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120
Computation in Networks of Passively Mobile FiniteState Sensors
 Distributed Computing
, 2004
"... We explore the computational power of networks of small resourcelimited mobile agents. We define two new models of computation based on pairwise interactions of finitestate agents in populations of finite but unbounded size. With a fairness condition on interactions, we define the concept of stabl ..."
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Cited by 124 (14 self)
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We explore the computational power of networks of small resourcelimited mobile agents. We define two new models of computation based on pairwise interactions of finitestate agents in populations of finite but unbounded size. With a fairness condition on interactions, we define the concept of stable computation of a function or predicate, and give protocols that stably compute functions in a class including Boolean combinations of thresholdk, parity, majority, and simple arithmetic. We prove that all stably computable predicates are in NL. With uniform random sampling of pairs to interact, we define the model of conjugating automata and show that any counter machine with O(1) counters of capacity O(n) can be simulated with high probability by a protocol in a population of size n. We prove that all predicates computable with high probability in this model are in P #RL.
Decidability and complexity of Petri net problems  an Introduction
 In Lectures on Petri Nets I: Basic Models
, 1998
"... . A collection of 10 "rules of thumb" is presented that helps to determine the decidability and complexity of a large number of Petri net problems. 1 ..."
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Cited by 106 (3 self)
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. A collection of 10 "rules of thumb" is presented that helps to determine the decidability and complexity of a large number of Petri net problems. 1
Petri Nets, Commutative ContextFree Grammars, and Basic Parallel Processes
, 1997
"... . The paper provides a structural characterisation of the reachable markings of Petri nets in which every transition has exactly one input place. As a corollary, the reachability problem for this class is proved to be NPcomplete. Further consequences are: the uniform word problem for commutative co ..."
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Cited by 68 (6 self)
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. The paper provides a structural characterisation of the reachable markings of Petri nets in which every transition has exactly one input place. As a corollary, the reachability problem for this class is proved to be NPcomplete. Further consequences are: the uniform word problem for commutative contextfree grammars is NPcomplete; weakbisimilarity is semidecidable for Basic Parallel Processes. Keywords: Petri nets, Commutative Contextfree Grammars, Basic Parallel Processes, Weak bisimilarity. 1. Introduction The reachability problem plays a central role in Petri net theory, and has been studied in numerous papers (see [5] for a comprehensive list of references). In the first part of this paper we study it for the nets in which every transition needs exactly one token to occur. Following [8], we call them communicationfree nets, because no cooperation between places is needed in order to fire a transition; every transition is activated by one single token, and the tokens may flow...
Decidability of Model Checking for InfiniteState Concurrent Systems
 Acta Informatica
"... We study the decidability of the model checking problem for linear and branching time logics, and two models of concurrent computation, namely Petri nets and Basic Parallel Processes. 1 Introduction Most techniques for the verification of concurrent systems proceed by an exhaustive traversal of the ..."
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Cited by 64 (1 self)
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We study the decidability of the model checking problem for linear and branching time logics, and two models of concurrent computation, namely Petri nets and Basic Parallel Processes. 1 Introduction Most techniques for the verification of concurrent systems proceed by an exhaustive traversal of the state space. Therefore, they are inherently incapable of considering systems with infinitely many states. Recently, some new methods have been developed in order to at least palliate this problem. Using them, several verification problems for some restricted infinitestate models have been shown to be decidable. These results can be classified into those showing the decidability of equivalence relations [8, 9, 24, 26], and those showing the decidability of model checking for different modal and temporal logics. In this paper, we contribute to this second group. The model checking problem has been studied so far for three infinitestate models: contextfree processes, pushdown processes, and...
BRIDGING THE GAP BETWEEN BUSINESS MODELS AND WORKFLOW SPECIFICATIONS
 INTERNATIONAL JOURNAL OF COOPERATIVE INFORMATION SYSTEMS
"... ..."
Diagnosing Workflow Processes Using Woflan
 THE COMPUTER JOURNAL
, 1999
"... ... This paper presents the verification tool Woflan. Woflan analyzes workflow process definitions downloaded from commercial workflow products using stateoftheart Petrinetbased analysis techniques. This paper describes the functionality of Woflan emphasizing diagnostics to locate the source of ..."
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Cited by 59 (9 self)
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... This paper presents the verification tool Woflan. Woflan analyzes workflow process definitions downloaded from commercial workflow products using stateoftheart Petrinetbased analysis techniques. This paper describes the functionality of Woflan emphasizing diagnostics to locate the source of a design error. Woflan is evaluated via two case studies, one involving twenty groups of students designing a complex workflow process and one involving an industrial workflow process designed by Staffware Benelux. The results are encouraging and show that Woflan guides the user in finding and correcting errors in the design of workflows.
A Type System for LockFree Processes
, 2002
"... Interpretation. An alternative way to analyze the behavior of a concurrent program would be to use abstract interpretation [4, 5]. Actually, from a very general viewpoint, our typebased analysis of locks can be seen as a kind of abstract interpretation. We can read a type judgment # P as "# ..."
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Cited by 55 (8 self)
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Interpretation. An alternative way to analyze the behavior of a concurrent program would be to use abstract interpretation [4, 5]. Actually, from a very general viewpoint, our typebased analysis of locks can be seen as a kind of abstract interpretation. We can read a type judgment # P as "# is an abstraction of a concrete process P ." (The relation "#" corresponds to a pair of abstraction /concretization functions.) Indeed, we can regard a type environment as an abstract process: we have defined reductions of type environments in Section 3.7.
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 52 (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.
Complexity Results for 1safe Nets
, 1993
"... We study the complexity of several standard problems for 1safe Petri nets and some of its subclasses. We prove that reachability, liveness, and deadlock are all PSPACEcomplete for 1safe nets. We also prove that deadlock is NPcomplete for freechoice nets and for 1safe freechoice nets. Finally, ..."
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Cited by 51 (7 self)
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We study the complexity of several standard problems for 1safe Petri nets and some of its subclasses. We prove that reachability, liveness, and deadlock are all PSPACEcomplete for 1safe nets. We also prove that deadlock is NPcomplete for freechoice nets and for 1safe freechoice nets. Finally, we prove that for arbitrary Petri nets, deadlock is equivalent to reachability and liveness. This paper is to be presented at FST&TCS 13, Foundations of Software Technology & Theoretical Computer Science, to be held 1517 December 1993, in Bombay, India. A version of the paper with most proofs omitted is to appear in the proceedings. 1 Introduction Petri nets are one of the oldest and most studied formalisms for the investigation of concurrency [33]. Shortly after the birth of complexity theory, Jones, Landweber, and Lien studied in their classical paper [24] the complexity of several fundamental problems for Place/Transition nets (called in [24] just Petri nets). Some years later, Howell,...
TypeBased Information Flow Analysis for the PiCalculus
 Acta Informatica
, 2003
"... We propose a new type system for information flow analysis for the ..."
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Cited by 49 (10 self)
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We propose a new type system for information flow analysis for the