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Verifying Programs with Unreliable Channels (Extended Abstract)
 Information and Computation
, 1992
"... The research on algorithmic verification methods for concurrent and parallel systems has mostly focussed on finitestate systems, with applications in e.g. communication protocols and hardware systems. For infinitestate systems, e.g. systems that operate on data from unbounded domains, algorithmic ..."
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Cited by 176 (35 self)
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The research on algorithmic verification methods for concurrent and parallel systems has mostly focussed on finitestate systems, with applications in e.g. communication protocols and hardware systems. For infinitestate systems, e.g. systems that operate on data from unbounded domains, algorithmic verification is more difficult, since most verification problems are in general undecidable. In this paper, we consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. The unboundedness of the channels makes these systems infinitestate. For this class of systems, we show that several interesting verification problems are decidable by giving algorithms for verifying the following classes of properties.
OntheFly Analysis of Systems with Unbounded, Lossy FIFO Channels
 In CAV'98. LNCS 1427
, 1998
"... . We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of proto ..."
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Cited by 71 (17 self)
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. We consider symbolic onthefly verification methods for systems of finitestate machines that communicate by exchanging messages via unbounded and lossy FIFO queues. We propose a novel representation formalism, called simple regular expressions (SREs), for representing sets of states of protocols with lossy FIFO channels. We show that the class of languages representable by SREs is exactly the class of downward closed languages that arise in the analysis of such protocols. We give methods for (i) computing inclusion between SREs, (ii) an SRE representing the set of states reachable by executing a single transition in a system, and (iii) an SRE representing the set of states reachable by an arbitrary number of executions of a control loop of a program. All these operations are rather simple and can be carried out in polynomial time. With these techniques, one can construct a semialgorithm which explores the set of reachable states of a protocol, in order to check variou...
Algorithmic analysis of programs with well quasiordered domains
 Information and Computation
"... Over the past few years increasing research effort has been directed towards the automatic verification of infinitestate systems. This paper is concerned with identifying general mathematical structures which can serve as sufficient conditions for achieving decidability. We present decidability res ..."
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Cited by 56 (13 self)
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Over the past few years increasing research effort has been directed towards the automatic verification of infinitestate systems. This paper is concerned with identifying general mathematical structures which can serve as sufficient conditions for achieving decidability. We present decidability results for a class of systems (called wellstructured systems) which consist of a finite control part operating on an infinite data domain. The results assume that the data domain is equipped with a preorder which is a well quasiordering, such that the transition relation is ``monotonic' ' (a simulation) with respect to the preorder. We show that the following properties are decidable for wellstructured systems: v Reachability: whether a certain set of control states is reachable. Other safety properties can be reduced to the reachability problem. 1
Verification of probabilistic systems with faulty communication
 IN PROCEEDINGS OF FOSSACS 2003
, 2003
"... ..."
Logicbased electronic institutions
 In this volume
, 2003
"... Abstract. We propose a logicbased rendition of electronic institutions – these are means to specify open agent organisations. We employ a simple notation based on firstorder logic and set theory to represent an expressive class of electronic institutions. We also provide a formal semantics for our ..."
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Cited by 11 (2 self)
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Abstract. We propose a logicbased rendition of electronic institutions – these are means to specify open agent organisations. We employ a simple notation based on firstorder logic and set theory to represent an expressive class of electronic institutions. We also provide a formal semantics for our constructs and present a distributed implementation of a platform to enact electronic institutions specified in our formalism. 1
An Improved Search Strategy for Lossy Channel Systems
 In Proc. Joint Int. Conf. Formal Description Techniques and Protocol Speci Testing, and Veri (FORTE/PSTV'97
, 1997
"... In [1] we considered lossy channel systems which are a particular class of infinite state systems consisting of finite state processes communicating through channels that are unbounded and unreliable. We presented a backward reachability algorithm which, starting from a set of "bad" states, check ..."
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Cited by 2 (0 self)
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In [1] we considered lossy channel systems which are a particular class of infinite state systems consisting of finite state processes communicating through channels that are unbounded and unreliable. We presented a backward reachability algorithm which, starting from a set of "bad" states, checks whether there is a backward path to the initial state of the system. Using standard techniques, the reachability algorithm can be used to check safety properties for lossy channel systems. In this paper we adopt partial order techniques to improve the algorithm in [1]. We define a preorder, which we call the better than relation, among the set of transitions of the system. Intuitively a transition is better than another if choosing the first transition instead of the second preserves the reachability of the initial state during the analysis. This relation is weaker than the independence relation, which is an equivalence relation, used in traditional partial order methods, in the...
Decidability of Simulation and Bisimulation between Lossy Channel Systems and Finite State Systems (Extended Abstract)
"... We consider the verification of a class of infinitestate systems called lossy channel systems, which consist of finitestate processes communicating via unbounded but lossy FIFO channels. This class is able to model several interesting protocols, such as HDLC, the Alternating Bit Protocol, and othe ..."
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We consider the verification of a class of infinitestate systems called lossy channel systems, which consist of finitestate processes communicating via unbounded but lossy FIFO channels. This class is able to model several interesting protocols, such as HDLC, the Alternating Bit Protocol, and other Sliding Window protocols. In earlier papers we have considered the decidability of various temporal properties for lossy channel systems. In this paper we study simulation and bisimulation relations between lossy channel systems and finite transition systems. More precisely, we show the decidability of (1) whether a state in a finite transition system simulates a state in a lossy channel system, and conversely, (2) whether a state in a finite transition system is bisimilar to a state in a lossy channel system, and (3) whether a state in a finite...
Verifying Programs with Unreliable
 Information and Computation
, 1996
"... We consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. For this class of syste ..."
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We consider the verification of a particular class of infinitestate systems, namely systems consisting of finitestate processes that communicate via unbounded lossy FIFO channels. This class is able to model e.g. link protocols such as the Alternating Bit Protocol and HDLC. For this class of systems, we show that several interesting verification problems are decidable by giving algorithms for verifying (1) the reachability problem: is a finite set of global states reachable from some other global state of the system, (2) safety properties over traces formulated as regular sets of allowed finite traces, and (3) eventuality properties: do all computations of a system eventually reach a given set of states. We have used the algorithms to verify some idealized slidingwindow protocols with reasonable time and space resources. Our results should be contrasted with the wellknown fact that these problems are undecidable for systems with unbounded perfect FIFO channels.