tailieunhanh - Báo cáo khoa học: "A View of Parsing"

The questions before this panel presuppose a distinction between parsing and interpretation. T h e r e are two other simple and obvious distinctions that I think are necessary for a reasonable discussion of the issues. First, we must clearly distinguish between the static specification of a process and its dynamic execution. Second, we must clearly distinguish two purposes that a natural language processing system might serve: one legitimate goal of a system is to perform some practical ~sk efficiently and well. . | A View of Parsing Ronald M. Kaplan Xerox Palo Alto Research Center The questions before this panel presuppose a distinction between parsing and interpretation. There are two other simple and obvious distinctions that I think arc necessary for a reasonable discussion of the issues. First we must clearly distinguish between the static specification of a process and its dynamic execution. Second we must clearly distinguish two purposes that a natural language processing system might serve one legitimate goal of a system is to perform some practical task efficiently and well while a second goal is to assist in developing a scientific understanding of the cognitive operations that underlie human language processing. 1 will refer to parsers primarily oriented towards the former goal as Practical Parsers PP and refer to the others as Performance Model Parsers PMP . With these distinctions in mind let me now turn to the questions at hand. 1. The Computational Perspective. From a computational point of view there are obvious reasons for distinguishing parsing from interpretation. Parsing is the process whereby linearly ordered sequences of character strings annotated with information found in a stored lexicon arc transduced into labelled hierarchical structures. Interpretation maps such structures either into structures with different formal properties such as logical formulas or into sequences of actions to be performed on a logical model or database. On the face of it unless we ignore the obvious formal differences between string-tO Structure and structurc-to--structure mappings parsing is thus formally and conceptually distinct from interpretation. The specifications of the two processes necessarily mention different kinds of operations that are sensitive to different- features of the input and express quite different generalizations about the correspondences between form and meaning. As far as I can see. these arc simply factual assertions about which there can be .