UniNE at CLEF 2009: Persian Ad Hoc Retrieval and IP

This paper describes the participation of the University of Neuchâtel to the CLEF 2008 evaluation campaign. In the Persian ad hoc task, we suggest using a light suffixstripping algorithm for the Farsi language and the evaluations demonstrated that such an approach performs better than a simple light stemmer, an approach ignoring the stemming stage or a language independent approach (n-gram). The use of a blind query expansion (e.g., Rocchio’s model) may improve the retrieval effectiveness. Combining different indexing and search strategies may further enhance the corresponding MAP. In the Intellectual Property (IP) task, we try different strategies to select and weight pertinent words to be extracted from a patent description in order to form an effective query. We also evaluated different search models and found that probabilistic models tend to perform better than vector-space schemes.