This book presents state-of-the-art research results in the area of formal methods for real-time and fault-tolerant systems. The papers consider problems and solutions in safety-critical system design and examine how wellthe use of formal techniques for design, analysis and verification serves in relating theory to practical realities. The book contains papers on real-time and fault-tolerance issues. Formal logic, process algebra, and action/event models are applied: - to specify and model qualitative and quantitative real-time and fault-tolerant behavior, - to analyze timeliness requirements and consequences of faulthypotheses, - to verify protocols and program code, - to formulate formal frameworks for development of real-time and fault-tolerant systems, - to formulate semantics of languages. The integration and cross-fertilization of real-time and fault-tolerance issues have brought newinsights in recent years, and these are presented in this book.

Verilog HDL is the standard hardware description language for the design of digital systems and VLSI devices. This volume shows designers how to describe pieces of hardware functionally in Verilog using a top-down design approach, which is illustrated with a number of large design examples. The work is organized to present material in a progressive manner, beginning with an introduction to Verilog HDL and ending with a complete example of the modelling and testing of a large subsystem.

In den Proceedings zur 5. Internationalen GI/ITG/GMA-Tagung }ber Fehlerorientierte Rechensysteme in N}rnberg standen Tests, Diagnose und Fehlerbehandlung als Leitthemen im Mittelpunkt. Allerdings wurden auch die Themen Zuverl{ssigkeit, Verf}gbarkeit und Sicherheit in Hard- und Softwaresystemen behandelt. Der Tagungsband gibt mit eingeladenen und eingereichten Beitr{gen, die von einem internationalen Programmausschu~ sorgf{ltig ausgew{hlt wurden, eine ]bersicht }ber den Stand der Forschung, Entwicklung und Anwendungen aller Fehlertoleranz- und Zuverl{ssigkeitsaspekte.

It is many years since Landin, Burge and others showed us how to apply higher order techniques and thus laid some foundations for modern functional programming. The advantage of higher order descriptions - that they can be very succinct and clear - has been percolating through ever since. Current research topics range from the design, implementation and use of higher order proof assistants and theorem provers, through program specification and verification, and programming language design, to its applications in hardware description and verification. The papers in this book represent the presentations made at a workshop held at Banff, Canada, September 10-14 1990 and organised by the Computer Science Department of the University of Calgary. The workshop gathered together researchers interested in applying higher order techniques to a range of problems. The workshop format had a few (but fairly long) presentations per day. This left ample time for healthy discussion and argument, many of which continued on into the small hours. With so much to choose from, the program had to be selective. This year's workshop was divided into five parts: 1. Expressing and reasoning about concurrency: Warren Burton and Ken Jackson, John Hughes, and Faron Moller. 2. Reasoning about synchronous circuits: Geraint Jones and Mary Sheeran (with a bonus on the fast Fourier transform from Geraint). 3. Reasoning about asynchronous circuits: Albert Camilleri, Jo Ebergen, and Martin Rem. 4. Categorical concepts for programming languages: Robin Cockett, Barry Jay, and Andy Pitts.

This volume contains the proceedings ofthe 4th Refinement Workshop which was organised by the British Computer Society specialist group in Formal Aspects of Computing Science and held in Wolfson College, Cambridge, on 9-11 January, 1991. The term refinement embraces the theory and practice of using formal methods for specifying and implementing hardware and software. Most of the achievements to date in the field have been in developing the theoretical framework for mathematical approaches to programming, and on the practical side in formally specifying software, while more recently we have seen the development of practical approaches to deriving programs from their speCifications. The workshop gives a fair picture of the state of the art: it presents new theories for reasoning about software and hardware and case studies in applying known theory to interesting small-and medium-scale problems. We hope the book will be Of interest both to researchers in formal methods, and to software engineers in industry who want to keep abreast of possible applications of formal methods in industry. The programme consisted both of invited talks and refereed papers. The invited speakers were Ib S0rensen, Jean-Raymond Abrial, Donald MacKenzie, Ralph Back, Robert Milne, Mike Read, Mike Gordon, and Robert Worden who gave the introductory talk. This is the first refinement workshop that solicited papers for refereeing, and despite a rather late call for papers the response was excellent.

Reiner Anderl The Advanced Modelling part of the CAD*I project aimed at the development of a new generation of modelling techniques as a basic functionality of future CAD/CAM systems. The methodology and concepts for advanced modelling techniques, their availability in the communication interface of a CAD/CAM system and their influence on internal interfaces in the software architecture of a CAD/CAM system are fundamental results of advanced modelling work. These results form the basis for the development of a new generation of CAD/CAM systems which are called product modelling systems. CAD/CAM systems today mainly support the geometric description of a technical part or its description as a technical drawing. Advanced geometric modelling capabilities deal with parametric design functions embedded into CAD/CAM systems. However, development strategies for future CAD/CAM systems are directed toward the following: 1. The development of product modelling systems and 2. the development of integrated systems based on CAD, CAP (Computer Aided Planning), CAM and other CIM (Computer Integrated Manu facturing) functionalities."

