Page 255 - DLIS402_INFORMATION_ANALYSIS_AND_REPACKAGING

Information Analysis and Repackaging

Notes The preceding runs on TIPSTER were done using the full length of the predefined queries. Online
queries are usually much simpler, and consist of few words. By dropping the description fields of
TIPSTER queries, online performance was measured. The improvement due to the use of a thesaurus
is greater than before, and as expected, “Both”-type query expansion provides the best results.

Make a chart on traditional view of the kinds of indexing languages.
Write a report on the development of indexing language.

Self Assessment

Fill in the blanks:
5. ..................... is indexing made by algorithmic procedures.
6. Related forms are the Permuterm Subject Index and the ................ known from ISI’s citation
indexes.
7. Our thesaurus will be made searchable through an .................... .
8. ................. the number of relevant items retrieved from a database compared to the total
number of items in the database.
9. Spelling usage is based on the ................ .
10. ................... and authority have been more of an issue for individual image collections.

11.8 Summary

• Indexed languages are a class of formal languages discovered by Alfred Aho.
• Indexed languages are a proper subset of context-sensitive languages.
• The word ‘Index’ comes from the Latin word ‘indicaire’, meaning ‘to point out or to guide’.
• Indexing results in an index whereas classification results in a class number.
• Index is a verbal representation of the subject contents of a document whereas the class num-
ber is represented in numbers or any other may be having ordinal value.
• Verbal indexing systems may be divided into “controlled vocabularies” and “free text sys-
tems”.
• The most important property of an indexing language is whether the indexer has to assign a
given unit to a pre-established conceptual system or not.
• There are two main kinds of controlled vocabulary tools used in libraries: subject headings
and thesauri.
• Subject headings were designed to describe books in library catalogues by cataloguers while
thesauri were used by indexers to apply index terms to documents and articles.
• While a thesaurus inherently contains a classification of terms in its hierarchical relation-
ships, it is intended for specific retrieval.
• Automatic indexing is indexing made by algorithmic procedures.
• Automatic indexing may be contrasted to human indexing.

250 LOVELY PROFESSIONAL UNIVERSITY