Event Oriented Query Expansion for News Event Queries

Query expansion techniques have been commonly used by participants in Temporal Summarization tack. However, many previous attempts focused on expanding queries based on their event types, which only covers partially of the information need represented by queries. The reason is that the queries in the TS track are about news events, and for an event query, the event related entities, which are the entities mentioned in the queries, are essential when defining the event. Given the query ”Vauxhall helicopter crash”, without ”Vauxhall” or ”helicopter”, the event cannot be specifically defined. Therefore, we argue that both event type and event related entities should be considered when expanding a query, and a model based query expansion framework is proposed which incorporates these two types of information. The framework is then employed by using external resources, such as external corpora and Wikipedia pages to build expansion models.