Random Articles (Page 3)
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π List of probability distributions
Many probability distributions that are important in theory or applications have been given specific names.
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- "List of probability distributions" | 2013-05-25 | 47 Upvotes 36 Comments
π Slow-Scan Television
Slow-scan television (SSTV) is a picture transmission method, used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color.
A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6Β MHz wide channels, because it transmits 25 or 30 picture frames per second (see ITU analog broadcast standards), but SSTV usually only takes up to a maximum of 3Β kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame.
Since SSTV systems operate on voice frequencies, amateurs use it on shortwave (also known as HF by amateur radio operators), VHF and UHF radio.
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- "Slow-Scan Television" | 2023-11-13 | 117 Upvotes 24 Comments
π Boltzmann machine
A Boltzmann machine (also called stochastic Hopfield network with hidden units) is a type of stochastic recurrent neural network. It is a Markov random field. It was translated from statistical physics for use in cognitive science. The Boltzmann machine is based on stochastic spin-glass model with an external field, i.e., a SherringtonβKirkpatrick model that is a stochastic Ising Model and applied to machine learning.
Boltzmann machines can be seen as the stochastic, generative counterpart of Hopfield networks. They were one of the first neural networks capable of learning internal representations, and are able to represent and (given sufficient time) solve combinatoric problems.
They are theoretically intriguing because of the locality and Hebbian nature of their training algorithm (being trained by Hebb's rule), and because of their parallelism and the resemblance of their dynamics to simple physical processes. Boltzmann machines with unconstrained connectivity have not proven useful for practical problems in machine learning or inference, but if the connectivity is properly constrained, the learning can be made efficient enough to be useful for practical problems.
They are named after the Boltzmann distribution in statistical mechanics, which is used in their sampling function. That's why they are called "energy based models" (EBM). They were invented in 1985 by Geoffrey Hinton, then a Professor at Carnegie Mellon University, and Terry Sejnowski, then a Professor at Johns Hopkins University.
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- "Boltzmann machine" | 2014-06-01 | 29 Upvotes 4 Comments
π Laconic Phrase
A laconic phrase or laconism is a concise or terse statement, especially a blunt and elliptical rejoinder. It is named after Laconia, the region of Greece including the city of Sparta, whose ancient inhabitants had a reputation for verbal austerity and were famous for their blunt and often pithy remarks.
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- "Laconic Phrase" | 2015-04-24 | 12 Upvotes 3 Comments
π ZigBee - Low Power, Low Cost, Mesh wireless for control/sensor network
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- "ZigBee - Low Power, Low Cost, Mesh wireless for control/sensor network" | 2008-10-05 | 12 Upvotes 2 Comments
π Cancer Alley
Cancer Alley (French: AllΓ©e du Cancer) is the regional nickname given to an 85-mile (137Β km) stretch of land along the Mississippi River between Baton Rouge and New Orleans, in the River Parishes of Louisiana, which contains over 200 petrochemical plants and refineries. This area accounts for 25% of the petrochemical production in the United States. Environmentalists consider the region a sacrifice zone where rates of cancer caused by air pollution exceed the federal government's own limits of acceptable risk. Others have referred to the same region as "Death Alley".
Community leaders such as Sharon Lavigne have led the charge in protesting the expansion of the petrochemical industry in Cancer Alley, as well as addressing the associated racial and economic disparities.
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- "Cancer Alley" | 2024-01-17 | 181 Upvotes 87 Comments
π Inventors killed by their own inventions
This is a list of inventors whose deaths were in some manner caused by or related to a product, process, procedure, or other innovation that they invented or designed.
