Automated Generation of Category-Specific Thesauri for Interactive Query Expansion⋆

The categorisation of documents into subject-specific categories is a useful enhancement for large document collections addressed by information retrieval (IR) systems, as a user can first browse a category tree in search of the category that best matches her interests, and then issue a query for more specific documents “from within the category”. This approach combines two modalities in information seeking that are most popular in Web-based search engines, i.e. category-based site browsing (as exemplified by e.g. Yahoo!) and keyword-based document querying (as exemplified by e.g. AltaVista). In the framework of the Eurosearch Project, we are addressing the problem of the automatic categorisation of Web documents and sites within Yahoo!-like hierarchies of categories [1,4]. The tools resulting from this project allow to overcome a major bottleneck in today’s Web information organisation, i.e. the need for manual categorisation of Web documents and sites; this latter modality is inadequate, in view of the ever increasing size of the Web and of its ever evolving content.