Many safety-related systems are built from generic software which is customised to work in a particular situation by static configuration data. Examples of such systems are railway interlockings and air traffic control systems. While there is now considerable experience and guidance on how to develop safety-related software, and there are a number of standards in this area, the topic of safety-...

As modern systems continue to increase in size and complexity, they pose increasingly significant safety and risk management challenges. A model-based safety approach is an efficient way of coping with the increasing system complexity. It helps better manage the complexity by utilizing reasoning tools that require abstract models to detect failures as early as possible during the design process...

Technological advancements have led to the use of computer based systems in safety critical applications. As computer based systems are being introduced in nuclear power plants, effective and efficient methods are needed to ensure dependability and compliance to high reliability requirements of systems important to safety. Even after several years of research, quantification of software reliabi...

Of special interest in formal verification are safety properties, which assert that the system always stays within some allowed region. Each safety property ψ can be associated with a set of bad prefixes: a set of finite computations such that an infinite computation violates ψ iff it has a prefix in the set. By translating a safety property to an automaton for its set of bad prefixes, verifica...

In this paper we present error estimates for kernel interpolation at scattered sites on manifolds. The kernels we consider will be obtained by the restriction of positive definite kernels on Rd, such as radial basis functions, to a smooth, compact embedded submanifold M ⊂ Rd with no boundary. For restricted kernels having finite smoothness, we provide a complete characterization of the native s...

Recent work proposed defining type-safe macros via interpretation into a multi-stage language. The utility of this approach was illustrated with a language called MacroML, in which all type checking is carried out before macro expansion. Building on this work, the goal of this paper is to develop a macro language that makes it easy for programmers to reason about terms locally. We show that def...

Foundational certified code systems seek to prove untrusted programs to be safe relative to safety policies given in terms of actual machine architectures, thereby improving the systems’ flexibility and extensibility. Previous efforts have employed a structure wherein the proofs are expressed in the same logic used to express the safety policy. We propose an alternative structure wherein safety...

Current best practice is that the acceptability of safety-critical software-based systems should be justified by a clear and defensible argument. This paper examines the structure that such an argument might take with regard to the allocation of system safety requirements to components, in particular software component requirements. A model solution is presented for a general class of control s...

We present a verification methodology for cooperating traffic agents covering analysis of cooperation strategies, realization of strategies through control, and implementation of control. For each layer, we provide dedicated approaches to formal verification of safety and stability properties of the design. The range of employed verification techniques invoked to span this verification space in...