Universal Decimal Classification

The Universal Decimal Classification is a system of library classification developed by the Belgian bibliographers Paul Otlet and Henri la Fontaine at the end of the 19th century. It is based on the Dewey Decimal Classification, but is much more powerful. It uses auxiliary signs to indicate various special aspects of a subject and relationships between subjects. It thus contains a significant faceted or analytico-synthetic element, and is used especially in specialist libraries. UDC has been modified and extended over many years to cope with the increasing output in all disciplines of human knowledge, and is still under continuous review to take account of new developments. The documents classified by UDC may be in any form. They will often be literature, i.e. written documents, but may also be in other media such as films, video and sound recordings, illustrations, maps, and realia such as museum pieces. UDC classifications use Arabic numerals and are based on the decimal system. Every number is thought of as a decimal fraction with the initial decimal point omitted, which determines filing order. For ease of reading, a UDC identifier is usually punctuated after every third digit. Thus, after 61 "Medical sciences" come the subdivisions 611 to 619; under 611 "Anatomy" come its subdivisions 611.1 to 611.9; under 611.1 come all of its subdivisions before 611.2 occurs, and so on; after 619 comes 62. An advantage of this system is that it is infinitely extensible, and when new subdivisions are introduced, they need not disturb the existing allocation of numbers. A document may be classified under a combination of different categories through the use of additional symbols. For example:
plus Addition e.g. 59+636 Zoology and animal breeding
nowiki>1 stroke Extension e.g. 592/599 Systematic zoology (everything from 592 to 599 inclusive)
nowiki>2 colon Relation e.g. 17:7 Relation of ethics to art
nowiki>3 square brackets Algebraic subgrouping e.g. 31:622+669(485) statistics of mining and metallurgy in Sweden (the auxiliary qualifies 622+669 considered as a unit)
nowiki>4 equals Language e.g. =20 in English; 59=20 Zoology, in English
UDC works extremely well with computers, as it did with earlier automatic sorting devices. A core version of UDC, with 60,000 subdivisions, is now available in database format, and is called the Master Reference File (MRF). The current full version of UDC has 220,000 subdivisions. See also: Bliss bibliographic classification, Colon classification, Library of Congress classification

External links

* Universal Decimal Classification Consortium home page

 

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ulvophyceae
united states navy
united states federalist party
united states army
united states marine corps
united states air force
university of toronto
university college of cape breton
university of new brunswick
university of sudbury
university of prince edward island
university of utah
university of victoria
university of manitoba
urban exploration
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urd
conservative party (uk)
upper peninsula of michigan
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umist
united nations convention to combat desertification
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university of chicago
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ultima
urethra
urethritis
u.s. virgin islands
history of the u.s. virgin islands
geography of the u.s. virgin islands
demographics of the u.s. virgin islands
politics of the u.s. virgin islands
economy of the u.s. virgin islands
communications on the united states virgin islands
transportation on the united states virgin islands
universal precautions
uniform resource identifier
union of international associations
unconsciousness
quarter (u.s. coin)
ural mountains