Estereoquímica

A classification is a system organized and arranged hierarchically of classification of knowledge in a particular field, even of the totality of knowledge.

The principal users of classifications are the specialists in sciences of nature, the librarians and the philosophers.

Classifications relating to a limited field of knowledge are generally quite allowed by the specialists in the field. Classifications with universal vocation cannot disregard point of view and are, so the object of many criticisms. They however bring a lighting on the nature of knowledge.

Classifications are important to organize knowledge and the work of each one within the unit. To classify knowledge, it is to say how they are located the ones compared to the others. Several complementary points of view can be considered.

Classifications resulting from the world of sciences of nature

• scientific of the species or systematic Classification. Exit of the classification of alive established by Carl von Linné on the morphological characteristics (by comparison), it divides the world alive into five reigns and many encased categories.
• phylogenetic Classification. Classification of the living beings expressing their relations of relationship. It thus replaces classifications with utility aiming or of arrangement. Methods of phylogenetic classification, while being able to use various typestyles (morphological, genetic,…), seek a representation of alive translating its evolutionary history.
• Classification APG II. The scientific classification of the angiospermes most recent established according to work of the Angiosperms Phylogeny Group .
• Classification of the stars.
• periodic Table of the elements. Also called table of Mendeleïev , periodic classification of the elements, or simply periodic table, it represents all the chemical elements, grouped by their Atomic number.

Classifications resulting from the world of the libraries

• Decimal system of Dewey (CDD)
• universal Decimal system (CDU). Exit of the CDD.
• BBK . Classification from Marxist-Leninist point of view, resulting from CDU, of use of the time of the the USSR.
• Classification of the Library of the Congress (LCC)
• Facetted classification of Ranganathan
• Principles of classification of the printed music (PCDM)
• Classification Freinet

Classification in the semantic Web

See also: Diagram of classification

Million documents “is installed” on the Web. But accessibility with these documents is only very partial. A usual Search engine allows a nonsemantic access.

An access “Sémantique” will be carried out when the words entered by the Net surfer his search engine are decoded in term of directions then connected to same documents them Indexé S according to their direction, thanks to special markers in the Web pages (“beacons” allowing to connect the pages). It is what one names the semantic Web.

For that it is necessary to develop a Langage semantic treatment/classification for example containing ontology.

Classification of defense

See also: classified Information

Other classifications

• Hierarchy of Chomsky (classification of the formal languages)
• Classification of sciences out of Russian headstocks
• musical Classification
• Classification of the engines

See too

• Thesaurus
• Theory of the prototype