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๐ Sรคkkijรคrven polkka
Sรคkkijรคrven polkka ("the Sรคkkijรคrvi polka"), also called the "Karelian-Finnish Polka," is a well-known folk tune from Finland, very popular with Finnish accordionists. It was especially popularized by Viljo "Vili" Vesterinen (1907โ1961). The tune was first recorded in Sรคkkijรคrvi (now Kondratyevo in the Leningrad Oblast, Russia), and the lyrics sometimes sung with the tune state that while Sรคkkijรคrvi itself might have been lost (ceded to the Soviet Union in 1940), the Finns at least still had the polka.
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- "Sรคkkijรคrven polkka" | 2020-05-05 | 172 Upvotes 56 Comments
๐ James while John had had had ... had had had a better effect on the teacher
"James while John had had had had had had had had had had had a better effect on the teacher" is an English sentence used to demonstrate lexical ambiguity and the necessity of punctuation, which serves as a substitute for the intonation,stress, and pauses found in speech. In human information processing research, the sentence has been used to show how readers depend on punctuation to give sentences meaning, especially in the context of scanning across lines of text. The sentence is sometimes presented as a puzzle, where the solver must add the punctuation.
It refers to two students, James and John, required by an English test to describe a man who had suffered from a cold in the past. John writes "The man had a cold", which the teacher marks incorrect, while James writes the correct "The man had had a cold". Since James's answer was right, it had had a better effect on the teacher.
The sentence is much easier to understand with added punctuation and emphasis:
James, while John had had "had", had had "had had"; "had had" had had a better effect on the teacher.
In each of the five "had had" word pairs in the above sentence, the first of the pair is in the past perfect form. The italicized instances denote emphasis of intonation, focusing on the differences in the students' answers, then finally identifying the correct one.
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- "James while John had had had ... had had had a better effect on the teacher" | 2013-03-03 | 114 Upvotes 74 Comments
๐ Deep Crack
In cryptography, the EFF DES cracker (nicknamed "Deep Crack") is a machine built by the Electronic Frontier Foundation (EFF) in 1998, to perform a brute force search of the Data Encryption Standard (DES) cipher's key space โ that is, to decrypt an encrypted message by trying every possible key. The aim in doing this was to prove that the key size of DES was not sufficient to be secure.
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- "Deep Crack" | 2009-04-24 | 23 Upvotes 6 Comments
๐ Petoskey stone
A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. Such stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula. In those same areas of Michigan, complete fossilized coral colony heads can be found in the source rocks for the Petoskey stones.
Petoskey stones are found in the Gravel Point Formation of the Traverse Group. They are fragments of a coral reef that was originally deposited during the Devonian period. When dry, the stone resembles ordinary limestone but when wet or polished using lapidary techniques, the distinctive mottled pattern of the six-sided coral fossils emerges. It is sometimes made into decorative objects. Other forms of fossilized coral are also found in the same location.
In 1965, it was named the state stone of Michigan.
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- "Petoskey stone" | 2017-07-24 | 113 Upvotes 35 Comments
๐ Late Capitalism
Late capitalism, late-stage capitalism, or end-stage capitalism is a term first used in print by German economist Werner Sombart around the turn of the 20th century. In the late 2010s, the term began to be used in the United States and Canada to refer to perceived absurdities, contradictions, crises, injustices, inequality, and exploitation created by modern business development.
Later capitalism refers to the historical epoch since 1940, including the postโWorld War II economic expansion called the "golden age of capitalism". The expression already existed for a long time in continental Europe, before it gained popularity in the English-speaking world through the English translation of Ernest Mandel's book Late Capitalism, published in 1975.
The German original edition of Mandel's work was subtitled in "an attempt at an explanation", meaning that Mandel tried to provide an orthodox Marxist explanation of the post-war epoch in terms of Marx's theory of the capitalist mode of production. Mandel suggested that important qualitative changes occurred within the capitalist system during and after World War II and that there are limits to capitalist development.
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- "Late Capitalism" | 2023-05-20 | 12 Upvotes 3 Comments
๐ Monty Hall Problem
The Monty Hall problem is a brain teaser, in the form of a probability puzzle, loosely based on the American television game show Let's Make a Deal and named after its original host, Monty Hall. The problem was originally posed (and solved) in a letter by Steve Selvin to the American Statistician in 1975 (Selvin 1975a), (Selvin 1975b). It became famous as a question from a reader's letter quoted in Marilyn vos Savant's "Ask Marilyn" column in Parade magazine in 1990 (vos Savant 1990a):
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?
Vos Savant's response was that the contestant should switch to the other door (vos Savant 1990a). Under the standard assumptions, contestants who switch have a 2/3 chance of winning the car, while contestants who stick to their initial choice have only a 1/3 chance.
