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Cyber-physical systems are multidisciplinary systems which involve different engineering disciplines in their design. Each engineering discipline tends to use its own domain-speci﬿c languages and tools to model different aspects of a system concurrently. The concurrent modelling process may introduce inconsistencies due to lack of common knowledge and communication among domain experts. Especially for co-modelling and co-simulation developments, a huge amount of models, versions of models and design alternatives may be produced, which highly increases the design space and the chance of having inconsistent models. This paper introduces a model management support and concurrent design flow to prevent inconsistencies and maintain synchronization among models. Besides the consistency checking scheme, a co-evolution graph can be generated by the model management system to visualize the concurrent development process and prevent inconsistencies. The model management system and concurrent design flow have been applied on a line following robot to show how to use this approach and its advantages.

Simulating formal models is a common means for validating the correctness of the system design and reduce the time-to-market. In most of the embedded control system design, multiple engineering disciplines and various domain-specific models are often involved, such as mechanical, control, software and hardware models. Close collaboration and well integration between all domain-specific models become more and more important for developing dependable and cost-efficient systems. Moreover, each disciplinary model can be de- veloped and evolved following its own semantics and development tools in different rates. The inconsistency between models and the evolution of the collection of models will increase the complexity of design as well as the difficulty of maintaining several models under simultaneous development and changes. Therefore, this paper introduces a model management approach for multi-disciplinary systems and co- simulation. Such model management approach can ensure the model integration and consistency, keep track of model evolution, and support decision making. The concepts of the DESTECS co-simulation framework (?) and the corresponding model evolution process are also explained.

Development of computerized embedded control systems is difficult because it brings together systems theory, electrical engineering and computer science. The engineering and analysis approaches advocated by these disciplines are fundamentally different which complicates reasoning about e.g. performance at the system level. We propose a light-weight approach that alleviates this problem to some extent. An existing formal semantic framework for discrete event models is extended to allow for consistent co-simulation of continuous time models from within this framework. It enables integrated models that can be checked by simulation in addition to the verification and validation techniques already offered by each discipline individually. The level of confidence in the design can now be raised in the very early stages of the system design life-cycle instead of postponing system-level design issues until the integration and test phase is reached. We demonstrate the extended semantic framework by co-simulation of VDM++ and bond-graph models on a case study, the level control of a water tank.