University of Hagen at CLEF 2004: Indexing and Translating Concepts for the GIRT Task

This paper describes the work done at the University of Hagen for our participation at the German Indexing and Retrieval Test (GIRT) task of the CLEF 2004 evaluation campaign. We conducted both monolingual and bilingual information retrieval experiments. For monolingual experiments with the German document collection, the focus is on applying and comparing three indexing methods targeting full word forms, disambiguated concepts, and extended semantic networks. The bilingual experiments for retrieving English documents for German topics rely on translating and expanding query terms based on a ranking of semantically related English terms for a German concept. English translations are compiled from heterogeneous resources, including multilingual lexicons such as EuroWordNet and dictionaries available online.