Abstract: Rigorous engineering of safety-critical Cyber- Physical Systems (CPS) requires integration of heterogeneous modeling methods from different disciplines. It is often necessary to view this integration from the perspective of analyses – algorithms that read and change models. Although analytic integration supports formal contract-based verification of model evolution, it suffers from the limitation of analytic dependency loops. Dependency loops between analyses cannot be resolved based on the existing contract-based verification. This paper makes a step towards using rich architectural description to resolve circular analytic dependencies. We characterize the dependency loop problem and discuss three algorithmic approaches to resolving such loops: analysis iteration, constraint solving, and genetic search. These approaches take advantage of information in multi-view architectures to resolve analytic dependency loops.

Abstract: Current methods for designing cyber-physical systems lack a unifying framework due to the heterogeneous nature of the constituent models and their respective analysis and verification tools. There is a need for a formal representation of the relationships between the different models. Our approach is to define these relationships at the architectural level, associating with each model a particular view of the overall system base architecture. This architectural framework captures critical structural and semantic information without including all the details of the various modeling formalisms. This paper introduces the use of logical constraints over parameters in the architectural views to represent the conditions under which the specifications verified for each model are true and imply the system-level specification. Interdependencies and connections between the constraints in the architectural views are managed in the base architecture using first-order logic of real arithmetic to ensure consistency and correct reasoning. The approach is illustrated in the context of heterogeneous verification of a leader-follower vehicle scenario.

Abstract: Current methods for modeling, analysis, and design of cyber-physical systems lack a unifying framework due to the complexity and heterogeneity of the constituent elements and their interactions. Our approach is to define relationships between system models at the architectural level, which captures the structural interdependencies and some semantic interdependencies between representations without attempting to comprehend all of the details of any particular modeling formalism. This paper addresses the issue of defining and evaluating consistency between architectural views imposed by various heterogeneous models and a base architecture (BA) for the complete system. This notion of structural consistency ensures that the model elements adhere to the cyber and physical types and the connections between components present in the BA, which serves as the unifying framework for model-based development. Consistency checking between a model and the underlying system architecture is formulated as a typed graph matching problem between the connectivity graphs of the corresponding architectural view and the system’s BA. The usefulness of the approach to check system modeling assumptions is illustrated in the context of two heterogeneous views of a quadrotor air vehicle.