Universal Decimal Classification

From Hispanopedia

The Universal Decimal Classification (Spanish: Clasificación Decimal Universal, CDU), also known by its English name 'Universal Decimal Classification' (UDC), is a knowledge classification system that arose from the need to arrange and classify the works in libraries.

Melvil Dewey, librarian of Amherst College in Massachusetts, United States, created the Dewey Decimal Classification (DDC) in 1876. This system was adapted by two Belgian jurists, Paul Otlet and Henri La Fontaine, and first published in French as 'Répertoire Bibliographique Universel' in 1905. Since then it has been continuously revised and developed, proving to be a very flexible and effective system for classifying and arranging library holdings. It is based on ordering and organizing knowledge by means of digits. A main group is assigned a digit, from 0 to 9, and a new digit is added for each level that must be created within that group.

Unlike other library classification schemes that began as national systems, the UDC was conceived and developed as an international scheme. Its translation into various languages of the world began in the early 20th century, and it has since been published in several print editions in more than 40 languages. The classification has been modified and expanded over the years to cope with the growth of output in all areas of human knowledge, and it is still continuously revised to take new developments into account.

Characteristics and principles of the UDC

Universal Decimal Classification labels at the Maison Losseau.

It is a CLASSIFICATION because it logically structures the concepts that compose it and arranges them systematically
DECIMAL because it is ordered by the principle of decimal numbers (from 0 to 9)
UNIVERSAL because it covers all human knowledge
Faceted: the subject of the document depends on the aspect/nuance chosen
Hierarchical: each subdivision can be subdivided into its logical components
Synthetic: the enumerated classes are building blocks on which compound and complex classes are constructed by means of the various synthetic notational devices it possesses
Multidimensional, which allows a subject to be divided by several characteristics at the same time
International: because of its Arabic and decimal notation system

There are two main versions of the UDC, which differ in that one of them divides the content of the other's group 8 between group 4 and group 8. Both versions of this classification attempt to divide all knowledge into ten broad fields, which correspond to the main tables. Each one consists of a single number:

(Note: those marked with * correspond to one version, those marked with ** correspond to the other, and those without asterisks correspond to both.)[1]

The UDC numbers and notations are ordered following the hierarchical principle that goes from the general to the particular. Each table is in turn divided into another ten groups, and so on without limit; it is a decimal classification. The notation is structured using Arabic numerals that do not function as whole numbers.

The UDC is structured by means of:
Main numbers: Main tables
Auxiliary numbers: Auxiliary tables
Letters and words: Notations foreign to the UDC
Signs and symbols: They coordinate, extend, relate, subgroup and fix the order

Auxiliary tables

Coordination and extension

The coordination sign ( + ) joins two or more non-consecutive UDC numbers to designate associated concepts or different aspects of the same concept for which no number exists to represent them.

Example: (470+571) Russia, both the European and the Asian part.

The extension sign ( / ) joins the first and the last of a series of consecutive divisions to designate associated concepts or different aspects of the same concept for which no number exists to represent them.

Example: (7/8) Central and North America and South America. The Americas

Relation, subgrouping and order-fixing

The relation sign (: ) indicates the relation between two or more subjects by connecting their UDC numbers. They restrict rather than extend the connected subjects.

Example: 17:7 Morality in relation to art

Square brackets ( [] ) can be used for subgrouping. They are rarely used and have no classificatory value. They are used to clarify relations within the notation, especially when there are more than two.

Example: [54+66] Pure and applied chemistry [622+699](485) Mining and metallurgy in Sweden

The fixed relation sign (:: ) is similar to the colon. It is used to indicate a relation that cannot be changed (with : the order does not matter, with :: it does).

Example: 575::576.3 Cytogenetics 77.044::355 War photographs

Common auxiliaries

They apply throughout all the tables (they are used with any number from the UDC tables). They are structured in the same way as the other tables. They have several divisions:

