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72
Regular Model Checking
, 2000
"... . We present regular model checking, a framework for algorithmic verification of infinitestate systems with, e.g., queues, stacks, integers, or a parameterized linear topology. States are represented by strings over a finite alphabet and the transition relation by a regular lengthpreserving re ..."
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Cited by 127 (20 self)
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. We present regular model checking, a framework for algorithmic verification of infinitestate systems with, e.g., queues, stacks, integers, or a parameterized linear topology. States are represented by strings over a finite alphabet and the transition relation by a regular lengthpreserving relation on strings. Major problems in the verification of parameterized and infinitestate systems are to compute the set of states that are reachable from some set of initial states, and to compute the transitive closure of the transition relation. We present two complementary techniques for these problems. One is a direct automatatheoretic construction, and the other is based on widening. Both techniques are incomplete in general, but we give sufficient conditions under which they work. We also present a method for verifying !regular properties of parameterized systems, by computation of the transitive closure of a transition relation. 1 Introduction This paper presents regular ...
EServices: A Look behind the Curtain
, 2003
"... The emerging paradigm of electronic services promises to bring to distributed computation and services the flexibility that the web has brought to the sharing of documents. An understanding of fundamental properties of eservice composition is required in order to take full advantage of the paradigm ..."
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Cited by 103 (5 self)
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The emerging paradigm of electronic services promises to bring to distributed computation and services the flexibility that the web has brought to the sharing of documents. An understanding of fundamental properties of eservice composition is required in order to take full advantage of the paradigm. This paper examines proposals and standards for eservices from the perspectives of XML, data management, workflow, and process models. Key areas for study are identified, including behavioral service signatures, verification and synthesis techniques for composite services, analysis of service data manipulation commands, and XML analysis applied to service specifications. We give a sample of the relevant results and techniques in each of these areas.
TReX: A Tool for Reachability Analysis of Complex Systems
, 2001
"... Introduction Finitestate modelcheckers such as Smv [13] and Spin [11] do not allow to deal with important aspects that appear in modelling and analysing complex systems, e.g., communication protocols. Among these aspects: realtime constraints, manipulation of unbounded data structures like count ..."
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Cited by 54 (2 self)
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Introduction Finitestate modelcheckers such as Smv [13] and Spin [11] do not allow to deal with important aspects that appear in modelling and analysing complex systems, e.g., communication protocols. Among these aspects: realtime constraints, manipulation of unbounded data structures like counters, communication through unbounded channels, parametric reasoning, etc. The tool we propose, called TReX, allows to analyse automatically automatabased models equipped with variables of different kinds of infinite domain data structures and with parameters (i.e., uninstantiated constants). These models are, at the present time, parametric (continuoustime) timed automata, extended with integer counters and communicating through unbounded lossy FIFO queues. The techniques used in TReX are based on symbolic reachability analysis. Symbolic representation structures are u
Transitive Closures of Regular Relations for Verifying InfiniteState Systems
"... . We consider a model for representing infinitestate and parameterized systems, in which states are represented as strings over a finite alphabet. Actions are transformations on strings, in which the change can be characterized by an arbitrary finitestate transducer. This program model is able ..."
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Cited by 47 (3 self)
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. We consider a model for representing infinitestate and parameterized systems, in which states are represented as strings over a finite alphabet. Actions are transformations on strings, in which the change can be characterized by an arbitrary finitestate transducer. This program model is able to represent programs operating on a variety of data structures, such as queues, stacks, integers, and systems with a parameterized linear topology. The main contribution of this paper is an effective derivation of a general and powerful transitive closure operation for this model. The transitive closure of an action represents the effect of executing the action an arbitrary number of times. For example, the transitive closure of an action which transmits a single message to a buffer will be an action which sends an arbitrarily long sequence of messages to the buffer. Using this transitive closure operation, we show how to model and automatically verify safety properties for severa...
Handling Global Conditions in Parameterized System Verification
, 1999
"... We consider symbolic verification for a class of parameterized systems, where a system consists of a linear array of processes, and where an action of a process may in general be guarded by both local conditions restricting the state of the process about to perform the action, and global conditions ..."
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Cited by 43 (13 self)
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We consider symbolic verification for a class of parameterized systems, where a system consists of a linear array of processes, and where an action of a process may in general be guarded by both local conditions restricting the state of the process about to perform the action, and global conditions defining the context in which the action is enabled. Such actions are present, e.g., in idealized versions of mutual exclusion protocols, such as the bakery and ticket algorithms by Lamport, Burn's protocol, Dijkstra's algorithm, and Szymanski's algorithm. The presence of both local and global conditions makes the parameterized versions of these protocols infeasible to analyze fully automatically, using existing model checking methods for parameterized systems. In all these methods the actions are guarded only by local conditions involving the states of a finite set of processes. We perform verification using a standard symbolic reachability algorithm enhanced by an operation to accelera...
Undecidable Problems in Unreliable Computations
 THEORETICAL COMPUTER SCIENCE
, 2000
"... Lossy counter machines are defined as Minsky ncounter machines where the values in the counters can spontaneously decrease at any time. While termination is decidable for lossy counter machines, structural termination (termination for every input) is undecidable. This undecidability result has f ..."
