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Traceability of Concerns and Observer-Based Verification for Railway Safety-Critical Software. (Traçabilité des Exigences et Vérification par Observateurs pour les Logiciels Critiques des Systèmes Ferroviaires)

In recent years, the development of critical systems demands more and more software. In order to reduce their costs of development and verification, actors in critical domains, such as avionics and automotive domains, are moving more and more towards model-driven engineering. In contrast, in the railway domain, for strategic and organizational reasons, actors remain faithful to traditional methods that allow them to take advantage of their knowledge. However, these conventional approaches suffer from a lack of abstraction and do not provide supports for traceability of concerns and formal verification, which are highly recommended, or even mandatory, for the development of railway safety-critical software. 
 
To address these shortcomings, we present in this thesis a systematic approach based on model driven engineering and component-based modelling, in order to better manage software complexity and traceability of concerns. In this dissertation, we provide in particular three major contributions. First, we provide an integrated set of meta-models for describing the concerns of software requirements, software components, and traceability between the concerns and software components. With the second contribution, we propose a formal support of our model to allow formal verification of temporal properties. Finally, with the last contribution, we propose a software component-based development and verification approach, called SARA, and included in V-lifecycle widely used in the railway domain. Experiments we conducted to validate our approach through a few case studies of the new European train control system ERTMS/ETCS, show that by using component model that explicitly include requirement traceability, we are able to provide a practical, scalable and reliable approach.