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Morse code, a famous type of code

A code is a rule for converting a piece of information (for example, a letter, word, phrase, or gesture) into another form or representation (one sign into another sign), not necessarily of the same type.

In communications and information processing, encoding is the process by which information from a source is converted into symbols to be communicated. 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, 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. Another person standing a great distance away can interpret the flags and reproduce the words sent.

Theory[link]

It has been suggested that this article or section be merged into Coding theory . (Discuss) Proposed since July 2010.

In information theory and computer science, a code is usually considered as an algorithm which uniquely represents symbols from some source alphabet, by encoded strings, which may be in some other target alphabet. An extension of the code for representing sequences of symbols over the source alphabet is obtained by concatenating the encoded strings.

Before giving a mathematically precise definition, we give a brief example. The mapping

Failed to parse (Missing texvc executable; please see math/README to configure.): C = \{\, a\mapsto 0, b\mapsto 01, c\mapsto 011\,\}

is a code, whose source alphabet is the set Failed to parse (Missing texvc executable; please see math/README to configure.): \{a,b,c\}

and whose target alphabet is the set Failed to parse (Missing texvc executable; please see math/README to configure.): \{0,1\}

. Using the extension of the code, the encoded string 0011001011 can be grouped into codewords as 0 – 011 – 0 – 01 – 011, and these in turn can be decoded to the sequence of source symbols acabc.

Using terms from formal language theory, the precise mathematical definition of this concept is as follows: Let S and T be two finite sets, called the source and target alphabets, respectively. A code Failed to parse (Missing texvc executable; please see math/README to configure.): C:\, S \to T^*

is a total function mapping each symbol from S to a sequence of symbols over T, and the extension of M to a homomorphism of Failed to parse (Missing texvc executable; please see math/README to configure.): S^*
into Failed to parse (Missing texvc executable; please see math/README to configure.): T^*

, which naturally maps each sequence of source symbols to a sequence of target symbols, is referred to as its extension.

Variable-length codes[link]

In this section we consider codes, which encode each source (clear text) character by a code word from some dictionary, and concatenation of such code words give us an encoded string. Variable-length codes are especially useful when clear text characters have different probabilities; see also entropy encoding.

A prefix code is a code with the "prefix property": there is no valid code word in the system that is a prefix (start) of any other valid code word in the set. Huffman coding is the most known algorithm for deriving prefix codes, so prefix codes are also widely referred to as "Huffman codes", even when the code was not produced by a Huffman algorithm. Other examples of prefix codes are country calling codes, the country and publisher parts of ISBNs, and the Secondary Synchronization Codes used in the UMTS W-CDMA 3G Wireless Standard.

Kraft's inequality characterizes the sets of code word lengths that are possible in a prefix code. Virtually, any uniquely decodable one-to-many code, not necessary a prefix one, must satisfy Kraft's inequality.

Block codes[link]

This section requires expansion.

Error correcting codes[link]

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. Examples include Hamming codes, Reed–Solomon, Reed–Muller, Walsh–Hadamard, Bose–Chaudhuri–Hochquenghem, Turbo, Golay, Goppa, low-density parity-check codes, and space–time codes. Error detecting codes can be optimised to detect burst errors, or random errors.

Examples[link]

Codes in communication used for brevity[link]

A cable code replaces words (e.g., ship or invoice) with shorter words, allowing the same information to be sent with fewer characters, more quickly, and most important, less expensively.

Codes can be used for brevity. When telegraph messages were the state of the art in rapid long distance communication, elaborate systems of commercial codes that 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?"), BMULD ("You're a skunk!"), or AYYLU ("Not clearly coded, repeat more clearly."). Code words were chosen for various reasons: length, pronounceability, etc. 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 the First and Second World Wars. 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. 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.

