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π Constraint Programming
Constraint programming (CP) is a paradigm for solving combinatorial problems that draws on a wide range of techniques from artificial intelligence, computer science, and operations research. In constraint programming, users declaratively state the constraints on the feasible solutions for a set of decision variables. Constraints differ from the common primitives of imperative programming languages in that they do not specify a step or sequence of steps to execute, but rather the properties of a solution to be found. In addition to constraints, users also need to specify a method to solve these constraints. This typically draws upon standard methods like chronological backtracking and constraint propagation, but may use customized code like a problem specific branching heuristic.
Constraint programming takes its root from and can be expressed in the form of constraint logic programming, which embeds constraints into a logic program. This variant of logic programming is due to Jaffar and Lassez, who extended in 1987 a specific class of constraints that were introduced in Prolog II. The first implementations of constraint logic programming were Prolog III, CLP(R), and CHIP.
Instead of logic programming, constraints can be mixed with functional programming, term rewriting, and imperative languages. Programming languages with built-in support for constraints include Oz (functional programming) and Kaleidoscope (imperative programming). Mostly, constraints are implemented in imperative languages via constraint solving toolkits, which are separate libraries for an existing imperative language.
Discussed on
- "Constraint Programming" | 2022-09-11 | 125 Upvotes 58 Comments
π Tony Buzan, Inventor of the βMind Mapβ, Has Died
Anthony Peter "Tony" Buzan (; 2 June 1942 β 13 April 2019) was an English author and educational consultant.
Buzan popularised the idea of mental literacy, radiant thinking, and a technique called mind mapping, inspired by techniques used by Leonardo da Vinci, Albert Einstein, and Joseph D. Novak's "concept mapping" techniques.
Discussed on
- "Tony Buzan, Inventor of the βMind Mapβ, Has Died" | 2019-04-16 | 33 Upvotes 12 Comments
π Cecil Kelley criticality accident
A criticality accident occurred on December 30, 1958, at the Los Alamos National Laboratory in Los Alamos, New Mexico, in the United States. It is one of 60 known criticality events that have occurred outside the controlled conditions of a nuclear reactor or test, though it was the third such event that took place in 1958 after events on June 16 at the Y-12 Plant in Oak Ridge, Tennessee, and on October 15 at the VinΔa Nuclear Institute in VinΔa, Yugoslavia. The accident involved plutonium compounds dissolved in liquid chemical reagents; within 35 hours, it killed chemical operator Cecil Kelley by severe radiation poisoning.
Discussed on
- "Cecil Kelley criticality accident" | 2023-07-28 | 73 Upvotes 6 Comments
π Mercantilism
Mercantilism is a nationalist economic policy that is designed to maximize the exports and minimize the imports of an economy. In other words, it seeks to maximize the accumulation of resources within the country and use those resources for one-sided trade.
The concept aims to reduce a possible current account deficit or reach a current account surplus, and it includes measures aimed at accumulating monetary reserves by a positive balance of trade, especially of finished goods. Historically, such policies may have contributed to war and motivated colonial expansion. Mercantilist theory varies in sophistication from one writer to another and has evolved over time.
Mercantilism promotes government regulation of a nation's economy for the purpose of augmenting and bolstering state power at the expense of rival national powers. High tariffs, especially on manufactured goods, were almost universally a feature of mercantilist policy. Before it fell into decline, mercantilism was dominant in modernized parts of Europe and some areas in Africa from the 16th to the 19th centuries, a period of proto-industrialization. Some commentators argue that it is still practised in the economies of industrializing countries in the form of economic interventionism.
With the efforts of supranational organizations such as the World Trade Organization to reduce tariffs globally, non-tariff barriers to trade have assumed a greater importance in neomercantilism.
Discussed on
- "Mercantilism" | 2025-04-05 | 70 Upvotes 78 Comments
π Passage Du Gois
The Passage du Gois (French pronunciation: [pasaΚ dy Ι‘wa]) or GΓ΄a is a causeway between Beauvoir-sur-Mer and the island of Noirmoutier, in VendΓ©e on the Atlantic coast of France. The causeway is 4.125 kilometres (2.6Β mi) long and is flooded twice a day by the high tide. A road runs along the causeway.
Every year, a foot race β the FoulΓ©es du Gois β is held across it, starting at the onset of high tide.
Discussed on
- "Passage Du Gois" | 2024-04-07 | 20 Upvotes 3 Comments
π Attempto Controlled English
Attempto Controlled English (ACE) is a controlled natural language, i.e. a subset of standard English with a restricted syntax and restricted semantics described by a small set of construction and interpretation rules. It has been under development at the University of Zurich since 1995. In 2013, ACE version 6.7 was announced.
ACE can serve as knowledge representation, specification, and query language, and is intended for professionals who want to use formal notations and formal methods, but may not be familiar with them. Though ACE appears perfectly natural β it can be read and understood by any speaker of English β it is in fact a formal language.