The given probabilities depend on specific assumptions about how the host and contestant choose their doors. A key insight is that, under these standard conditions, there is more information about doors 2 and 3 than was available at the beginning of the game when door 1 was chosen by the player: the host's deliberate action adds value to the door he did not choose to eliminate, but not to the one chosen by the contestant originally. Another insight is that switching doors is a different action than choosing between the two remaining doors at random, as the first action uses the previous information and the latter does not. Other possible behaviors than the one described can reveal different additional information, or none at all, and yield different probabilities. Yet another insight is that your chance of winning by switching doors is directly related to your chance of choosing the winning door in the first place: if you choose the correct door on your first try, then switching loses; if you choose a wrong door on your first try, then switching wins; your chance of choosing the correct door on your first try is 1/3, and the chance of choosing a wrong door is 2/3.
Many readers of vos Savant's column refused to believe switching is beneficial despite her explanation. After the problem appeared in Parade, approximately 10,000 readers, including nearly 1,000 with PhDs, wrote to the magazine, most of them claiming vos Savant was wrong (Tierney 1991). Even when given explanations, simulations, and formal mathematical proofs, many people still do not accept that switching is the best strategy (vos Savant 1991a). Paul Erdลs, one of the most prolific mathematicians in history, remained unconvinced until he was shown a computer simulation demonstrating vos Savantโs predicted result (Vazsonyi 1999).
The problem is a paradox of the veridical type, because the correct choice (that one should switch doors) is so counterintuitive it can seem absurd, but is nevertheless demonstrably true. The Monty Hall problem is mathematically closely related to the earlier Three Prisoners problem and to the much older Bertrand's box paradox.
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- "Monty Hall Problem" | 2022-06-09 | 24 Upvotes 116 Comments
- "Monty Hall Problem" | 2019-10-24 | 122 Upvotes 252 Comments
- "Monty Hall problem" | 2010-02-22 | 14 Upvotes 27 Comments
๐ Background of .plan files: the 1977 Finger Protocol
In computer networking, the Name/Finger protocol and the Finger user information protocol are simple network protocols for the exchange of human-oriented status and user information.
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- "Background of .plan files: the 1977 Finger Protocol" | 2011-12-18 | 19 Upvotes 7 Comments
๐ Mellified man
A mellified man, or a human mummy confection, was a legendary medicinal substance created by steeping a human cadaver in honey. The concoction is detailed in Chinese medical sources, most significantly the Bencao Gangmu of the 16th-century Chinese medical doctor and pharmacologist Li Shizhen. Relying on a second-hand account, Li reports a story that some elderly men in Arabia, nearing the end of their lives, would submit themselves to a process of mummification in honey to create a healing confection.
This process differed from a simple body donation because of the aspect of self-sacrifice; the mellification process would ideally start before death. The donor would stop eating any food other than honey, going as far as to bathe in the substance. Shortly, his feces (and even his sweat, according to legend) would consist of honey. When this diet finally proved fatal, the donor's body would be placed in a stone coffin filled with honey.
After a century or so, the contents would have turned into a sort of confection reputedly capable of healing broken limbs and other ailments. This confection would then be sold in street markets as a hard to find item with a hefty price.
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- "Mellified man" | 2017-02-14 | 35 Upvotes 5 Comments
๐ Tunnel of Eupalinos
The Tunnel of Eupalinos or Eupalinian aqueduct (Greek: ฮฯ ฯฮฑฮปฮฏฮฝฮนฮฟฮฝ ฯฯฯ ฮณฮผฮฑ, romanized:ย Efpalinion orygma) is a tunnel of 1,036ย m (3,399ย ft) length running through Mount Kastro in Samos, Greece, built in the 6th century BC to serve as an aqueduct. The tunnel is the second known tunnel in history which was excavated from both ends (Ancient Greek: แผฮผฯฮฏฯฯฮฟฮผฮฟฮฝ, romanized:ย amphistomon, "having two openings"), and the first with a geometry-based approach in doing so. Today it is a popular tourist attraction.
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- "Tunnel of Eupalinos" | 2023-05-06 | 195 Upvotes 32 Comments
๐ Anisotropic Filtering
In 3D computer graphics, anisotropic filtering (abbreviated AF) is a method of enhancing the image quality of textures on surfaces of computer graphics that are at oblique viewing angles with respect to the camera where the projection of the texture (not the polygon or other primitive on which it is rendered) appears to be non-orthogonal (thus the origin of the word: "an" for not, "iso" for same, and "tropic" from tropism, relating to direction; anisotropic filtering does not filter the same in every direction).
Like bilinear and trilinear filtering, anisotropic filtering eliminates aliasing effects, but improves on these other techniques by reducing blur and preserving detail at extreme viewing angles.
Anisotropic filtering is relatively intensive (primarily memory bandwidth and to some degree computationally, though the standard spaceโtime tradeoff rules apply) and only became a standard feature of consumer-level graphics cards in the late 1990s. Anisotropic filtering is now common in modern graphics hardware (and video driver software) and is enabled either by users through driver settings or by graphics applications and video games through programming interfaces.
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- "Anisotropic Filtering" | 2023-01-09 | 11 Upvotes 3 Comments