  • Independent: they are used attached to any UDC table or on their own as if they were main numbers. They are auxiliaries of language, form, place, race and time.
    • Language =...: it is distinguished by being a number preceded by the equals sign ( = ). The only thing this auxiliary does is designate the language in which the document is written.
      • Example: 61=111 Medical writing in English. The language is indicated when it is deemed necessary. It will also serve us as the basis for the subdivisions of table 8 (811 and 821)
      • Example: 663.4(493)(075)=112.5 The beer industry in Belgium written in Flemish. When a document has more than three languages it is considered multilingual. Up to three are placed one after another (ascending order)
    • Form (0...): the common auxiliaries of form indicate the form or presentation of the documents. They are not used to indicate the subject of the documents. They are normally placed after the subject notation, but if desired, all documents of the same form or presentation can be grouped under the appropriate form auxiliary, whatever the subject. Example: 54(035) Handbooks (035) of chemistry '54'
    • Place (1/9): they indicate the geographical area, locality and other matters relating to the spatial aspect of a concept classified by a main UDC number. It is normally used after the subject notation.
      • Example: 354(460) Central administration '354' in Spain (460)
    • Races, peoples and nationalities (=...): they indicate the nationality or ethnic aspects of a subject represented by a main UDC number. They derive from the common auxiliaries of language and can serve to distinguish linguistic-cultural groups. They normally follow the main UDC number.
      • Example: 398(=81/=82) Folklore of the Indians of North America
    • Time "...": they indicate the date, point in time or time interval of a subject represented by a main UDC number. It is cited after the main number, but in a compound index it could be interposed at the beginning or the end. Dates are indicated following the sequence year-month-day within double quotation marks. The year is always expressed with four digits, and the month and the day with two digits, padding with zeros when necessary. BC and AD dates can be indicated with the prefix ( - ) for BC years and the sign ( + ) for AD years. Centuries and decades can be indicated with two and three digits respectively. Intervals of several centuries, decades or years can be indicated with the initial and final figures, using the slash ( / ). When one of the dates is indeterminate, it is represented with three dots (...). If it is necessary to indicate the exact hour, minute or second of an event, it can be indicated using two-digit notations separated by a period (.)
      • Examples: 785.7"18" Chamber music of the 19th century ("18")
        "1898.12.11" December 11, 1898
        "-0054" the year 54 BC
        "03" 4th century
        "1815/1830" Period from 1815 to 1830
        930.9".../18" History of the world up to the end of the 19th century
        "1898.12.07.15.56.03" December 7, 1898, at 15 hours, 56 minutes and 3 seconds
  • Dependent: they are always used with a number from the main tables. They are auxiliaries of points of view, materials and persons.
      • Properties -02 express general properties or attributes of entities. They are applicable in all the main tables if the property aspect is secondary to the subject. They are always added as suffixes to the main number or the notation that expresses the subject to be qualified.
        • example: -021.181 Fantasy
        • -024.12 Synthetic
        • -028.14 Abridged
      • Materials -03...: they indicate the materials or components in which an object is made or of which it consists. They are applied in all the main tables when the material aspect is secondary. They cannot be used independently or cited first in a compound notation. They always go after a main number. They can be indicated by replacing -03 with an apostrophe ( ' )
          • Example: -036.674 Polyester resins
            -037.52 Fiberglass
            -036.674'752 Polyester and fiberglass
            Persons and personal characteristics -05: they always indicate persons or their characteristics, but are never applied to objects or disciplines. They are applicable to all the main tables if the personal aspect is secondary with respect to the subject. The subdivisions can be combined with each other or with other auxiliaries. They cannot be used independently or cited first in a compound notation. They always go after a main number or notation that expresses the subject it qualifies.
          • Example: 294.3 Buddhism
            294.3-05 Buddhists

The order when all of them appear is as follows: points of view, place, time, form, materials and persons, language, races and peoples.

Parallel subdivision

Its symbol resembles ( ≈ ). One must start from the number before the sign, and then, from the number of interest in the table that follows the sign, we find the corresponding number that indicates the auxiliary we need.

Example:

061.232 Societies formed by specific social groups 061.232≈323.3 indicates that it can be specified by going to table 323.3 We want the class of agricultural workers: 323.333

The 323.333 no longer interests us,

061.232 323.333

therefore, the result is: 061.232.33

Specification of a subject by means of notations foreign to the UDC

  • The asterisk (*): introduces a notation that is not an authorized UDC number. The source of the code must be indicated in a note. It can also be used to indicate the assignment of an unauthorized notation used only locally for a concept missing from the UDC.

Example: 523.44*433 Minor planet Eros (number authorized by the IAU) 546.42.027*90 Strontium 90 (atomic mass number of the isotope)

  • Direct alphabetical specification (A/Z): for alphabetical specification, the alphabetical notation is added directly to the UDC base number without using the asterisk or leaving a blank space.

Example: (492.83Utrecht) City of Utrecht

Subdivisions of special auxiliaries

The special auxiliary subdivisions -1/-9, .01/.09 and '0/'9 are of limited application. In special auxiliaries, the same notation can be used with different meanings in different parts of the main tables.

