BUPT at TREC 2009: Entity Track

in Entity Track in TREC2009. The task and data are both new this year. In our work, an improved two-stage retrieval model is proposed according to the task. The first stage is document retrieval, in order to get the similarity of the query and documents. The second stage is to find the relationship between documents and entities. We also focus on entity extraction in the second stage and the final ranking. 1