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Kr

Specialty Definition: Kr

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Specialty Definition: ISO 3166-2:KR

(From Wikipedia, the free Encyclopedia)

The ISO 3166-2 standard for South Korea (ISO 3166-1: KR) assigns codes to 9 provinces, 1 special city, and 6 metropolitan cities.

The purpose of this family of standards is to establish a worldwide series of short abbreviations for places, for use on package labels, containers and such, or anywhere where a short alphanumeric code can serve to clearly indicate a location in a more convenient and less ambiguous form than the full place name. US readers may wish to consider them as the equivalent of worldwide zip or postal codes. Within the Wikipedia, the codes from the country pages link to the pages for the locations they identify.

Code system: "KR-" + 2-character-numeric

Latest change: ISO 3166-2:2000-06-21

Encoding list (16)

Note: Names are not spelled according to the ISO list, but to the official Revised Romanization of Korean as used in South Korea.

Special and Metropolitan Cities (7)

KR-11 Seoul Special City
KR-26 Busan Metropolitan City
KR-27 Daegu Metropolitan City
KR-28 Incheon Metropolitan City
KR-29 Gwangju Metropolitan City
KR-30 Daejeon Metropolitan City
KR-31 Ulsan Metropolitan City

Provinces (9)

KR-41 Gyeonggi-do
KR-42 Gangwon-do
KR-43 Chungcheongbuk-do
KR-44 Chungcheongnam-do
KR-45 Jeollabuk-do
KR-46 Jeollanam-do
KR-47 Gyeongsangbuk-do
KR-48 Gyeongsangnam-do
KR-49 Jeju-do

See also

• ISO 3166-2, the reference table for all country region codes.
• ISO 3166-1, the reference table for all country codes, as used for domain names on the internet.

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "ISO 3166-2:KR."

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Knowledge representation

(From Wikipedia, the free Encyclopedia)

Knowledge representation is a central problem in artificial intelligence. The question is how to store and manipulate knowledge in an information system in a formal way so that it may be used by mechanisms to accomplish a given task. Examples of applications are expert systems, machine translation systems, computer-aided maintenance systems and information retrieval systems (including database front-ends).

Some people think it would be best to represent knowledge in the same way that it is represented in human mind, which is the only known working intelligence so far, or to represent knowledge in the form of human language. Unfortunately, we don't know how knowledge is represented in the human mind, or how to manipulate human languages in the same way as the human mind.

For this reason, various artificial languages and notations have been proposed for representing knowledge. They are typically based on logic and mathematics, and have an easily parsed grammar to ease machine processing.

Recent fashion in knowledge representation languages is to use XML as the low-level syntax. This tends to make the output of these KR languages easy for machines to parse, at the expense of human readability.

First-order predicate calculus is commonly used as a mathematical basis for these systems, to avoid excessive complexity. However, even simple systems based on this simple logic can be used to represent data which is well beyond the processing capability of current computer systems: see computability for reasons.

Examples of notations:

• DATR is an example for representing lexical knowledge
• RDF is a simple notation for representing relationships between objects

Examples of artificial languages intended for knowledge representation include:

• CycL
• Loom
• OWL

Techniques of knowledge representation

Semantic networks may be used to represent knowledge. Each node represents a concept and the arcs are used to define relations between the concepts.

From earliest times, the knowledge frame or just frame has been used. A frame consists of slots which contain values; for instance, the frame for house might contain a color slot, number of floors slot, etc.

Frames can behave something like object-oriented programming languages, with inheritance of features described by the "is-a" link. However, there has been no small amount of inconsistency in the usage of the "is-a" link: Richard P. Gabriel wrote a paper titled "What IS-A is and isn't", wherein 29 different semantics were found in projects whose knowledge representation schemes involved an "is-a" link. Other links include the "has-part" link.

Frames suffer from the frame problem of knowledge linking.

