Results 1  10
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142
An Improvement of McMillan's Unfolding Algorithm
 Formal Methods in System Design
, 1996
"... McMillan has recently proposed a new technique to avoid the state explosion problem in the verification of systems modelled with finitestate Petri nets. The technique requires to construct a finite initial part of the unfolding of the net. McMillan's algorithm for this task may yield initial parts ..."
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Cited by 180 (9 self)
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McMillan has recently proposed a new technique to avoid the state explosion problem in the verification of systems modelled with finitestate Petri nets. The technique requires to construct a finite initial part of the unfolding of the net. McMillan's algorithm for this task may yield initial parts that are larger than necessary (exponentially larger in the worst case). We present a refinement of the algorithm which overcomes this problem. 1 Introduction In a seminal paper [10], McMillan has proposed a new technique to avoid the state explosion problem in the verification of systems modelled with finitestate Petri nets. The technique is based on the concept of net unfolding, a well known partial order semantics of Petri nets introduced in [12], and later described in more detail in [4] under the name of branching processes. The unfolding of a net is another net, usually infinite but with a simpler structure. McMillan proposes an algorithm for the construction of a finite initial part...
Deciding Properties for Message Sequence Charts
, 1998
"... Message sequence charts (MSC) are commonly used in designing communication systems. They allow describing the communication skeleton of a system and can be used for finding design errors. First, a specification formalism that is based on MSC graphs, combining finite message sequence charts, is p ..."
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Cited by 52 (9 self)
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Message sequence charts (MSC) are commonly used in designing communication systems. They allow describing the communication skeleton of a system and can be used for finding design errors. First, a specification formalism that is based on MSC graphs, combining finite message sequence charts, is presented. We present then an automatic validation algorithm for systems described using the message sequence charts notation. The validation problem is tightly related to a natural languagetheoretic problem over semitraces (a generalization of Mazurkiewicz traces, which represent partially ordered executions). We show that a similar and natural decision problem is undecidable. 1
Modeling and Analysis of Timed Petri Nets Using Heaps of Pieces
, 1997
"... We show that safe timed Petri nets can be represented by special automata over the (max,+) semiring, which compute the height of heaps of pieces. This extends to the timed case the classical representation a la Mazurkievicz of the behavior of safe Petri nets by trace monoids and trace languages. Fo ..."
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Cited by 44 (15 self)
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We show that safe timed Petri nets can be represented by special automata over the (max,+) semiring, which compute the height of heaps of pieces. This extends to the timed case the classical representation a la Mazurkievicz of the behavior of safe Petri nets by trace monoids and trace languages. For a subclass including all safe Free Choice Petri nets, we obtain reduced heap realizations using structural properties of the net (covering by safe state machine components). We illustrate the heapbased modeling by the typical case of safe jobshops. For a periodic schedule, we obtain a heapbased throughput formula, which is simpler to compute than its traditional timed event graph version, particularly if one is interested in the successive evaluation of a large number of possible schedules. Keywords Timed Petri nets, automata with multiplicities, heaps of pieces, (max,+) semiring, scheduling. I. Introduction The purpose of this paper 1 is to prove the following result: Timed safe Pe...
An Expressively Complete Linear Time Temporal Logic for Mazurkiewicz Traces
, 1997
"... A basic result concerning LTL, the propositional temporal logic of linear time, is that it is expressively complete; it is equal in expressive power to the first order theory of sequences. We present here a smooth extension of this result to the class of partial orders known as Mazurkiewicz traces. ..."
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Cited by 42 (5 self)
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A basic result concerning LTL, the propositional temporal logic of linear time, is that it is expressively complete; it is equal in expressive power to the first order theory of sequences. We present here a smooth extension of this result to the class of partial orders known as Mazurkiewicz traces. These partial orders arise in a variety of contexts in concurrency theory and they provide the conceptual basis for many of the partial order reduction methods that have been developed in connection with LTLspecifications. We show that LTrL, our linear time temporal logic, is equal in expressive power to the first order theory of traces when interpreted over (finite and) infinite traces. This result fills a prominent gap in the existing logical theory of infinite traces. LTrL also constitutes a characterisation of the so called trace consistent (robust) LTLspecifications. These are specifications expressed as LTL formulas that do not distinguish between different linearisations of the same trace and hence are amenable to partial order reduction methods.
