tailieunhanh - Báo cáo khoa học: "A RULE-BASED APPROACH TO EVALUATING IMPORTANCE IN DESCRIPTIVE TEXTS"

Importance evaluation is one of the most challenging problems in the field of text processing. In the paper we focus on the notion of importance from a computational standpoint, and we propose a procedural, rule-based approach to importance evaluation. T h i s novel approach is supported by a prototype experimental system, called importance evaluator, that can deal with descriptive texts taken from computer science l i t e r a t u r e on operating systems. The evaluator relies on a set of importance rules that are used to assign importance values to the different parts. | A RULE-BASED APPROACH TO EVALUATING IMPORTANCE IN DESCRIPTIVE TEXTS Danilo Fun Giovanni Guida t Carlo Tasso i ỉsùtuto di Matematica Infonnatica e Sistemistica Università di Udine Udine Italy ABSTRACT Importance evaluation is one of the most challenging problems in the field of text processing. In the paper we focus on the notion of importance from a computational standpoint and we propose a procedural rule-based approach to importance evaluation. This novel approach is supported by a prototype experimental system called importance evaluator that can deal with descriptive texts taken from computer science literature on operating systems. The evaluator relies on a set of importance rules that are used to assign importance values to the different parts of a text and to resolve or explain conflicting evaluations. The system utilizes world knowledge on the subject domain contained in an encyclopedia and takes into account a goal assigned by the user for specifying the pragmatic aspects of the understanding activity. The paper describes the role of the evaluator in the frame of a larger system for text summarization SUSY it illustrates its overall mode of operation and discusses some meaningful examples. 1. INTRODUCTION Text understanding has received increasing attention in recent years. A major problem in this area is that of importance evaluation not all the components of a sufficiently large and structured piece of text are equally important for the reader and humans are able to evaluate the relative importance of the parts of the texts they read. This issue has been faced so far only in an indirect way in the literature on discourse structure Kintsch and van Dijk 1978 van Dijk and Kintsch 1983 summarization Lehrert 1982 and 1984 Wilensky 1982 Hahn and Reimer 1984 and inference Schank 1979 . Moreover several studies in the field of summarization . Schank 1979 and 1982 Lehnert 1982 and 1984 Wilensky 1982 have mostly been concerned with narrative texts stories and .