Scripts are a type of frame that describes what happens temporally; the usual example given is that describing going to a restaurant. The steps include waiting to be seated, receiving a menu, ordering, etc.

See also:

• Metadata
• Ontology
• Douglas Lenat's Cyc project
• Semantic Web

References:

• Ronald J. Brachman; What IS-A is and isn't. An Analysis of Taxonomic Links in Semantic Networks; IEEE Computer, 16 (10); October 1983 [1]
• Jean-Luc Hainaut, Jean-Marc Hick, Vincent Englebert, Jean Henrard, Didier Roland: Understanding Implementations of IS-A Relations. ER 1996: 42-57 [1]

External links

• What is a Knowledge Representation? by Randall Davis and others
• DATR Lexical knowledge representation language
• Loom Project Home Page
• Description Logic in Practice: A CLASSIC Application
• Tools from Java-Channel.org
• Citations from CiteSeer.org

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Knowledge representation."

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Krypton

(From Wikipedia, the free Encyclopedia)

Bromine - Krypton Ar Kr Xe       Full table
General
Name, Symbol, Number	Krypton, Kr, 36
Chemical series	Noble gases
Group, Period, Block	18 (VIIIA), 4 , p
Density, Hardness	3.708 kg/m3 (273 K), NA
Appearance	colorless
Atomic Properties
Atomic weight	83.798 amu
Atomic radius (calc.)	no data (88) pm
Covalent radius	110 pm
van der Waals radius	202 pm
Electron configuration	[Ar]33d10 4s2 4p6
e- 's per energy level	2, 8, 18, 8
Oxidation states (Oxide)	0 (unknown)
Crystal structure	Cubic face centered
Physical Properties
State of matter	gas (nonmagnetic)
Melting point	115.79 K (-251.25 °F)
Boiling point	119.93 K (-153.22 °F)
Molar volume	27.99 ×1010-3 m3/mol
Heat of vaporization	9 .029 kJ/mol
Heat of fusion	1 .638 kJ/mol
Vapor pressure	NA
Speed of sound	1120 m/s at 293.15 K
Miscellaneous
Electronegativity	3.00 (Pauling scale)
Specific heat capacity	248 J/(kg*K)
Electrical conductivity	no data
Thermal conductivity	0.00949 W/(m*K)
1st ionization potential	1350.8 kJ/mol
2nd ionization potential	2350.4 kJ/mol
3rd ionization potential	3565 kJ/mol
4th ionization potential	5070 kJ/mol
5th ionization potential	6240 kJ/mol
6th ionization potential	7570 kJ/mol
7th ionization potential	10710 kJ/mol
8th ionization potential	12138 kJ/mol
Most Stable Isotopes
iso NA half-life DM DE MeV DP 78Kr 0.35% Kr is stable with 42 neutrons 80Kr 2.25% Kr is stable with 44 neutrons 81Kr {syn.} 229000 y Epsilon 0.281 81Br 82Kr 11.6% Kr is stable with 46 neutrons 83Kr 11.5% Kr is stable with 47 neutrons 84Kr 57% Kr is stable with 48 neutrons 85Kr {syn.} 10.756 y Beta- 0.687 85Rb 86Kr 17.3% Kr is stable with 50 neutrons
SI units & STP are used except where noted.

Alternate meanings: Krypton (planet), KRYPTON (programming language), others

Krypton is a chemical element in the periodic table that has the symbol Kr and atomic number 36. A colorless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionating liquefied air, and is often used with other rare gases in fluorescent lamps. Krypton is inert for most practical purposes but it is known to form compounds with fluorine.

Notable Characteristics

Krypton is a so-called noble gas due to its very low chemical reactivity and it is characterized by a brilliant green and orange spectral signature. It is one of the products of uranium fission. Solidified krypton is white and crystalline with a face-centered cubic crystal structure which is a common property of all "rare gases."

Applications

The international definition of the length of the meter was, from 1960 to 1983, based on the light emitted by excited krypton atoms as a standard: specifically, the meter was defined as 1,650,763.73 wavelengths of the orange-red emission line emitted by krypton-86 atoms.

