Extraction Model
  Extraction Model:A nswer sentence selection   Due to increasing complexity in question answering, deep learning has become a popular trend in solving difficult problems.   Approaches   Word Count:  counts the number of non-stopwords in the question that also occur in the answer sentence.    Weighted Word Count:  re-weights the counts by the IDF values of the question words.   LCLR  :makes use of rich lexical semantic features, including word/lemma matching, WordNet and vector-space lexical semantic models.   Convolutional Neural Network   Recurrent Neural Network   
