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.

The third European Software Engineering Conference follows ESEC'87 and ESEC'89. This series of conferences was set up by the European societies with the aim of providing an international forum for researchers, developersand users of software engineering technology. The need for a meeting point to discuss new results and useful experiences was clear from the large amount of high-quality European software engineering researchin recent years, stimulated, for example, through major European research programmes. The 22 papers in these proceedings were selected from 133 papers submitted from 26 different countries. They cover a fairly broad range of themes such as formal methods and practical experiences with them, special techniques for real-time systems, software evolution and re-engineering, software engineering environments, and software metrics. Invited papers by well-known experts address further important areas: perspectives on configuration management, software factories, user interfacedesign, computer security, and technology transfer.

This book presents a coherent description of the theoretical and practical aspects of Coloured Petri Nets (CP-nets or CPN). It shows how CP-nets have been de veloped - from being a promising theoretical model to being a full-fledged lan guage for the design, specification, simulation, validation and implementation of large software systems (and other systems in which human beings and/or com puters communicate by means of some more or less formal rules). The book contains the formal definition of CP-nets and the mathematical theory behind their analysis methods. However, it has been the intention to write the book in such a way that it also becomes attractive to readers who are more interested in applications than the underlying mathematics. This means that a large part of the book is written in a style which is closer to an engineering textbook (or a users' manual) than it is to a typical textbook in theoretical computer science. The book consists of three separate volumes. The first volume defines the net model (i. e. , hierarchical CP-nets) and the basic concepts (e. g. , the different behavioural properties such as deadlocks, fair ness and home markings). It gives a detailed presentation of many small exam ples and a brief overview of some industrial applications. It introduces the for mal analysis methods. Finally, it contains a description of a set of CPN tools which support the practical use of CP-nets.

This book constitutes the refereed proceedings of the 20th International Conference on Application and Theory of Petri Nets, ICATPN'99, held in Williamsburg, Virginia, USA, in June 1999. The 21 revised full papers presented were carefully selected from 45 submissions. Also included are three invited presentations. The book presents state-of-the-art research results on all current aspects of Petri nets as well as advanced applications in a variety of areas.

Using formal methods for the specification and verification of hardware and software systems is becoming increasingly important as systems increase in size and complexity. The aim of the book is to illustrate progress in formal methods based on Petri net formalisms. It presents both practical and theoretical foundations for the use of Petri nets in complex system engineering tasks. In doing so it bridges the gap between Petri nets and the systems modeling and implementation process. It contains a collection of examples arising from different fields, such as flexible manufacturing, telecommunication and workflow management systems.

The proceedings of the fourth Vienna Development Method Symposium, VDM'91, are published here in two volumes. Previous VDM symposia were held in 1987 (LNCS 252), 1988 (LNCS 328), and 1990 (LNCS 428). The VDM symposia have been organized by VDM Europe, formed in 1985 as an advisory board sponsored by the Commission of the European Communities. The VDM Europe working group consisted of researchers, software engineers, and programmers, allinterested in promoting the industrial usage of formal methods for software development. The fourth VDM symposium presented not only VDM but also a large number of other methods for formal software development. Volume 1 contains conference contributions. It has four parts: contributions of invited speakers, papers, project reports, and tools demonstration abstracts. The emphasis is on methods and calculi for development, verification and verification tools support, experiences from doing developments, and the associated theoretical problems. Volume 2 contains four introductory tutorials (on LARCH, Refinement Calculus, VDM, and RAISE) and four advanced tutorials (on ABEL, PROSPECTRA, The B Method, and The Stack). They present a comprehensive account of the state of theart.