New Articles (Page 414)

To stay up to date you can also follow on Mastodon.

🔗 Mode X

🔗 Computing

Mode X is an alternative graphics display mode of the IBM VGA graphics hardware that was popularized by Michael Abrash. It was first published in July 1991 in Dr. Dobb's Journal, and republished in chapters 47-49 of Abrash's Graphics Programming Black Book (now freely available online). The term "Mode X" was coined by Abrash.

The primary advantage of Mode X is that it has square pixels: a resolution of 320×240 instead of the standard VGA Mode 13h which is 320×200. Additionally, Abrash enabled the VGA's planar memory mode (also called "unchained mode"). Even though planar memory mode is a documented part of the VGA standard and was used in earlier commercial games, it was first widely publicized in the Mode X articles, leading many programmers to consider Mode X and planar memory synonymous. It is possible to enable planar memory in standard 320x200 mode, which became known as Mode Y in the Usenet rec.games.programmer group.

Planar memory arrangement splits the pixels horizontally into groups of four. For any given byte in PC video memory, four pixels on screen can be accessed depending on which plane(s) are enabled. This is more complicated for the programmer, but the advantages gained by this arrangement—primarily the ability to use all 256 KB of VGA memory for one or more display buffers, instead of only one quarter of that (64 KB)—were considered worthwhile by many.

Discussed on

🔗 Development of Doom

🔗 Video games

Doom, a first-person shooter game by id Software, was released in December 1993 and is considered one of the most significant and influential titles in video game history. Development began in November 1992, with programmers John Carmack and John Romero, artists Adrian Carmack and Kevin Cloud, and designer Tom Hall. Late in development, Hall was replaced by Sandy Petersen and programmer Dave Taylor joined. The music and sound effects were created by Bobby Prince.

The Doom concept was proposed in late 1992, after the release of Wolfenstein 3D and its sequel Spear of Destiny. John Carmack was working on an improved 3D game engine from those games, and the team wanted to have their next game take advantage of his designs. Several ideas were proposed, including a new game in their Commander Keen series, but John proposed a game about using technology to fight demons inspired by the Dungeons & Dragons campaigns the team played. The initial months of development were spent building prototypes, while Hall created the Doom Bible, a design document for his vision of the game and its story; after id released a grandiose press release touting features that the team had not yet begun working on, the Doom Bible was rejected in favor of a plotless game with no design document at all.

Over the next six months, Hall designed levels based on real military bases, Romero built features, and artists Adrian and Cloud created textures and demons based on clay models they built. Hall's level designs, however, were deemed uninteresting and Romero began designing his own levels; Hall, increasingly frustrated with his limited influence, was fired in July. He was replaced by Petersen in September, and the team worked increasingly long hours until the game was completed in December 1993. Doom was self-published by id on December 10, 1993, and immediately downloaded by thousands of players.

Discussed on

🔗 Dempster–Shafer theory

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Epistemology

The theory of belief functions, also referred to as evidence theory or Dempster–Shafer theory (DST), is a general framework for reasoning with uncertainty, with understood connections to other frameworks such as probability, possibility and imprecise probability theories. First introduced by Arthur P. Dempster in the context of statistical inference, the theory was later developed by Glenn Shafer into a general framework for modeling epistemic uncertainty—a mathematical theory of evidence. The theory allows one to combine evidence from different sources and arrive at a degree of belief (represented by a mathematical object called belief function) that takes into account all the available evidence.

In a narrow sense, the term Dempster–Shafer theory refers to the original conception of the theory by Dempster and Shafer. However, it is more common to use the term in the wider sense of the same general approach, as adapted to specific kinds of situations. In particular, many authors have proposed different rules for combining evidence, often with a view to handling conflicts in evidence better. The early contributions have also been the starting points of many important developments, including the transferable belief model and the theory of hints.

Discussed on

🔗 The knowledge argument

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Philosophy of mind

The knowledge argument (also known as Mary's room or Mary the super-scientist) is a philosophical thought experiment proposed by Frank Jackson in his article "Epiphenomenal Qualia" (1982) and extended in "What Mary Didn't Know" (1986). The experiment is intended to argue against physicalism—the view that the universe, including all that is mental, is entirely physical. The debate that emerged following its publication became the subject of an edited volume—There's Something About Mary (2004)—which includes replies from such philosophers as Daniel Dennett, David Lewis, and Paul Churchland.