Character encodings[link]

Probably the most widely known data communications code so far (aka character representation) in use today is ASCII. In one or another (somewhat compatible) version, it is used by nearly all personal computers, terminals, printers, and other communication equipment. It represents 128 characters with seven-bit binary numbers—that is, as a string of seven 1s and 0s. In ASCII a lowercase "a" is always 1100001, an uppercase "A" always 1000001, and so on. There are many other encodings, which represent each character by a byte (usually referred as code pages), integer code point (Unicode) or a byte sequence (UTF-8).

Genetic code[link]

Biological organisms contain genetic material that is used to control their function and development. This is DNA which contains units named genes that can produce proteins through a code (genetic code) in which a series of triplets {codons} of four possible nucleotides are translated into one of twenty possible amino acids. A sequence of codons results in a corresponding sequence of amino acids that form a protein.

Gödel code[link]

In mathematics, a Gödel code was the basis for the proof of Gödel's incompleteness theorem. Here, the idea was to map mathematical notation to a natural number (using a Gödel numbering).

Other[link]

There are codes using colors, like traffic lights, the color code employed to mark the nominal value of the electrical resistors or that of the trashcans devoted to specific types of garbage (paper, glass, biological, etc.)

In marketing, coupon codes can be used for a financial discount or rebate when purchasing a product from an internet retailer.

In military environments, specific sounds with the cornet are used for different uses: to mark some moments of the day, to command the infantry in the battlefield, etc.

Communication systems for sensory impairments, as the sign language for deaf people and braille for blind people, are based in movement or tactile codes.

Musical scores are the most common way to encode music.

Specific games, as chess, have their own code systems to record the matches (chess notation).

Cryptography[link]

In the history of cryptography, codes were once common for ensuring the confidentiality of communications, although ciphers are now used instead. See code (cryptography).

Secret codes intended to obscure the real messages, ranging from serious (mainly espionage in military, diplomatic, business, etc.) to trivial (romance, games) can be any kind of imaginative encoding: flowers, game cards, clothes, fans, hats, melodies, birds, etc., in which the sole requisite is the previous agreement of the meaning by both the sender and the receiver.

Other examples[link]

Other examples of encoding include:

• Encoding (in cognition) is a basic perceptual process of interpreting incoming stimuli; technically speaking, it is a complex, multi-stage process of converting relatively objective sensory input (e.g., light, sound) into subjectively meaningful experience.
• A content format is a specific encoding format for converting a specific type of data to information.
• Text encoding uses a markup language to tag the structure and other features of a text to facilitate processing by computers. (See also Text Encoding Initiative.)
• Semantics encoding of formal language A in formal language B is a method of representing all terms (e.g. programs or descriptions) of language A using language B.
• Electronic encoding transforms a signal into a code optimized for transmission or storage, generally done with a codec.
• Neural encoding is the way in which information is represented in neurons.
• Memory encoding is the process of converting sensations into memories.
• Television encoding: NTSC, PAL and SECAM

Other examples of decoding include:

• Digital-to-analog converter, the use of analog circuit for decoding operations
• Decoding (Computer Science)
• Decoding methods, methods in communication theory for decoding codewords sent over a noisy channel
• Digital signal processing, the study of signals in a digital representation and the processing methods of these signals
• Word decoding, the use of phonics to decipher print patterns and translate them into the sounds of language

Codes and acronyms[link]

Acronyms and abbreviations can be considered codes, and in a sense all languages and writing systems are codes for human thought.

International Air Transport Association airport codes are three-letter codes used to designate airports and used for bag tags. Station codes are similary used on railways, but are usually national, so the same code can be used for different stations if they are in different countries.

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".

