tailieunhanh - Báo cáo khoa học: "Semantic Class Induction and Coreference Resolution"

This paper examines whether a learningbased coreference resolver can be improved using semantic class knowledge that is automatically acquired from a version of the Penn Treebank in which the noun phrases are labeled with their semantic classes. Experiments on the ACE test data show that a resolver that employs such induced semantic class knowledge yields a statistically significant improvement of 2% in F-measure over one that exploits heuristically computed semantic class knowledge. In addition, the induced knowledge improves the accuracy of common noun resolution by 2-6%. . | Semantic Class Induction and Coreference Resolution Vincent Ng Human Language Technology Research Institute University of Texas at Dallas RichardsOn TX 75083-0688 vince@ Abstract This paper examines whether a learningbased coreference resolver can be improved using semantic class knowledge that is automatically acquired from a version of the Penn Treebank in which the noun phrases are labeled with their semantic classes. Experiments on the ACE test data show that a resolver that employs such induced semantic class knowledge yields a statistically significant improvement of 2 in F-measure over one that exploits heuristically computed semantic class knowledge. In addition the induced knowledge improves the accuracy of common noun resolution by 2-6 . 1 Introduction In the past decade knowledge-lean approaches have signihcantly influenced research in noun phrase NP coreference resolution the problem of determining which NPs refer to the same real-world entity in a document. In knowledge-lean approaches coreference resolvers employ only morpho-syntactic cues as knowledge sources in the resolution process . Mitkov 1998 Tetreault 2001 . While these approaches have been reasonably successful see Mitkov 2002 Kehler et al. 2004 speculate that deeper linguistic knowledge needs to be made available to resolvers in order to reach the next level of performance. In fact semantics plays a crucially important role in the resolution of common NPs allowing us to identify the coreference relation between two lexically dissimilar common nouns . talks 536 and negotiations and to eliminate George W. Bush from the list of candidate antecedents of the city for instance. As a result researchers have re-adopted the once-popular knowledge-rich approach investigating a variety of semantic knowledge sources for common noun resolution such as the semantic relations between two NPs . Ji et al. 2005 their semantic similarity as computed using WordNet . Poesio et al. .