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The engineering of dependable cyber-physical systems (CPSs) is inherently collaborative, demanding cooperation between diverse disciplines. A goal of current research is the development of integrated tool chains for model-based CPS design that support co-modelling, analysis, co-simulation, testing and implementation. We discuss the role of formal methods in addressing three key aspects of this goal: providing reasoning support for semantically heterogeneous models, managing the complexity and scale of design space exploration, and supporting traceability and provenance in the CPS design set. We briefly outline an approach to the development of such a tool chain based on existing tools and discuss ongoing challenges and open research questions in this area. IEEE/ACM 3rd FME Workshop on Formal Methods in Software Engineering978-1-4673-7043-1/15 $31.00

Abstract. Arguing that intricate concurrent programs satisfy their specifications can be difficult; recording understandable explanations is important for subsequent readers. Abstraction is a key tool even for sequential programs. The purpose here is to explore some abstractions that help readers (and writers) understand the design of concurrent programs. As an illustration, the paper presents a formal development of a non-trivial parallel program: Simpson's implementation of asynchronous communication mechanisms (ACMs). Although the correctness of this "4-slot algorithm" has been shown elsewhere, earlier proofs fail to offer much insight into the design. From an understandable (yet formal) design history of this one algorithm, the techniques employed in the explanation are teased out for wider application. Among these techniques is using a "fiction of atomicity" as an aid to understanding the initial steps of development. The rely-guarantee approach is, here, combined with notions of read/write frames and "phased" specifications; furthermore, the atomicity assumptions implied by the rely/guarantee conditions are achieved by clever choice of data representations.

Abstract. This paper presents initial results of research aimed at developing methods and tools for multidisciplinary collaborative development of dependable embedded systems. We focus on the construction and analysis by co-simulation of formal models that combine discrete-event specifications of computer-based controllers with continuous-time models of the environment with which they interact. Basic concepts of collaborative modelling and co-simulation are presented. A pragmatic realisation using the VDM and Bond Graph formalisms is described and illustrated by means of an example, which includes the modelling of both normal and faulty behaviour. Consideration of a larger-scale example from the personal transportation domain suggests the forms of support needed to explore the design space of collaborative models. Based on experience so far, challenges for future research in this area are identified.