Czech Monolingual Information Retrieval Using Off-The-Shelf Components - the University of West Bohemia at CLEF 2007 Ad-Hoc track

The paper provides a brief description of the system assembled for the CLEF 2007 Ad-Hoc track by the University of West Bohemia. We have performed only monolingual experiments (Czech documents Czech queries) using two incarnations of the tf.idf model — one with raw term frequency and the other with the BM25 term frequency weighting — as implemented in the Lemur toolkit. The effect of the blind relevance feedback was also explored. Czech morphological analyser and tagger were used for lemmatization and stop word removal. The results achieved seem to be quite reasonable, with MAP ranging from 0.11. to 0.30.