Currently available fault tree analysis techniques are not powerful enough to allow engineers to fully exploit these trees. Large fault trees require hours of CPU time on mainframe computers to be analysed, and this analysis provides designers only with approximate qualitative and quantitative informations. This paper presents data structures and algorithms that support the interactive exact an...

Fault tree analysis is commonly used to assess the reliability of potentially hazardous industrial systems. The type of logic is usually restricted to AND and OR gates which makes the fault tree structure coherent. In non-coherent structures not only components’ failures but also components’ working states contribute to the failure of the system. The qualitative and quantitative analyses of suc...

We present a semantics for fault tree analysis, a technique used for the analysis of safety critical systems, in the real-time interval logic Duration Calculus with Liveness and show how properties of fault trees can be checked automatically. We apply this technique in two examples and show how it can be connected to other verification techniques.

Reliability studies and system health predictions are mostly based on the use of probability laws to model the failure of components. Behavior of the components of the system under study is represented by probability distributions, derived from failure statistics. The parameters of these laws are assumed to be precise and well known, which is not always true in practice. Impact of such imprecis...

One major objection to Brown and Levinson’s politeness theory [Questions and Politeness: Strategies in Social Interaction, Cambridge University Press, 1978, pp. 56–311; Politeness: Some Universals in Language Usage, Cambridge University Press, Cambridge, 1987] raised by Matsumoto [J. Pragmatics 12 (1988) 403; Multilingua 8 (1989) 207; Japanese/Korean Linguistics, vol. 2, Center for the Study of...

A safety case contains safety arguments together with supporting evidence that together should demonstrate that a system is acceptably safe. System changes pose a challenge to the soundness and cogency of the safety case argument. Maintaining safety arguments is a painstaking process because it requires performing a change impact analysis through interdependent elements. Changes are often perfo...

Fault tree analysis (FTA) is a very prominent method to analyze the risks related to safety and economically critical assets, like power plants, airplanes, data centers and web shops. FTA methods comprise of a wide variety of modelling and analysis techniques, supported by a wide range of software tools. This paper surveys over 150 papers on fault tree analysis, providing an in-depth overview o...

This paper considers the design-phase safety analysis of vehicle guidance systems. The proposed approach constructs dynamic fault trees (DFTs) to model a variety of safety concepts and E/E architectures for drive automation. The fault trees can be used to evaluate various quantitative measures by means of model checking. The approach is accompanied by a large-scale evaluation: The resulting DFT...

In this paper, we outline a new approach to safety analysis in which concepts of computer HAZOP are fused with the idea of software fault tree analysis to enable a continuous assessment of an evolving programmable design developed in Matlab-Simulink. We also discuss the architecture of a tool that we have developed to support the new method and enable its application in complex environments. We...

Among all kinds of possible faults in a manufacturing system, operational faults occur most often (about 70%). Efficient diagnosis of these faults is critical for improving the availability and productivity of the manufacturing system. This paper presents a hierarchical diagnosis model based on fault tree analysis and two other diagnosis models respectively based on the logic and sequential con...