Forward and Backward Reasoning in Automatic Abstracting

COLING 82, Jr. Horec~ le~ ] North-Holland Publishing Company © Academia, 1982 FORWARD AND BACKWARD REASONING IN AUTOMATIC ABSTRACTING Danilo FUM ? Giovanni GUIDA, Carlo TASSO Istituto di Matematica, Informatica e Sistemistica, Universita' di Udine. Italy. o Laboratorio di Psicologia E.E., Universita' di Trieste, Italy. The paper is devoted to present a new approach to automatic abstracting which is supported by the development of SUSY, an experimental system currently being implemented at the University of Udine (Italy). The original contribution of the research reported is mostly focused on the role of forward and backward reasoning in the abstracting activity. In the paper the specifications and basic methodologies of SUSY are introduced, its architecture is illustrated with particular attention to the organization of the basic algorithms, and an example to support the novel approach proposed is described. INTRODUCTION For its theoretic and practical implications automatic abstracting has recently emerged as one of the most promising and interesting research topics in the field of natural language studies covered by computational linguistics. artificial intelligence, and psycholinguistics. In this paper we present the first results of a research project aimed at developing a new approach to automatic abstracting which is supported by the development of SUSY (SUmmarizing SYstem), an experimental system which is currently being implemented on VAX-11/780 at the University of Udine (Italy). The system is conceived to accept in input a natural language text (a scientific paper in the current application) together with the user's requirements and to produce as output a summary of the specified kind. SUSY relies on two basic assumptions~ - to ground parsing, summarizing, and generation activities mostly on the semantics of the language, and to avoid any kind of reasoning merely based on syntactic or structural properties which are not adequate for an intelligent and effective summarizer; - to take strongly into account recent results of psycholinguistic research (Kintsch. 1974; Kintsch and van Dijk, 1978) as a conceptual background and a valid standpoint for designing a general purpose summarizing method. The most relevant and original features of SUSY consist, in our opinion, in the remarkable flexibility of the system which allows the user to obtain different abstracts depending on his particular goals and needs, and in the strategies used to summarize (i.e.. forward and backward processing) that simulate at a certain level of abstraction those utilized'by humans. 83 84 D. FUM, G. GUIDA and C. TASSO SPECIFICATIONSAND BASIC METHODOLOGIES In defining SUSY's specifications we have tried to implement at a certain level of abstraction an important human feature: the capability to generate summaries of different content and extent depending on the user's goals. The system is therefore able to process a text following the two principles of variable-length processing and of user-taylored abstracting. With variable-length processing we mean the Capability to generate, starting from the same text. summaries of different length, complexity, and level of abstraction depending on the user's requirements. With user-taylored abstractingwe mean the capability to generate s~ries of different content depending on the user's …

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