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147
Diagnosis of Asynchronous Discrete Event Systems, a Net Unfolding Approach
 IEEE TRANS. ON AUTOMATIC CONTROL
, 2001
"... In this paper we formulate asynchronous diagnosis by means of hidden state history reconstruction, from alarm observations. We follow a socalled true concurrency approach, in which no global state and no global time is available. Instead, we use only local states in combination with a partial order ..."
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Cited by 64 (27 self)
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In this paper we formulate asynchronous diagnosis by means of hidden state history reconstruction, from alarm observations. We follow a socalled true concurrency approach, in which no global state and no global time is available. Instead, we use only local states in combination with a partial order model of time, in which local events are ordered if they are either generated on the same site, or related via some causality relation. Our basic mathematical tool is that of net unfoldings originating from the Petri net research area. This study was motivated by the problem of event correlation in telecommunications network management.
Using Logic Programs with Stable Model Semantics to Solve Deadlock and Reachability Problems for 1Safe Petri Nets
, 1999
"... McMillan has presented a deadlock detection method for Petri nets based on finite complete prefixes (i.e. net unfoldings). The approach transforms the PSPACEcomplete deadlock detection problem for a 1safe Petri net into a potentially exponentially larger NPcomplete problem of deadlock detection f ..."
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Cited by 51 (7 self)
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McMillan has presented a deadlock detection method for Petri nets based on finite complete prefixes (i.e. net unfoldings). The approach transforms the PSPACEcomplete deadlock detection problem for a 1safe Petri net into a potentially exponentially larger NPcomplete problem of deadlock detection for a finite complete prefix. McMillan devised a branchandbound algorithm for deadlock detection in prefixes. Recently, Melzer and Römer have presented another approach, which is based on solving mixed integer programming problems. In this work it is shown that instead of using mixed integer programming, a constraintbased logic programming framework can be employed, and a linearsize translation from deadlock detection in prexes into the problem of finding a stable model of a logic program is presented. As a side result also such a translation for solving the reachability problem is devised. Correctness proofs of both the translations are presented. Experimental results are given from an implementation combining a prefix generator from a PEP tool, the translation, and an implementation of a constraint logic programming framework, the smodels system. The experiments show the approach to be quite competetive, when compared to the approaches of McMillan and Melzer/Römer.
A Static Analysis Technique for Graph Transformation Systems
 In Proc. of CONCUR ’01
, 2001
"... In this paper we introduce a static analysis technique for graph transformation systems. We present an algorithm which, given a graph transformation system and a start graph, produces a nite structure consisting of a hypergraph decorated with transitions (Petri graph) which can be seen as an app ..."
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Cited by 43 (17 self)
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In this paper we introduce a static analysis technique for graph transformation systems. We present an algorithm which, given a graph transformation system and a start graph, produces a nite structure consisting of a hypergraph decorated with transitions (Petri graph) which can be seen as an approximation of the Winskel style unfolding of the graph transformation system. The fact that any reachable graph has an homomorphic image in the Petri graph and the additional causal information provided by transitions allow us to prove several interesting properties of the original system. As an application of the proposed technique we show how it can be used to verify the absence of deadlocks in an innitestate Dining Philosophers system.
Deadlock Checking Using Net Unfoldings
 In Proceeding of 9th International Conference on Computer Aided Verification (CAV’97
, 1997
"... McMillan presented a deadlock detection technique based on unfoldings of Petri net systems. It is realized by means of a backtracking algorithm that has its drawback for unfoldings that increase widely. We present an approach that exploits precisely this property. Moreover, we introduce a fast imple ..."
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Cited by 37 (1 self)
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McMillan presented a deadlock detection technique based on unfoldings of Petri net systems. It is realized by means of a backtracking algorithm that has its drawback for unfoldings that increase widely. We present an approach that exploits precisely this property. Moreover, we introduce a fast implementation of McMillan's algorithm and compare it with our new technique. 1 Introduction In the field of static analysis of concurrent systems deadlock freeness is almost always a desirable property. Many research has been carried out to propose methods that check this property [3]. One of these was presented by McMillan in [8]. It is based on net unfoldings of Petri net systems. A net unfolding is class of partial order semantics of Petri nets, also known as branching process [4]. The heuristic used in McMillan's algorithm is particularly good where the unfolding grows more deeply than widely and thereby only few end points of the unfolding (i.e., cutoff points) have to be considered. The...
The PEP Tool
, 1997
"... The PEP tool is a Programming Environment based on Petri Nets. Comprehensive modelling, compilation, simulation and verification components are embedded in a userfriendly graphical interface. The basic idea is that the modelling component allows the user to design parallel systems by parallel finit ..."
