Boigelot B. and Godefroid P. [1996], Symbolic veri cation of communication protocols with in nite state spaces using qdds, in R. Alur and T. Henzinger, eds, `Proc. 8th Workshop on Computer Aided Veri cation (CAV '96)', Vol. 1102 of LNCS, Springer, pp. 1-12.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....approaches which are based on the symbolic reachability analysis. Intuitively, these approaches reduce the state space when they analyze the model of the system. Essentially, a nite representation of the set of all reachable con gurations of the system is calculated (see [ACH 95, CH78, BEM97, BG96] It is de ned a nite quotient of the large (in nite) set of states of the systems obtaining a (equivalent) nite state system. The rst kind of approaches can be viewed as representation approaches while the second ones can be viewed as reduction approaches. Intuitively, representation ....

B. Boigelot and P. Godefroid. Symbolic Veri cation of Communication Protocols with in nite State Spaces using QDDs. In R. Alur and T. A. Henzinger, editors, Proceedings of the 8th International Conference on Computer Aided Veri cation, volume 1102, pages 1-12, Berlin, 1996. Springer Verlag.

.... modulo some abstraction relation [7, 15, 25] Recently, regular model checking was proposed as a technique of symbolic representation of sets of con gurations in the analysis of in nite state systems like pushdown automata, fo channel systems, and parametrized networks of processes, see e.g. [2, 4 6, 12, 20, 26]. A fundamental problem which arises in these areas is then the following one: Given a regular language L and a relation R on sequences given either by a transducer or a rewriting system, we want to compute if possible the set (L) which is the R closure of L (R denotes the re exive, ....

B. Boigelot and P. Godefroid. Symbolic veri cation of communication protocols with in nite state spaces using QDDs. In Proc. of CAV'96, LNCS 1102, pp. 1-12, 1996.

....used to reduce the representation of the state space in memory without discarding any transition nor state, rather by compressing the representation. A very much used technique in model checking is the representation of the transition relation with binary decision diagrams (BDDs) or QDDs as in [3] associated with symbolic representations of states [28] Some amount of work has been devoted to on the y techniques, also in model checking, see for instance [31] Only a part of the state space is represented during the analysis, because there is no need in general to construct rst the ....

Bernard Boigelot and Patrice Godefroid. Symbolic veri cation of communication protocols with in nite state spaces using QDDs. Formal Methods in System Design: An International Journal, 14(3):237-255, May 1999.

....iteratively A 0 = A t , the automaton accepting the set ft g with t 2 D , and A n 1 = A n T ) A n will not converge. Hence we need a means to calculate the e ect of an in nite number of transitions in a nite number of steps. This is reminiscent to the technique of acceleration [BG96] BH97] ABJ98] used in symbolic modelchecking. One way to solve the problem is to nd a representation of the transitive closure T of the transduction T . In general, the transitive closure of a nite state or regular transduction will not be regular. For instance, given the one letter ....

....the e ect of loops is known as acceleration. It has been investigated for communicating systems with unbounded Fifo bu ers, represented by so called queue content decision diagrams (QDDs) a special form of nite state word automata for the symbolic representation of unbounded Fifo queues [BW94, BG96, BH97, WB98, ABJ98, BG96, BGWW97] Acknowledgments We like to thank Armin K uhnemann and Thomas Wilke for discussions and helpful hints to the literature. ....

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B. Boigelot and P. Godefroid. Symbolic verication of communication protocols with innite state spaces using QDDs. In Rajeev Alur, editor, Proceedings of CAV '96, volume 1102 of Lecture Notes in Computer Science, pages 1-12, 1996.

....compute linear constraints that relate the program variables. In recent years, the subject has known a renewal of interest with the development of symbolic model checking techniques for some classes of in nite state systems as timed and hybrid automata [HNSY92,HPR94] nite communicating automata [BG96,ABJ98] parameterized networks [KMM 97,ABJN99,BBLS] and automata with counters [BGP97,WB98] In this paper, we consider transition systems with nite control and with counters as data variables. A transition consists of a guard and a set of assignments. A guard is given by a Presburger ....

B. Boigelot and P. Godefroid. Symbolic verication of communication protocols with innite state spaces using QDDs. In CAV'96, volume 1102 of LNCS, pages 1-12, 1996.

.... but it is not eoeectively computable [CFP96] Half duplex systems and quasi stable systems have a recognizable reachability set and it is eoeectively computable [CF97] Semi algorithms computing a symbolic representation for the reachability set of a Fifo Automaton have also been established [BG96,BGWW97,BH97,Que96,ABJ98]. 1 Our contribution. Our work intends to establish similar results for the new class of Reactive Fioeo Automata (RFAs) CR97] that models Electre programs. The three main results of the paper are: 1. the reachability set of a Reactive Fioeo Automaton is recognizable (section 4) 2. the ....