References[link]

See also[link]

Wikimedia Commons has media related to: Codes

• Asemic writing
• Equipment codes
• Semiotics
• Quantum error correction

Wiz Khalifa
Wiz Khalifa in Brooklyn, New York in August 2009.
Background information
Birth name	Cameron Jibril Thomaz
Born	(1987-09-08) September 8, 1987 (age 24) Minot, North Dakota, United States
Genres	Hip hop
Occupations	Rapper, singer, songwriter, actor
Years active	2005–present
Labels	Rostrum, Taylor Gang, Warner Bros., Atlantic
Associated acts	Snoop Dogg, Rick Ross, Curren$y, Big Sean, Chevy Woods, Mac Miller, Juicy J, Tinie Tempah, Yelawolf, Maroon 5, Big K.R.I.T.
Website	wizkhalifa.com

Cameron Jibril Thomaz (born September 8, 1987), better known by the stage name Wiz Khalifa, is an American rapper. He released his debut album, Show and Prove, in 2006, and signed to Warner Bros. Records in 2007. His Eurodance-influenced single, "Say Yeah", received urban radio airplay, charting on the Rhythmic Top 40 and Hot Rap Tracks charts in 2008.^[1] Khalifa parted with Warner Bros. and released his second album, Deal or No Deal, in November 2009. He released the mixtape Kush and Orange Juice as a free download in April 2010; he then signed with Atlantic Records.^[2] He is also well known for his debut single for Atlantic, "Black and Yellow", which peaked at number 1 on the Billboard Hot 100. His debut album for the label, Rolling Papers, was released on March 29, 2011.^[3]

Early life[link]

Khalifa was born on September 8, 1987 to a mother and a father serving in the military.^[1][4] His parents divorced when Khalifa was about three years old. His parents' military service caused him to move regularly: Khalifa lived in Germany, the United Kingdom, and Japan before settling in Pittsburgh where he attended Taylor Allderdice High School.^[1][4]

His stage name is derived from khalifa, an Arabic word meaning "successor", and wisdom, which was shortened to Wiz when Khalifa was a young boy .^[5] Khalifa stated to spinner.com that the name also came from being called "young Wiz 'cause I was good at everything I did, and my granddad is Muslim, so he gave me that name; he felt like that's what I was doing with my music." He got his stage name tattooed on his 17th birthday.^[6][7] He includes Jimi Hendrix, Camp Lo, The Notorious B.I.G. and Bone Thugs-n-Harmony among his influences.^[8]

Career[link]

[edit] 2005–08: Early mixtapes and Show and Prove

Rostrum Records president Benjy Grinberg first heard about Wiz Khalifa in 2004 when the rapper's contribution to a mixtape of various new Pittsburgh artists attracted his interest.^[9] When Grinberg finally met the 16-year-old artist, he immediately decided he wanted to work with him, later telling HitQuarters: "Even though he wasn’t all the way developed you could just tell that he was a diamond in the rough, and that with some polishing, guidance and backing he could become something special."^[9] Khalifa signed to the label shortly after and began a seven year period of artist development.^[9]

Khalifa released his first mixtape, Prince of the City: Welcome to Pistolvania, in 2005. The mixtape paved the way for his first full length album entitled Show and Prove in 2006. Khalifa was declared an "artist to watch" that year in Rolling Stone magazine.^[10][11]

In 2007, Khalifa signed to Warner Bros. Records and released two mixtapes through Rostrum Records: Grow Season, hosted by DJ Green Lantern and released on July 4, 2007, and Prince of the City 2, released on November 20, 2007. His debut Warner Bros. single "Say Yeah" reached number 25 on the Billboard Rhythmic Top 40 music chart and number 20 on Billboard's Hot Rap Tracks. The song samples "Better Off Alone" by Alice Deejay. Khalifa's vocals from "Say Yeah" appear near the end of Pittsburgh mash up producer Girl Talk's 2008 album, Feed the Animals, over music from Underworld's "Born Slippy", Usher's "Love in This Club", and the Cure's "In Between Days".^[12] Khalifa appeared with The Game, David Banner and Play-n-Skillz at U92's Summer Jam at the USANA Amphitheatre in West Valley City, Utah on August 2, 2008.^[13] Khalifa released the mixtapes Star Power in September 2008, and Flight School in April 2009 on Rostrum Records.

