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πŸ”— Gallery of animations that explain math ideas

Below is a mostly comprehensive gallery of all images β€” illustrations, diagrams and animations β€” that I have created for Wikipedia over the years, some of which have been selected as featured pictures, or even picture of the day. As you'll probably notice, they're mostly related to physics and mathematics, which are my main areas of interest.

If you have any comments, requests, suggestions or corrections, feel free to drop me a message on my talk page. But please, before making a suggestion, first take a look and see what sort of stuff I can do. Due to time, knowledge and complexity constraints, I cannot guarantee I'll be able to make a good illustration of any topic.

You can also follow me on tumblr for WIPs, current and failed projects and other creations.

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πŸ”— Atanasoff–Berry Computer

πŸ”— United States πŸ”— Computing πŸ”— Computing/Computer hardware πŸ”— Computing/Early computers πŸ”— United States/Iowa

The Atanasoff–Berry computer (ABC) was the first automatic electronic digital computer. Limited by the technology of the day, and execution, the device has remained somewhat obscure. The ABC's priority is debated among historians of computer technology, because it was neither programmable, nor Turing-complete. Conventionally, the ABC would be considered the first electronic ALU (arithmetic logic unit) – which is integrated into every modern processor's design.

Its unique contribution was to make computing faster by being the first to use vacuum tubes to do the arithmetic calculations. Prior to this, slower electro-mechanical methods were used by Konrad Zuse's Z1, and the simultaneously developed Harvard MarkΒ I. The first electronic, programmable, digital machine, the Colossus computer from 1943 to 1945, used similar tube-based technology as ABC.

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πŸ”— Kensington Security Slot

πŸ”— Computing πŸ”— Computing/Computer hardware πŸ”— Computing/Computer Security

A Kensington Security Slot (also called a K-Slot or Kensington lock) is part of an anti-theft system designed in the early 1990s and patented by Kryptonite in 1999–2000, assigned to Schlage in 2002, and since 2005 owned and marketed by Kensington Computer Products Group, a division of ACCO Brands.

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πŸ”— Whistled language

πŸ”— Constructed languages

Whistled languages use whistling to emulate speech and facilitate communication. A whistled language is a system of whistled communication which allows fluent whistlers to transmit and comprehend a potentially unlimited number of messages over long distances. Whistled languages are different in this respect from the restricted codes sometimes used by herders or animal trainers to transmit simple messages or instructions. Generally, whistled languages emulate the tones or vowel formants of a natural spoken language, as well as aspects of its intonation and prosody, so that trained listeners who speak that language can understand the encoded message.

Whistled language is rare compared to spoken language, but it is found in cultures around the world. It is especially common in tone languages where the whistled tones transmit the tones of the syllables (tone melodies of the words). This might be because in tone languages the tone melody carries more of the functional load of communication while non-tonal phonology carries proportionally less. The genesis of a whistled language has never been recorded in either case and has not yet received much productive study.

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πŸ”— Canadian Traveller Problem

πŸ”— Computer science πŸ”— Mathematics

In computer science and graph theory, the Canadian traveller problem (CTP) is a generalization of the shortest path problem to graphs that are partially observable. In other words, the graph is revealed while it is being explored, and explorative edges are charged even if they do not contribute to the final path.

This optimization problem was introduced by Christos Papadimitriou and Mihalis Yannakakis in 1989 and a number of variants of the problem have been studied since. The name supposedly originates from conversations of the authors who learned of a difficulty Canadian drivers had: traveling a network of cities with snowfall randomly blocking roads. The stochastic version, where each edge is associated with a probability of independently being in the graph, has been given considerable attention in operations research under the name "the Stochastic Shortest Path Problem with Recourse" (SSPPR).

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πŸ”— Man or boy test

πŸ”— Computer science

The man or boy test was proposed by computer scientist Donald Knuth as a means of evaluating implementations of the ALGOL 60 programming language. The aim of the test was to distinguish compilers that correctly implemented "recursion and non-local references" from those that did not.

There are quite a few ALGOL60 translators in existence which have been designed to handle recursion and non-local references properly, and I thought perhaps a little test-program may be of value. Hence I have written the following simple routine, which may separate the man-compilers from the boy-compilers.

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πŸ”— Multiple Time Dimensions

πŸ”— Physics πŸ”— Philosophy πŸ”— Time

The possibility that there might be more than one dimension of time has occasionally been discussed in physics and philosophy. Similar ideas appear in folklore and fantasy literature.

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πŸ”— Operation Legacy

πŸ”— International relations πŸ”— Military history πŸ”— British Empire πŸ”— Military history/Cold War πŸ”— Military history/European military history πŸ”— Military history/British military history πŸ”— Commonwealth

Operation Legacy was a British Colonial Office (later Foreign Office) programme to destroy or hide files, to prevent them being inherited by its ex-colonies. It ran from the 1950s until the 1970s, when the decolonisation of the British Empire was at its height.

MI5 or Special Branch agents vetted all secret documents in the colonial administrations to find those that those that could embarrass the British governmentβ€”for instance by showing racial or religious bias. They identified 8,800 files to conceal from at least 23 countries and territories in the 1950s and 1960s, and destroyed them or sent them to the United Kingdom. Precise instructions were given for methods to be used for destruction, including burning and dumping at sea. Some of the files detailed torture methods used against opponents of the colonial administrations, such as during the Mau Mau Uprising.

As decolonisation progressed, British officials were keen to avoid a repeat of the embarrassment that had been caused by the overt burning of documents that took place in New Delhi in 1947, which had been covered by Indian news sources. On 3 May 1961, Iain Macleod, who was Secretary of State for the Colonies, wrote a telegram to all British embassies to advise them on the best way to retrieve and dispose of sensitive documents. To prevent post-colonial governments from ever learning about Operation Legacy, officials were required to dispatch "destruction certificates" to London. In some cases, as the handover date approached, the immolation task proved so huge that colonial administrators warned the Foreign Office that there was a danger of "celebrating Independence Day with smoke."

Academic study of the end of the British Empire has been assisted in recent years by the declassification of the migrated archives in the Foreign and Commonwealth Office (FCO) 141 series. After the UK government admitted in 2011 that it had secret documents related to the Mau Mau Uprising, it began to declassify documents and by November 2013 some 20,000 files had been declassified. These documents can now be accessed at the National Archives in Kew, London.

πŸ”— Antifuse, the opposite of a fuse

πŸ”— Electronics

An antifuse is an electrical device that performs the opposite function to a fuse. Whereas a fuse starts with a low resistance and is designed to permanently break an electrically conductive path (typically when the current through the path exceeds a specified limit), an antifuse starts with a high resistance, and programming it converts it into a permanent electrically conductive path (typically when the voltage across the antifuse exceeds a certain level). This technology has many applications.

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πŸ”— Tell HN: There will be a Blue moon in December

πŸ”— Time πŸ”— Moon

A blue moon is an additional full moon that appears in a subdivision of a year: either the third of four full moons in a season, or a second full moon in a month of the common calendar.

The phrase in modern usage has nothing to do with the actual color of the Moon, although a visually blue Moon (the Moon appearing with a bluish tinge) may occur under certain atmospheric conditions – for instance, if volcanic eruptions or fires release particles in the atmosphere of just the right size to preferentially scatter red light.

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