While the obtained aspects may contain some synonym terms, such as "earphone" and "headphone," we further perform synonym clustering to get unique aspects.
we first expand each aspect term with its synonym terms obtained from the synonym terms Web site 2 , and then cluster the terms to obtain unique aspects based on 1 http://nlp.stanford.edu/software/lex-parser.shtml 2 http://thesaurus.com unigram feature.