astronomy

Universal Decimal Classification

Universal Decimal Classification is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Universal Decimal Classification rather than just read about it. In short: 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. The UDC is a faceted classification system featuring detailed vocabulary and syntax that enables powerful content indexing and information retrieval in large collection…

Key takeaways

Universal Decimal Classification belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Universal Decimal Classification to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Universal Decimal Classification from memory before moving on to harder problems.

Reference excerpt

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. The UDC is a faceted classification system featuring detailed vocabulary and syntax that enables powerful content indexing and information retrieval in large collections. Since 1991, the UDC has been owned and managed by the UDC Consortium, a non-profit international association of publishers with headquarters in The Hague, Netherlands. Unlike other library classification schemes that started their life as national systems, the UDC was conceived and maintained as an international scheme. Its translation into other languages started at the beginning of the 20th century and has since been published in various printed editions in over 40 languages. UDC Summary, an abridged Web version of the scheme, is available in over 50 languages. 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. 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. 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.

History

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. 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 grew to more than eleven million records in the period before World War I. The catalogue and its content organized by UDC can still be seen in Mundaneum in Mons, Belgium. In 2013 this catalogue was accepted onto the UNESCO Memory of the World international register, recognising it as documentary heritage of global importance.

Application 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. UDC is also used in national bibliographies of around 30 countries. Examples of large databases indexed by UDC include:

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 (ISSN 1330-9862) 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" (ISSN 2070-4798). 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 (ISSN 1580-2949). 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. 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. The 2011 version of the MRF (released in 2012) contains over 70,000 classes. In the past full printed editions used to have around 220,000 subdivisions.

Structure

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Universal Decimal Classification

Start with the simplest possible case. Write down what Universal Decimal Classification claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Universal Decimal Classification before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Universal Decimal Classification ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Universal Decimal Classification

In research: Universal Decimal Classification appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Universal Decimal Classification in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Universal Decimal Classification is common in secondary-school and first-year university syllabi. It links to neighbouring topics Belgian inventions, Controlled vocabularies, Decimal classification systems, so understanding it makes those chapters shorter.
In everyday life: Look for Universal Decimal Classification outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Universal Decimal Classification in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Universal Decimal Classification means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Universal Decimal Classification out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Universal Decimal Classification in simple terms?

Why does Universal Decimal Classification matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Universal Decimal Classification?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Universal Decimal Classification.