Random Articles (Page 370)
Have a deep view into what people are curious about.
π Hector (Cloud)
Hector is a cumulonimbus thundercloud cluster that forms regularly nearly every afternoon on the Tiwi Islands in the Northern Territory of Australia, from approximately September to March each year. Hector, or sometimes Hector the Convector, is known as one of the world's most consistently large thunderstorms; specifically, a small mesoscale convective system (MCS) or large multicellular thunderstorm. It reaches heights of approximately 20 kilometres (66,000Β ft).
π Computus β The calculation to determine the day of Easter
The computus (Latin for 'computation') is a calculation that determines the calendar date of Easter. Easter is traditionally celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (an approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the calendar. The calculations produce different results depending on whether the Julian calendar or the Gregorian calendar is used.
In late antiquity, it was feasible for the entire Christian church to receive the date of Easter each year through an annual announcement from the Pope. By the early third century, however, communications had deteriorated to the point that the church put great value in a system that would allow the clergy to independently and consistently determine the date for themselves. Additionally, the church wished to eliminate dependencies on the Hebrew calendar, by deriving Easter directly from the vernal equinox.
In The Reckoning of Time (725), Bede uses computus as a general term for any sort of calculation, although he refers to the Easter cycles of Theophilus as a "Paschal computus." By the end of the 8th century, computus came to refer specifically to the calculation of time.
Discussed on
- "Computus β The calculation to determine the day of Easter" | 2019-04-21 | 10 Upvotes 1 Comments
π Peirce Quincuncial Projection
The Peirce quincuncial projection is a conformal map projection developed by Charles Sanders Peirce in 1879. The projection has the distinctive property that it can be tiled ad infinitum on the plane, with edge-crossings being completely smooth except for four singular points per tile. The projection has seen use in digital photography for portraying 360Β° views. The description quincuncial refers to the arrangement of four quadrants of the globe around the center hemisphere in an overall square pattern. Typically the projection is oriented such that the north pole lies at the center.
Discussed on
- "Peirce Quincuncial Projection" | 2021-07-01 | 26 Upvotes 2 Comments
π Finite Element Method
The finite element method (FEM) is the most widely used method for solving problems of engineering and mathematical models. Typical problem areas of interest include the traditional fields of structural analysis, heat transfer, fluid flow, mass transport, and electromagnetic potential. The FEM is a particular numerical method for solving partial differential equations in two or three space variables (i.e., some boundary value problems). To solve a problem, the FEM subdivides a large system into smaller, simpler parts that are called finite elements. This is achieved by a particular space discretisation in the space dimensions, which is implemented by the construction of a mesh of the object: the numerical domain for the solution, which has a finite number of points. The finite element method formulation of a boundary value problem finally results in a system of algebraic equations. The method approximates the unknown function over the domain. The simple equations that model these finite elements are then assembled into a larger system of equations that models the entire problem. The FEM then uses variational methods from the calculus of variations to approximate a solution by minimizing an associated error function.
Studying or analyzing a phenomenon with FEM is often referred to as finite element analysis (FEA).
Discussed on
- "Finite Element Method" | 2020-02-17 | 75 Upvotes 44 Comments
π Loving v. Virginia
Loving v. Virginia, 388 U.S. 1 (1967), was a landmark civil rights decision of the U.S. Supreme Court in which the Court ruled that laws banning interracial marriage violate the Equal Protection and Due Process Clauses of the Fourteenth Amendment to the U.S. Constitution. Beginning in 2013, it was cited as precedent in U.S. federal court decisions holding restrictions on same-sex marriage in the United States unconstitutional, including in the 2015 Supreme Court decision Obergefell v. Hodges.
The case involved Mildred Loving, a woman of color, and her white husband Richard Loving, who in 1958 were sentenced to a year in prison for marrying each other. Their marriage violated Virginia's Racial Integrity Act of 1924, which criminalized marriage between people classified as "white" and people classified as "colored". The Lovings appealed their conviction to the Supreme Court of Virginia, which upheld it. They then appealed to the U.S. Supreme Court, which agreed to hear their case.
