SINAI at CLEF 2006 Ad Hoc Robust Multilingual Track: query expansion using the

This year, we have participated on Ad-Hoc Robust Multilingual track with the aim to evaluate two issues of CLIR systems. Firstly, this paper describes the method fol-lowed for query expansion in a multilingual environment by using web search results provided by the Google engine in order to increment retrieval robustness. Unfortu-nately, the results obtained are disappointing. The second issue reported is relative to the robustness of several usual merging algorithms. We have found that 2-step RSV merging algorithms perform better than others algorithms when geometric precision is applied.