Rapid development of digital technologies has led to the widespread use of software in all aspects of our life. The degree of reliance that can be justifiably placed on software-intensive systems is expressed by the notion of dependability. The complexity of modern software-intensive systems poses the greatest threat to dependability. Furthermore, software the most complex system component is recognized to be the most error-prone part of the system. Dependability and Computer Engineering: Concepts for Software-Intensive Systems offers a state-of-the-art overview of the dependability research, from engineering various software-intensive systems to validating existing IT-frameworks and solving generic and particular problems related to the dependable use of IT in our society. It is important to understand how dependability is manifested in software-intensive systems, how it is developed, and how it can be enhanced at various levels in systems and organizations. This book uncovers the existing research on the topic as well as the key challenges associated with the engineering of dependable IT systems in the future.

This book constitutes the refereed proceedings of the Third International Conference on Integrated Formal Methods, IFM 2002, held in Turku, Finland, in May 2002.The 18 revised full papers presented together with three invited papers were carefully reviewed and selected from a total of 46 submissions. The papers are organized in topical sections on integration, simulation, and animation; from specification to verification; statcharts and B: integration and translation; model checkers and theorem provers; links between object-Z and CSP; combining graphical and formal approaches; and refinement and proof.

The Idea of Program Refinement Programs are complex. They are typically so complex, that they go beyond the full comprehension even of the programmer or team who designed them, with all the consequences this has. How can we cope with such complexity in a satisfactory way? An approach, advocated for a long time, is to separate a concise specification of a program - the "what" - from a possibly involved implementation - the "how". Once a specification is obtained from the set of requirements on the program, there can still be a large gap to an efficient implementation. The development from specification to implementation can then proceed by a succession oflayers, such that each layer is a refinement of the previous one. Design decisions can be introduced in refinement steps one at a time. By this, the refinement steps can be kept small and manageable. Still, the set of all requirements can be far too large to be taken completely into account in the initial specification. Even if they could, they might obscure issues more than clarify them. For example: * An information system for stored goods needs to produce an error message on il legal input. Yet, the exact wording - and even the language - of those messages is irrelevant for an understanding of the essence of the system. * A banking application interacts with customers with a graphical interface. Yet the specification of the graphical layout is secondary compared to the specification of the possible transactions.