ACE and its related tools have been used in the fields of software specifications, theorem proving, text summaries, ontologies, rules, querying, medical documentation and planning.
Here are some simple examples:
- Every woman is a human.
- A woman is a human.
- A man tries-on a new tie. If the tie pleases his wife then the man buys it.
ACE construction rules require that each noun be introduced by a determiner (a, every, no, some, at least 5, ...). Regarding the list of examples above, ACE interpretation rules decide that (1) is interpreted as universally quantified, while (2) is interpreted as existentially quantified. Sentences like "Women are human" do not follow ACE syntax and are consequently not valid.
Interpretation rules resolve the anaphoric references in (3): the tie and it of the second sentence refer to a new tie of the first sentence, while his and the man of the second sentence refer to a man of the first sentence. Thus an ACE text is a coherent entity of anaphorically linked sentences.
The Attempto Parsing Engine (APE) translates ACE texts unambiguously into discourse representation structures (DRS) that use a variant of the language of first-order logic. A DRS can be further translated into other formal languages, for instance AceRules with various semantics, OWL, and SWRL. Translating an ACE text into (a fragment of) first-order logic allows users to reason about the text, for instance to verify, to validate, and to query it.
Discussed on
- "Attempto Controlled English" | 2023-05-14 | 100 Upvotes 69 Comments
- "Attempto Controlled English" | 2019-09-12 | 243 Upvotes 60 Comments
π Norsk Data
Norsk Data was a (mini-)computer manufacturer located in Oslo, Norway. Existing from 1967 to 1992, it had its most active period in the years from the early 1970s to the late 1980s. At the company's peak in 1987 it was the second largest company in Norway and employed over 4,500 people.
Throughout its history Norsk Data produced a long string of extremely innovative systems, with a disproportionately large number of world firsts. Some examples of this are the NORD-1, the first minicomputer to have memory paging as a standard option, and the first machine to have floating-point instructions standard, the NORD-5, the world's first 32-bit minicomputer (beating the VAX, often claimed the first, by 6 years)
Discussed on
- "Norsk Data" | 2020-05-06 | 301 Upvotes 91 Comments
π OFFSystem
The Owner-Free File System (OFF System, or OFF for short) is a peer-to-peer distributed file system in which all shared files are represented by randomized multi-used data blocks. Instead of anonymizing the network, the data blocks are anonymized and therefore, only data garbage is ever exchanged and stored and no forwarding via intermediate nodes is required. OFF claims to have been created with the expressed intention "to cut off some gangrene-infested bits of the copyright industry."
Discussed on
- "OFFSystem" | 2020-05-01 | 127 Upvotes 93 Comments
π Pyroflatulence
Fart lighting also known as pyroflatulence, or flatus ignition is the practice of igniting the gases produced by flatulence. The resulting flame is often of a blue hue hence the act being known colloquially as a "blue angel", "blue dart" or in Australia, a "blue flame". The fact that flatus is flammable and the actual combustion of it through this practice gives rise to much humorous derivation. Other colors of flame such as orange and yellow are possible depending on the mixture of gases formed in the colon.
In 1999 author Jim Dawson observed that fart lighting has been a novelty practice primarily among young men or college students for decades but is discouraged for its potential for causing harm. Such experiments typically occur on camping trips and in same-sex group residences, such as tree-houses, dormitories, or fraternity houses. With the advent of video sharing features online, hundreds of self-produced videos, both documentary as well as spoof, have been posted to sites such as YouTube. The people appearing in the videos are predominantly young teen males. In his book The Curse of the Self: Self-Awareness, Egotism, and the Quality of Human Life author Mark Richard Leary explains how a great deal of unhappiness is due to people's inability to exert control over their thoughts and behavior and that "stupid stunts", including lighting flatulence, were a way to make an impression and be included in group bonding or hazing.
Although there is little scientific discourse on the combustive properties of flatus, there are many anecdotal accounts of flatus ignition and the activity has increasingly found its way into popular culture with references in comic routines, movies, and television; including cartoons. In Electric Don Quixote: The Definitive Story of Frank Zappa author Neil Slaven quotes Frank Zappa for calling fart lighting "The manly art of fart-burning", and another book quotes the musician Kenny Williams for saying that it demonstrates "compression, ignition, combustion and exhaust."
There have been documented cases of flatulence during surgery being inadvertently ignited causing patient injury and the risk of death.
Discussed on
- "Pyroflatulence" | 2021-08-21 | 11 Upvotes 2 Comments
π John C. Reynolds, Eminent Programming Language Researcher, has Died
John Charles Reynolds (June 1, 1935 β April 28, 2013) was an American computer scientist.
Discussed on
- "John C. Reynolds, Eminent Programming Language Researcher, has Died " | 2013-04-29 | 136 Upvotes 15 Comments