a b s t r a c tThe architectural design of embedded software has a direct impact on the final implementation, with respect to performance and other quality attributes. Therefore, guaranteeing that an architectural model meets the specified requirements is beneficial for detecting software flaws early in the development process. In this paper, we present a formal modeling and verification methodology for safety-critical automotive products that are originally described in the domain-specific architectural language EAST-ADL. We propose a model-based approach that integrates the architectural models with component-aware model checking, and describe its tool support called ViTAL. The functional and timing behavior of each function block in the EAST-ADL model, as well as the interactions between function blocks are formally captured and expressed as Timed Automata models, which have precise semantics and can be formally verified with ViTAL. Furthermore, we show how our approach, supported by ViTAL, can be used to formally prove that the EAST-ADL system model fulfills the specified real-time requirements and behavioral constraints. We demonstrate that the approach improves the modeling and verification capability of EAST-ADL and identifies dependencies, as well as potential conflicts between different automotive functions before implementation. The method is substantiated by verifying an automotive braking system model, with respect to particular functional and timing requirements.

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Since modern ambient assisted living solutions integrate a multitude of assisted-living functionalities, out of which some are safety critical, it is desirable that these systems are analyzed at their design stage to detect possible errors. To achieve this, one needs suitable architectures that support the seamless design of the integrated assisted-living functions, as well as capabilities for the formal modeling and analysis of the architecture. In this paper, we attempt to address this need, by proposing a generic integrated ambient assisted living system architecture, consisting of sensors, data collection, local and cloud processing schemes, and an intelligent decision support system, which can be easily extended to suit specific architecture categories. Our solution is customizable, therefore, we show three instantiations of the generic model, as simple, intermediate, and complex configurations, respectively, and show how to analyze the first and third categories by model checking. Our approach starts by specifying the architecture, using an architecture description language, in our case, the Architecture Analysis and Design Language, which can also account for the probabilistic behavior of such systems, and captures the possibility of component failure. To enable formal analysis, we describe the semantics of the simple and complex architectures within the framework of timed automata. We show that the simple architecture is amenable to exhaustive model checking by employing the UPPAAL tool, whereas for the complex architecture we resort to statistical model checking for scalability reasons. In this case, we apply the statistical extension of UPPAAL, namely UPPAAL SMC. Our work paves the way for the development of formally assured future ambient assisted living solutions.

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EAST-ADL is an architectural description language dedicated to automotive embedded systems design, with focus on structural and functional modeling. The current architectural notations lack support for modeling and analysis of resource-usage, and therefore it is not possible to reason about resource requirements. In this paper, we describe our work towards filling the gap between EAST-ADL language and formal modeling and analysis of system's resource usage, by extending the EAST-ADL language with embedded resources, such as storage, energy, communication and computation. To formalize this approach and provide a basis for rigorous analysis, we show how to analyze EAST-ADL models using the framework of priced timed automata and weighted CTL. We report our experiences from applying this approach for integrating resource-wise analysis into EAST-ADL.