GeoTime Retrieval through Passage-based Learning to Rank

The NTCIR-9 GeoTime task is to retrieve documents to answer such questions as when and where certain events happened. In this paper we propose a Passage-Based Learning to Rank (PGLR) method to address this task. The proposed method recognizes texts both strongly related to the target topics and containing geographic and temporal expressions. The implemented system provides more accurate search results than a system without PGLR. Performance, according to the official evaluation, is average among submitted systems.