Branching processes of Petri nets

Engelfriet, Joost

doi:10.1007/bf01463946

Cited by 252 publications

(191 citation statements)

References 9 publications

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“…These processes are those described in [1]. We define them inductively and use a canonical coding like in [8]. The processes provide a partial order representation of the executions.…”

Section: Partial Order Semanticsmentioning

confidence: 99%

Time Supervision of Concurrent Systems Using Symbolic Unfoldings of Time Petri Nets

Chatain

Jard

2005

Lecture Notes in Computer Science

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Monitoring real-time concurrent systems is a challenging task. In this paper we formulate (model-based) supervision by means of hidden state history reconstruction, from event (e.g. alarm) observations. We follow a so-called true concurrency approach using time Petri nets: the model defines explicitly the causality and concurrency relations between the observable events, produced by the system under supervision on different points of observation, and constrained by time aspects. The problem is to compute on-the-fly the different partial order histories, which are the possible explanations of the observable events. We do not impose that time is observable: the aim of supervision is to infer the partial ordering of the events and their possible firing dates. This is achieved by considering a model of the system under supervision, given as a time Petri net, and the on-the-fly construction of an unfolding, guided by the observations. Using a symbolic representation, this paper presents a new definition of the unfolding of time Petri nets with dense time.

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“…These processes are those described in [1]. We define them inductively and use a canonical coding like in [8]. The processes provide a partial order representation of the executions.…”

Section: Partial Order Semanticsmentioning

confidence: 99%

Time Supervision of Concurrent Systems Using Symbolic Unfoldings of Time Petri Nets

Chatain

Jard

2005

Lecture Notes in Computer Science

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“…In particular, given a finite configuration K the set of conditions Cut( K) is a reachable global state, which we denote GS( K). The basic algorithm will eventually produce any reachable global state under only the fairness assumption that every tile candidate to be added is eventually chosen to extend the puzzle (the correctness proof follows from the definitions and from the results of [11]). …”

Section: Construction Of the Unfoldingmentioning

confidence: 99%

Principles of Distributed Test Synthesis Based on True-Concurrency Models

Jard

2002

IFIP Advances in Information and Communication Technology

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Automatic synthesis of test cases for conformance testing has been principally developed with the objective of generating sequential test cases. In the distributed system context, it is worth extending the synthesis techniques to the generation of multiple testers. We base our work on our experience in using model-checking techniques, as successfully implemented in the TGV tool. Continuing the works of A. Ulrich and H. Konig, we propose to use a trueconcurrency model based on graph unfolding. The article presents the principles of a complete chain of synthesis, starting from the definition of test purposes and ending with a projection onto a set of testers.Key words: Test, Distributed systems, Synthesis, True-concurrency models, Interoperability INTRODUCTIONAlgorithms for automatic test synthesis have been proposed both in the academic world, and in industry. However, the use of these tools reaches a limit when testing distributed systems. This is because they are dedicated to the synthesis of sequential test cases (represented by event sequences or finite automata). Such synthesis is not always well-suited to test systems containing parallel activities. It is also known that a state representation of a specification with parallelism often suffers from a combinatorial explosion. 302 TESTING DISTRIBUTED SYSTEMSThe interest in generating distributed test cases was recognised a few years ·ago, as demonstrated by the inclusion of concurrent constructs in the TTCN standard. We retain three main motivations to synthesise distributed test cases:It can be naturally imposed by the test architecture under consideration. Let us consider a system geographically scattered on a network. The idea is to design a set of testers, each tester being located at the communicating entity to be checked, and communicating with the other testers to co-ordinate the test activity and the production of diagnosis.It allows more compact and clear test cases to be obtained. This is the case when the system under test produces concurrent observable events: a sequential representation would require all possible interleavings to be computed. This rapidly suffers from a combinatorial explosion as the concurrency increases.In certain cases parallel testing is needed to check particular behaviours. For example, one often considers for controllability reasons that the testers must wait for the system stabilisation before injecting new interactions. Under this assumption, it was shown by [2] that a distributed test case can position the system under test into states which are not reachable by a sequential test. More generally, the situation will also occur in the context of real-time testing.One can distinguish two main approaches to synthesising distributed test cases:The generation of sequential test cases, followed by their automated distribution. The idea is to produce a set of communicating testers which behave like the sequential test (i.e. in the sense of trace equivalence). The advantage of this approach is that it requires no more th...

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“…The representation of all runs of a Petri net as an unfolding [2], [3] allows one to avoid the state-space explosion due to interleavings when exploring the runs of a Petri net. Unfoldings are infinite in general, but can be represented efficiently by a finite complete prefix [4], [5], for instance to check LTL formulas [6].…”

Section: Introductionmentioning

confidence: 99%

Building Tight Occurrence Nets from Reveals Relations

Balaguer

Chatain

Haar

2011

2011 Eleventh International Conference on Application of Concurrency to System Design

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Abstract-Occurrence nets are a well known partial order model for the concurrent behavior of Petri nets. The causality and conflict relations between events, which are explicitly represented in occurrence nets, induce logical dependencies between event occurrences: the occurrence of an event e in a run implies that all its causal predecessors also occur, and that no event in conflict with e occurs. But these structural relations do not express all the logical dependencies between event occurrences in maximal runs: in particular, the occurrence of e in any maximal run may imply the occurrence of another event that is not a causal predecessor of e, in that run. The reveals relation has been introduced in [1] to express this dependency between two events. Here we generalize the reveals relation to express more general dependencies, involving more than two events, and we introduce ERL logic to express them as boolean formulas. Finally we answer the synthesis problem that arises: given an ERL formula ϕ, is there an occurrence net N such that ϕ describes exactly the dependencies between the events of N ?

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Branching processes of Petri nets

Cited by 252 publications

References 9 publications

Time Supervision of Concurrent Systems Using Symbolic Unfoldings of Time Petri Nets

Time Supervision of Concurrent Systems Using Symbolic Unfoldings of Time Petri Nets

Principles of Distributed Test Synthesis Based on True-Concurrency Models

Building Tight Occurrence Nets from Reveals Relations

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