Random Articles (Page 6)
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๐ B.a.t.m.a.n
The Better Approach to Mobile Ad-hoc Networking (B.A.T.M.A.N.) is a routing protocol for multi-hop mobile ad hoc networks which is under development by the German "Freifunk" community and intended to replace the Optimized Link State Routing Protocol (OLSR).
B.A.T.M.A.N.'s crucial point is the decentralization of knowledge about the best route through the networkย โ no single node has all the data. This technique eliminates the need to spread information about network changes to every node in the network. The individual node only saves information about the "direction" it received data from and sends its data accordingly. The data gets passed from node to node, and packets get individual, dynamically created routes. A network of collective intelligence is created.
In early 2007, the B.A.T.M.A.N. developers started experimenting with the idea of routing on layer 2 (Ethernet layer) instead of layer 3. To differentiate from the layer 3 routing daemon, the suffix "adv" (for: advanced) was chosen. Instead of manipulating routing tables based on information exchanged via UDP/IP, it provides a virtual network interface and transparently transports Ethernet packets on its own. The batman-adv kernel module has been part of the official Linux kernel since 2.6.38.
๐ OODA Loop
The OODA loop is the cycle observeโorientโdecideโact, developed by military strategist and United States Air Force Colonel John Boyd. Boyd applied the concept to the combat operations process, often at the operational level during military campaigns. It is now also often applied to understand commercial operations and learning processes. The approach explains how agility can overcome raw power in dealing with human opponents. It is especially applicable to cyber security and cyberwarfare.
The OODA loop has become an important concept in litigation, business, law enforcement, management education, and military strategy. According to Boyd, decision-making occurs in a recurring cycle of observeโorientโdecideโact. An entity (whether an individual or an organization) that can process this cycle quickly, observing and reacting to unfolding events more rapidly than an opponent, can thereby "get inside" the opponent's decision cycle and gain the advantage.
Discussed on
- "OODA Loop" | 2023-02-21 | 155 Upvotes 63 Comments
๐ Aleatoric Music
Aleatoric music (also aleatory music or chance music; from the Latin word alea, meaning "dice") is music in which some element of the composition is left to chance, and/or some primary element of a composed work's realization is left to the determination of its performer(s). The term is most often associated with procedures in which the chance element involves a relatively limited number of possibilities.
The term became known to European composers through lectures by acoustician Werner Meyer-Eppler at the Darmstadt International Summer Courses for New Music in the beginning of the 1950s. According to his definition, "a process is said to be aleatoric ... if its course is determined in general but depends on chance in detail". Through a confusion of Meyer-Eppler's German terms Aleatorik (noun) and aleatorisch (adjective), his translator created a new English word, "aleatoric" (rather than using the existing English adjective "aleatory"), which quickly became fashionable and has persisted. More recently, the variant "aleatoriality" has been introduced.
Discussed on
- "Aleatoric Music" | 2022-11-27 | 46 Upvotes 31 Comments
๐ Business Plot
The Business Plot was a political conspiracy in 1933 in the United States. Retired Marine Corps Major General Smedley Butler revealed that wealthy businessmen were plotting to create a fascist veterans' organization with Butler as its leader and use it in a coup d'รฉtat to overthrow President Franklin D. Roosevelt. In 1934, Butler testified before the United States House of Representatives Special Committee on Un-American Activities (the "McCormackโDickstein Committee") on these revelations. No one was prosecuted.
At the time of the incidents, news media dismissed the plot, with a New York Times editorial characterizing it as a "gigantic hoax". While historians have not accepted the notion of a plot, they agree that Butler described one.
Discussed on
- "Business Plot" | 2020-01-10 | 24 Upvotes 2 Comments
๐ Zellige
Zellige (Arabic:ย [zหliส]; Arabic: ุงูุฒููุฌโ; also zelige or zellij or zileej) is mosaic tilework made from individually chiseled geometric tiles set into a plaster base. This form of Islamic art is one of the main characteristics of Moroccan architecture. It consists of geometrically patterned mosaics, used to ornament walls, ceilings, fountains, floors, pools and tables. The Moroccan traditional patterns and styles are found inside famous buildings such as Al-Qarawiyyin Mosque in Fez, the Alhambra in Granada, Spain, the Great Mosque of Cordoba, the Ben Youssef Madrasa in Marrakech, and the Hassan II mosque in Casablanca, which adds a new color palette with traditional designs.
