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Recently, opacity has proved to be a promising technique for describing security properties. Much of the work has been couched in terms of Petri nets. Here, we extend the notion of opacity to the model of labelled transition systems and generalise opacity in order to better represent concepts from the work on information flow. In particular, we establish(More)
We consider opacity as a property of the local states of the secure (or high-level) part of the system, based on the observation of the local states of a low-level part of the system as well as actions. We propose a Petri net modelling technique which allows one to specify different information flow properties, using suitably defined observations of system(More)
We consider the modelling of the behaviour of membrane systems using Petri nets. First, a systematic, structural, link is established between a basic class of membrane systems and Petri nets. To capture the compartmentisation of membrane systems, localities are proposed as an extension of Petri nets. This leads to a locally maximal concurrency semantics for(More)
The paper presents a new method for checking Uniqueand Complete State Coding, the crucial conditions in thesynthesis of asynchronous control circuits from Signal TransitionGraphs (STGs). The method detects state coding conflictsin an STG using its partial order semantics (unfoldingprefix) and an integer programming technique. This leads tohuge memory(More)
Automated verication of dynamic multi-threaded computing systems is severely aected by problems relating to dynamic process creation. In this paper, we describe an abstraction technique aimed at generating reduced state space representations for such systems. To make the new technique applicable to a wide range of dierent system models, we express it in(More)
Automated verification of dynamic multi-threaded computing systems can be adversely affected by problems relating to dynamic process creation. We therefore investigate — in a general setting of labelled transition systems – a way of reducing the state spaces of multi-threaded systems. At the heart of our method is a state equivalence, which may produce a(More)