Abstract. Message sequence charts (MSCs) are commonly used to specify interactions between agents in communicating systems. Their visual nature makes them attractive for describing scenarios, but also leads to ambiguities that can result in incomplete or inconsistent descriptions.One such problem is that of implied scenarios-a set of MSCs may imply new MSCs which are "locally consistent" with the given set. If local consistency is defined in terms of local projections of actions along each process, it is undecidable whether a set of MSCs is closed with respect to implied scenarios, even for regular MSC languages [3].We introduce a new and natural notion of local consistency called causal closure, based on the causal view of a process-all the information it collects, directly or indirectly, through its actions. Our main result is that checking whether a set of MSCs is closed with respect to implied scenarios modulo causal closure is decidable for regular MSC languages.
In this paper, we model a distributed system consisting of n processes by a respective set of n Communicating Finite State Machines (CFSMs). The processes run concurrently and communicate with each other to accomplish a common goal. As opposed to the traditional product automaton built from the specified CFSMs, whose state-space explodes, we build a compressed model of what are defined as Communicating Minimal Prefix Machines (CMPMs) by simulating the CFSMs concurrently in parallel. The states of CMPMs form a well-founded, partial order. This model can be used to perform reachability analysis of the given system to check the safety properties such as communication deadlocks. The algorithm to generate the CMPMs model from CFSMs is presented in pseudo-code and its complexity discussed
In this paper, the goal is to perform the verification of fault-tolerant properties of a peer-to-peer (P2P) network consisting of n nodes running n corresponding parallel processes. The specification of the processes is in the form of communicating finite state machines (CFSMs). The work to be reported in this paper follows the prequel work wherein, instead of the traditional approach to construct a single synchronous product machine by composing the given CFSMs, we simulate each of the CFSMs in the non-local environment of other CFSMs and generate a set of what are called Communicating Minimal Prefix Machines(CMPMs). In this paper, we take the CMPMs model and perform the reachability analysis of certain global state vectors without losing the locality of the CFSMs of the given specification. This method cuts down the state space explosion and also opens out the possibility of distributed exploration of the local CFSM states. Faulttolerance consists of both safety and liveness properties and our approach provides a sound platform for performing state exploration/model-checking to verify these properties of the given set of application tasks that run in the P2P network.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.