tailieunhanh - Báo cáo khoa học: "PLANNING COHERENT MULTISENTENTIAL TEXT"

Though most text generators are capable of simply stringing together more than one sentence, they cannot determine which order will ensure a coherent paragraph. A paragraph is coherent when the information in successive sentences follows some pattern of inference or of knowledge with which the hearer is familiar. To signal such inferences, speakers usually use relations that llnk successive sentences in fixed ways. A set of 20 relations that span most of what people usually say in English is proposed in the Rhetorical Structure Theory of M a n n and Thompson. This paper describes the formalization of these. | PLANNING COHERENT MƯLTISENTENTIAL TEXT Eduard H. Hovy USC Information Sciences Institute 4676 Admiralty Way Suite 1001 Marina del Rey CA 90292-6695 . HOVY@ Abstract Though most text generators are capable of simply stringing together more than one sentence they cannot determine which order will ensure a coherent paragraph. A paragraph is coherent when the information in successive sentences follows some pattern of inference or of knowledge with which the hearer is familiar. To signal such inferences speakers usually use relations that link successive sentences in fixed ways. A set of 20 relations that span most of what people usually say in English is proposed in the Rhetorical Structure Theory of Mann and Thompson. This paper describes the formalization of these relations and theừ use in a prototype text planner that structures input elements into coherent paragraphs. 1 The Problem of Coherence The example texts in this paper are generated by Penman a systemic grammar-based generator with larger coverage than probably any other existing text generator. Penman was developed at ỈSI see Mann Matthiessen 83 Mann 83 Matthiessen 84 . The input to Penman is produced by PEA Programming Enhancement Advisor see Moore 87 a program that inspects a user s LISP program and suggests enhancements. PEA is being developed to interact with the user in order to answer his or her questions about the suggested enhancements. Its theoretical focus is the production of explanations over extended interactions in ways that are superior to the simple goal-tree traversal of systems such as TYRESIAS Davis 76 and MYCIN Shortliffe 76 . Supported by DARPA contract MDA903 81 C0335. In answer to the question how does the system enhance a program the following text not generated by Penman is not satisfactory a . The system performs the enhancement. Before that the system resolves conflicts. First the system asks the user to tell it the characteristic of the program to be enhanced. .