Krypton clathrates have been made with hydroquinone and phenol. Kr-85 is used in chemical analysis. When it is placed in various solids kryptonates are formed and their activity is sensitive to surface chemical reactions. This noble gas is also used in photographic flash lamps needed for high-speed photography but this use is limited because of the high cost of krypton.

History

Krypton (Greek kryptos meaning "hidden") was discovered in 1898 by William Ramsay and Morris Travers in residue left from evaporating nearly all components of liquid air. In 1960 an international agreement defined the meter in terms of light emitted from a krypton isotope. This agreement replaced the longstanding standard meter located in Paris which was a metal bar made of a platinum-iridium alloy (the bar was originally estimated to be one ten millionth of a quadrant of the earth's polar circumference). In October 1983 the krypton standard was in turn replaced by the International Bureau of Weights and Measures. A meter is now defined as the distance that light travels in a vacuum during 1/299,792,458 s.

Occurrence

The concentration of this gas in earth's atmosphere is about 1 ppm. It can be extracted from liquid air by fractional distillation.

Compounds

Like the other rare gases krypton is widely considered to be chemically inert. However, studies conducted since the 1960s have uncovered some compoundss of krypton. Krypton difluoride has been made in gram quantities and can be produced in several different ways. Other fluorides and a salt of a krypton called oxyacid have also been found. ArKrKr+ and KrH+ molecule-ions have been investigated and there is evidence for KrXe or KrXe+.

Isotopes

Naturally occurring krypton is composed of six stable isotopes. Krypton's spectral signature is easily produced with some very sharp lines. Kr-81 is the product of atmospheric reactions with the other naturally occurring isotopes of krypton. It is radioactive with a half-life of 250,000 years. Like xenon, krypton is highly volatile when it is near surface waters and Kr-81 has therefore been used for dating old (50,000 - 800,000 year) groundwater. Kr-85 is an inert radioactive noble gas with a half-life of 10.76 years, that is produced by fission of uranium and plutonium. Sources have included nuclear bomb testing, nuclear reactors, and the release of Kr-85 during the reprocessing of fuel rods from nuclear reactors. A strong gradient exists between the northern and southern hemispheres where concentrations at the North Pole are approximately 30% higher than the South Pole due to convective mixing.

External Links

• WebElements.com - Krypton
• EnvironmentalChemistry.com - Krypton

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Krypton."

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KRYPTON

(From Wikipedia, the free Encyclopedia)

The KRYPTON programming language is a frame language.

"An Essential Hybrid Reasoning System: Knowledge and Symbol Level Accounts of KRYPTON", R.J. Brachman et al, Proc IJCAI-85, 1985.

This article (or an earlier version of it) contains material from FOLDOC, used with permission.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "KRYPTON."

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List of people by name: Kr

(From Wikipedia, the free Encyclopedia)

List of people by name: A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z Ka - Kb - Kc - Kd - Ke - Kf - Kg - Kh - Ki - Kj - Kk - Kl - Km - Kn - Ko - Kp - Kq - Kr - Ks - Kt - Ku - Kv - Kw - Kx - Ky - Kz

