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22
Deciding BisimulationLike Equivalences with FiniteState Processes
, 1999
"... We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many mo ..."
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Cited by 41 (14 self)
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We show that characteristic formulae for nitestate systems up to bisimulationlike equivalences (e.g., strong and weak bisimilarity) can be given in the simple branchingtime temporal logic EF. Since EF is a very weak fragment of the modal µcalculus, model checking with EF is decidable for many more classes of infinitestate systems. This yields a general method for proving decidability of bisimulationlike equivalences between infinitestate processes and finitestate ones. We apply this method to the class of PAD processes, which strictly subsumes PA and pushdown (PDA) processes, showing that a large class of bisimulationlike equivalences (including, e.g., strong and weak bisimilarity) is decidable between PAD and finitestate processes. On the other hand, we also demonstrate that no `reasonable' bisimulationlike equivalence is decidable between stateextended PA processes and finitestate ones. Furthermore, weak bisimilarity with finitestate processes is shown to be undecidable even for state...
Automated Compositional Markov Chain Generation for a PlainOld Telephone System
 SCIENCE OF COMPUTER PROGRAMMING
, 1999
"... Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper w ..."
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Cited by 34 (20 self)
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Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper we argue by means of a nontrivial example  a plainold telephone system (POTS)  that a stochastic extension of process algebra can diminish these problems by permitting an automatic generation of Markov chains. We introduce a stochastic process algebra that separates the advance of time and action occurrences. For the sake of specification convenience we incorporate an elapse operator that allows the modular description of time constraints where delays are described by continuous phasetype distributions. Using this language we provide a formal specification of the POTS and show how a stochastic process of more than 10 7 states is automatically obtained from this system description. ...
Argos: an automatonbased synchronous language
, 2001
"... Argos belongs to the family of synchronous languages, designed for programming reactive systems: (Lustre ..."
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Cited by 25 (5 self)
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Argos belongs to the family of synchronous languages, designed for programming reactive systems: (Lustre
Rooted branching bisimulation as a congruence
 Journal of Computer and System Sciences
, 2000
"... This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, an ..."
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Cited by 15 (6 self)
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This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, and negative premises. 1
A Process Algebra with Distributed Priorities
 Theoretical Computer Science
, 1996
"... . This paper presents a process algebra for distributed systems in which some actions may take precedence over others. In contrast with existing approaches to priorities, our algebra only allows actions to preempt others at the same #location" and therefore captures a notion of localizedprecedence. ..."
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Cited by 14 (3 self)
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. This paper presents a process algebra for distributed systems in which some actions may take precedence over others. In contrast with existing approaches to priorities, our algebra only allows actions to preempt others at the same #location" and therefore captures a notion of localizedprecedence. Using Park's and Milner's notion of strong bisimulation as a basis, we develop a behavioral congruence and axiomatize it for #nite processes; we also derive an associated observational congruence. Simple examples highlight the utility of the theory. 1 Introduction Process algebras #11, 13# provide widely studied frameworks for modeling and verifying concurrent systems #9#. Such theories typically consist of a simple language with a wellde#ned operational semantics given in terms of labeled transition systems; a behavioral equivalence is then used to relate implementations and speci#cations, which are both given as terms in the language. In order to facilitate compositional reasoning, in wh...
A Complete Equational Axiomatization for MPA with String Iteration
 DEPARTMENT OF MATHEMATICS AND COMPUTER SCIENCE, AALBORG UNIVERSITY
, 1995
"... We study equational axiomatizations of bisimulation equivalence for the language obtained by extending Milner's basic CCS with string iteration. String iteration is a variation on the original binary version of the Kleene star operation p*q obtained by restricting the first argument to be a none ..."
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Cited by 13 (5 self)
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We study equational axiomatizations of bisimulation equivalence for the language obtained by extending Milner's basic CCS with string iteration. String iteration is a variation on the original binary version of the Kleene star operation p*q obtained by restricting the first argument to be a nonempty sequence of atomic actions. We show that, for every positive integer k, bisimulation equivalence over the set of processes in this language with loops of length at most k is finitely axiomatizable. We also offer a countably infinite equational theory that completely axiomatizes bisimulation equivalence over the whole language. We prove that this result cannot be improved upon by showing that no finite equational axiomatization of bisimulation equivalence over basic CCS with string iteration can exist, unless the set of actions is empty.
Modal Model Theory
 ANNALS OF PURE AND APPLIED LOGIC
, 1995
"... This paper contributes to the model theory of modal logic using bisimulations as the fundamental tool. A uniform presentation is given of modal analogues of wellknown definability and preservation results from firstorder logic. These results include algebraic characterizations of modal equivalen ..."
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Cited by 9 (5 self)
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This paper contributes to the model theory of modal logic using bisimulations as the fundamental tool. A uniform presentation is given of modal analogues of wellknown definability and preservation results from firstorder logic. These results include algebraic characterizations of modal equivalence, and of the modally definable classes of models; the preservation results concern preservation of modal formulas under submodels, unions of chains, and homomorphisms.
Verifying Semantic Relations in SPIN
 IN PROC. 1ST SPIN WORKSHOP
, 1996
"... Spin is a general verification tool for proving correctness properties of concurrent/distributed systems specified in the CSPlike modeling language PROMELA. We extend PROMELA's syntax to differentiate between external and internal transitions in a given model and the SPIN tool with the ability to v ..."
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Cited by 7 (5 self)
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Spin is a general verification tool for proving correctness properties of concurrent/distributed systems specified in the CSPlike modeling language PROMELA. We extend PROMELA's syntax to differentiate between external and internal transitions in a given model and the SPIN tool with the ability to verify a particular class of semantic relations between two PROMELA models. This document describes this extension and gives an overview of the relevant theoretical foundations.
Modelling IP Mobility
 IN PROCEEDINGS OF CONCUR '98: CONCURRENCY THEORY. LNCS 1466
, 1997
"... We study the modelling of mobile hosts on a network in a simple namepassing process calculus, with the intention of being able to prove properties about a protocol for supporting mobility. Our model may be considered a highly simplified version of proposals for mobility support in the version 6 of ..."
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Cited by 6 (2 self)
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We study the modelling of mobile hosts on a network in a simple namepassing process calculus, with the intention of being able to prove properties about a protocol for supporting mobility. Our model may be considered a highly simplified version of proposals for mobility support in the version 6 of the Internet Protocols (IP). Being fairly general, the model may also apply to mobile software architectures. We believe that such simplied models help in prototyping mobility protocols and reasoning about them while abstracting away excessive details. We concentrate on the issue of ensuring that messages to and from mobile agents are delivered without loss of connectivity. We provide three models of increasingly complex nature of a network of routers and computing agents that are interconnected via the routers: the first is without mobile agents and is treated as a specification for the next two; the second supports mobile agents, and the third additionally allows correspondent agents to cache...