The Universal Decimal Classification (UDC) is a bibliographic and library classification representing the systematic arrangement of all branches of human knowledge organized as a coherent system in which knowledge fields are related and inter-linked.[1][2][3][4] The UDC is an analytico-synthetic and faceted classification system featuring detailed vocabulary and syntax that enables powerful content indexing and information retrieval in large collections.[5][6] Since 1991, the UDC has been owned and managed by the UDC Consortium,[7] a non-profit international association of publishers with headquarters in The Hague (Netherlands).
Unlike other library classification schemes that have started their life as national systems, the UDC was conceived and maintained as an international scheme. Its translation in world languages started at the beginning of the 20th century and has since been published in various printed editions in over 40 languages.[8][9] UDC Summary, an abridged Web version of the scheme, is available in over 50 languages.[10] The classification has been modified and extended over the years to cope with increasing output in all areas of human knowledge, and is still under continuous review to take account of new developments.[11][12]
Albeit originally designed as an indexing and retrieval system, due to its logical structure and scalability, UDC has become one of the most widely used knowledge organization systems in libraries, where it is used for either shelf arrangement, content indexing or both.[13] UDC codes can describe any type of document or object to any desired level of detail. These can include textual documents and other media such as films, video and sound recordings, illustrations, maps as well as realia such as museum objects.
Unlike other library classification schemes that have started their life as national systems, the UDC was conceived and maintained as an international scheme. Its translation in world languages started at the beginning of the 20th century and has since been published in various printed editions in over 40 languages.[8][9] UDC Summary, an abridged Web version of the scheme, is available in over 50 languages.[10] The classification has been modified and extended over the years to cope with increasing output in all areas of human knowledge, and is still under continuous review to take account of new developments.[11][12]
Albeit originally designed as an indexing and retrieval system, due to its logical structure and scalability, UDC has become one of the most widely used knowledge organization systems in libraries, where it is used for either shelf arrangement, content indexing or both.[13] UDC codes can describe any type of document or object to any desired level of detail. These can include textual documents and other media such as films, video and sound recordings, illustrations, maps as well as realia such as museum objects.
The UDC was developed by the Belgian bibliographers Paul Otlet and Henri La Fontaine at the end of the 19th century. In 1895, they created the Universal Bibliographic Repertory (Répertoire Bibliographique Universel) (RBU) which was intended to become a comprehensive classified index to all published information. The idea that the RBU should take the form of a card catalogue came from the young American zoologist Herbert Haviland Field, who was at the time himself setting up a bibliographical agency in Zurich, the Concilium Bibliographicum.[14] A means of arranging the entries would be needed, and Otlet, having heard of the Dewey Decimal Classification, wrote to Melvil Dewey and obtained permission to translate it into French. The idea outgrew the plan of mere translation, and a number of radical innovations were made, adapting the purely enumerative classification (in which all the subjects envisaged are already listed and coded) into one which allows for synthesis (that is, the construction of compound numbers to denote interrelated subjects that could never be exhaustively foreseen); various possible relations between subjects were identified, and symbols assigned to represent them. In its first edition in French "Manuel du Répertoire bibliographique universel" (1905), the UDC already included many features that were revolutionary in the context of knowledge classifications: tables of generally applicable (aspect-free) concepts—called common auxiliary tables; a series of special auxiliary tables with specific but re-usable attributes in a particular field of knowledge; an expressive notational system with connecting symbols and syntax rules to enable coordination of subjects and the creation of a documentation language proper.
The Universal Bibliographic Repertory itself has developed into a remarkable information resource. In the period before World War I it grew to more than eleven million records. The catalogue and its content organized by UDC can still be seen in Mundaneum in Mons, Belgium (in 2013 recommended for inclusion in the UNESCO Memory of the World Register[15]).
The application of UDC
UDC is used in around 150,000 libraries in 130 countries and in many bibliographical services which require detailed content indexing. In a number of countries it is the main classification system for information exchange and is used in all types of libraries: public, school, academic and special libraries.[16][17][18]
UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include:[19]
NEBIS (The Network of Libraries and Information Centers in Switzerland) — 2.6 million records
COBIB.SI (Slovenian National Union Catalogue) — 3.5 million records
Hungarian National Union Catalogue (MOKKA) — 2.9 million records
VINITI RAS database (All-Russian Scientific and Technical Information Institute of Russian Academy of Science) with 28 million records
Meteorological & Geoastrophysical Abstracts (MGA) with 600 journal titles
PORBASE (Portuguese National Bibliography) with 1.5 million records
UDC has traditionally been used for the indexing of scientific articles which was an important source of information of scientific output in the period predating electronic publishing. Collections of research articles in many countries covering decades of scientific output contain UDC codes. Examples of journal articles indexed by UDC:
UDC code 663.12:57.06 in the article "Yeast Systematics: from Phenotype to Genotype" in the journal Food Technology and Biotechnology (ISSN1330-9862)[20]
UDC code 37.037:796.56, provided in the article "The game method as means of interface of technical-tactical and psychological preparation in sports orienteering" in the Russian journal "Pedagogico-psychological and medico-biological problems of the physical culture and sport" (ISSN2070-4798).[21]
UDC code 621.715:621.924:539.3 in the article Residual Stress in Shot-Peened Sheets of AIMg4.5Mn Alloy - in the journal Materials and technology (ISSN1580-2949).[22]
The design of UDC lends itself to machine readability, and the system has been used both with early automatic mechanical sorting devices, and modern library OPACs.[23][24] Since 1993, a standard version of UDC has been maintained and distributed in a database format: UDC Master Reference File (UDC MRF) which is updated and released regularly.[25] The 2011 version of the MRF (released in 2012) contains over 70,000 classes.[1] In the past full printed editions used to have around 220,000 subdivisions.[10]
UDC is used in around 150,000 libraries in 130 countries and in many bibliographical services which require detailed content indexing. In a number of countries it is the main classification system for information exchange and is used in all types of libraries: public, school, academic and special libraries.[16][17][18]
UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include:[19]
NEBIS (T
UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include:[19]
UDC has traditionally been used for the indexing of scientific articles which was an important source of information of scientific output in the period predating electronic publishing. Collections of research articles in many countries covering decades of scientific output contain UDC codes. Examples of journal articles indexed by UDC:
UDC code 663.12:57.06 in the article "Yeast Systematics: from Phenotype to Genotype" in the journal Food Technology and Biotechnology (