1. QUESTION ANALYSIS PRIOR STUDIES ON QUESTION ANALYSIS CAN ROUGHLY...

2.1. Question analysis

Prior studies on question analysis can roughly be divided into two classes: 1) question

classification and 2) Named Entity Recognition (NER) in questions.

Question Classification. Several approaches have been proposed to classify

questions, including rule-based methods [18], statistical learning methods [9], deep

neural network methods [12, 17], and transfer learning methods [16]. Madabushi and

Lee [18] present a purely rule-based system for question classification which

achieves 97.2% accuracy on the TREC 10 dataset [27]. Their system consists of two

steps: 1) extracting relevant words from a question by using the question structure;