Although subjects, objects, and their combination are widely used contextual information, the performances for subj and obj categories, as well as their combination subj+obj, were relatively poor.
because nouns are the main target of synonym acquisition, here we limit the target of acquisition to nouns, and firstly extract the cooccurrences between nouns and three categories of contextual information -dependency, sentence co-occurrence, and proximity -from each of three different corpora, and the performance of individual categories and their combinations are evaluated.