Discussed on

🔗 Graham Island (Sicily)

🔗 Volcanoes 🔗 Islands 🔗 Sicily 🔗 Seamounts

Graham Island (also Graham Bank or Graham Shoal; Italian: Isola Ferdinandea) is a submerged volcanic island in the Mediterranean Sea. It was discovered when it last appeared on 1 August 1831 by Humphrey Fleming Senhouse, the captain of the first rate Royal Navy ship of the line St Vincent and named after Sir James Graham, the First Lord of the Admiralty. It was claimed by the United Kingdom. It forms part of the underwater volcano Empedocles, 30 km (19 mi) south of Sicily, and which is one of a number of submarine volcanoes known as the Campi Flegrei del Mar di Sicilia. Seamount eruptions have raised it above sea level several times before erosion submerged it again.

When it last rose above sea level after erupting in 1831, a four-way dispute over its sovereignty began, which was still unresolved when it disappeared beneath the waves again in early 1832. During its brief life, French geologist Constant Prévost was on hand, accompanied by an artist, to witness it in July 1831; he named it Île Julia, for its July appearance, and reported in the Bulletin de la Société Géologique de France. Some observers at the time wondered if a chain of mountains would spring up, linking Sicily to Tunisia and thus upsetting the geopolitics of the region. It showed signs of volcanic activity in 2000 and 2002, forecasting a possible appearance; however, as of 2016 it remains 6 m (20 ft) under sea level.

Discussed on

🔗 Naming law in Sweden

🔗 Anthroponymy 🔗 Sweden

The naming law in Sweden (Swedish: lag om personnamn) is a Swedish law which requires approval of the government agency for names to be given to Swedish children. The parents must submit the proposed name of a child within three months of birth. The current law was enacted in 2017, replacing a 1982 law. The Swedish Tax Agency administers the registration of names in Sweden. The law has been revised since originally enacted; in 1983, it was made possible for men to adopt their wife's or partner's name, as well as for women to adopt their husband's name.

The 1982 law states, in part: "First names shall not be approved if they can cause offense or can be supposed to cause discomfort for the one using it, or names which for some obvious reason are not suitable as a first name" (§ 34). This text applies both when parents name their children and when an adult wants to change their own name. When changing a name, the first change is free of charge as long as at least one of the names given at birth is kept, and such a change is only allowed once per person. Further name changes require fee payment. The law states nothing about registering which name is used on a daily basis, but the tax authority can register that if requested.

Discussed on

🔗 Normally distributed and uncorrelated does not imply independent

🔗 Statistics

In probability theory, although simple examples illustrate that linear uncorrelatedness of two random variables does not in general imply their independence, it is sometimes mistakenly thought that it does imply that when the two random variables are normally distributed. This article demonstrates that assumption of normal distributions does not have that consequence, although the multivariate normal distribution, including the bivariate normal distribution, does.

To say that the pair ( X , Y ) {\displaystyle (X,Y)} of random variables has a bivariate normal distribution means that every linear combination a X + b Y {\displaystyle aX+bY} of X {\displaystyle X} and Y {\displaystyle Y} for constant (i.e. not random) coefficients a {\displaystyle a} and b {\displaystyle b} has a univariate normal distribution. In that case, if X {\displaystyle X} and Y {\displaystyle Y} are uncorrelated then they are independent. However, it is possible for two random variables X {\displaystyle X} and Y {\displaystyle Y} to be so distributed jointly that each one alone is marginally normally distributed, and they are uncorrelated, but they are not independent; examples are given below.

Discussed on

🔗 Neo Geo System

🔗 Video games

The Neo Geo (Japanese: ネオジオ, Hepburn: Neojio), stylised as NEO・GEO, also written as NEOGEO, is a cartridge-based arcade system board and fourth-generation home video game console released on April 26, 1990, by Japanese game company SNK Corporation. It was the first system in SNK's Neo Geo family. The Neo Geo was marketed as 24-bit; its CPU is technically a 16/32-bit 68000-based system with an 8/16-bit Z80 coprocessor, while its GPU chipset has a 24-bit graphics data bus.

