Most people expected that the same thing would happen when dirt is added to the paper before the message was written—the more dirt, the less information can be reliably sent.
In 1983, Costa showed the surprising result that we can send just as much information on such a dirty piece of paper as we can when writing on a clean sheet of paper, and gave a way to get that capacity.
A dirty paper code is a way for the writer to adapt his message to the dirt already on the paper.
The writer and the reader agree ahead of time on which dirty paper code they will use for the messages.
People have thought up several dirty paper codes, including Costa precoding (1983), Tomlinson-Harashima precoding (1971) and the vector perturbation technique of Hochwald et al. (2005).
A similar problem called "writing on dirty tape (WDT)" is more complicated.
As of 2005, the capacity computation problem and the capacity-achieving
problem for writing on dirty tape are unsolved
"Writing on wet paper" is a related problem in steganography
Many wireless networks use dirty paper coding, especially MIMO systems.
In a wireless network, often a transmitter has many different messages, and each one needs to be sent to a different person.
The sum-rate capacity of a system that transmits all the messages at the same time—and uses dirty-paper codes to reduce the interference between messages—can be many times the sum-rate capacity of a similar system that only sends one message at a time (TDMA).
Any one receiver is only concerned with the messages for that receiver—all the other messages the transmitter is simultaneously sending to everyone else are—to that receiver—irrelevant noise that only interferes with the desired message.
The "dirty paper" story can be seen as a parable for wireless communication.
Recently, there has been interest in DPC as a possible solution to optimize the efficiency of wireless networks, in particular multiuser MIMO networks and into an interference aware coding technique for dynamic wireless networks.
People doing "informed digital watermarking" use dirty paper codes, using this analogy:
Klamath River
The Klamath River flows through Oregon and northern California in the United States. It is long. The river empties into the Pacific Ocean.
The Klamath is the second largest river in California after the Sacramento River.
Bandai
Bandai Co., Ltd. is a Japanese company that makes toys and video games. It is the third largest toy maker in the world.
Battle, East Sussex
Battle is a town in East Sussex, England, UK. It is known as this because it was the place where the Battle of Hastings was fought.
John Key
John Phillip Key (born 9 August 1961) was the 38th Prime Minister of New Zealand and was the leader of the New Zealand National Party.
John Key entered the New Zealand Parliament in 2002 representing the north-west Auckland area of Helensville as a National MP, a seat that he still holds. In 2006 he succeeded Don Brash as the National Party leader in 2006. Key led his party to victory in the November 2008 general election.
On 5 December 2016, Key resigned as prime minister and as party leader. Bill English soon replaced Key as prime minister and party leader.
Key was born in Auckland, New Zealand, to George Key and Ruth Key. His father, who was from the UK, died of a heart attack in 1967. Key and his two sisters were raised in a state house in Christchurch by his Jewish mother.
He attended Burnside High School, and earned a Bachelor of Commerce degree in accounting from the University of Canterbury in 1981. He has attended management studies courses at Harvard University, although he did not receive a degree from this institution.
Key met his wife Bronagh when they were both students at Burnside High School. They married in 1984. She is currently full-time mother of their two children, Stephie and Max.
In 1995, he joined Merrill Lynch as head of Asian foreign exchange in Singapore. That same year he was promoted to Merrill's global head of foreign exchange, based in London, where he may have earned around US$2.25 million a year including bonuses, which is about NZ$5 million at 2001 exchange rates. Some co-workers called him "the smiling assassin" for maintaining his usual cheerfulness while sacking dozens (some say hundreds) of staff after heavy losses from the 1998 Russian financial crisis. He was a member of the Foreign Exchange Committee of the New York Federal Reserve Bank from 1999 to 2001.
Key became Prime Minister following the general election on 8 November 2008 which ended the Labour-led government of nine years under Helen Clark. The National Party, promoting a policy of "change", won 45% of the party vote and 59 of the 122 seats in Parliament, a big margin over the Labour Party which won 43 seats.
Key was sworn in as Prime Minister on 19 November 2008 along with his new cabinet. His first international outing as Prime Minister was the 20th APEC meeting in Peru the following day.
Key announced he will step down from the role of Prime Minister and leader of the National Party effective 12 December 2016.
List of people from Dunedin
The New Zealand city of Dunedin is noted for producing a large number of famous people. Many of these are natives of the city; others travelled to Dunedin to be educated at the University of Otago.
Peter Warlock
Peter Warlock (born London, 30 October 1894; died London, 17 December 1930), was an English composer. “Peter Warlock” was not his real name. His real name was Philip Heseltine. He was also a music critic. When he wrote about music he used his real name, but when he composed music he used the pseudonym (borrowed name) "Peter Warlock", which is the name by which he is usually remembered today.
Philip Heseltine did not come from a musical family. When he was two years old his father died. His mother married again and went back to live in Wales, where she came from. Philip went to school at Eton College.
He was still a teenager when he was introduced to the composer Delius, who lived in France. They became good friends and Philip made piano arrangements of some of Delius’s music. Later he wrote a book about Delius. He studied in Germany for a time, and then at Oxford where he studied classics. He learned about music by teaching himself. He did not fight in World War I. He was a conscientious objector, but also, his health was not good enough for him to be in the army.
He spent most of his life in London, but he did visit Ireland for a year, and also spent three years with his mother in Wales, and four years in Kent where he lived with Ernest Moeran. Heseltine and Moeran often got drunk together. He became friends with the composer Bernard van Dieren whose music influenced him a lot. He also liked poetry from the time of Queen Elizabeth I.
He died in his apartment from gas poisoning. It is not certain whether it was suicide, but he did let his cat out before he turned on the gas.
His music, written under the name of Peter Warlock, often has links with his literary writings. Some of the best works he wrote are his songs, especially the song-cycle "The Curlew", which has lyrics from poems by W. B. Yeats. One of his most popular works is the "Capriol Suite" for string orchestra.
Warlock wrote many carols, such as "Adam Lay Ybounden", "Tyrley Tyrlow", and "Bethlehem Down".
Warlock was not influenced by folksong like many other English composers of the time. He liked many different styles, including Renaissance music and the music of Bartók whom he met.
Land mine