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144
Multiple counters automata, safety analysis and Presburger arithmetic
, 1998
"... We consider automata with counters whose values are updated according to signals sent by the environment. A transition can be fired only if the values of the counters satisfy some guards (the guards of the transition). We consider guards of the form y i #y j +c i;j where y i is either x 0 i or ..."
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Cited by 89 (1 self)
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We consider automata with counters whose values are updated according to signals sent by the environment. A transition can be fired only if the values of the counters satisfy some guards (the guards of the transition). We consider guards of the form y i #y j +c i;j where y i is either x 0 i or x i , the values of the counter i respectively after and before the transition, and # is any relational symbol in f=; ; ; ?; !g. We show that the set of possible counter values which can be reached after any number of iterations of a loop is definable in the additive theory of N (or Z or R depending on the type of the counters). This result can be used for the safety analysis of multiple counters automata. 1 Introduction Finite state automata provide a nice framework for the verification of reactive systems. Their main advantage is the equivalence between recognizability and definability in some decidable logic (e.g. Monadic Second Order Logic or some of its fragments such as tempora...
The Computational Analysis of the Syntax and Interpretation of "Free" Word Order in Turkish
, 1995
"... ..."
ContextFree Languages and PushDown Automata
 Handbook of Formal Languages
, 1997
"... Contents 1. Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 1.1 Grammars : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 1.2 Examples : : : : : : : : : : : : : : : : : : : : : : : : : : : ..."
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Cited by 62 (0 self)
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Contents 1. Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 1.1 Grammars : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 1.2 Examples : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 4 2. Systems of equations : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 5 2.1 Systems : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 6 2.2 Resolution : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 11 2.3 Linear systems : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 12 2.4 Parikh's theorem : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :
The computational power of population protocols
 Distributed Computing
"... We consider the model of population protocols introduced by Angluin et al. [AAD + 04], in which anonymous finitestate agents stably compute a predicate of the multiset of their inputs via twoway interactions in the allpairs family of communication networks. We prove that all predicates stably com ..."
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Cited by 29 (4 self)
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We consider the model of population protocols introduced by Angluin et al. [AAD + 04], in which anonymous finitestate agents stably compute a predicate of the multiset of their inputs via twoway interactions in the allpairs family of communication networks. We prove that all predicates stably computable in this model (and certain generalizations of it) are semilinear, answering a central open question about the power of the model. Removing the assumption of twoway interaction, we also consider several variants of the model in which agents communicate by anonymous messagepassing where the recipient of each message is chosen by an adversary and the sender is not identified to the recipient. These oneway models are distinguished by whether messages are delivered immediately or after a delay, whether a sender can record that it has sent a message, and whether a recipient can queue incoming messages, refusing to accept new messages until it has had a chance to send out messages of its own. We characterize the classes of predicates stably computable in each of these oneway models using natural subclasses of the semilinear predicates. 1
Counting in Trees for Free
, 2004
"... In [22], it was shown that MSO logic for ordered unranked trees becomes undecidable if Presburger constraints are allowed at children of nodes. We now show that a decidable logic is obtained if we use a a modal fixpoint logic instead. We present an automata theoretic characterization of this logi ..."
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Cited by 27 (1 self)
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In [22], it was shown that MSO logic for ordered unranked trees becomes undecidable if Presburger constraints are allowed at children of nodes. We now show that a decidable logic is obtained if we use a a modal fixpoint logic instead. We present an automata theoretic characterization of this logic by means of deterministic Presburger tree automata (PTA) and show how it can be used to express numerical document queries. Surprisingly, the complexity of satisfiability for the extended logic is asymptotically the same as for the original logic. The nonemptiness for PTAs is in general pspacecomplete which is moderate given that it is already pspacehard to test whether the complement of a regular expression is nonempty. We also identify a subclass of PTAs with a tractable nonemptiness problem. Further, to decide whether a tree t satisfies a formula # is polynomial in the size of # and linear in the size of t.
