Combining ontological profiles with context in information retrieval

An ontology is a formal conceptualization of a domain, specifying the concepts of the domain and the relations between them. It is however not a straight forward task to use this knowledge for information retrieval purposes. In this paper we describe the concept of an ontological profile, which is a semantic extension of an ontology where each ontology concept is given a description in terms of a vector of weighted keywords. An experiment has been conducted with a prototype search engine using ontological profiles for query expansion. The evaluation shows encouraging results compared to standard keyword based search. Furthermore, we describe the notion of context in an information retrieval setting and address how we can combine semantics and context in search based on query expansion.