De l'importance des synonymes pour la sélection de passages en question-réponse

Most of the question answering systems currently developped adopt a fairly similar architecture, which can be divided into three modules : question analysis, document retrieval and answer extraction. However they differ in their tools (indexing engine, parsers...) and the knowledge bases they use. Thus, for each of these systems, it is important to estimate the contribution of these tools or knowledge bases. In the context of the Equer campaign (evalution campaign for French question answering systems), our system FRASQUES produced two runs : one used synonyms for bi-terms only, the other for mono-terms too. The comparison of these two tests and the study of a broader corpus, in French and in English, allow us to measure the contribution of this kind of semantic knowledge. MOTS-CLÉS : Système de question-réponse, synonymie, évaluation