Formal methods enable computer architecture and software design to be mathematically proved correct before they are implemented. The complexity and time-consuming nature of such proofs have limited the applications of formal methods in the main to defence and safety-critical applications. The mural project (a joint Alvey-funded project between "M"anchester "U"niversity and "R"utherford "A"ppleton "L"aboratories) has developed a software support system to help the user of formal methods. mural has created a user-friendly software environment (with extensive use of windows) that makes best use of human talents to produce computer systems that are proved to be correctly designed. Professor Cliff Jones is internationally known as the developer of the VDM system of formal notation (Vienna Development Method). This book describes the requirements, concepts, and realisation of the mural system. The authors present systematically and completely the results of this substantial research project, from the basic theoretical level to its effective implementation. The book will be of equal interest to academics working on formal methods at research level (and perhaps to graduate research students), and to practitioners and software engineers who are using - or who will have to use for defence contracts, etc. - formal methods.

CAiSE '91, held at the Norwegian Institute of Technology in May 1991, is the third in a series of conferences on advanced information systems engineering. The call for papers for CAiSE '91 was given a wide international distribution. The programme committee was chosen from very well reputed researchers in the international information systems engineering community, as well as key professionals in European industrial and consultant companies. The number and quality of papers submitted was very satisfactory, and 29 papers were selected for publication in this volume.

The research described in this monograph concerns the formal specification and compositional verification of real-time systems. A real-time programminglanguage is considered in which concurrent processes communicate by synchronous message passing along unidirectional channels. To specifiy functional and timing properties of programs, two formalisms are investigated: one using a real-time version of temporal logic, called Metric Temporal Logic, and another which is basedon extended Hoare triples. Metric Temporal Logic provides a concise notationto express timing properties and to axiomatize the programming language, whereas Hoare-style formulae are especially convenient for the verification of sequential constructs. For both approaches a compositional proof system has been formulated to verify that a program satisfies a specification. To deduce timing properties of programs, first maximal parallelism is assumed, modeling the situation in which each process has itsown processor. Next, this model is generalized to multiprogramming where several processes may share a processor and scheduling is based on priorities. The proof systems are shown to be sound and relatively complete with respect to a denotational semantics of the programming language. The theory is illustrated by an example of a watchdog timer.

With the SPARC (Scalable Processor ARChitecture) architecture and system software as the underlying foundation, Sun Microsys terns is delivering a new model of computing-easy workgroup computing-to enhance the way people work, automating processes across groups, departments, and teams locally and globally. Sun and a large and growing number of companies in the computer industry have embarked on a new approach to meet the needs of computer users and system developers in the 1990s. Originated by Sun, the approach targets users who need a range of compatible computer systems with a variety of application soft ware and want the option to buy those systems from a choice of vendors. The approach also meets the needs of system developers to be part of a broad, growing market of compatible systems and software-developers who need to design products quickly and cost-effecti vel y. The SPARe approach ensures that computer systems can be easy to use for all classes of users and members of the workgroup, end users, system administrators, and software developers. For the end user, the SPARC technologies facilitate system set-up and the daily use of various applications. For the system administrator supporting the computer installation, setting up and monitoring the network are easier. For the software developer, there are ad vanced development tools and support. Furthermore, the features of the SPARC hardware and software technologies ensure that SPARC systems and applications play an important role in the years to come."

This book discusses inverse problems that arise in the estimation and control of distributed parameter systems in the face of uncertainty, as well as applications of these techniques to mathematical modelling for problems of applied system analysis (eg environmental issues, technological issues, technological processes, biomethematical models, mathematical economy and other fields). The main topics of the research papers which comprise this book are: estimation of the state and of the parameters for distributed parameter systems, control problems with state constraints, exponential stabilization and shape optimization. This book of proceedings on control theory, applied system analysis and estimation theory is intended for researchers, advanced students and engineers.

During the last few years, computers have evolved from pure number crunching machines to "intelligent" problem solving tools. Increasing effort has been spent on the investigation of new approaches and the application of solutions to real world problems. In this way, exciting new techniques have evolved providing support for an increasing number of technical and economical aspects. Applications range from the design and development of ultra highly integrated circuits to totally new man-machine interfaces, from software engineering tools to fault diagnosis systems, from decision support to even the analysis of unemployment. Following a first joint workshop on Advanced Information Processing held in July 1988 at the Institute for Problems of Informatics of the USSR Academy of Sciences (IPIAN) at Moscow, this was the second time that scientists and researchers from the USSR Academy of Sciences and Siemens AG, Corporate Research and Development, exchanged results and discussed recent advances in the field of applied computer sciences. Initiated by Prof. Dr. I. Mizin, Corresponding Member of the USSR Academy of Sciences and Director of IPIAN, and Prof. Dr. H. Schwartzel, Vice President of the Siemens AG and Head of the Applied Computer Science & Software Department, a joint symposium was arranged at the USSR Academy of Sciences in Moscow on June 5th and 6th 1990. The meetings on Information Processing and Software and Systems Design Automation provided a basis both for presentations of ongoing research and for discussions about specific problems.

