Abstract
This paper describes a dialog based QA system, Dialog Navigator, which can answer questions based on large text knowledge base. This system is targeted at users of personal computers. We released the system on the WWW in April 2002. In real world QA systems, vagueness of questions is a big problem. Our system can navigate users to the desired answers using the following methods: asking users back with dialog cards, and description extraction of each retrieved text. Another feature of the system is that it retrieves relevant texts precisely, using question types, synonymous expression dictionary, and modifier-head relations in Japanese sentences.
