Expert Systems are so far the most promising achievement of artificial intelligence research. Decision making, planning, design, control, supervision and diagnosis are areas where they are showing great potential. However, the establishment of expert system technology and its actual industrial impact are still limited by the lack of a sound, general and reliable design and construction methodology.This book has a dual purpose: to offer concrete guidelines and tools to the designers of expert systems, and to promote basic and applied research on methodologies and tools. It is a coordinated collection of papers from researchers in the USA and Europe, examining important and emerging topics, methodological advances and practical experience obtained in specific applications. Each paper includes a survey introduction, and a comprehensive bibliography is provided.

The main idea behind the series of volumes Advances in Petri Nets is to present to the general computer science community recent results which are the most representative and significant for the development of the area. Thepapers for the volumes are drawn mainly from the annual International Conferences on Applications and Theory of Petri Nets. Selected papers from the latest conference are independently refereed, and revised and extended as necessary. Some further papers submitted directly to the editor are included. Advances in Petri Nets 1991 covers the 11th International Conference on Applications and Theory of Petri Nets held in Paris, France in June 1991. The volume contains the Bibliography of Petri Nets 1990 prepared by H. Pl}nnecke and W. Reisig, with over 4000 entries.