tailieunhanh - Báo cáo khoa học: "STRUCTURAL AMBIGUITY AND LEXICAL RELATIONS"

We propose that ambiguous prepositional phrase attachment can be resolved on the basis of the relative strength of association of the preposition with noun and verb, estimated on the basis of word distribution in a large corpus. This work suggests that a distributional approach can be effective in resolving parsing problems that apparently call for complex reasoning. | STRUCTURAL AMBIGUITY AND LEXICAL RELATIONS Donald Hindle and Mats Rooth AT T Bell Laboratories 600 Mountain Avenue Murray Hill NJ 07974 Abstract We propose that ambiguous prepositional phrase attachment can be resolved on the basis of the relative strength of association of the preposition with noun and verb estimated on the basis of word distribution in a large corpus. This work suggests that a distributional approach can be effective in resolving parsing problems that apparently call for complex reasoning. Introduction Prepositional phrase attachment is the canonical case of structural ambiguity as in the time worn example 1 I saw the man with the telescope The existence of such ambiguity raises problems for understanding and for language models. It looks like it might require extremely complex computation to determine what attaches to what. Indeed one recent proposal suggests that resolving attachment ambiguity requires the construction of a discourse model in which the entities referred to in a text must be reasoned about Altmann and Steedman 1988 . Of course if attachment ambiguity demands reference to semantics and discourse models there is little hope in the near term of building computational models for unrestricted text to resolve the ambiguity. Structure based ambiguity resolution There have been several structure-based proposals about ambiguity resolution in the literature they are particularly attractive because they are simple and don t demand calculations in the semantic or discourse domains. The two main ones are Right Association - a constituent tends to attach to another constituent immediately to its right Kimball 1973 . Minimal Attachment - a constituent tends to attach so as to involve the fewest additional syntactic nodes Frazier 1978 . For the particular case we are concerned with attachment of a prepositional phrase in a verb object context as in sentence 1 these two principles - at least in the version of syntax that Frazier assumes - make .