Khalifa parted ways with Warner Bros. Records in July 2009 after numerous delays in releasing his planned debut album for the label, First Flight. Khalifa stated to the Pittsburgh Post-Gazette that, "I learned a lot during my time there and matured as an artist during the process. I'm happy to be moving on with all of my material and having the chance to be in control of my next moves".^[14] Khalifa appeared with Girl Talk, Modey Lemon, Donora, Grand Buffet, and Don Caballero at the Amphitheatre at Station Square in Pittsburgh on July 31, 2009, where he announced that his relationship with Warner Bros. was over.^[15]

Wiz Khalifa performing at Columbia University in New York City in April 2010.

[edit] 2009–10: Deal or No Deal

Continuing his association with Rostrum Records, Khalifa released the single "Teach U to Fly", and the mixtape How Fly, a collaboration with New Orleans rapper Curren$y, on August 9, 2009.^[14] Khalifa introduced a more melodic style on the mixtape, alternating between singing and rapping. He opened for Wu-Tang Clan member U-God at the 2009 CMJ Music Marathon in New York City.^[16] Khalifa released the mixtape Burn After Rolling on November 2, 2009, where he raps over familiar beats from other artists, including the songs "If I Were A Boy" and "Diva" by Beyoncé, "Walking on a Dream" by Empire of the Sun, "Luchini AKA This Is It" by Camp Lo, and "Best I Ever Had" by Drake.^[17] Khalifa released his second album, Deal or No Deal, on November 24, 2009.^[18]

Khalifa performed at Emo's in Austin, Texas in March 2010 as part of the 2010 South by Southwest Music Festival.^[19] He appeared on the cover of XXL magazine that same month, for the magazine's annual list of Top 10 Freshman, which included Donnis, J. Cole, Pill, Freddie Gibbs, and Fashawn. Wiz Khalifa was named 2010 "Rookie Of The Year" by "The Source", with alongside Rick Ross, "The Man Of The Year".^[20] He toured with rapper Yelawolf on a 20-date tour, the Deal Or No Deal Tour.^[21] Khalifa released the free mixtape Kush and Orange Juice for download on April 14, 2010. Due to Khalifa's devoted grassroots fan base, the mixtape became the No. 1 trending topic on Twitter with the hash tag #kushandorangejuice, and "Kush and Orange Juice download” ranked No. 1 on Google’s hot search trends.^[22]

2010: Signing with Atlantic Records[link]

Citing music industry insiders, New York magazine wrote that Khalifa signed with Atlantic Records in April 2010, although the rapper did not confirm it.^[23] He stated to AllHipHop in June 2010 that he was working on a new album, but was weighing his options and had not yet decided on a label to distribute it.^[24] Khalifa confirmed to MTV on July 30 that he was signing an Atlantic Records deal.^[25]

Wiz Khalifa on stage in Boston in August 2010.

Khalifa was featured in a remix and video for the 2010 Rick Ross single "Super High", alongside Curren$y.^[26] He guested on the mixtape Grey Goose, Head Phones, and Thirsty Women by St. Louis rapper M.C,^[27] and was featured on the track "The Breeze (Cool)" on rapper Wale's August 2010 mixtape More About Nothing.^[28] Khalifa was named MTV's Hottest Breakthrough MC of 2010, winning with nearly 70,000 votes, and beating out finalists Nicki Minaj, J. Cole, Travis Porter, and Diggy Simmons.^[29]

