Design and Safety Assessment of Critical Systems

Safety-critical systems—namely, systems whose failure may cause death or injury to people, harm to the environment, or economical loss—are becoming more complex, both in the type of functionality they provide and in the way they are demanded to interact with the environment. Traditionally, safety analysis techniques and procedures are used to identify risks and hazards, with the goal of eliminating, avoiding, or reducing the probability of failure. However, these techniques are often performed manually and hence are a time-consuming activity, itself vulnerable to human error, because they rely on the ability of the safety engineer to understand and to foresee system behavior. The growing complexity of safety-critical systems requires an adequate increase in the capability of safety engineers to assess system safety, encouraging the adoption of formal techniques. This book is an introduction to the area of design and verification of safetycritical systems, with a focus on safety assessment using formal methods. After an introduction covering the fundamental concepts in the areas of safety and reliability, the book illustrates the issues related to the design, development, and safety assessment of critical systems. The core of the book covers some of the most well-known notations, techniques, and procedures, and explains in detail how formal methods can be used to realize such procedures. Traditional verification and validation techniques and new trends in formal methods for safety assessment are described. The book ends with a discussion on the role of formal methods in the certification process. The book provides an in-depth and hands-on view of the application of formal techniques that are applicable to a variety of industrial sectors, such as transportation, avionics and aerospace, and nuclear power