Then the feature based method explicitly extracts a variety of lexical, syntactic and semantic features for statistical learning, either generative or discriminative (Miller et al., 2000;Kambhatla, 2004;Boschee et al., 2005;Zhou et al., 2005;Jiang and Zhai, 2007).
we study the impact of the size of training data on cluster features and analyze the performance improvements through an extensive experimental study.