This link has been bookmarked by 52 people . It was first bookmarked on 06 Apr 2007, by Wisely.
-
31 Dec 17
-
19 Aug 13
-
02 Jul 13
-
21 Dec 12
-
10 Aug 12
-
In recent years free text search as a means of access to documents has become popular. This involves using natural language indexing with an indexing exhaustively set to maximum (every word in the text is indexed)
-
-
23 Jun 12
Dante-Gabryell MonsonControlled vocabularies provide a way to organize knowledge for subsequent retrieval. They are used in subject indexing schemes, subject headings, thesauri, taxonomies and other form of knowledge organization systems. Controlled vocabulary schemes mandate the use of predefined, authorised terms that have been preselected by the designer of the vocabulary, in contrast to natural language vocabularies, where there is no restriction on the vocabulary.
-
05 Mar 12
-
Controlled vocabularies solve the problems of homographs, synonyms and polysemes by a bijection between concepts and authorized terms. In short, controlled vocabularies reduce ambiguity inherent in normal human languages where the same concept can be given different names and ensure consistency.
-
There are two main kinds of controlled vocabulary tools used in libraries: subject headings and thesauri.
-
once the correct authorized term is searched, you don't need to worry about searching for other terms that might be synonyms of that term.
-
The use of controlled vocabulary ensures that everyone is using the same word to mean the same thing
-
-
11 Nov 11
-
In library and information science controlled vocabulary is a carefully selected list of words and phrases, which are used to tag units of information (document or work) so that they may be more easily retrieved by a search
-
-
06 Jul 11
-
Controlled vocabulary schemes mandate the use of predefined, authorised terms that have been preselected by the designer of the vocabulary, in contrast to natural language vocabularies, where there is no restriction on the vocabulary.
-
Controlled vocabularies solve the problems of homographs, synonyms and polysemes by a bijection between concepts and authorized term
-
Controlled vocabularies also typically handle the problem of homographs, with qualifiers. For example, the term "pool" has to be qualified to refer to either swimming pool, or the game pool to ensure that each authorized term or heading refers to only one concept.
-
-
Compared to free text searching, the use of a controlled vocabulary can dramatically increase the performance of an information retrieval system, if performance is measured by precision (the percentage of documents in the retrieval list that are actually relevant to the search topic).
-
In some cases controlled vocabulary can enhance recall as well, because unlike natural language schemes, once the correct authorized term is searched, you don't need to worry about searching for other terms that might be synonyms of that term.
-
However, a controlled vocabulary search may also lead to unsatisfactory recall, in that it will fail to retrieve some documents that are actually relevant to the search question.
This is particularly problematic when the search question involves terms that are sufficiently tangential to the subject area such that the indexer might have decided to tag it using a different term (but the searcher might consider the same). Essentially, this can be avoided only by an experienced user of controlled vocabulary whose understanding of the vocabulary coincides with the way it is used by the indexer.
-
ontrolled vocabularies are also quickly out-dated and in fast developing fields of knowledge
-
-
26 Jun 11
-
15 Apr 11
-
26 Feb 11
-
24 Feb 10
-
18 Jul 09
-
16 Jul 09
Melanie WackerWikipedia article providing an introduction to controlled vocabularies.
-
07 Jan 09
-
19 Apr 08
-
05 Feb 08
-
30 Nov 07
-
06 Apr 07
Would you like to comment?
Join Diigo for a free account, or sign in if you are already a member.