Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Those systems identified and repaired errors in various ways, including using grammar-specific rules (metarules) (Weischedel and Sondheimer, 1983), least-cost error recovery based on chart parsing (Lyon, 1974; A n d e r s o n and Backhouse, 1981), semantic preferences (Fass and Wilks, 1983), and heuristic approaches based on a shift-reduce parser (Vosse, 1992). Systems that focus on a particular level miss errors that can only be detected using higher level knowledge. | Integrated Control of Chart Items for Error Repair Kyongho MIN and William H. WILSON School of Computer Science Engineering University of New South Wales Sydney NSW 2052 Australia min.billw @ cse.unsw.edu. au Abstract This paper describes a system that performs hierarchical error repair for ill-formed sentences with heterarchical control of chart items produced at the lexical syntactic and semantic levels. The system uses an augmented context-free grammar and employs a bidirectional chart parsing algorithm. The system is composed of four subsystems for lexical syntactic surface case and semantic processing. The subsystems are controlled by an integrated-agenda system. The system employs a parser for well-formed sentences and a second parser for repairing single error sentences. The system ranks possible repairs by penalty scores which are based on both grammar-dependent factors e.g. the significance of the repaired constituent in a local tree and grammar-independent factors e.g. error types . This paper focuses on the heterarchical processing of integrated-agenda items i.e. chart items at three levels in the context of single error recovery. Introduction Weischedel and Sondheimer 1983 described two types of ill-formedness relative i.e. limitations of the computer system and absolute e.g. misspellings mistyping agreement violation etc . These two types of problem cause ill-formedness of a sentence at various levels including typographical orthographical morphological phonological syntactic semantic and pragmatic levels. Typographical spelling errors have been studied by many people Damerau 1964 Peterson 1980 Pollock and Zamora 1983 . Mitton 1987 found a large proportion of real-word errors were orthographical to too were where. At the sentential level types of syntactic errors such as co-occurrence violations ellipsis conjunction errors and exưaneous terms have been studied Young Eastman and Oakman 1991 . In addition Min 1996 found 0.6 of words misspelt 447 68966 in
