M. Dojat, E. Keravnou, and P. Barahona (Eds.): AIME 2003, LNAI 2780, pp. 209–213, 2003. © Springer-Verlag Berlin Heidelberg 2003 Knowledge-Based Query Expansion over a Medical Terminology Oriented Ontology on the Web Linda Fatima Soualmia 1,2 , Catherine Barry 3 , and Stefan J. Darmoni 1,2 1 CISMeF & L@STICS, Rouen University Hospital, 76031 Rouen, France {lina.soualmia,stefan.darmoni}@chu-rouen.fr 2 PSI FRE CNRS 2645, INSA-Rouen, 76131 Mont-Saint Aignan, France 3 LaRIA, Picardie University, 80000 Amiens, France barry@laria.u-picardie.fr Abstract. This paper deals with the problem of information retrieval on the Web and present the CISMeF project (acronym of Catalogue and Index of French-speaking Medical Sites). Information retrieval in the CISMeF catalogue is done with a terminology that is similar to ontology of medical domain and a set of metadata. This allows us to place the project at an overlap between the present Web, which is informal, and the forthcoming Semantic Web. We also describe an ongoing work, which consists of applying three knowledge-based methods in order to enhance information retrieval. 1 Introduction Nowadays the problematic is intelligent information retrieval on the Web. The Se- mantic Web [1] is an infrastructure that has to be built. It aims at creating a web where information semantics are represented in a form that can be understood by human as well as machines in order to enable computers and people to work in co- operation. One of its advantages is to bring sufficient information on the resources, by adding annotations in the form of metadata and to describe formally and significantly their content according to an ontology. Ontologies are considered to be powerful tools to lift ambiguity by providing a controlled vocabulary of terms and some specification of their meaning and are very useful for interoperability and for browsing and search- ing. Metadata describe Web information resources enhancing information retrieval. In this paper we present the CISMeF 1 project [2] (acronym of Catalogue and Index of French-speaking Medical Sites) developed since 1995. The objective of CISMeF is to help health professionals, as well as students and the general public, during their search for electronic health information. The CISMeF catalogue describes and in- dexes a large number of health information resources (n=11,504). A resource can be a Web site, Web pages, documents, reports and teaching material: any support that may contain health information. The resources are selected according to strict criteria by the librarian team and are indexed according to a methodology. The resources indexed in the CISMeF catalogue are described according to a terminology that is similar to an ontology of the medical domain, and a set of metadata elements. This structure en- 1 http://www.chu-rouen.fr/cismef/