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- "List of Inventors Killed by Their Own Inventions" | 2021-02-07 | 73 Upvotes 22 Comments
- "Inventors killed by their own inventions" | 2019-06-06 | 273 Upvotes 149 Comments
- "List of inventors killed by their own inventions" | 2019-06-05 | 16 Upvotes 4 Comments
- "Inventors killed by their own inventions" | 2016-12-19 | 67 Upvotes 27 Comments
- "List of Inventors Killed By Their Own Inventions" | 2009-09-02 | 109 Upvotes 59 Comments
π A Canticle for Leibowitz
A Canticle for Leibowitz is a post-apocalyptic science fiction novel by American writer Walter M. Miller Jr., first published in 1959. Set in a Catholic monastery in the desert of the southwestern United States after a devastating nuclear war, the book spans thousands of years as civilization rebuilds itself. The monks of the Albertian Order of Leibowitz preserve the surviving remnants of man's scientific knowledge until the world is again ready for it.
The novel is a fixup of three short stories Miller published in The Magazine of Fantasy & Science Fiction that were inspired by the author's participation in the bombing of the monastery at the Battle of Monte Cassino during World War II. The book is considered one of the classics of science fiction and has never been out of print. Appealing to mainstream and genre critics and readers alike, it won the 1961 Hugo Award for best science fiction novel, and its themes of religion, recurrence, and church versus state have generated a significant body of scholarly research. A sequel, Saint Leibowitz and the Wild Horse Woman, was published posthumously in 1997.
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- "A Canticle for Leibowitz" | 2024-03-02 | 59 Upvotes 16 Comments
- "A Canticle for Leibowitz" | 2020-06-20 | 12 Upvotes 3 Comments
π Bastion Fort
A bastion fort or trace italienne (a phrase improperly derived from French, literally meaning Italian outline), is a fortification in a style that evolved during the early modern period of gunpowder when the cannon came to dominate the battlefield. It was first seen in the mid-15th century in Italy. Some types, especially when combined with ravelins and other outworks, resembled the related star fort of the same era.
The design of the fort is normally a polygon with bastions at the corners of the walls. These outcroppings eliminated protected blind spots, called "dead zones", and allowed fire along the curtain from positions protected from direct fire. Many bastion forts also feature cavaliers, which are raised secondary structures based entirely inside the primary structure.
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- "Bastion Fort" | 2024-03-14 | 21 Upvotes 7 Comments
- "Bastion Fort" | 2020-09-12 | 76 Upvotes 49 Comments
- "Bastion Fort" | 2019-02-02 | 60 Upvotes 20 Comments
π Farmers' Suicide in the United States
Farmers' suicides in the United States refers to the instances of American farmers taking their own lives, largely since the 1980s, partly due to their falling into debt, but as a larger mental-health crisis among U.S. agriculture workers. In the Midwest alone, over 1,500 farmers have taken their own lives since the 1980s. It mirrors a crisis happening globally: in Australia, a farmer dies by suicide every four days; in the United Kingdom, one farmer a week takes their own life, in France it is one every two days. More than 270,000 farmers have died by suicide since 1995 in India.
Farmers are among the most likely to die by suicide, in comparison to other occupations, according to a study published in January 2020 by the Centers for Disease Control and Prevention (CDC). Researchers at the University of Iowa found that farmers, and others in the agricultural trade, had the highest suicide rate of all occupations from 1992 to 2010, the years covered in a 2017 study. The rate was 3.5 times that of the general population. This echoed a study conducted the previous year by the CDC and another undertaken by the National Rural Health Association (NRHA).
Most family farmers seem to agree on what led to their plight: government policy. In the years after the New Deal, they say, the United States set a price floor for farmers, essentially ensuring they received a minimum wage for the crops they produced. But the government began rolling back this policy in the 1970s, and now the global market largely determines the price they get for their crops. Big farms can make do with lower prices for crops by increasing their scale; a few cents per gallon of cow's milk adds up if you have thousands of cows.
βTime, November 27, 2019
As of April 2023, the suicide rate within the farming community exceeds that of the general population by three and a half times.
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- "Farmers' Suicide in the United States" | 2024-11-18 | 77 Upvotes 35 Comments