Knowledge Systems and Prolog: A Logical Approach to Expert Systems and Natural Language Processing
Michael C. McCord, John F. Sowa, Walter G. Wilson, Adrian Walker · Medical Entomology and Zoology · 1987
This book is about knowledge systems and Prolog. By 'knowledge systems' the authors mean expert systems, natural language understanding systems, and the combination of the two. According to the authors, the book caters to several groups of readers, viz. those who are interested in knowledge systems, those wishing to familiarize themselves with Prolog programming, and those who are already Prolog programmers but would like to take a more in-depth look at this language. Different chapter sequences are recommended for each group. The introduction to Prolog naturally invites comparisons with more introductory texts, e.g., Clocksin and Mellish, 1981. The book under review covers many of the basic topics, sometimes somewhat more in-depth than Clocksin and Mellish. Especially for those who wish to have a self-contained work on Prolog and its major applications, this comprehensiveness may be an advantage, although many of those curious about knowledge systems and the use of logicbased database query techniques are likely to be familiar with at least the basis of Prolog already. I will leave the knowledge system applications undiscussed here, and concentrate for a moment on the natural language understanding part. The book's main topic as far as natural language processing is concerned is the querying of structured databases in English. Two comments are in order here. In the first place, the book has a flavor of definiteness about results in natural language processing that is not wholly appropriate. As anyone who has worked in the field, particularly those who have worked on large grammars for computers, will know, natural language is notoriously hard to process completely. In the second place, even assuming that every possible query in English is translatable into some logical language according to a wholly formal process, there is still no answer to problems of linguistic performance. That is, language use allows for an almost unlimited variety in paraphrasing statements and questions, and writing a grammar for all these possible paraphrases would most likely lead to the