There are three types of notations for the subdivisions of special auxiliaries:

  • Hyphen series -1/-9: they are analytical or function-differentiating, and serve to indicate elements, components, properties and other details of the subject of the main UDC number.
  • Point-zero series .01/.09: they are used for more diverse purposes. They offer classes and subclasses of recurring characteristics such as aspects, studies, activities, processes, installations and equipment.
  • Apostrophe series '0/'9: they have a synthesizing or integrating function, indicating compound subjects by means of compound notations. They are often fully enumerated, but elsewhere they derive from main numbers by parallel division.

Special auxiliaries can be used alone or in combination with other auxiliaries:

  • Citing a single auxiliary
  • Citing several auxiliaries with the same symbol (homogeneous chain)
  • Citing several auxiliaries with different symbols (heterogeneous chain)

Advantages and disadvantages

Advantages

  • Unambiguousness of the numbers
  • Possibility of expanding the system
  • Its usefulness when arranging documents
  • The main tables have a hierarchical structure, which makes the scheme flexible to a certain extent. This is an advantage, not a disadvantage: the fact that it is flexible means that such a combination of numbers facilitates thematic expansion.

Disadvantages

  • The slowness in introducing any change
  • The fact that it allows different elements to be combined with each other to indicate complete subjects makes the syntax complicated
  • The alphabetical index is very poor
  • Many concepts appear in duplicate in the tables
  • It is an artificial code, so it may provoke a certain rejection in the user

Differences between the UDC and the DDC

  • The UDC has evolved and been applied more generally in continental Europe (Germany, France, Spain, Italy...), while the Dewey classification has been used above all in Anglo-Saxon countries (Ireland, United Kingdom, United States, part of the Commonwealth of Nations) and Latin America.
  • The UDC is more complex to use than the DDC, offering not only a system of subdivisions every three digits, but also the possibility of combining some subjects with others by means of various symbols. It is even possible to create new categories without modifying the classification by relating some figures with others. A clear example in this respect, often given in library science faculties to students learning to use the UDC, is Bioethics, which is classified by relating the digits of Ethics (Philosophy, within class 1) with those of Biology (Health sciences, within class 6).
  • The UDC therefore offers a system of scientific use for the organization of knowledge, while the DDC generally confines itself to the classification of documents and the organization of a library.
  • In the UDC there is a vacant main class (4), which is reserved for future restructurings of the classification, while in the DDC all classes from 0 to 9 are used.

The UDC today

In Spain the UDC was known from its beginnings. Writers such as Manuel Castillo, for example, wrote articles about it. As early as 1915, instructions were approved determining that the UDC had to be used in the new popular libraries that were created. The director of the National Library chose the UDC to compile the systematic subject catalog. After the Civil War, a ministerial order established that public libraries had to use the UDC.

From 1989 its use ceased to be mandatory, but it was still compulsory to produce a systematic subject catalog, without specifying with which classification. Although the UDC is an appropriate system for users of open-access general libraries to be able to easily locate documents that deal with a single subject, it is also true that it has many limitations in university and specialized libraries. Nevertheless, this type of library continues to use the UDC for reasons of standardization and convenience, since cooperative cataloging and interlibrary loan would be more complicated without a common classification system.

The latest Spanish update of the UDC was translated and revised by the Classification Service belonging to the Technical Processing Department of the National Library of Spain in 2019, using the UDC Master Reference File (MRF), the master file that contains all UDC notations, originally in English, and which is periodically maintained and updated by the UDC Editorial Team, based in The Hague. On this occasion it was the UDC MRF12, which was published in December 2018 and includes changes in more than 6,000 classes (more than 2,000 new classes, 3,000 modifications and more than 700 cancellations). Among the most notable changes are those made in the tables of Common auxiliaries of language (Romance languages, African languages), Common auxiliaries of place (Central America, Antarctic territories, Scandinavian countries, Russian Federation), as well as in the main tables of Computer science, Media, Botany (invertebrates), Zoology (algae, fungi), Hygiene and Medicine.

The UDC Online in Spanish always shows the latest version of the MRF, translated and updated with the new classes that are added. As of 2019 it contains 70,000 entries, in addition to 11,000 records of currently canceled notations. This is a subscription service maintained and managed by AENOR, the Spanish publisher of the UDC Consortium.[2]

See also

References

  1. ↑ http://www.diba.cat/biblioteques/guia/serveis/cdu.asp Archived 2010-08-23 at the Wayback Machine (ca, in Catalan) Retrieved Monday, November 25 at 13:11 CET.
  2. ↑ https://es.udc-hub.com/
Retrieved from "https://en.hispanopedia.com/index.php?title=Universal_Decimal_Classification&oldid=2240"