Advances in Open-Domain Question Answering

Question answering is one of the research hotspots in information retrieval and natural language understanding.This paper summarizes the up-to-date research advances in open-domain question answering,compares the different approaches in question analysis,document and passage retrieval,answer extraction according to different question types.The shortcomings of state-of-art techniques are also discussed,and further research directions for question answering are analyzed and prospected at last.