In June 1967, the Supreme Court issued a unanimous decision in the Lovings' favor and overturned their convictions. Its decision struck down Virginia's anti-miscegenation law and ended all race-based legal restrictions on marriage in the United States. Virginia had argued that its law was not a violation of the Equal Protection Clause because the punishment was the same regardless of the offender's race, and thus it "equally burdened" both whites and non-whites. The Court found that the law nonetheless violated the Equal Protection Clause because it was based solely on "distinctions drawn according to race" and outlawed conductβnamely, getting marriedβthat was otherwise generally accepted and which citizens were free to do.
Discussed on
- "Loving v. Virginia" | 2022-06-25 | 18 Upvotes 5 Comments
π Kwangmyong, the North-Korea-Wide-Web
Kwangmyong (literally βBright Lightβ) is a North Korean "walled garden" national intranet service opened in 2000.
The network uses domain names under the .kp top level domain that are not accessible from the global Internet. As of 2016 the network uses IPv4 addresses reserved for private networks in the 10.0.0.0/8 range. North Koreans often find it more convenient to access sites by their IP address rather than by URL using Latin characters. Like the global Internet, the network hosts content accessible with web browsers, and provides an internal web search engine. It also provides email services and news groups.
Only foreigners and a small number of government officials/scholars/elites are allowed to use the global Internet in North Korea, making Kwangmyong the only computer network available to most North Korean citizens. It is a free service for public use.
Discussed on
- "Kwangmyong, the North-Korea-Wide-Web" | 2010-06-13 | 45 Upvotes 14 Comments
π Cognitive Architecture
A cognitive architecture refers to both a theory about the structure of the human mind and to a computational instantiation of such a theory used in the fields of artificial intelligence (AI) and computational cognitive science. One of the main goals of a cognitive architecture is to summarize the various results of cognitive psychology in a comprehensive computer model. However, the results need to be formalized so far as they can be the basis of a computer program. The formalized models can be used to further refine a comprehensive theory of cognition, and more immediately, as a commercially usable model. Successful cognitive architectures include ACT-R (Adaptive Control of Thought - Rational) and SOAR.
The Institute for Creative Technologies defines cognitive architecture as: "hypothesis about the fixed structures that provide a mind, whether in natural or artificial systems, and how they work together β in conjunction with knowledge and skills embodied within the architecture β to yield intelligent behavior in a diversity of complex environments."
π Zooko's Triangle
Zooko's triangle is a trilemma of three properties that are generally considered desirable for names of participants in a network protocol:
- Human-meaningful: Meaningful and memorable (low-entropy) names are provided to the users.
- Secure: The amount of damage a malicious entity can inflict on the system should be as low as possible.
- Decentralized: Names correctly resolve to their respective entities without the use of a central authority or service.
Discussed on
- "Zooko's Triangle" | 2022-08-17 | 79 Upvotes 40 Comments
- "Zooko's Triangle" | 2021-02-17 | 153 Upvotes 54 Comments
- "Zooko's Triangle" | 2010-08-22 | 23 Upvotes 7 Comments
π THX 1138
THX 1138 is a 1971 American social science fiction film directed by George Lucas in his feature film directorial debut. It is set in a dystopian future in which the populace is controlled through android police and mandatory use of drugs that suppress emotions. Produced by Francis Ford Coppola and written by Lucas and Walter Murch, it stars Robert Duvall and Donald Pleasence.
THX 1138 was developed from Lucas's student film Electronic Labyrinth: THX 1138 4EB, which he made in 1967 while attending the USC School of Cinematic Arts. The feature film was produced in a joint venture between Warner Bros. and American Zoetrope. A novelization by Ben Bova was published in 1971. The film received mixed reviews from critics and failed to find box-office success on initial release; however, the film has subsequently received critical acclaim and gained a cult following, particularly in the aftermath of Lucas' success with Star Wars in 1977.
π Kim Ung-yong: The man with the highest IQ
Kim Ung-Yong (Hangul: κΉμ μ©; born March 8, 1962) is a South Korean professor and former child prodigy, who once held the Guinness World Record for highest IQ, at a score of 230+.
Discussed on
- "Kim Ung-yong: The man with the highest IQ" | 2010-03-01 | 106 Upvotes 120 Comments