Model checking multithreaded programs with asynchronous atomic methods
 In 18th International Conference on Computer Aided Verification (CAV’06). LNCS
, 2006
"... Abstract. In order to make multithreaded programming manageable, programmers often follow a design principle where they break the problem into tasks which are then solved asynchronously and concurrently on different threads. This paper investigates the problem of model checking programs that follow ..."
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Cited by 27 (5 self)
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Abstract. In order to make multithreaded programming manageable, programmers often follow a design principle where they break the problem into tasks which are then solved asynchronously and concurrently on different threads. This paper investigates the problem of model checking programs that follow this idiom. We present a programming language SPL that encapsulates this design pattern. SPL extends simplified form of sequential Java to which we add the capability of making asynchronous method invocations in addition to the standard synchronous method calls and the ability to execute asynchronous methods in threads atomically and concurrently. Our main result shows that the control state reachability problem for finite SPL programs is decidable. Therefore, such multithreaded programs can be model checked using the counterexample guided abstractionrefinement framework. 1
Interprocedural Analysis of Asynchronous Programs
, 2007
"... An asynchronous program is one that contains procedure calls which are not immediately executed from the callsite, but stored and “dispatched” in a nondeterministic order by an external scheduler at a later point. We formalize the problem of interprocedural dataflow analysis for asynchronous progra ..."
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Cited by 26 (2 self)
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An asynchronous program is one that contains procedure calls which are not immediately executed from the callsite, but stored and “dispatched” in a nondeterministic order by an external scheduler at a later point. We formalize the problem of interprocedural dataflow analysis for asynchronous programs as AIFDS problems, a generalization of the IFDS problems for interprocedural dataflow analysis. We give an algorithm for computing the precise meetovervalidpaths solution for any AIFDS instance, as well as a demanddriven algorithm for solving the corresponding demand AIFDS instances. Our algorithm can be easily implemented on top of any existing interprocedural dataflow analysis framework. We have implemented the algorithm on top of BLAST, thereby obtaining the first safety verification tool for unbounded asynchronous programs. Though the problem of solving AIFDS instances is EXPSPACEhard, we find that in practice our technique can efficiently analyze programs by exploiting standard optimizations of interprocedural dataflow analyses.
A robust class of contextsensitive languages
 In LICS
, 2007
"... We define a new class of languages defined by multistack automata that forms a robust subclass of contextsensitive languages, with decidable emptiness and closure under boolean operations. This class, called multistack visibly pushdown languages (MVPLs), is defined using multistack pushdown auto ..."
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Cited by 25 (6 self)
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We define a new class of languages defined by multistack automata that forms a robust subclass of contextsensitive languages, with decidable emptiness and closure under boolean operations. This class, called multistack visibly pushdown languages (MVPLs), is defined using multistack pushdown automata with two restrictions: (a) the pushdown automaton is visible, i.e. the input letter determines the operation on the stacks, and (b) any computation of the machine can be split into�stages, where in each stage, there is at most one stack that is popped. MVPLs are an extension of visibly pushdown languages that captures noncontext free behaviors, and has applications in analyzing abstractions of multithreaded recursive programs, significantly enlarging the search space that can be explored for them. We show that MVPLs are closed under boolean operations, and problems such as emptiness and inclusion are decidable. We characterize MVPLs using monadic secondorder logic over appropriate structures, and exhibit a Parikh theorem for them. 1.
Dependency Analysis of Mobile Systems
, 2002
"... We propose an Abstract Interpretationbased static analysis for automatically detecting the dependencies between the names linked to the agents of a mobile system. We focus our study on the mobile systems written in the picalculus. We first refine the standard semantics in order to restore the rela ..."
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Cited by 22 (6 self)
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We propose an Abstract Interpretationbased static analysis for automatically detecting the dependencies between the names linked to the agents of a mobile system. We focus our study on the mobile systems written in the picalculus. We first refine the standard semantics in order to restore the relation between the names and the agents that have declared them. We then abstract the dependency relations that are always satisfied by the names of the agents of a mobile system. That is to say we will detect which names are always pairwisely equal, and which names have necessarily been declared by the same recursive instance of an agent.