This paper described the combination of two typical safety analysis techniques: fault tree analysis (FTA) from engineering and formal methods from software engineering. This combination was developed to cope with software-based systems, like the radio-based crossing control which we used for explanation, where both disciplines get together. For the presentation of the formal fault tree analysis the authors introduced the conventional FTA, necessary formal foundations, and the formalization of FTA. The formalization resulted in proof obligations guaranteeing complete and correct fault trees. The focus of this paper is the presentation of the methodology for the application of the formal FTA. An essential point is, that FTA and formal methods are applied independendly, at first, and stepwise adjusted within the analysis process. This retains the different points of view of both methods and nevertheless ends up with an integrated model. The integration of the FTA and the formal model can be done loosely or tighdy coupled, resulting in different levels of formalization. The first level exchanges safety properties which are proven over the formal model. The second level also formalizes the fault tree and proves it correct and complete. The authors propose to apply both levels for high assurance systems, as transportation control systems are. For finite systems, the proof conditions can be verified by model checking. For infinite systems, they are developing proof support for the interactive verification of fault tree conditions in the KIV system. Statechart specifications and the corresponding proof calculus is integrated to specify and verify dynamic systems.


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    Title :

    Formal safety analysis in transportation control


    Contributors:
    Thums, A. (author) / Schellhorn, G. (author)


    Publication date :

    2003


    Size :

    13 Seiten, 5 Bilder, 21 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Formal Safety Analysis in Transportation Control

    Ortmeier, F. / Thums, A. / Zentrum fur Verkehr der Technischen Universitat Braunschweig et al. | British Library Conference Proceedings | 2003


    Transportation Safety Analysis

    H. C. Joksch | NTIS | 1976


    Comparison of Modelling Methodologies for the Formal Safety Assessment in Shipping Transportation

    Konstantinidou, Monica / Mennis, Evangelos / Nikitakos, Nikitas et al. | Springer Verlag | 2004



    Formal safety assessment

    British Library Online Contents | 1996