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Fair testing
 Concur ’95: Concurrency Theory, volume 962 of Lecture Notes in Computer Science
, 1995
"... In this paper we present a solution to the longstanding problem of characterising the coarsest livenesspreserving precongruence with respect to a full (TCSPinspired) process algebra. In fact, we present two distinct characterisations, which give rise to the same relation: an operational one base ..."
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In this paper we present a solution to the longstanding problem of characterising the coarsest livenesspreserving precongruence with respect to a full (TCSPinspired) process algebra. In fact, we present two distinct characterisations, which give rise to the same relation: an operational one based on a De NicolaHennessylike testing modality which we call shouldtesting, and a denotational one based on a refined notion of failures. One of the distinguishing characteristics of the shouldtesting precongruence is that it abstracts from divergences in the same way as Milner’s observation congruence, and as a consequence is strictly coarser than observation congruence. In other words, shouldtesting has a builtin fairness assumption. This is in itself a property long soughtafter; it is in notable contrast to the wellknown musttesting of De Nicola and Hennessy (denotationally characterised by a combination of failures and divergences), which treats divergence as catrastrophic and hence is incompatible with observation congruence. Due to these characteristics, shouldtesting supports modular reasoning and allows to use the proof techniques of observation congruence, but also supports additional laws and techniques.
Coverage Preserving Reduction Strategies for Reachability Analysis
"... We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be ..."
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Cited by 60 (8 self)
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We study the effect of three new reduction strategies for conventional reachability analysis, as used in automated protocol validation algorithms. The first two strategies are implementations of partial order semantics rules that attempt to minimize the number of execution sequences that need to be explored for a full state space exploration. The third strategy is the implementation of a state compression scheme that attempts to minimize the amount of memory that is used to built a state space. The three strategies are shown to have a potential for substantially improving the performance of a conventional search. The paper discusses the optimal choices for reducing either run time or memory requirements by four to six times. The strategies can readily be combined with each other and with alternative state space reduction techniques such as supertrace or state space caching methods.
The weakest compositional semantic equivalence preserving nexttimeless linear temporal logic
 In Proceedings of CONCUR’92
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An Application Of Petri Net Reduction For Ada Tasking Deadlock Analysis
, 1996
"... As part of our continuing research on using Petri nets to support automated analysis of Ada tasking behavior, we have investigated the application of Petri net reduction for deadlock analysis. Although reachability analysis is an important method to detect deadlocks, it is in general inefficient or ..."
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Cited by 25 (6 self)
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As part of our continuing research on using Petri nets to support automated analysis of Ada tasking behavior, we have investigated the application of Petri net reduction for deadlock analysis. Although reachability analysis is an important method to detect deadlocks, it is in general inefficient or even intractable. Net reduction can aid the analysis by reducing the size of the net while preserving relevant properties. We introduce a number of reduction rules and show how they can be applied to Ada nets, which are automatically generated Petri net models of Ada tasking. We define a reduction process and a method by which a useful description of a detected deadlock state can be obtained from the reduced net's information. A reduction tool and experimental results from applying the reduction process are discussed.
An Efficient Verifier of Truly Concurrent Properties
 PROCEEDINGS OF PACT'95, LNCS 964
, 1995
"... We present a parametric tool for the analysis of distributed concurrent systems. Processes are internally represented as proved transition systems. Actually, we use a fragment of them, in which only one transition exits from a node among those mutually concurrent. This permits to have compact repres ..."
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Cited by 8 (7 self)
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We present a parametric tool for the analysis of distributed concurrent systems. Processes are internally represented as proved transition systems. Actually, we use a fragment of them, in which only one transition exits from a node among those mutually concurrent. This permits to have compact representations that are linear in average with the number of actions in the term of the language that describes the system. Another important property of these compact transition systems is that they preserve truly concurrent bisimulations, that can be checked in average in polynomial time. Parametricity is achieved by resorting to the rich labelling of the transitions encoding the parallel structure of processes. These labels are then "observed" for retrieving the interleaving, causal and locational semantics.
A.: Using TruthPreserving Reductions to Improve the Clarity of KripkeModels
 in CONCUR'91, LNCS
, 1991
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A Compact Representation of Finite State Processes
, 1993
"... We generate in SOS style compact representations of finite state concurrent processes. The representation of a possibly recursive process with n actions requires O(n) space in average. Our starting point are proved transition systems, that record in the labels of transitions their proofs. The concu ..."
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We generate in SOS style compact representations of finite state concurrent processes. The representation of a possibly recursive process with n actions requires O(n) space in average. Our starting point are proved transition systems, that record in the labels of transitions their proofs. The concurrency and conflict relation on the transitions of a term are derived from labels and are used to discard some transitions. In the compact transition system, all the paths originated by the possible interleavings of concurrent actions are represented by at least one path, actually a single one if all the actions are visible and there is no autoconcurrency. The generation of the compact transition system is correct, because the complete one can be retrieved from it. Finally, it is shown that our reduction preserves bisimulations when applied to truly concurrent models, thus giving evidence that these representations may be more economic than the interleaving ones. The compact representation o...
The Successes and Failures of Behavioural Models
 In Millennial Perspectives in Computer Science, Palgrave
, 2000
"... We examine the advantages and disadvantages of modelling concurrent processes in the style of Hoare, where a process is modelled as a set of relatively simple behavioours, as opposed to modelling them as transition systems. A special study is made of the way these two theories handle the topic of no ..."
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We examine the advantages and disadvantages of modelling concurrent processes in the style of Hoare, where a process is modelled as a set of relatively simple behavioours, as opposed to modelling them as transition systems. A special study is made of the way these two theories handle the topic of noninterference from computer security. 1
A.: “Merging StateBased and ActionBased Verification
 Proc. ACSD 2003, Third International Conference on Application of Concurrency to System Design, IEEE Computer Society 2003
, 2003
"... A formalism is presented that is intended to combine basic properties of both statebased and actionbased verification. In statebased verification the behaviour of the system is described in terms of the properties of its states, whereas actionbased methods concentrate on transitions between st ..."
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A formalism is presented that is intended to combine basic properties of both statebased and actionbased verification. In statebased verification the behaviour of the system is described in terms of the properties of its states, whereas actionbased methods concentrate on transitions between states. A typical statebased approach consists of representing requirements as temporal logic formulae, and modelchecking the state space of the system against them. Actionbased verification often consists of comparing systems according to some equivalence or preorder relation. We add state propositions to a typical processalgebraic action framework. Values of state propositions are propagated through processalgebraic compositions and reductions by augmenting actions with changes of proposition values. A modified parallel composition operator is used for synchronisation of processes and handling of state propositions. Efficient onthefly verification is obtained with four kinds of rejection conditions. The formalism is implemented in a new verification tool TVT. 1.