Khalifa appeared at the Soundset 2010 festival in May 2010 in Minneapolis, Minnesota, alongside Method Man & Redman, Del the Funky Homosapien and Hieroglyphics, Atmosphere, Murs, Cage, and others.^[30] He also performed at the 2010 Rock the Bells festival, along with hip hop veterans Wu-Tang Clan, Snoop Dogg, Lauryn Hill, A Tribe Called Quest, Rakim, KRS-One, Jedi Mind Tricks and Slick Rick.^[31] Khalifa declined an invitation to tour with rapper Drake and launched his own "Waken Baken" tour, a 50-city national tour with rapper Yelawolf. The tour, scheduled to last from September to November 2010, has, as of October, sold out every venue.^[8] On November 2010, during his "Waken Baken" tour at East Carolina University, Wiz Khalifa was arrested for possession and trafficking of marijuana. He was then released the next morning after a $300K bail, and resumed his tour. Khalifa performed in a cypher during the 2010 BET Hip-Hop Awards. He recited his verse from the song, "The Check Point", from his mixtape with Curren$y, How Fly.^[32]

[edit] 2010–11: Mainstream success and Rolling Papers

Wiz Khalifa at SXSW in 2010

Khalifa released "Black and Yellow", his first single for Rostrum/Atlantic, produced by Stargate, which has received radio airplay.^[8][33] The single was peaked at number 1 on the Billboard Hot 100; the title of the song refers to the colours of the City of Pittsburgh.^[34] Khalifa released his debut album with Atlantic Records in 2011.^[35] He appeared with Curren$y on the track "Scaling the Building" on producer Ski Beatz' 2010 album, 24 Hour Karate School.^[36] Khalifa's record label is Taylor Gang Records, named after his love of Chuck Taylor All-Stars^[8], and Taylor Allderdice High School in Pittsburgh, PA, where he graduated from.

On March 29, 2011, Khalifa released his first studio album, Rolling Papers. The album debuted at number two on the US Billboard 200 chart, with first-week sales of 197,000 copies in the United States.^[37] Shortly afterward on March 31, 2011 Wiz Khalifa performed at Emory University in Atlanta, Georgia as part of the school's annual Dooley's Weekend.^[38] On June 26, 2011, Khalifa was nominated and won Best New Artist at the BET Awards of 2011.^[39] Khalifa collaborated with British rapper Tinie Tempah whom Tinie announced in an interview with Rolling Stone that his next single is to be called "Till I'm Gone" and would feature Wiz Khalifa and is to be produced by Stargate.^[40][41] The single and the video song were released at the end of June 2011.^[42]

Personal life[link]

Thomaz proposed to model Amber Rose on March 1, 2012 showing off the ring on Twitter.^[43] He is personal friends with Snoop Dogg, Juicy J, Yelawolf, and fellow Pittsburgh rapper Mac Miller.^[44]

In March 2012, Thomaz purchased a 2.8 private wooded acres with a 3,891-square-foot residence in Canonsburg, Pennsylvania, a small community southwest of Pittsburgh. The residence includes 5-bedroom, 4-bath eco-friendly, Brazilian Koa floors, stainless steel appliances, a separate guest house, and a lavish master suite with high ceilings.^[45] He currently resides there with his fiancée Amber Rose.

Discography[link]

Studio albums

• 2006: Show and Prove
• 2009: Deal or No Deal
• 2011: Rolling Papers
• 2012: O.N.I.F.C. ^[11][46][47]

Collaborative albums

• 2011: Mac & Devin Go to High School (with Snoop Dogg)
• 2012: TBA (with Taylor Gang)

Awards and nominations[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Wiz Khalifa

• Official website
• Wiz Khalifa on Facebook
• Wiz Khalifa on Myspace
• Wiz Khalifa on Twitter
• Wiz Khalifa at MTV
• Non-commercial Wiz Khalifa mixtapes

Juicy J
Juicy J (front) performing with Three 6 Mafia bandmate DJ Paul.
Background information
Birth name	Jordan Houston
Origin	Memphis, Tennessee
Genres	Hip hop, dirty south, gangsta rap, crunk, horrorcore
Occupations	Rapper, Record producer, Actor, Screenwriter, Songwriter
Years active	1990–present
Labels	Taylor Gang, Columbia, Hypnotize Minds
Associated acts	Three 6 Mafia, DJ Paul, Project Pat, Young Buck, Wiz Khalifa, Lex Luger
Website	juicyjofthree6mafia.com

