A Monolithic Approach and a Type-by-Type Approach for Non-Factoid Question-answering - Yokohama National University at NTCIR-6 QAC

In order to process non-factoid questions in NTCIR6 QAC, we introduced two types of approaches. First one has a monolithic architecture that retrieves answer passages related to a question using lexical chain. The other one has a type-by-type architecture and consists of four subsystems: i) the subsystem for definitional and other-type questions, ii) the subsystem for why-type questions, iii) the subsystem for how-type questions, and iv) the subsystem for factoid questions. Each of two approaches is based on a common hypothesis that the appropriateness of answer candidate for non-factoid questions can be measured by the combination of a) appropriateness of writing style and b) relevance to the question.