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Cited by 35 (2 self)
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The PEP tool is a Programming Environment based on Petri Nets. Comprehensive modelling, compilation, simulation and verification components are embedded in a userfriendly graphical interface. The basic idea is that the modelling component allows the user to design parallel systems by parallel finite automata, parallel programs, process algebra terms, highlevel or lowlevel Petri nets, and that the PEP system then automatically generates Petri nets from such models in order to use Petri net theory for simulation and verification purposes. This paper describes the typical usage of the PEP tool by considering the design of the wellknown `alternatingbit' protocol. Among others, the usefulness of new concepts for the handling of hierarchies and synchronous communication is explained. PEP has been implemented on Solaris 2.x, SunOS 4.1.x and Linux. Ftpable versions are available via http://www.informatik.unihildesheim.de/¸pep. Keywords: `Alternating bit' protocol, B(PN) 2 , Hierarc...
Unfolding and Finite Prefix for Nets with Read Arcs
 In Proceedings of CONCUR’98, volume 1466 of LNCS
"... Petri nets with read arcs are investigated with respect to their unfolding, where read arcs model reading without consuming, which is often more adequate than the destructivereadandrewrite modelled with loops in ordinary nets. The paper redefines the concepts of a branching process and unfoldi ..."
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Cited by 31 (0 self)
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Petri nets with read arcs are investigated with respect to their unfolding, where read arcs model reading without consuming, which is often more adequate than the destructivereadandrewrite modelled with loops in ordinary nets. The paper redefines the concepts of a branching process and unfolding for nets with read arcs and proves that the set of reachable markings of a net is completely represented by its unfolding.
Markov Nets: Probabilistic Models for distributed and concurrent systems
 IEEE Transactions on Automatic Control
, 2001
"... For distributed systems, i.e. large networked complex systems, there is a drastic difference between a local view and knowledge of the system, and its global view. Distributed systems have local state and time, but do not possess global state and time in the usual sense. In this paper, motivated by ..."
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Cited by 30 (15 self)
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For distributed systems, i.e. large networked complex systems, there is a drastic difference between a local view and knowledge of the system, and its global view. Distributed systems have local state and time, but do not possess global state and time in the usual sense. In this paper, motivated by the monitoring of distributed systems and in particular of telecommunications networks, we develop Markov nets as an extension of Markov chains and hidden Markov models (Hmm) for distributed and concurrent systems. By a concurrent system, we mean a system in which components may evolve independently, with sparse synchronizations. We follow a socalled true concurrency approach, in which neither global state nor global linear time are available. Instead, we use only local states in combination with a partial order model of time. Our basic mathematical tool is that of Petri net unfoldings. Keywords : discrete event systems, stochastic Petri nets, unfoldings. 1 Motivations Distributed network...
PEP  More than a Petri Net Tool
, 1996
"... The PEP system (Programming Environment based on Petri Nets) supports the most important tasks of a good net tool, including HL and LL net editing and comfortable simulation facilities. In addition, these features are embedded in sophisticated programming and verification components. The programming ..."
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Cited by 24 (2 self)
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The PEP system (Programming Environment based on Petri Nets) supports the most important tasks of a good net tool, including HL and LL net editing and comfortable simulation facilities. In addition, these features are embedded in sophisticated programming and verification components. The programming component allows the user to design concurrent algorithms in an easytouse imperative language, and the PEP system then generates Petri nets from such programs. The PEP tool's comprehensive verification components allow a large range of properties of parallel systems to be checked efficiently on either programs or their corresponding nets. This includes userdefined properties specified by temporal logic formulae as well as specific properties for which dedicated algorithms are available. PEP has been implemented on Solaris 2.4, SunOS 4.1.3 and Linux. Ftpable versions are available.
Causal atomicity
 In CAV, LNCS 4144
, 2006
"... Abstract. Atomicity is an important generic specification that assures that a programmer can pretend blocks occur sequentially in any execution. We define a notion of atomicity based on causality. We model the control flow of a program with threads using a Petri net that naturally abstracts data, an ..."
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Cited by 22 (4 self)
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Abstract. Atomicity is an important generic specification that assures that a programmer can pretend blocks occur sequentially in any execution. We define a notion of atomicity based on causality. We model the control flow of a program with threads using a Petri net that naturally abstracts data, and faithfully captures the independence and interaction between threads. The causality between events in the partially ordered executions of the Petri net is used to define the notion of causal atomicity. We show that causal atomicity is a robust notion that many correct programs adopt, and show how we can effectively check causal atomicity using Petri net tools based on unfoldings, which exploit the concurrency in the net to yield automatic partialorder reduction in the statespace. 1
Canonical Prefixes of Petri Net Unfoldings
, 2001
"... In this paper, we develop a general technique for truncating Petri net unfoldings, parameterized according to the level of information about the original unfolding one wants to preserve. Moreover, we propose a new notion of completeness of a truncated unfolding, which with the standard parameters ..."
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Cited by 21 (7 self)
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In this paper, we develop a general technique for truncating Petri net unfoldings, parameterized according to the level of information about the original unfolding one wants to preserve. Moreover, we propose a new notion of completeness of a truncated unfolding, which with the standard parameters is strictly stronger than that given in [5, 6], and is more appropriate for the existing model checking algorithms.