• Kraepelin, Emil, (1856-1926), psychologist
• Krafft-Ebing, Richard von, (1840-1902), sexologist
• Kraft, William, composer
• Krahl, Hilde, (1917-1999), actress
• Krajicek, Richard, (Netherlands)
• Krakar, Lojze, (1929-1995), poet
• Kralj, Alojz, (born 1937), electrical engineer.
• Kralj, Franc, (1895-1960), painter
• Kralj, Tone, (1900-1975), painter
• Krall, Diana, (born 1964), jazz pianist
• Kramberger, Ivan, (1936-1992), charitable man
• Kramberger, Taja, (born 1970), poet
• Kramer, Jack, (born 1921), tennis star
• Kramer, Jerry, (born 1936), American football star
• Kramer, Josef, (1906-1945), head of Bergen-Belsen concentration camp
• Kramer, Stanley, (1913-2001), US film director
• Kramnik, Vladimir, (born 1975), chess player
• Kramp, Willi, (1909-1986), writer
• Krantz, Judith, (born 1937), US author
• Krasovec, Metka, (born 1941), painter, graphic artist
• Kraus, Alfredo, (died 1999)
• Kraus, Joseph Martin, (1756-1792), composer
• Kraus, Karl, (1874-1936), dramatist, author
• Kravitz, Lenny, (born 1964), US guitarist & singer
• Kravos, Marko, (born 1943), poet
• Krebs, Johann Tobias, (died 1762), composer
• Kreisky, Bruno, (1911-1990), Chancellor of Austria
• Kreskin, (born 1935), mentalist
• Kress, Nancy, (born 1948), US science fiction writer
• Kretschmer, Otto, (1912-1998), U-boat commander
• Kreuger, Ivar, industrialist
• Kreuk, Kristin, (born 1982), US actress
• Kreutzmann, Bill, (born 1946), of The Grateful Dead
• Kreviazuk, Chantal, Canadian singer
• Krieger, Robby, (born 1946), musician ("The Doors")
• Krienbühl, Franz, (1929-2002), speed skater
• Kripke, Saul, (born 1940), philosopher
• Krishnamurti, Jiddu, (1895-1986), Indian philosopher
• Kristel, Sylvia, (born 1952), French erotic actress
• Kristen, Wulf, (born 1934), writer and recipient of the Heinrich Mann Prize 1989
• Kristl, Stanko, (born 1922), architect.
• Kristofferson, Kris, (born 1936), US singer-songwriter
• Krizaj, Bojan, (born 1957), alpine skier, Olympic athlete.
• Krizkovsky, Pavel, (born 1820), composer
• Kroc, Ray, (1902-1984), business person
• Kroetz, Franz Xaver, (born 1946), dramatist, author
• Krog, Nicolay Johan Lohmann, (1840-1841), Norwegian Prime Minister
• Krol, Joe, Canadian athlete
• Kroller-Muller, Helene, (1869-1939), German-born Dutch art collector
• Kroll, Leon, (1884-1974), American painter
• Kronecker, Leopold, (1823-1891), mathematician
• Kropotkin, Peter, (1842-1921), Russian anarchist
• Kroto, Sir Harold, (born 1939), English chemist
• KRS One, US rapper
• Krug, Manfred, (born 1937), actor
• Kruger, Paul, (1825-1904), South African statesman
• Krugman, Paul, (born 1953), American economist and newspaper columnist
• Krum, (died 814), khan of Bulgaria (brain haemorrage)
• Krupa, Gene, (1909-1973), US jazz drummer
• Krupp, Alfred, (died 1887), (Alfried Felix Alwyn Krupp von Bohlen und Halbach}, German munitions manufacturer
• Krupp, Friedrich Alfred, (1854-1902), industrialist
• Kruse, Martin, (born 1929), theologian
• Krusenstern, Adam Johann von, (1770-1846), naval commander
• Krush, Irina, (born 1983), chess player
• Kruss, James, (1926-1997), author

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "List of people by name: Kr."

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Abbreviations & Acronyms: Kr

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Commercial Usage: Kr

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Photo Album: Kr

Thumbnail	Description & Credit
	De gamle partier har-i-enighed-naaet, at vi nu betaler 5600 mill. kr. i direkte og indirekte skatter ... stem pa Retsforbundet, E. Credit: Library of Congress.
Source: pictures compiled by the editor from various references; see picture credits.

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Non-Fiction Usage: Kr

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Usage Frequency: Kr

Source: compiled by the editor from several corpora; see credits.

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Frequency of Internet Keywords: Kr

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Modern Translation: Kr

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Derivations: Kr

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Anagrams: Kr

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