ISO 25964-1-2011 pdf free download

ISO 25964-1-2011 pdf free download.Information and documentation Thesauri and interoperability with other vocabularies Part 1:Thesauri for information retrieval
Information et documentation — Thesaurus et interopOrabilitO avec d’autres vocabulaires — Partie 1: Thesaurus pour la recherche documentaire.
because a concept can often be expressed in more than one way. Furthermore, in ordinary discourse one term can have more than one meaning. Vocabulary control is therefore essential, and thesauri are used to achieve this by the following two principal means.
a) Concepts and terms are deliberately restricted in scope to selected meanings. Unlike the terms in a dictionary, which are often accompanied by a number of different definitions reflecting common usage. each term in a thesaurus is generally restricted to whichever single meaning serves the needs of a retrieval system most effectively, The structure of a thesaurus, notably its display of hierarchical relationships, frequently indicates the intended meaning of a term. If this technique is not sufficiently explicit, a scope note should accompany the term. This note should state the chosen meaning, and it may also indicate other meanings that are recognized in natural language but which have been deliberately excluded for indexing purposes.
b) When the same concept can be expressed by two or more synonyms or quasi-synonyms in the same language, one of these terms is usually s&ected as the preferred term, which is then used consistently in indexing or simply as the first or only term representing the concept. Reference to the preferred term should be made from any synonym that might also function as a user’s access point.
One consequence of using the measures in a) and b) for vocabulary control is that the resultant language might not correspond to a user’s preferences. The thesaurus has an important role in mediating between terms used in discourse and those that function effectively for information retrieval. To achieve the retrieval benefits, users need to accept a degree of artificiality in the controlled vocabulary (although in some systems this difficulty can be overcome by automatic substitution of the user’s term with the preferred form).
So that a thesaurus can function effectively in a multilingual context, the concepts included need to be represented in all of the languages present, enabling speakers of these languages to have access to them. If the thesaurus is symmetncal” as described in this part of ISO 25964 and modelled in Clause 15, each concept should have a preferred term in each language, and the scope should be the same in all the languages. This constraint sometimes adds to the artificiality of the vocabulary. Alternative approaches (for example the use of mappings between vocabularies) will be described in ISO 25964-2.
4.3 Paradigmatic versus syntagmatic relationships
The purpose of establishing and displaying relationships is likewise to guide users (or intelligent agents acting on their behalf) to choose the most appropriate term(s) for expressing a given concept. This is achieved by presenting terms that a user might consider instead of, or as well as, the term entered first. Means for displaying relationships are described in Clause 12.
Two kinds of relationship are commonly encountered between indexing terms in any one language.
a) Relationships that exist only because the concepts occur together in the context of a particular document are called syntagmatic relationships. When two or more indexing terms are assigned to the same document, this act effectively records a syntagmatic relationship between them. In a thesaurus, however, inclusion of syntagmatic relationships is not recommended.ISO 25964-1-2011 pdf free download.