CONCUR'91 is the second international conference on concurrency theory, organized in association with the NFI project Transfer. It is a sequel to the CONCUR'90 conference. Its basic aim is to communicate ongoing work in concurrency theory. This proceedings volume contains 30 papers selected for presentation at the conference (from 71 submitted) together with four invited papers and abstracts of the other invited papers. The papers are organized into sections on process algebras, logics and model checking, applications and specification languages, models and net theory, design and real-time, tools and probabilities, and programming languages. The proceedings of CONCUR'90 are available asVolume 458 of Lecture Notes in Computer Science.

This book contains a selection of research papers describing recent advancesin the theory of concurrent systems and their applications. The papers were all presented at the CONCUR '92 conference, which has emerged as the premiere conference on formal aspects of concurrency. The authors include such prominent researchers as R. Milner, A. Pnueli, N. Lynch, and V.R. Pratt. The results represent advances in the mathematical understanding of the behavior of concurrent systems: topics covered include process algebras, models of true concurrency, compositional verification techniques, temporal logic, verification case studies, models of probabilistic and real-time systems, models of systems with dynamic structure, and algorithms and decidability results for system analysis. A key feature of CONCUR is its breadth: in one volume it presents a snapshot of the state of the art in concurrency theory. Assuch, it is indispensible to researchers - and would-be researchers - in theformal analysis of concurrent systems.

This volume presents the proceedings of an international workshop on the processing of declarative knowledge. The workshop was organized and hosted by the German Research Center for Artificial Intelligence (DFKI) in cooperation with the Association for Logic Programming (ALP) and the Gesellschaft f}r Informatik (GI). Knowledge is often represented using definite clauses, rules, constraints, functions, conceptual graphs, and related formalisms. The workshop addressed such high-level representations and their efficient implementation required for declarative knowledge bases. Many of the papers treat representation methods, mainly concept languages, and many treat implementation methods, such as transformation techniques and WAM-like abstract machines. Several papers describe implemented knowledge-processing systems. The competition between procedural and declarative paradigms was discussed in a panel session, and position statements of the panelists are included in the volume.

A large class of computing systems can be specified and verified by abstracting away from the temporal aspects of their behavior. In real-time systems,instead, time issues become essential. Their correctness depends not only on which functions they can perform, but also on the action execution time. Due to their importance and design challenges, real-time systems have attracted the attention of a considerable number of computer scientists and engineers from various research areas. This volume collects a set of papers accompanying the lectures of the fourth edition of the International School on Formal Methods for the Design of Computer, Communication and Software Systems (SFM). The school addressed the use of formal methods in computer science as a prominent approach to the r- orous design of computer, communication and software systems. The main aim of the SFM series is to o?er a good spectrum of current research in foundations as well as applications of formal methods, which can be of help for graduate students and young researchers who intend to approach the field. SFM-04:RT was devoted to real-time systems. It covered formal models and languages for the specification,modeling,analysis,and verification of the seti- critical systems, the expressiveness of such models and languages, as well as supporting tools and related applications in different domains.

ETAPS2000wasthethirdinstanceoftheEuropeanJointConferencesonTheory and Practice of Software. ETAPS is an annual federated conference that was established in 1998 by combining a number of existing and new conferences. This year it comprisedv e conferences (FOSSACS, FASE, ESOP,CC, TACAS), ve satellite workshops (CBS, CMCS, CoFI, GRATRA, INT), seven invited lectures, a panel discussion, and ten tutorials. The events that comprise ETAPS address various aspects of the system - velopmentprocess,includingspeci cation,design,implementation,analysis,and improvement. The languages, methodologies, and tools which support these - tivities are all well within its scope. Die rent blends of theory and practice are represented, with an inclination towards theory with a practical motivation on one hand and soundly-based practice on the other. Many of the issues involved in software design apply to systems in general, including hardware systems, and the emphasis on software is not intended to be exclusive. ETAPS is a loose confederation in which each event retains its own identity, with a separate program committee and independent proceedings. Its format is open-ended, allowing it to grow and evolve as time goes by. Contributed talks and system demonstrations are in synchronized parallel sessions, with invited lectures in plenary sessions. Two of the invited lectures are reserved for \u- fying" talks on topics of interest to the whole range of ETAPS attendees.

The ECOOP '91 Workshop on Object-Based Concurrent Computing was organized toprovide a forum on concurrent, distributed and open-ended computing. The emphasis was on conceptual, theoretical and formal aspects, as well as practical aspects and sound experience, since such a viewpoint was deemed indispensible to investigate and establish a basis for future development. This volume contains 12 papers selected from 25 presented at the workshop, together with a paper by J.A. Goguen, who was an invited speaker at the workshop. The papers are classified into four categories: Formal methods (1): three papers are concerned with the formal semantics of concurrent objects based on process calculi. Formal methods (2): four papers are concerned with various formal approaches to the semantics of concurrent programs. Concurrent programming: three papers. Models: three papers areconcerned with models for concurrent systems.