The Neo Geo originally launched as the MVS (Multi Video System) coin-operated arcade machine. The MVS offers owners the ability to put up to six different cartridges into a single cabinet, a unique feature that was also a key economic consideration for operators with limited floorspace, as well as saving money long-term. With its games stored on self-contained cartridges, a game cabinet can be exchanged for a different game title by swapping the game's ROM cartridge and cabinet artwork. A home console version was also made, called AES (Advanced Entertainment System). It was originally launched as a rental console for video game stores in Japan (called Neo Geo Rental System), with its high price causing SNK not to release it for home use – this was later reversed due to high demand and it came into the market as a luxury console. The AES had the same raw specs as the MVS and had full compatibility, thus managed to bring a true arcade experience to home users. The Neo Geo was revived along with the brand overall in December 2012 through the introduction of the Neo Geo X handheld and home system.

The Neo Geo was a very powerful system when released, more powerful than any video game console at the time, and many arcade systems such as rival Capcom's CPS, which did not surpass it until the CP System II in 1993. The Neo Geo MVS was a success during the 1990s due to the cabinet's low cost, six ROM slots, and compact size. Several successful video game series were released for the platform, such as Fatal Fury, Art of Fighting, Samurai Shodown, The King of Fighters and Metal Slug. The AES had a very niche market in Japan, though sales were very low in the U.S. due to its high price for both the hardware and software; but it has since gained a cult following and is now considered a collectable. Neo Geo hardware production lasted seven years, discontinued in 1997, whereas game software production lasted until 2004, making Neo Geo the longest supported arcade system of all time. The AES console was succeeded by the Neo Geo CD and the MVS arcade by the Hyper Neo Geo 64. As of March 1997, the Neo Geo and the Neo Geo CD combined had sold 980,000 units worldwide. In 2009, the Neo Geo was ranked 19th out of the 25 best video game consoles of all time by video game website IGN.

Discussed on

🔗 This page crashes my chrome tab

🔗 India 🔗 Numismatics

The Indian rupee sign (sign: ; code: INR) is the currency symbol for the Indian rupee, the official currency of India. Designed by Udaya Kumar, it was presented to the public by the Government of India on 15 July 2010, following its selection through an "open" competition among Indian residents. Before its adoption, the most commonly used symbols for the rupee were Rs, Re or, in texts in Indian languages, an appropriate abbreviation in the language used.

The design is based on the Devanagari letter "र" (ra) with a double horizontal line at the top. It also resembles the Latin capital letter "R", especially R rotunda (Ꝛ).

The Unicode character for the Indian rupee sign is U+20B9 INDIAN RUPEE SIGN. Other countries that use a rupee, such as Sri Lanka, Pakistan and Nepal, still use the generic U+20A8 RUPEE SIGN character.

Discussed on

🔗 Succinct Data Structures

🔗 Computer science

In computer science, a succinct data structure is a data structure which uses an amount of space that is "close" to the information-theoretic lower bound, but (unlike other compressed representations) still allows for efficient query operations. The concept was originally introduced by Jacobson to encode bit vectors, (unlabeled) trees, and planar graphs. Unlike general lossless data compression algorithms, succinct data structures retain the ability to use them in-place, without decompressing them first. A related notion is that of a compressed data structure, in which the size of the data structure depends upon the particular data being represented.

Suppose that Z {\displaystyle Z} is the information-theoretical optimal number of bits needed to store some data. A representation of this data is called:

  • implicit if it takes Z + O ( 1 ) {\displaystyle Z+O(1)} bits of space,
  • succinct if it takes Z + o ( Z ) {\displaystyle Z+o(Z)} bits of space, and
  • compact if it takes O ( Z ) {\displaystyle O(Z)} bits of space.

For example, a data structure that uses 2 Z {\displaystyle 2Z} bits of storage is compact, Z + Z {\displaystyle Z+{\sqrt {Z}}} bits is succinct, Z + lg Z {\displaystyle Z+\lg Z} bits is also succinct, and Z + 3 {\displaystyle Z+3} bits is implicit.

Implicit structures are thus usually reduced to storing information using some permutation of the input data; the most well-known example of this is the heap.