Jordan Houston, better known by his stage name Juicy J (born April 5, 1977) is an Academy Award-winning American rapper and record producer from Memphis, Tennessee and is the co-founder and a member of the duo Three 6 Mafia (formerly known as Triple Six Mafia). He is also the younger brother of fellow member, Project Pat.^[1] His second solo album, Hustle Till I Die,^[2] was released June 16, 2009. He won an Academy Award for Best Original Song for "It's Hard out Here for a Pimp". In December 2011 Juicy J confirmed rumors that he was the newest member of Wiz Khalifa's "Taylor Gang." He is featured with other members of Taylor Gang on the cover of Source Magazine's May 2012 issue.

Juicy J is most notable for his crunk style of rapping, highlighted by his patented "heavy-breathing" and "stomping" background sound effects. Juicy J's production style is characterized by fast-rolling high hats, sharp snares, and deep cinematic bass. He also incorporates samples from classic soul artists such as Willie Hutch, David Ruffin, and Isaac Hayes.

Guest appearances[link]

Discography[link]

Music Videos[link]

See also[link]

• Three 6 Mafia
• Hypnotize Minds
• Wiz Khalifa

References[link]

External links[link]

• Three 6 Mafia Official Website
• Juicy J on Myspace
• Jordan Houston at the Internet Movie Database

LoLa Monroe
Monroe performing at Yardfest
Background information
Also known as	Angel, Lola Luv
Born	(1986-10-23) October 23, 1986 (age 25) Addis Ababa, Ethiopia
Origin	Washington D.C., U.S.
Genres	Hip hop
Occupations	Rapper, model, actress
Years active	2006–present
Labels	Blue Rose, The Commission, 1017 Brick Squad, Taylor Gang
Associated acts	Wiz Khalifa, Lil Boosie, Trina, Juicy J, Los, J-Doe
Website	theeofficiallolamonroe.com

Lola Monroe (born October 24, 1986) is an American rapper, model and actress.^[1]

Early life[link]

Monroe was born in Addis Ababa, the capital of Ethiopia. She is of mixed Trinidadian and Ethiopian background.^[2]

She was raised in Garfield Terrace, Washington D.C.. Monroe began writing poems and songs at the age of 12, using music as an escape and a form of expression.^[3]

Career[link]

She made her acting debut in the Wendy Wiliams biopic "Queen of Media" and later acted in "Crazy like a Fox." She began modeling and appearing in music videos for various artists. She later became LoLa Monroe in 2007; "Monroe" is a reference to the actress, model, film producer and singer Marilyn Monroe.^[4]

In June 2009, she released her first mixtape, Boss Bitch's World. In October the same year, she released her second mixtape, The Art of Motivation. That year, she also released her collaboration mixtape, Untouchables.^[5]

In September 2010, Monroe released her first single, Overtime, from her mixtape. A video was recorded and released on 106 & Park for this single. In December 2010 LoLa released her fourth mixtape, Batteries Not Included.^[6]

She was nominated for Best Female Hip Hop Artist at the BET Awards of 2011.^[7]

Artists who have influenced her musical style include Jay-Z, Tupac Shakur, MC Lyte, Salt-n-Pepa, Trina, and Lauryn Hill.^[3]

Discography[link]

Collaborative albums

• TBA (with Taylor Gang) (2012)

Mixtapes

• Boss Bitch's World (2009)
• The Lola Monroe Chronicles: The Art of Motivation (2009)
• Untouchables (with Lil' Boosie) (2009)
• Batteries Not Included (2010)
• Crown Ain't Safe (2012)

Singles

Filmography[link]

References[link]

External links[link]

• LoLa Monroe at the Internet Movie Database