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Cited by 43 (2 self)
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Lossy counter machines are defined as Minsky ncounter machines where the values in the counters can spontaneously decrease at any time. While termination is decidable for lossy counter machines, structural termination (termination for every input) is undecidable. This undecidability result has far reaching consequences. Lossy counter machines can be used as a general tool to prove the undecidability of many problems, for example (1) The verification of systems that model communication through unreliable channels (e.g. model checking lossy fifochannel systems and lossy vector addition systems). (2) Several problems for reset Petri nets, like structural termination, boundedness and structural boundedness. (3) Parameterized problems like fairness of broadcast communication protocols.
Symbolic Verification of Lossy Channel Systems: Application to the Bounded Retransmission Protocol
 In TACAS'99. LNCS 1579
, 1999
"... We consider the problem of verifying automatically infinitestate systems that are systems of finite machines that communicate by exchanging messages through unbounded lossy fifo channels. In a previous work [1], we proposed an algorithmic approach based on constructing a symbolic representation ..."
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Cited by 36 (5 self)
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We consider the problem of verifying automatically infinitestate systems that are systems of finite machines that communicate by exchanging messages through unbounded lossy fifo channels. In a previous work [1], we proposed an algorithmic approach based on constructing a symbolic representation of the set of reachable configurations of a system by means of a class of regular expressions (SREs). The construction of such a representation consists of an iterative computation with an acceleration technique which enhance the chance of convergence. This technique is based on the analysis of the effect of iterating control loops. In the work we present here, we experiment our approach and show how it can be effectively applied. For that, we developed a tool prototype based on the results in [1]. Using this tool, we provide a fully automatic verification of (the parameterized version of) the Bounded Retransmission Protocol, for arbitrary values of the size of the transmitted files, and the allowed number of retransmissions. ? Contact author. 1 1
A survey of regular model checking
 In Proc. of CONCUR’04, volume 3170 of LNCS
, 2004
"... Abstract. Regular model checking is being developed for algorithmic verification of several classes of infinitestate systems whose configurations can be modeled as words over a finite alphabet. Examples include parameterized systems consisting of an arbitrary number of homogeneous finitestate proc ..."
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Cited by 33 (7 self)
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Abstract. Regular model checking is being developed for algorithmic verification of several classes of infinitestate systems whose configurations can be modeled as words over a finite alphabet. Examples include parameterized systems consisting of an arbitrary number of homogeneous finitestate processes connected in a linear or ringformed topology, and systems that operate on queues, stacks, integers, and other linear data structures. The main idea is to use regular languages as the representation of sets of configurations, and finitestate transducers to describe transition relations. In general, the verification problems considered are all undecidable, so the work has consisted in developing semialgorithms, and decidability results for restricted cases. This paper provides a survey of the work that has been performed so far, and some of its applications. 1
Regular Model Checking Using Inference of Regular Languages
, 2004
"... Regular model checking is a method for verifying infinitestate systems based on coding their configurations as words over a finite alphabet, sets of configurations as finite automata, and transitions as finite transducers. We introduce a new general approach to regular model checking based on infer ..."
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Cited by 28 (2 self)
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Regular model checking is a method for verifying infinitestate systems based on coding their configurations as words over a finite alphabet, sets of configurations as finite automata, and transitions as finite transducers. We introduce a new general approach to regular model checking based on inference of regular languages. The method builds upon the observation that for infinitestate systems whose behaviour can be modelled using lengthpreserving transducers, there is a finite computation for obtaining all reachable configurations up to a certain length n. These configurations are a (positive) sample of the reachable configurations of the given system, whereas all other words up to length n are a negative sample. Then, methods of inference of regular languages can be used to generalize the sample to the full reachability set (or an overapproximation of it). We have implemented our method in a prototype tool which shows that our approach is competitive on a number of concrete examples. Furthermore, in contrast to all other existing regular model checking methods, termination is guaranteed in general for all systems with regular sets of reachable configurations. The method can be applied in a similar way to dealing with reachability relations instead of reachability sets too.
Flatness is not a Weakness
, 2000
"... We propose an extension, called L + p , of the temporal logic LTL, which enables talking about finitely many register values: the models are infinite words over tuples of integers (resp. real numbers). The formulas of L + p are flat: on the left of an until, only atomic formulas or LTL formu ..."
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Cited by 28 (0 self)
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We propose an extension, called L + p , of the temporal logic LTL, which enables talking about finitely many register values: the models are infinite words over tuples of integers (resp. real numbers). The formulas of L + p are flat: on the left of an until, only atomic formulas or LTL formulas are allowed. We prove, in the spirit of the correspondence between automata and temporal logics, that the models of a L + p formula are recognized by a piecewise flat counter machine; for each state q, at most one loop of the machine on q may modify the register values. Emptiness of (piecewise) flat counter machines is decidable (this follows from a result in [9]). It follows that satisfiability and modelchecking the negation of a formula are decidable for L + p . On the other hand, we show that inclusion is undecidable for such languages. This shows that validity and modelchecking positive formulas are undecidable.