Napaw 92

This volume contains papers from the North American Process Algebra Workshop, held in Stony Brook, New York, 28 August 1992. This was the first in a proposed series of workshops, intended to increase awareness of process algebras in the United States and Canada, and to promote their use and development. The workshop was held simultaneously with CONCUR 92, the annual conference on concurrency theories. It provided an important forum for the discussion and exchange of ideas, and allowed recent developments in the application of algebraic techniques to concurrency theory to be presented. The resulting volume provides a good cross-section of current research work in Canada, USA and Europe. Among the specific topics covered are: real-time calculi and expansion theorems; modal logics in timed process algebra; process communication environment; a process calculus with incomparable priorities; exception handling in process algebra; bisimulations on observation structures; computing ready simulations efficiently; analysis of value-passing CCS agents with infinite sorts; an extension of the testing method for processes passing infinite values; constructive semantics; a causality-based semantics for CCS. NAPAW 92 provides an comprehensive overview of this important, up-and-coming area of computer science. It will provide essential reading for both postgraduate students and researchers in industry and academia.

Logic and object-orientation have come to be recognized as being among the most powerful paradigms for modeling information systems. The term "information systems" is used here in a very general context to denote database systems, software development systems, knowledge base systems, proof support systems, distributed systems and reactive systems. One of the most vigorously researched topics common to all information systems is "formal modeling". An elegant high-level abstraction applicable to both application domain and system domain concepts will always lead to a system design from "outside in"; that is, the aggregation of ideas is around real-life objects about which the system is to be designed. Formal methods \yhen applied with this view in mind, especially during early stages of system development, can lead to a formal reasoning on the intended properties, thus revealing system flaws that might otherwise be discovered much later. Logic in different styles and semantics is being used to model databases and their transactions; it is also used to specify concurrent, distributed, real-time, and reactive systems. ,The notion of "object" is central to the modeling of object oriented databases, as well as object-oriented design and programs in software engineering. Both database and software engineering communities have undoubtedly made important contributions to formalisms based on logic and objects. It is worthwhile bringing together the ideas developed by the two communities in isolation, and focusing on integrating their common strengths.

This is the latest volume in the Workshops in Computing series, and contains the papers presented at the International Workshop on Structures in Concurrency Theory (STRICT), held in Berlin, from 11 - 13 May 1995. Concurrency theory deals with formal aspects of concurrent systems. It uses partly competing and partly complementary formalisms and structures. This workshop was jointly organised by the Humboldt-Universität zu Berlin and the ESPRIT Basic Research Working Group CALIBAN. CALIBAN and its predecessor DEMON are ESPRIT Basic Research projects with the aim of developing design methodologies based on causal models such as Petri nets. The workshop marked the third year of the project, and surveyed the results of CALIBAN and DEMON since 1989.

The Theory and Formal Methods Section of the Imperial College Department of Computing has an international reputation for research into the foundations of computer science, and the application of this theory to real computing problems. In March 1993 it held the first in a proposed series of workshops on theory and formal methods at the Isle of Thorns Conference Centre in Sussex, UK. Almost every member of the section contributed to the workshop, thereby providing comprehensive coverage of the work being done by this important research group. This volume contains revised versions of the papers presented at the workshop. They cover four main areas - semantics, concurrency, logic, and specification - with some papers spanning a variety of disciplines. The papers fall into two main categories: review papers which provide the reader with a good introduction to some of the specific areas being studied by the section, and research papers which give details of the latest results in these areas.