click links in text for more info
SUMMARY / RELATED TOPICS

Channel access method

In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminals connected to the same transmission medium to transmit over it and to share its capacity. Examples of shared physical media are wireless networks, bus networks, ring networks and point-to-point links operating in half-duplex mode. A channel access method is based on multiplexing, that allows several data streams or signals to share the same communication channel or transmission medium. In this context, multiplexing is provided by the physical layer. A channel access method may be a part of the multiple access protocol and control mechanism known as medium access control. Medium access control deals with issues such as addressing, assigning multiplex channels to different users and avoiding collisions. Media access control is a sub-layer in the data link layer of the OSI model and a component of the link layer of the TCP/IP model. Channel access schemes fall into the following categories.

The frequency-division multiple access channel-access scheme is the most standard analog system, based on the frequency-division multiplexing scheme, which provides different frequency bands to different data streams. In the FDMA case, the frequency bands are allocated to different devices. An example of FDMA systems were the first-generation 1G cell-phone systems, where each phone call was assigned to a specific uplink frequency channel, another downlink frequency channel; each message signal is modulated on a specific carrier frequency. A related technique is wavelength division multiple access, based on wavelength-division multiplexing, where different data streams get different colors in fiber-optical communications. In the WDMA case, different network nodes in a bus or hub network get a different color. An advanced form of FDMA is the orthogonal frequency-division multiple access scheme, for example, used in 4G cellular communication systems. In OFDMA, each node may use several sub-carriers, making it possible to provide different quality of service to different users.

The assignment of sub-carriers to users may be changed dynamically, based on the current radio channel conditions and traffic load. Single-carrier FDMA, a.k.a. linearly-precoded OFDMA, is based on single-carrier frequency-domain-equalization. The time-division multiple access channel access scheme is based on the time-division multiplexing scheme. TDMA provides different time slots to different transmitters in a cyclically repetitive frame structure. For example, node 1 may use time slot 1, node 2 time slot 2, etc. until the last transmitter when it starts over. An advanced form is dynamic TDMA, where an assignment of transmitters to time slots vary one each frame. Multi-frequency time-division multiple access combines frequency multiple access; as an example, 2G cellular systems are based on a combination of TDMA and FDMA. Each frequency channel is divided into eight time slots, of which seven are used for seven phone calls, one for signaling data. Statistical time division multiplexing multiple access is also based on time-domain multiplexing, but not in a cyclically repetitive frame structure.

Due to its random character, it can be categorized as statistical multiplexing methods and capable of dynamic bandwidth allocation. This requires a media access control protocol, i.e. a principle for the nodes to take turns on the channel and to avoid collisions. Common examples are CSMA/CD, used in Ethernet bus networks and hub networks, CSMA/CA, used in wireless networks such as IEEE 802.11. The code division multiple access scheme is based on spread spectrum, meaning that a wider radio channel bandwidth is used than the data rate of individual bit streams requires, several message signals are transferred over the same carrier frequency, utilizing different spreading codes. Per the Shannon–Hartley theorem, the wide bandwidth makes it possible to send with a signal-to-noise ratio of much less than 1, meaning that the transmission power can be reduced to a level below the level of the noise and co-channel interference from other message signals sharing the same frequency range. One form is direct-sequence CDMA, based on direct-sequence spread spectrum, used for example in 3G cell phone systems.

Each information bit is represented by a long code sequence of several pulses, called chips. The sequence is the spreading code, each message signal uses a different spreading code. Another form is frequency-hopping CDMA, based on frequency-hopping spread spectrum, where the channel frequency is changed according to a sequence that constitutes the spreading code; as an example, the Bluetooth communication system is based on a combination of frequency-hopping and either CSMA/CA statistical time division multiplexing communication or TDMA. All nodes belonging to the same user use the same frequency hopping sequence synchronously, meaning that they send on the same frequency channel, but CDMA/CA or TDMA is used to avoid collisions within the VPAN. Frequency-hopping is used by Bluetooth to reduce the cross-talk and collision probability between nodes in different VPANs. Other techniques include orthogonal frequency-division multiple access and multi-carrier code division multiple access. Space-division multiple access transmits different information in different physical areas.

Examples include simple cellular radio systems and more advanced cellular systems that use directional antennas

Racial democracy

Racial democracy is a term used by some to describe race relations in Brazil. The term denotes some scholars' belief that Brazil has escaped racial discrimination; those researchers contend that Brazilians do not view each other through the lens of race and do not harbor racial prejudice towards one another. Because of that, while social mobility of Brazilians may be constrained by many factors and class included, racial discrimination is considered irrelevant. Racial democracy was first advanced by Brazilian sociologist Gilberto Freyre in his work Casa-Grande & Senzala, published in 1933. Although Freyre never uses this term in the book, he did adopt it in publications, his theories paved the way for other scholars who would popularize the concept. Freyre argued that several factors, including close relations between masters and slaves prior to their legal emancipation in 1888 and the benign character of Portuguese imperialism prevented the emergence of strict racial categories. Freyre argued that continued miscegenation between the three races would lead to a "meta-race", i.e. a "postracial race" or a "race beyond race".

