Random Articles (Page 22)
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๐ Stellar Sonata
SONATA VI are two paintings, Stellar sonata. Allegro and Stellar sonata. Andante, of Mikalojus Konstantinas ฤiurlionis from 1908.
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- "Stellar Sonata" | 2019-11-09 | 68 Upvotes 7 Comments
๐ Judy arrays are patented
In computer science, a Judy array is a data structure implementing a type of associative array with high performance and low memory usage. Unlike most other key-value stores, Judy arrays use no hashing, leverage compression on their keys (which may be integers or strings), and can efficiently represent sparse data, that is, they may have large ranges of unassigned indices without greatly increasing memory usage or processing time. They are designed to remain efficient even on structures with sizes in the peta-element range, with performance scaling on the order of O(log n). Roughly speaking, Judy arrays are highly optimized 256-ary radix trees.
Judy trees are usually faster than AVL trees, B-trees, hash tables and skip lists because they are highly optimized to maximize usage of the CPU cache. In addition, they require no tree balancing and no hashing algorithm is used.
The Judy array was invented by Douglas Baskins and named after his sister.
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- "Judy arrays are patented" | 2013-01-11 | 42 Upvotes 56 Comments
๐ 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.
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- "Constraint Programming" | 2022-09-11 | 125 Upvotes 58 Comments
๐ Horseshoe Theory
In popular discourse, the horseshoe theory asserts that the far-left and the far-right, rather than being at opposite and opposing ends of a linear continuum of the political spectrum, closely resemble each other, analogous to the way that the opposite ends of a horseshoe are close together. The theory is attributed to the French philosopher and writer of fiction and poetry Jean-Pierre Faye in his 2002 book Le Siรจcle des idรฉologies ("The Century of Ideologies").
Several political scientists, psychologists, and sociologists have criticized the horseshoe theory. Proponents point to a number of perceived similarities between extremes and allege that both have a tendency to support authoritarianism or totalitarianism; this does not appear to be supported by scholars in the field of political science, and the few instances of peer-reviewed research on the subject are scarce. Existing studies and comprehensive reviews often find only limited support and only under certain conditions; they generally contradict the theory's central premises.
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- "Horseshoe Theory" | 2024-02-22 | 11 Upvotes 7 Comments
๐ Williams tube โ cathode ray tube used as computer memory
The Williams tube, or the WilliamsโKilburn tube after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early computers.
The Williams tube works by displaying a grid of dots on a cathode ray tube (CRT). Due to the way CRTs work, this creates a small charge of static electricity over each dot. The charge at the location of each of the dots is read by a thin metal sheet just in front of the display. Since the display faded over time, it was periodically refreshed. It cycles faster than earlier acoustic delay line memory, at the speed of the electrons inside the vacuum tube, rather than at the speed of sound. However, the system was adversely affected by any nearby electrical fields, and required constant alignment to keep operational. WilliamsโKilburn tubes were used primarily on high-speed computer designs.
Williams and Kilburn applied for British patents on 11 December 1946, and 2 October 1947, followed by United States patent applications on 10 December 1947, and 16 May 1949.
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- "Williams tube โ cathode ray tube used as computer memory" | 2015-11-26 | 57 Upvotes 16 Comments
๐ Cool Japan
Cool Japan (ใฏใผใซใธใฃใใณ, Kลซru Japan) refers to the aspects of Japanese culture that non-Japanese people perceive as "cool". The Cool Japan strategy is part of Japan's overall brand strategy, aiming to disseminate Japan's attractiveness and allure to the world. The target of Cool Japan "encompasses everything from games, manga, anime, and other forms of content, fashion, commercial products, Japanese cuisine, and traditional culture to robots, eco-friendly technologies, and other high-tech industrial products".
Cool Japan has been described as a form of soft power, with the ability to "indirectly influence behavior or interests through cultural or ideological means".
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- "Cool Japan" | 2023-10-04 | 17 Upvotes 1 Comments
๐ Goodhart's Law
Goodhart's law is an adage named after economist Charles Goodhart, which has been phrased by Marilyn Strathern as "When a measure becomes a target, it ceases to be a good measure." One way in which this can occur is individuals trying to anticipate the effect of a policy and then taking actions that alter its outcome.
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- "Goodhart's Law" | 2021-09-17 | 178 Upvotes 83 Comments
- "Goodhart's Law: When a measure becomes a target, it ceases to be a good measure" | 2018-06-15 | 229 Upvotes 134 Comments
๐ Hagia Triada Sarcophagus
The Hagia Triada Sarcophagus is a late Minoan 137ย cm (54ย in)-long limestone sarcophagus, dated to about 1400 BC or some decades later, excavated from a chamber tomb at Hagia Triada, Crete in 1903, and now on display in the Heraklion Archaeological Museum ("AMH") in Crete.
Uniquely for such a piece from this date on Crete, it is coated in plaster and painted in fresco on all faces. Otherwise the Minoans (unlike the ancient Egyptians) only used frescoes to decorate palaces and houses for the enjoyment of the living and not in funerary practice. It is the only limestone sarcophagus of its era discovered to date; there are a number of smaller terracotta "ash-chests" (larnax), painted far more crudely, usually in a single colour. It is the only object with a series of narrative scenes of Minoan funerary ritual (later sarcophagi found in the Aegean were decorated with abstract designs and patterns). It was probably originally used for the burial of a prince.
It provides probably the most comprehensive iconography of a pre-Homeric thysiastikis ceremony and one of the best pieces of information on noble burial customs when Crete was under Mycenaean rule, combining features of Minoan and Mycenaean style and subject matter, as well as probable influence from Ancient Egyptian religion.
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- "Hagia Triada Sarcophagus" | 2022-02-10 | 42 Upvotes 1 Comments
๐ $100 Hamburger
$100 hamburger ("hundred-dollar hamburger") is aviation slang for the excuse a general aviation pilot might use to fly.
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- "$100 Hamburger" | 2025-06-14 | 139 Upvotes 52 Comments
๐ Stigler's Law of Eponymy
Stigler's law of eponymy, proposed by University of Chicago statistics professor Stephen Stigler in his 1980 publication Stiglerโs law of eponymy, states that no scientific discovery is named after its original discoverer. Examples include Hubble's law, which was derived by Georges Lemaรฎtre two years before Edwin Hubble, the Pythagorean theorem, which was known to Babylonian mathematicians before Pythagoras, and Halley's Comet, which was observed by astronomers since at least 240 BC (although its official designation is due to the first ever mathematical prediction of such astronomical phenomenon in the sky, not to its discovery). Stigler himself named the sociologist Robert K. Merton as the discoverer of "Stigler's law" to show that it follows its own decree, though the phenomenon had previously been noted by others.
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- "Stigler's Law of Eponymy" | 2022-07-24 | 26 Upvotes 10 Comments