The 1989 Workshop on the Assessment of Formal Methods for Trustworthy Com puter Systems (FM89} was an invitational workshop that brought together repre sentatives from the research, commercial and governmental spheres of Canada, the United Kingdom, and the United States. The workshop was held in Halifax, Nova Scotia, Canada, from July 23 through July 27, 1989. This document reports the activities, observations, recommendations and conclusions resulting. from FM89. 1. 1 Purpose of Workshop The primary purpose for holding FM89 was to assess the role of formal methods in the development and fielding of trustworthy critical systems. The need for this assessment was predicated upon four observations: 1. Critical systems are increasingly being controlled by computer systems; 2. Existing techniques for developing, assuring and certifying computer-based critical systems are inadequate; 3. Formal methods have the potential for playing the same role in the devel opment of computer-based systems as applied mathematics does for other engineering disciplines; and 4. Formal methods have had limited impact on the development of comput- based systems and supporting technologies. . The goal of the workshop was to complete the following tasks: 1. Assess the problems retarding the development of trustworthy critical systems; 2. Determine the (potential) impact of applying formal methods techniques to the development of trustworthy critical systems; 3. Determine the research and development required to facilitate a broader ap plication of formal methods techniques; 4."

The growing importance of the systems for symbolic computation has greatly influenced the decision of organizing DISCO '90 which is short for International Symposium on Design and Implementation of Symbolic Computation Systems. DISCO '90 focuses mainly on the most innovative methodological and technological aspects of hardware and software system design and implementation for Symbolic and Algebraic Computation, Automated Reasoning, Software Environments (Languages and User Interfaces), and Automatic Programming. In particular, it includes papers on the design and the development of significant running systems. The general objective of DISCO '90 is to present an up-to-date view of the field, while encouraging the scientific exchange among academic, industrial and user communities of the development of systems for symbolic computation.

This volume contains the proceedings of a workshop held in Grenoble in June 1989. This was the first workshop entirely devoted to the verification of finite state systems. The workshop brought together researchers and practitioners interested in the development and use of methods, tools and theories for automatic verification of finite state systems. The goal at the workshop was to compare verification methods and tools to assist the applications designer. The papers in this volume review verification techniques for finite state systems and evaluate their relative advantages. The techniques considered cover various specification formalisms such as process algebras, automata and logics. Most of the papers focus on exploitation of existing results in three application areas: hardware design, communication protocols and real-time systems.

This research monograph gives a complete discussion of the theory of the discrete-time hyperbolic map. Both scalar and matrix representations are considered. The dynamics of the map are analyzed and discussions of stability, quasiperiodicity, and chaos are included. Several applications are discusssed, the most important being the discrete-time linear time-invariant quadratic regulator. The results obtained from this analysis are then extended to the continuous-time linear regulator. A discussion of the linear quadratic regulator with negative state weighting provides some important insights into the general regulator theory. The results contained in this monograph should be accessible to the first year graduate student or advanced senior undergraduate. Interested readers should also have a background in ODE's, difference equations, optimization theory, and/or digital control theory.

Computer simulation has developed into a powerful tool for problem solving in a variety of areas, in the sciences as well as in industrial environments. New developments such as parallel simulation techniques will further improve the efficiency of the tool. Decision support systems, either based on mathematical models or on knowledge based expert systems will make computer simulation accessible to more users, and will provide better environments for systems analysis, modeling and simulation. Systems Analysis and Simulation presents the papers accepted for the 3rd International Symposium for Systems Analysis and Simulation held in Berlin (GDR) in September of 1988. The contributions selected for this two-volume set present the state of the art and current trends in computer simulation. Volume I emphasizes the theoretical foundations and the methodology for computer simulation and systems analysis. Volume II presents a variety of applications in fields such as manufacturing, robotics, economics, and biology.

Dieses Buch enthalt die Beitrage der 4. GI/ITG/GMA-Fachtagung uber Fehlertolerierende Rechensysteme, die im September 1989 in einer Reihe von Tagungen in Munchen 1982, Bonn 1984 sowie Bremerhaven 1987 veranstaltet wurde. Die 31 Beitrage, darunter 4 eingeladene, sind teils in deutscher, uberwiegend aber in englischer Sprache verfasst. Insgesamt wird durch diese Beitrage die Entwicklung der Konzeption und Implementierung fehlertoleranter Systeme in den letzten zwei Jahren vor allem in Europa dokumentiert. Samtliche Beitrage berichten uber neue Forschungs- oder Entwicklungsergebnisse.

This volume contains the papers which were presented at the second workshop "Computer Science Logic" held in Duisburg, FRG, October 3-7, 1988. These proceedings cover a wide range of topics both from theoretical and applied areas of computer science. More specifically, the papers deal with problems arising at the border of logic and computer science: e.g. in complexity, data base theory, logic programming, artificial intelligence, and concurrency. The volume should be of interest to all logicians and computer scientists working in the above fields.

The field of modern mathematical system theory has its origins in the work of R.E. Kalman in the late fifties. It came to a rapid development in the early sixties, and has seen a continuing and still growing stream of contributions in the years that followed. Today, it stands as a well-established discipline. The volume Three Decades of Mathematical System Theory surveys the developments in this field by presenting 21 articles covering the broad area of system and control theory. All articles have been written by well-known authors, who were invited to give their personal expert view on a particular direction of research. Together, the contributions in this volume review the wide range of mathematical methods that are being applied in modern system and control theory. The mathematical fields that are involved included differential and algebraic geometry, linear and commutative algebra, and functional and stochastic analysis.

Computer aided systems theory is urgently needed for the design of software for CAD. New generation workstations together with the methods and tools of artificial intelligence allow the implementation of the powerful user-driven interactive systems required for CAST. Implementation of CAST software requires a sound meth- odology from systems theory, user functions tailored to specific applications, and a man-machine interface designed using latest results from cognition research and AI. Most of the papers in this volume are based on talks delivered at EUROCAST '89 held in the Canary Islands in February/March 1989.

The Nordic Conference on Advanced Information Systems Engineering (CAiSE) is an annual international conference for users, developers and researchers of information systems technology and methodology. A distinctive characteristic of the CAiSE conference series is the objective to appeal to advanced practitioners as well as to researchers, and to promote communication between the two groups. In this second CAiSE conference, the program was divided into two types of sessions that were not run in parallel: Technical Paper sessions, with formally reviewed technical papers, and Practice and Experience sessions, with invited speakers and panel discussions. The proceedings include the formally reviewed technical papers and abstracts of the invited presentations. The technical papers present important international (mainly European) work in Information Systems Engineering within such areas as conceptual modelling, prototyping, requirements engineering, design support, software process modelling, tool design, and tool experiences. The abstracts of invited speakers' presentations give an indication of current best industrial practice.

This volume contains selected papers for the Parcella '88, the Fourth International Workshop on "Parallel Processing by Cellular Automata and Arrays" held in Berlin from October 17 to 21, 1988. The profile of the Parcella workshop series is focused on problems of processing by regular structures, i.e. their "flexibilization" or adapting to "irregular" algorithms and, closely related to this, on the "regularization" of algorithms for their embedding into regular structures. It seems that these problems will have an increasing priority within the list of central problems in parallelization and will determine the profile of Parcella for the next years.

Current research into formal methods for hardware design is presented in the papers in this volume. Because of the complexity of VLSI circuits, assuring design validity before circuits are manufactured is imperative. The goal of research in this area is to develop methods of improving the design process and the quality of the resulting designs. The major trend apparent at the workshop is that researchers are rapidly moving away from post hoc proof techniques with their great expense. A number of papers were presented that dealt with problems of synthesizing correct circuits and of designing with the goal of verification. Researchers are also beginning to deal with the theoretical issues of reasoning about concurrent systems and asynchronous systems, and to introduce new logical tools such as constructive type theory and category theory. Most of the research reported was performed in the United States.

This "Lecture Notes" volume is based on the "International Workshop on High Performance Transaction Systems" held in the Asilomar Conference Center, September 28-30, 1987. Many of the problems identified during the workshop are liable to determine the future development of transaction systems and distributed high performance systems in general for many years to come. So the organizers of HPTS '87 felt encouraged to collect the papers presented at the workshop in order to make them accessible to a wider audience of interested developers and researchers. Since some of the contributions represented work in progress, the authors agreed to prepare revised and updated versions of their papers for this publication. This accounts for the long delay between the event itself and the publication, but on the other hand it provides the reader with a state-of-the-art account of transaction processing topics. The book is organized according to the major sections of the workshop. In the network section the reader finds an analysis of two of the major "paradigms" in networking, ISO/OSI and SNA, from the perspective of transaction processing. In the next section four different transaction processing and database systems are described: Model 204 - a database management system marketed by Computer Corporation of America, Tandem's NonStop SQL, Citicorp's transaction processing system and ALCS, which basically is a version of TPF running under MVS/XA. The section on architectural issues contains four very different contributions which are fairly representative of the type of problems in transaction systems investigated in the research community. Finally, performance evaluations and system comparisons are presented.