Discussed on
- "Zellige" | 2015-08-16 | 37 Upvotes 6 Comments
๐ N. W. Ayer and Son
N. W. Ayer & Son was a Philadelphia advertising agency founded in 1869. It called itself the oldest advertising agency in the United States. Named after Francis Ayer's father N. W. Ayer, it ventured into advertising in 1884. It created a number of memorable slogans for firms such as De Beers, AT&T and the U.S. Army. The company started to decline in the 1960s and, after a series of mergers, was closed in 2002 with its assets sold to the Publicis Groupe.
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- "N. W. Ayer and Son" | 2015-10-11 | 14 Upvotes 1 Comments
๐ National Popular Vote Interstate Compact
The National Popular Vote Interstate Compact (NPVIC) is an agreement among a group of U.S. states and the District of Columbia to award all their electoral votes to whichever presidential candidate wins the overall popular vote in the 50 states and the District of Columbia. The compact is designed to ensure that the candidate who receives the most votes nationwide is elected president, and it would come into effect only when it would guarantee that outcome. As of Marchย 2020, it has been adopted by fifteen states and the District of Columbia. Together, they have 196 electoral votes, which is 36% of the Electoral College and 73% of the 270 votes needed to give the compact legal force. Certain legal questions, however, may affect implementation of the compact.
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- "National Popular Vote Interstate Compact" | 2024-08-12 | 38 Upvotes 63 Comments
- "National Popular Vote Interstate Compact" | 2016-11-10 | 19 Upvotes 7 Comments
๐ Death by Coconut
Coconuts falling from their trees and striking individuals can cause serious injury to the back, neck, shoulders and head, and are occasionally fatal.
Following a 1984 study on "Injuries Due to Falling Coconuts", exaggerated claims spread concerning the number of deaths by falling coconuts. Falling coconuts, according to urban legend, kill a few people a year. This legend gained momentum after the 2002 work of a noted expert on shark attacks was characterized as saying that falling coconuts kill 150 people each year worldwide. This statistic has often been contrasted with the number of shark-caused deaths per year, which is around five.
Concern about the risk of fatality due to falling coconuts led local officials in Queensland, Australia, to remove coconut trees from beaches in 2002. One newspaper dubbed coconuts "the killer fruit". Historical reports of actual death by coconut nonetheless date back to the 1770s.
Another way to "die by coconut" is to suffer sudden cardiac death as a result of hyperkalemia, after consuming moderate to large quantities of coconut water, due to the high levels of potassium in coconut water.
Discussed on
- "Death by Coconut" | 2021-12-21 | 107 Upvotes 80 Comments
๐ Random oracle
In cryptography, a random oracle is an oracle (a theoretical black box) that responds to every unique query with a (truly) random response chosen uniformly from its output domain. If a query is repeated, it responds the same way every time that query is submitted.
Stated differently, a random oracle is a mathematical function chosen uniformly at random, that is, a function mapping each possible query to a (fixed) random response from its output domain.
Random oracles as a mathematical abstraction were firstly used in rigorous cryptographic proofs in the 1993 publication by Mihir Bellare and Phillip Rogaway (1993). They are typically used when the proof cannot be carried out using weaker assumptions on the cryptographic hash function. A system that is proven secure when every hash function is replaced by a random oracle is described as being secure in the random oracle model, as opposed to secure in the standard model of cryptography.
Discussed on
- "Random oracle" | 2018-07-02 | 36 Upvotes 9 Comments
๐ Von Neumann-Landauer limit
Landauer's principle is a physical principle pertaining to the lower theoretical limit of energy consumption of computation. It holds that "any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information-bearing degrees of freedom of the information-processing apparatus or its environment".
Another way of phrasing Landauer's principle is that if an observer loses information about a physical system, the observer loses the ability to extract work from that system.
A so-called logically-reversible computation, in which no information is erased, may in principle be carried out without releasing any heat. This has led to considerable interest in the study of reversible computing. Indeed, without reversible computing, increases in the number of computations-per-joule-of-energy-dissipated must come to a halt by about 2050: because the limit implied by Landauer's principle will be reached by then, according to Koomey's law.
At 20ย ยฐC (room temperature, or 293.15ย K), the Landauer limit represents an energy of approximately 0.0175ย eV, or 2.805ย zJ. Theoretically, roomโtemperature computer memory operating at the Landauer limit could be changed at a rate of one billion bits per second (1Gbps) with energy being converted to heat in the memory media at the rate of only 2.805 trillionths of a watt (that is, at a rate of only 2.805 pJ/s). Modern computers use millions of times as much energy per second.
Discussed on
- "Landauer's Principle" | 2023-05-27 | 80 Upvotes 32 Comments
- "Von Neumann-Landauer limit" | 2017-09-30 | 183 Upvotes 36 Comments