Freyre's theory became a source of national pride for Brazil, which contrasted itself favorably with the racial divisions and violence taking place in the United States. Over time, racial democracy would become accepted among Brazilians of all stripes and many foreign academics. Black researchers in the United States would make unfavorable comparisons between their own country and Brazil during the 1960s. In the past four decades, beginning around the publication in 1974 of Thomas E. Skidmore's Black into White, a revisionist study of Brazilian race relations, scholars have begun to criticize the notion that Brazil is a "racial democracy". Skidmore argues that the predominantly white elite within Brazilian society promoted racial democracy to obscure real forms of racial oppression. Michael Hanchard, a political scientist at the University of Pennsylvania, has argued that the ideology of racial democracy promoted by state apparatuses, prevents effective action to combat racial discrimination by leading people to ascribe discrimination to other forms of oppression and allowing government officials charged with preventing racism to deny its existence a priori.

France Winddance Twine's 1997 ethnography appears to support those contentions. Hanchard compiles a great deal of research from other scholars demonstrating widespread discrimination in employment and electoral politics; the paradoxical use of racial democracy to obscure the realities of racism has been referred to by scholar Florestan Fernandes as the "prejudice of having no prejudices". That is, because the state assumes the absence of racial prejudice, it fails to enforce what few laws exist to counter racial discrimination, as it believes that such efforts are unnecessary. More North American anthropologist John Collins has argued that shifting engagements with collective memory, genealogically-based accounts of ancestry, UNESCO World Heritage programs have articulated with efforts by the Black Movement and progressive government actors to undermine claims about racial democracy in ways that lead Brazilians to self-identify as Black; the life of Gilberto Freyre, after he published Casa-Grande & Senzala, became an eternal source of explanation.

He repeated several times that he did not create the myth of a racial democracy and that the fact that his books recognized the intense mixing between "races" in Brazil did not mean a lack of prejudice or discrimination. He pointed out that many people have claimed the United States to have been an "exemplary democracy" whereas slavery and racial segregation were present throughout most of the history of the United States."The interpretation of those who want to place me among the sociologists or anthropologists who said prejudice of race among the Portuguese or the Brazilians never existed is extreme. What I have always suggested is that such prejudice is minimal... when compared to that, still in place elsewhere, where laws still regulate relations between Europeans and other groups". "It is not. They exist, but no one here would have thought of "white-only" Churches. No one in Brazil would have thought of laws against interracial marriage... Fraternal spirit is stronger among Brazilians than racial prejudice, class or religion.

It is true that equality has not been reached since the end of slavery... There was racial prejudice among plantation owners, there was social distance between the masters and the slaves, between whites and blacks... But few wealthy Brazilians were as concerned with racial purity as the majority were in the Old South"

Rupert Gavin

Rupert Gavin is a British entrepreneur and theatre impresario. He is Chairman of Historic Royal Palaces and is a former CEO of BBC Worldwide and of Odeon Cinemas; as a producer/financier he is notable for a series of successful plays and musicals through his company Incidental Colman. He chairs the Honours Committee for Media. In 2015 Gavin was appointed Chairman of Historic Royal Palaces, the charity responsible for the management and conservation of the Tower of London, Kensington Palace, Hampton Court Palace, Banqueting House, Kew Palace and Hillsborough Castle, his tenure was extended for a second term in May 2018. He is executive Chairman of the theatre production company Incidental Colman, which has produced/co-produced in the West End and on Broadway and is a winner of fourteen Olivier Awards, he is non-executive Chairman of the leading movie and TV VFX business. Gavin is a non-executive director of Wyevale Garden Centres and Countrywide plc, he is Chairman of the Honours Committee for Media and the Arts and commences his second term as of January 2019.

