by Gosse Bouma and Sergio Duarte Torres.
We developed two systems (for Dutch and Spanish) for the GikiCLEF task, in which Wikipedia pages have to be found that match a description in natural language. We concentrated on linguistic analysis of the query, for mapping the question onto the most relevant Wikipedia categories, and for extracting additional constraints that matching pages have to satisfy. In addition, for Spanish we experimented with query expansion for improved recall of the IR process. In both the Dutch and Spanish system we tried to incorporate additional knowledge sources (WordNet, Yago, DbPedia) for better question analysis and retrieval results. The Dutch system obtained a GikiCLEF score of 2.5 (7th overall and 7th for Dutch). The Spanish system was still under development at the time of the official evaluation, and performed poorly. We show that the completed system would have performed well at the 2009 task. Read the paper.