Analogues to much of today's work in ontologies have existed for centuries in text retrieval. The use of controlled vocabularies, or thesauri, has been fundamental to document indexing in library science. Thesauri serve several purposes, including:
[bull ] Knowledge organisation A thesaurus provides
a hierarchy of concepts that organises domain-specific knowledge.
[bull ] Terminology normalisation By
selecting a unique word or phrase to represent each domain
concept, then linking synonymous terms to it, a thesaurus enforces
terminological consistency.
[bull ] Query expansion A thesaurus facilitates the addition of terms
to a query by providing explicit hierarchical and lateral relationships
among terms.
These properties serve to mediate the information flow from indexer to user. Thesauri thus
serve many
of the same functions for people that ontologies are designed to serve for software agents. As
automated retrieval has developed over the decades since the inception of computer processing of text,
many techniques have been introduced to apply this typically manual work to the automated arena (see
Soergel (1985) for an introduction to library information systems, also Anderson and Pélrez-Carballo
(2001a, 2001b) for a summary of the intersection of human and machine indexing).