He is a member of The Court of the Worshipful Company of Grocers, having been Master in 2017/18. Gavin was educated at Eton College, an independent boys' school in Berkshire, followed by Magdalene College at the Cambridge University, where he read Economics. After graduation he took a copywriting role at Sharps advertising agency. While working at Sharps he established close links with Dixons Stores Group, would go on to become deputy managing director of the electronics retailer. In 1994, he joined British Telecom to work on its internet and multimedia strategy. In 1998 he became chief executive of BBC Worldwide, he was CEO of Odeon Cinemas and UCI Cinemas Group from 2006 to 2014Gavin has served as Board member and shareholder of Ambassador Theatre Group, Chairman of Contender Entertainment Group, Chairman of Screenstage, Governor of the National Film and Television School and Treasurer of the Contemporary Art Society. Mojo The Ferryman The Book of Mormon Jersey Boys West Side Story Brainiac Shockheaded Peter Othello with Lenny Henry A View from the Bridge with Ken Stott Ghosts with Lesley Manville Long Days Journey into Night with David Suchet All My Sons with David Suchet Death of a Salesman with Philip Seymour Hoffman and Andrew Garfield South Pacific Legally Blonde The Sunshine Boys with Danny DeVito Jerusalem with Mark Rylance Twelfth Night and Richard III with Mark Rylance Farinelli and the King with Mark Rylance Private Lives with Kim Cattrall Clybourne Park The Birthday Party with Toby Jones, Zoë Wanamaker and Stephen Mangan Old Times with Kristin Scott Thomas Betrayal with Kristin Scott Thomas Electra with Kristin Scott Thomas Three Sisters all with Kristin Scott Thomas King Charles III with Tim Pigott-Smith 1984 King Lear with Ian McKellen Hamlet with Benedict Cumberbatch Hamlet with Andrew Scott Gypsy with Imelda Staunton Sunny Afternoon The River with Hugh Jackman Dreamgirls The Jungle Consent Who's Afraid of Virginia Woolf? with Imelda Staunton Tina Turner – The Musical The Inheritance All About Eve with Gillian Anderson and Lily James The King and I Caroline, or Change with Sharon D. Clarke Uncle Vanya with Toby Jones Leopoldstadt by Sir Tom Stoppard Betrayal with Tom Hiddleston Cyrano de Bergerac with James McAvoyAll of the dramatic works of Arthur Smith since 1980In 2012 the Evening Standard newspaper dubbed Gavin "Mr West End", in reference to London's Theatreland.

Productions/co-productions by Incidental Colman have won fourteen Olivier awards, for either Best New Play, Best Play Revival, Best New Musical, Best Musical Revival or Best Entertainment. He is married to Ellen Miller. Debrett's lists his leisure activities as "...theatre producer and gardener". He is a Fellow of the Royal Television Society, he is Chairman of the charity Historic Royal Palaces. He has been a lifelong contributor to the Grocers' Charity, which supports a range of small charities, he sits on the Education and Charities Committee of the Grocers' Company. He is a patron of the Hay Literary Festival, the London Library and the Purbeck International Chamber Music Festival, he sits on the Development Council of the Almeida Theatre. He is of direct descent from James Gavin the Kirk Beadle of Angus, his family motto is'By industry we prosper'. Historic Royal Palaces Incidental Colman Terra Firma biography

Motoo Hayashi

Motoo Hayashi is a Japanese politician of the Liberal Democratic Party. He has been a member of the House of Representatives in the national Diet since 1993 and represents the Chiba 10th district. A native of Katori District, Hayashi graduated the Nihon University's College of Arts in 1970. Hayashi began his political career as a secretary to his late father, Taikan Hayashi, who served as chief of the former Environment Agency in the early 1990s. Motoo Hayashi was elected to the assembly of Chiba Prefecture for the first time in 1983 and served for three times, he was elected to the House of Representatives for the first time in 1993. An expert on issues related to Narita International Airport, he was appointed Senior Vice-Minister of Land and Transport in 2003, he has pledged to improve Japan's transport network. On August 1, 2008 Prime Minister Yasuo Fukuda appointed him to the cabinet position of National Public Chairman, State Minister in Charge of Okinawa and Affairs Related to the Northern Territories.

