A Hybrid Extraction Model for Chinese Noun/Verb Synonymous bi-gram Collocations

A Hybrid Extraction Model for Chinese Noun/Verb Synonym bi-gram Collocations  Wanyin Li and Qin Lu Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong csclaireli@gmail.com, csluqin@comp.polyu.edu.hk Abstract. Statistical-based collocation extraction approaches suffer from (1) low precision rate because high co-occurrence bi-grams may be syntactically unrelated and are thus not true collocations; (2) low recall rate because some true collocations with low occurrences cannot be identified successfully by statistical-based models. To integrate both syntactic rules as well as semantic knowledge into a statistical model for collocation extraction is one way to achieve a high precision while keeping a reasonable recall. This paper designs a cascade system which employs a hybrid model by integrating both syntactic and semantic knowledge into a statistical model for Chinese synonymous noun/verb collocations extraction. The grammatically bounded noun/verb collocations are extracted first from a syntactic-rule based module, which is then inputted to a semantic-based module for further retrieval of low frequent bi-gram collocations. Keywords: Collocation extraction, statistical model, syntactic rules, semantic relationship, similarity calculation, HowNet. 1. Introduction According to (Benson, 1990), “collocation is an arbitrary and recurrent word combination”, and (Manning, 1999), “A collocation is an expression consisting of two or more words that corresponds to some conventional way of saying things”. The definitions imply the feasibility of statistics calculation on collocation identification, which has been widely employed by traditional collocation extraction systems (Dunning, 1993; Smadja, 1996; Sun, 1997; Manning, 1999). These statistical models which depended on word frequencies and association strength of co-occurrence (bi-grams) made them difficult to detect bi-gram collocations with lower frequencies. Moreover, bi-grams which occur with high frequencies may not be syntactically related. For example, “这/r 就/d 要/v 从/p 各自/r 的/u 实际/n 情况/n 出发/v” (It should be thought about according to the real condition). The bi-gram “实际(…)出发” bears a higher co-occurrence frequency from the corpus based on statistical models. However, it is syntactically ill-formed as a noun/verb phrases. (Choueka, 1993) defined collocations as “a sequence of two or more consecutive words, that has characteristics of a syntactic and semantic unit”, and (Cowie, 1978) defined them as “co-occurrence of two or more lexical items as realizations of structural elements within a given syntactic pattern”. This paper investigates how to extract the so called bi-gram synonym collocations which satisfy the synonym substitution rule in which a co-word or head-word of a given bigram can be replaced by another synonym word (Liu, 2002) and the substituted bigram is also existed. For example “重要/位置” and “主要/位置” are one synonym collocation pair because “重要” and “主要” are synonyms and “重要/位置” and “主要/位置” co-occurs in Chinese corpus. “重要/位置” and “重要/地位” is another synonym collocation pair because “位置” and “地位” are synonyms. Based on the  Acknowledgments “The work is partially supported by a grant from The Chiang Ching-kuo Foundation for International Scholarly Exchange under the project RG013-D-09” . Copyright 2011 by Wanyin Li, Qin Lu 25th Pacific Asia Conference on Language, Information and Computation, pages 430–439 430 previous work (Li et. al., 2005; Li …

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