Decreased-Adding-Based Question-Answering System Using Simple Connection Method for Contextual Questions

We participated in NTCIR QAC-1, QAC-2, and QAC-3, which were evaluation workshops for answering questions held by the National Institute of Informatics of Japan and studied question-answering systems for contextual questions. Contextual questions are defined as a series of questions with contexts. For example, the first question is “What is the capital of Japan?” and the one succeeding is related to the first such as “What was it called in ancient times?”. Contextual question-answering can be considered interactive. This paper describes our system for contextual questions. Our question-answering system used numerous effective methods to answer questions. We used a method of connecting question sentences to handle contextual questions. We also used a method of using multiple documents to obtain more accurate answers. We confirmed that these methods were effective in the experiments. Our question-answering system obtained the second best accuracy in QAC-1 and the best accuracy in both QAC-2 and QAC-3 for contextual question answering. It is thus a high-performance system.