Message Sequence Graphs and Decision Problems on Mazurkiewicz Traces
 In Proc. of MFCS'99, LNCS 1672
, 1999
"... Message sequence charts (MSC) are a graphical specification language widely used for designing communication protocols. Our starting point are two decision problems concerning the correctness and the consistency of a design based by MSC graphs. Both problems are shown to be undecidable, in gener ..."
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Cited by 41 (11 self)
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Message sequence charts (MSC) are a graphical specification language widely used for designing communication protocols. Our starting point are two decision problems concerning the correctness and the consistency of a design based by MSC graphs. Both problems are shown to be undecidable, in general. Using a natural connectivity assumption from Mazurkiewicz trace theory we show both problems to be EXPSPACEcomplete for locally synchronized graphs. The results are based on new complexity results for starconnected rational trace languages.
Logical Definability on Infinite Traces
 Theoretical Computer Science
, 1993
"... The main results of the present paper are the equivalence of definability by monadic secondorder logic and recognizability for real trace languages, and that firstorder definable, starfree, and aperiodic real trace languages form the same class of languages. This generalizes results on infinite w ..."
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Cited by 31 (4 self)
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The main results of the present paper are the equivalence of definability by monadic secondorder logic and recognizability for real trace languages, and that firstorder definable, starfree, and aperiodic real trace languages form the same class of languages. This generalizes results on infinite words and on finite traces to infinite traces. It closes an important gap in the different characterizations of recognizable languages of infinite traces. 1 Introduction In the late 70's, A. Mazurkiewicz introduced the notion of trace as a suitable mathematical model for concurrent systems [16] (for surveys on this topic see also [1, 6, 10, 17]). In this framework, a concurrent system is seen as a set \Sigma of atomic actions together with a fixed irreflexive and symmetric independence relation I ` \Sigma \Theta \Sigma. The relation I specifies pairs of actions which can be carried out in parallel. It generates an equivalence relation on the set of sequential observations of the system. As ...
Recognizable sets of message sequence charts
 STACS 2002, LNCS 2030
, 2002
"... Abstract. Highlevel Message Sequence Charts are a wellestablished formalism to specify scenarios of communications in telecommunication protocols. In order to deal with possibly unbounded specifications, we focus on starconnected HMSCs. We relate this subclass with recognizability and MSOdefinab ..."
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Cited by 27 (4 self)
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Abstract. Highlevel Message Sequence Charts are a wellestablished formalism to specify scenarios of communications in telecommunication protocols. In order to deal with possibly unbounded specifications, we focus on starconnected HMSCs. We relate this subclass with recognizability and MSOdefinability by means of a new connection with Mazurkiewicz traces. Our main result is that we can check effectively whether a starconnected HMSC is realizable by a finite system of communicating automata with possibly unbounded channels. Message Sequence Charts (MSCs) are a popular model often used for the documentation of telecommunication protocols. They profit by a standardized visual and textual presentation (ITUT recommendation Z.120 [11]) and are related to other formalisms such as sequence diagrams of UML. An MSC gives a graphical description of communications between processes. It usually abstracts away from the values of variables and the actual contents of messages. However, this formalism can be used at a very early stage of design to detect errors in the specification
Infinitestate highlevel MSCs: Modelchecking and realizability
 In ICALP 2002, volume 2380 of LNCS
, 2002
"... Abstract. We consider three natural classes of infinitestate HMSCs: ..."
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Cited by 25 (5 self)
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Abstract. We consider three natural classes of infinitestate HMSCs:
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