is forgotten or at least no longer has the precise meaning attributed to the code word. For example, '30' was widely used in journalism to mean "end of story", and it is sometimes used in other contexts to signify "the end". Journalism is the profession of writing or communicating formally employed by publications and broadcasters for the benefit of a particular Community of people

Coupon Codes

In marketing, coupon codes can be used for a financial discount or rebate when purchasing a product from an internet retailer. In popular usage "marketing" is the promotion of products especially Advertising and Branding However in professional usage the term has a wider meaning of In Marketing a coupon is a ticket or document that can be exchanged for a financial discount or rebate when purchasing a product. Coupon codes are also referred to as "promotional codes," "promotion codes," "discount codes," "key codes," "promo codes," "shopping codes," "voucher codes" or "source codes. "[1]

Gödel code

In mathematics, a Gödel code was the basis for the proof of Gödel's incompleteness theorem. Mathematics is the body of Knowledge and Academic discipline that studies such concepts as Quantity, Structure, Space and In Mathematical logic, a Gödel numbering is a function that assigns to each symbol and Well-formed formula of some Formal language a unique Kurt Gödel (kʊɐ̯t ˈgøːdl̩ (April 28 1906 – January 14 1978 was an Austrian American Logician, Mathematician and Philosopher In Mathematical logic, Gödel's incompleteness theorems, proved by Kurt Gödel in 1931 are two Theorems stating inherent limitations of all but the most Here, the idea was to map mathematical notation to a natural number (a Gödel number). See also Table of mathematical symbols Mathematical notation is used in Mathematics, and throughout the Physical sciences, Engineering In Mathematics, a natural number (also called counting number) can mean either an element of the set (the positive Integers or an In Mathematical logic, a Gödel numbering is a function that assigns to each symbol and Well-formed formula of some Formal language a unique

References

  1. ^ The History of Coupons


See also

Asemic writing is a wordless open Semantic form of Writing. The word asemic means "having no specific semantic content"

Dictionary

code

-noun

  1. A very short abbreviation, often with little correlation to the item it represents
  2. A body of law, sanctioned by legislation, in which the rules of law to be specifically applied by the courts are set forth in systematic form; a compilation of laws by public authority; a digest.
  3. Any system of priciples, rules or regulations relating to one subject; as, the medical code, a system of rules for the regulation of the professional conduct of physicians; the naval code, a system of rules for making communications at sea means of signals.
  4. A set of rules for converting information into another form or representation.
  5. (cryptography) A cryptographic system using a codebook that converts words or phrases into codewords.
  6. Source code.
  7. A computer program, or more generally, any defined computing process.

-verb

  1. (computing) To write software programs.
  2. To categorise by assigning identifiers from a schedule, for example CPT coding for medical insurance purposes.
  3. (cryptography) To encode.
© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic