As computer technology is used to control critical systems to an increasing degree, it is vital that the methods for developing and understanding these systems are substantially improved. The mathematical and scientific foundations currently used are extremely limited which means that their correctness and reliability cannot be ensured to an acceptable level. Systems engineering needs to become a fully fledged scientific discipline and formal methods, which are characterised by their firm mathematical foundations, are playing a vital role in achieving this transition. This volume is based on the proceedings of the Formal Methods Workshop (FM91), held in Drymen, Scotland, 24-27 September 1991. This was the second workshop sponsored by the Canadian and US governments to address the role of formal methods in the development of digital systems. Traditionally, formal methods have evolved in isolation from more conventional approaches, and one of the aims of this workshop was to emphasise the benefits of integrating the two areas. The workshop concentrated on the themes of quality assurance, design methods and mathematical modelling techniques. Particular emphasis was given to safety and security applications. Among the topics covered in this volume are: what is a formal method?; social research on formal methods; current quality assurance methods and formal methods; a pragmatic approach to validation; integrating methods in practice; composition of descriptions; and topics in large program formal development. Formal Methods in Systems Engineering provides an overview of many of the major approaches to formal methods and the benefits which can result from them. It is relevant to academic and industrial researchers, industrial practitioners and government workers with an interest in certification.

Inhaltsangabe1 Introduction.- 1.1 What Are Formal Methods?.- 1.2 Formal Methods and Mathematics.- 1.3 What Good Are Formal Methods?.- 1.4 The Myth of Control.- 1.5 Hyperprogramming.- 1.6 Recommendations.- 2 Formal Methods of Software Development: Painted into the Corner of High-Integrity Computing?.- 2.1 The Dominant Rationale for Formal Methods.- 2.2 Some Pragmatic Objections to Formal Methods.- 2.3 Dissolving Resistance to Formal Methods?.- 2.4 A Brief Sketch of Formal Methods in High-Integrity Computing.- 2.5 The Projects.- 2.6 The Formal Methods Community in High-Integrity Computing.- 2.6.1 The Clients.- 2.6.2 The Developers.- 2.7 The Information Networks.- 2.8 Does the Use of Formal Methods Within High-Integrity Computing Perpetuate its "Myths"?.- 3 The Social Negotiation of Proof: An Analysis and a Further Prediction.- 3.1 Background.- 3.2 VIPER.- 3.3 Disputing "Proof".- 3.4 Formal Proof and Rigorous Argument.- 3.5 A Further Prediction.- 3.6 Conclusion.- 4 On Constructing Large Software Systems.- 4.1 Introduction.- 4.2 People.- 4.3 Frames.- 4.4 Sets.- 4.5 Programs.- 4.6 Proof.- 4.7 Tools.- 4.8 Conclusion.- 4.9 Acknowledgments.- 5 Composition of Descriptions: A Progress Report.- 5.1 Introduction.- 5.2 Why Compose Descriptions ?.- 5.3 What is Described?.- 5.4 What is a Description?.- 5.5 What is Composition?.- 5.6 Description Reuse.- 5.7 Conclusion.- 6 Integrating Methods in Practice.- 6.1 Introduction.- 6.2 Development and Development Methods.- 6.3 Aspects of Specification.- 6.4 Aspects of Design.- 6.4.1 Detail and Structure.- 6.4.2 Reification and Algorithm Design.- 6.4.3 Summary.- 6.5 Implications for Research and Development.- 7 Formal Methods and Product Documentation.- 7.1 Introduction.- 7.2 The Fully Formalised Software Product.- 7.3 The Elements of Product Documentation.- 7.4 Product Documentation and the Product Range.- 7.5 Product Documentation and Product Development.- 7.6 Product Documentation and Customers.- 7.7 Developing from a Fully Formalised Base.- 7.8 New Requirements.- 7.9 Errors Detected Before Release.- 7.10 Errors Detected After Release.- 7.11 How to Get There.- 7.12 Summary.- 7.13 Acknowledgments.- 8 Software Quality: A Modelling and Measurement View.- 8.1 Software Quality Needs.- 8.2 Modelling Software Experiences.- 8.3 Model Evolution.- 8.4 An Organization for Packaging Experience Models for Reuse.- 8.5 Conclusions.- 9 Modelling Working Group Summary.- 9.1 Description.- 9.2 Discussion Topics.- 9.3 Discussion.- 9.3.1 Why and to What End Formal Methods?.- 9.3.2 What is a Formal Method?.- 9.4 How Does Mathematical Modelling Help to Increase our Understanding of Digital Systems?.- 9.4.1 What Are the Limits of Mathematical Modelling?.- 9.5 What is Required to Validate that a Mathematical Model Describes a Digital System Accurately?.- 9.5.1 What Insights do Other Fields of Engineering Provide?.- 9.5.2 What Can we Do by 1995 with the Mathematical Modelling Capabilities we Have Now?.- 9.5.3 What Is our Target for the Year 2000?.- 9.5.4 Formal Methods and Safety Standards.- 9.6 Conclusions.- 10 Quality Assurance Working Group.- 10.1 Group Description.- 10.2 Quality Assurance vs. Quality Control.- 10.3 What Is a Formal Method?.- 10.4 Integration of Formal Methods and Quality Control.- 10.5 A Plan to Integrate Formal Methods into QC/QA.- 10.5.1 Phase 1.- 10.5.2 Phase 2.- 10.5.3 Phase 3.- 10.5.4 Phase 4.- 11 Design Methods Working Group.- 11.1 Description.- 11.2 The Context of Formal Methods.- 11.3 The Role of Proof in Assurance.- 11.4 Analytical Capabilities of Formal Methods.- 11.5 Foundational Capabilities of Formal Methods.- 11.6 The Role of Formal Methods with Respect to the Software Development Process.- 11.7 Formal Methods During Development and Implementation.- 11.8 Education.- 11.9 Tools.- 12 Conclusions.- A Survey of Formal Methods Tools.- B Survey of Formal Methods Applications.- C Acronyms and Trademarks.- List of Contributors.