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. 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.