B. Boigelot and P. Godefroid. Symbolic verication of communication protocols with innite state spaces using qdds. In Proc. of the 8 th Conference on Computer-Aided Verication (CAV), volume 1102, pages 112. LNCS, August 1996.

....however, is translated to a clause with the constraint x:a = y expressing the concatenation to the right of the word x modeling the queue contents. p(x) x = a:y; q(y) dequeue) p(x) x:a = y; q(y) enqueue) Model checking for systems with queues is a topic of ongoing research; see e.g. [2, 3, 7]. One possible (quite insucient) inference rule is p(x) x:a = y; q(y) q(x) x = a:y; r(y) r(x) x = 9 = p(x) x = This rule can be generalized to any set of clauses specifying a nite automaton that accepts only words ending with the letter a (here, q 0 1 ; q 0 ....

.... = 8 : p(x) x = y; q 0 1 (y) q 0 1 (x) x = b 1 :y; q 0 2 (y) q 0 n 1 (x) x = b n 1 :y; q 0 n (y) q 0 n (x) x = This schematic inference rule is used by Boigelot and Godefroid (see [2, 3]) 7 Related Work and Conclusion Since a xpoint equation is a constraint over sets of states, the existence of a characterization of a temporal property by a second order Constraint is not surprising. Our characterization (in Theorem 1) using clausal syntax with rst order constraints seems to ....

B. Boigelot and P. Godefroid. Symbolic verication of communications protocols with innite state spaces using QDDs. In Proceedings of CAV'96, volume 1102 of LNCS, Berlin, 1996. Springer.

....system (of communicating nite state machines) is potentially innite. Consequently, if one expect to compute it, one has to be able to compute in a nite number of steps an innite number of reachable congurations. Symbolic transitions (or meta transitions) have been proposed to achieve this purpose [BG96,FM96,BGWW97,BH97]. The idea of symbolic transitions is to compute in one step the eoeect of a (potentially innite) set of transition sequences. As an example, assume (q; ab) with q a control state and ab the content of a channel c, is a reachable conguration of a system S. Suppose in addition, there exists a ....

....Indeed, the notions of rationality and recognizability are not equivalent in ( Sigma ) p , with p 2 . Recognizable subsets of ( Sigma ) p can be dened by a restrictive subclass of the automata associated with rational subsets of ( Sigma ) p . Such a construction is given by QDDs [BG96,BW98]. The common denition is however in terms of inverse morphisms of subsets of nite monoids. The details can be found in [Ber79] we just sum up in the two following propositions the properties we need in this paper. Proposition 2.1. The class of rational subsets of ( Sigma ) p is ....

B. Boigelot and P. Godefroid. Symbolic verication of communication protocols with innite state spaces using QDDs. In Proc. of 8 th CAV (August), USA, volume 1102, pages 112. LNCS, 1996.

....through unbounded message queues. This is an undecidable class and thus only semi algorithmic solutions are possible. The approach we will consider represents queue contents by nite automata and focuses on cycles in the control graph in order to nitely generate in nite state spaces [BW94, BG96, BGWW97] The last class of systems we will consider is that of nite state systems augmented with a number of integer variables. The traditional way to represent sets of integer values is to use arithmetic constraints. Here, we will turn to an alternative representation with potential ....

....one queue alphabet can simulate arbitrary Turing machines. This does not, however, exclude partial algorithmic approaches to computing the set of reachable states of queue systems. One such approach relies upon the concept of meta transition introduced in [BW94] and applied to queue systems in [BG96] A meta transition is a derived transition that in one step generates a potentially in nite set of states. Precisely, a meta transition is a triple (c; f; c 0 ) where c; c 0 2 C are the origin and the destination locations and f : M 2 M is the memory function of the meta transition. The ....

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B. Boigelot and P. Godefroid. Symbolic verication of communication protocols with innite state spaces using QDDs. In Proceedings of ComputerAided Verication, volume 1102 of Lecture Notes in Computer Science, pages 1-12, New-Brunswick, NJ, USA, July 1996. Springer-Verlag.

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Boigelot B. and Godefroid P. [1996], Symbolic veri cation of communication protocols with in nite state spaces using qdds, in R. Alur and T. Henzinger, eds, `Proc. 8th Workshop on Computer Aided Veri cation (CAV '96)', Vol. 1102 of LNCS, Springer, pp. 1-12.

No context found.

B. Boigelot and P. Godefroid. Symbolic veri cation of communication protocols with in nite state spaces using QDDs. In Proceedings of the 8th International Conference on Computer Aided Veri cation, volume 1102 of Lecture Notes in Computer Science, pages 1-12. Springer-Verlag, 1996.

No context found.

B. Boigelot and P. Godefroid. Symbolic veri cation of communication protocols with in nite state spaces using QDDs. In 8th International Conference on Computer Aided Veri cation, number 1102 in LNCS, pages 1-12. Springer{Verlag, 1996.

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