ArcAngelC: a Refinement Tactic Language for Circus

AbstractCircus is a refinement language, in which specifications define both data and behavioural aspects of concurrent systems using a combination of Z and CSP. Its refinement theory and calculus are distinctive, but refinements may be long and repetitive, and using this technique can be hard. Some useful strategies have already been identified, described, and used. By documenting and using them as tactics, a lot can be gained since they can be repeatedly used as single transformation rules. Here, we present ArcAngelC, a language for defining such refinement tactics; we present the language and its application in the formalisation of an existing informal strategy for verification of Ada implementations of control systems

Conformance relations for distributed testing based on CSP

Copyright @ 2011 Springer Berlin HeidelbergCSP is a well established process algebra that provides comprehensive theoretical and practical support for refinement-based design and verification of systems. Recently, a testing theory for CSP has also been presented. In this paper, we explore the problem of testing from a CSP specification when observations are made by a set of distributed testers. We build on previous work on input-output transition systems, but the use of CSP leads to significant differences, since some of its conformance (refinement) relations consider failures as well as traces. In addition, we allow events to be observed by more than one tester. We show how the CSP notions of refinement can be adapted to distributed testing. We consider two contexts: when the testers are entirely independent and when they can cooperate. Finally, we give some preliminary results on test-case generation and the use of coordination messages. © 2011 IFIP International Federation for Information Processing

Data Flow Coverage for Circus-Based Testing

International audienceCircus is a state-rich process algebra based on Z and CSP that can be used for testing. In this paper, we consider data-flow coverage. In adapting the classical results on coverage of programs to Circus models, we define a notion of specification traces, consider models with data-flow anomalies, and cater for the internal nature of state. Our results are a framework for data-flow coverage of such abstract models, a novel data-flow criterion suited to state-rich process models, and the conversion of specification traces into symbolic traces

Control law diagrams in Circus

Abstract. Control diagrams are routinely used by engineers in the design of control systems. Yet, currently the formal verification of programs that implement the diagrams is a challenge. We present a strategy to translate block diagrams to Circus, a notation that combines Z, CSP, and a refinement calculus. This work is based on existing tools that produce Z and CSP specifications from discrete-time block diagrams. By using a combined notation, we provide a specification that considers both functional and behavioural aspects of the diagrams, and can cover a wider range of blocks. Moreover, the Circus refinement calculus can be used to derive or verify implementations, and reason about the block diagrams