Hayashi is serving in the Lower House representing Chiba's Tenth District and is a member of Shinzō Abe's cabinet with many responsibilities: Minister of Economy and Industry, Minister in charge of Industrial Competitiveness, Minister in charge of the Response to the Economic Impact caused by the Nuclear Accident, Minister of State for the Nuclear Damage Compensation and Decommissioning Facilitation Corporation. Hayashi served as Chairman of the Committee on Land, Infrastructure and Tourism of Diet, Minister of State, Chairman of National Public Safety Commission, Acting Chairman, Election Strategy Committee. Hayashi is affiliated to the revisionist lobby Nippon Kaigi, a member of the following right-wing Diet groups: Nippon Kaigi Diet discussion group Conference of parliamentarians on the Shinto Association of Spiritual Leadership - NB: SAS a.k.a. Sinseiren, Shinto Political LeagueHayashi gave the following answers to the questionnaires submitted by Mainichi to parliamentarians: in 2012:in favor of the revision of the Constitution in favor of the right of collective self-defense in favor of the reform of the National assembly in favor of reactivating nuclear power plants against the goal of zero nuclear power by 2030s in favor of the relocation of Marine Corps Air Station Futenma in favor of evaluating the purchase of Senkaku Islands by the Government in favor of an effort to avoid conflict with China against the participation of Japan to the Trans-Pacific Partnership against a nuclear-armed Japan against the reform of the Imperial Household that would allow women to retain their Imperial status after marriage in 2014:in favor of the revision of the Article 9 of the Japanese Constitution in favor of the right of collective self-defense in favor of nuclear plants no problem for visits of a Prime Minister to the controversial Yasukuni Shrine no answer regarding the revision of the Murayama Statement no answer regarding the revision of the Kono Statement no answer regarding laws preventing hate speech no answer regarding question whether Marine Corps Air Station Futenma is a burden for Okinawa in favor of the Special Secrecy Law in favor of teaching'morality' in school 政治家情報 〜林 幹雄〜.

ザ・選挙. JANJAN. Retrieved 2007-10-11. Official website in Japanese

Asquith Xavier

Asquith Camile Xavier was a West Indian-born Briton who ended a colour bar at British Railways in London by fighting to become the first non-white train guard at Euston railway station in 1966. Trevor Phillips, when chairman of the Commission for Racial Equality, said in 2006: "Asquith's stand against discrimination brought to light the inadequacy of early race discrimination laws and persistent widespread discrimination faced by ethnic minorities." A plaque at the station commemorates his achievement. Xavier was born on 18 July 1920 in Dominica, a British colony, he was a member of the Windrush generation of British African-Caribbean people who migrated to the United Kingdom after the second world war to fill vacancies in service industries. Xavier joined British Railways. In 1966 he was working as a guard at Marylebone station in central London, he was rejected. A letter from a staff committee at Euston—which was dominated by members of the National Union of Railwaymen—explained it was because of his colour.

Unions and management had informally agreed in the 1950s to ban non-white people from jobs at Euston that involved contact with the public. The Race Relations Act of 1965 had made discrimination on "grounds of colour, race, or ethnic or national origins" unlawful in public places in Great Britain. Xavier could not use this legislation to further his case. Xavier persisted. A union official publicised the rejection by writing a letter of protest to the head of the National Union of Railwaymen on his behalf. Two members of parliament wrote to the secretary of state for transport, Barbara Castle, to ask her to direct British Railways to end racial discrimination. On 15 July 1966 British Railways announced that colour bars at stations in London had been abandoned. Xavier was offered the job with his pay backdated to May, when he had been rejected. Xavier could not take up the job as he was recovering from hospital treatment for an ulcer, he received hate mail and death threats, asked for police protection.

He started work on 15 August 1966. Xavier died in 1980 in Kent. Oona King presented a BBC Radio 4 documentary, "Asquith's Fight for Equality", about his story in 2016—the fiftieth anniversary of his victory; the same year, The One Show on BBC One television interviewed Xavier's family and covered the unveiling of the plaque at Euston station that marked his fight. Bristol Bus Boycott—a protest in 1963 against a bus company's refusal to employ non-white bus crews in Bristol. Institutional racism Race Relations Act 1965—the first legislation in the United Kingdom to address racial discrimination. Race Relations Act 1968—an extension to the 1965 act that prohibited racial discrimination in housing and public service. Racism in the United Kingdom Rosa Parks—an activist in the United States civil rights movement, best known for her pivotal role in the Montgomery Bus Boycott. Hansards copy

Tony Fiore (ice hockey)

Tony Fiore is a Canadian-Italian retired professional ice hockey center. After scoring 82 goals and 110 assists in 147 games with the QMJHL's Montreal Juniors between 1980 and 1982, Fiore was selected 165nd overall by the Boston Bruins at the 1982 NHL Entry Draft, he never played in NHL. He spent the next two seasons split between the IHL with Hershey Bears and Flint Generals, he played most in Italian Serie A with HC Auronzo, Alleghe Hockey, HC Milano Saima, SG Milano Saima and HC Milano 24. He won a scudetto with HC Milano Saima in year 1991, he was a member of the Italian national team at the Group B World Championships in 1989 and 1991. After his retirement during the summer 1996, he was hired as General Manager of HC Milano 24, but president Quintavalle fired Fiore due to lack of result in January 1997, he became a sports agent. Serie A:HC Milano Saima: 1990-1991Gary F. Longman Memorial Trophy: 1982-1983 Biographical information and career statistics from Eliteprospects.com, or Eurohockey.com, or The Internet Hockey Database