Retrieval Using Structure for Question Answering

This paper examines the use of XML for modern extractionbased question answering (QA). We feel that the XML community has taken too narrow a view of structured retrieval, and that examining specific applications such as QA can give the XML retrieval community a broader view of the problems and challenges that structured retrieval faces. In our examination of QA, we argue that the next steps for retrieval supporting QA should be the use of a structured database for retrieval of passages. We believe retrieving passages could provide higher precision result lists without sacrificing the recall. This could greatly reduce the processing time for question extraction or allow the examination of more passages. The application of XML search technologies to QA is a realistic scenario and presents several interesting challenges to XML database systems. These challenges come in many forms: representation of structured documents in XML, indexing documents for efficient querying, and representation of queries. This paper explores these issues by considering techniques for question answering and also considers future directions for QA. Specific queries are provided as motivating examples.