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93
Termination in Timed Process Algebra
 Formal Aspects of Computing
, 2000
"... We investigate different forms of termination in timed process algebras. The integrated framework of discrete and dense time, relative and absolute time process algebras is extended with forms of successful and unsuccessful termination. The different algebras are interrelated by embeddings and conse ..."
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Cited by 155 (25 self)
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We investigate different forms of termination in timed process algebras. The integrated framework of discrete and dense time, relative and absolute time process algebras is extended with forms of successful and unsuccessful termination. The different algebras are interrelated by embeddings and conservative extensions.
Priorities in process algebra
, 1999
"... This chapter surveys the semantic rami cations of extending traditional process algebras with notions of priority that allow for some transitions to be given precedence over others. The need for these enriched formalisms arises when one wishes to model system features such asinterrupts, prioritized ..."
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Cited by 102 (11 self)
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This chapter surveys the semantic rami cations of extending traditional process algebras with notions of priority that allow for some transitions to be given precedence over others. The need for these enriched formalisms arises when one wishes to model system features such asinterrupts, prioritized choice, orrealtime behavior. Approaches to priority in process algebras can be classi ed according to whether the induced notion of preemption on transitions is global or local and whether priorities are static or dynamic. Early work in the area concentrated on global preemption and static priorities and led to formalisms for modeling interrupts and aspects of realtime, such as maximal progress, in centralized computing environments. More recent research has investigated localized notions of preemption in which the distribution of systems is taken into account, as well as dynamic priority approaches, i.e., those where priority values may change as systems evolve. The latter allows one to model behavioral phenomena such as scheduling algorithms and also enables the e cient encoding of realtime semantics. Technically, this chapter studies the di erent models of priorities by presenting extensions of Milner's Calculus of Communicating Systems (CCS) with static and dynamic priority as well as with notions of global and local preemption. In each case the operational semantics of CCS is modi ed appropriately, behavioral theories based on strong and weak bisimulation are given, and related approaches for di erent processalgebraic settings are discussed.
Algebraic Process Verification
 Handbook of Process Algebra, chapter 17
"... This chapter addresses the question how to verify distributed and communicating systems in an e#ective way from an explicit process algebraic standpoint. This means that all calculations are based on the axioms and principles of the process algebras. ..."
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Cited by 62 (16 self)
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This chapter addresses the question how to verify distributed and communicating systems in an e#ective way from an explicit process algebraic standpoint. This means that all calculations are based on the axioms and principles of the process algebras.
Focus points and convergent process operators: A proof strategy for protocol verification
, 1995
"... We present a strategy for finding algebraic correctness proofs for communication systems. It is described in the setting of µCRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [ ..."
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Cited by 39 (11 self)
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We present a strategy for finding algebraic correctness proofs for communication systems. It is described in the setting of µCRL [11], which is, roughly, ACP [2, 3] extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in [4] and [10], but was not explicitly identified as such. Moreover, the protocols that were verified in these papers were rather complex, so that the general picture was obscured by the amount of details. In this paper, the proof strategy is materialised in the form of definitions and theorems. These results reduce a large part of protocol verification to a number of trivial facts concerning data parameters occurring in implementation and specification. This greatly simplifies protocol verifications and makes our approach amenable to mechanical assistance � experiments in this direction seem promising. The strategy is illustrated by several small examples and one larger example, the Concurrent Alternating Bit Protocol (CABP). Although simple, this protocol contains a large amount of internal parallelism, so that all relevant issues make their appearance.
Refinementoriented probability for CSP
, 1995
"... Jones and Plotkin give a general construction for forming a probabilistic powerdomain over any directedcomplete partial order [Jon90, JP89]. We apply their technique to the failures/divergences semantic model for Communicating Sequential Processes [Hoa85]. The resulting probabilistic model supports ..."
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Cited by 35 (5 self)
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Jones and Plotkin give a general construction for forming a probabilistic powerdomain over any directedcomplete partial order [Jon90, JP89]. We apply their technique to the failures/divergences semantic model for Communicating Sequential Processes [Hoa85]. The resulting probabilistic model supports a new binary operator, probabilistic choice, and retains all operators of CSP including its two existing forms of choice. An advantage of using the general construction is that it is easy to see which CSP identities remain true in the probabilistic model. A surprising consequence however is that probabilistic choice distributes through all other operators; such algebraic mobility means that the syntactic position of the choice operator gives little information about when the choice actually must occur. That in turn leads to some interesting interaction between probability and nondeterminism. A simple communications protocol is used to illustrate the probabilistic algebra, and several sugg...
Formal Characterisation of Immediate Actions in SPA with Nondeterministic Branching
 IN PROCEEDINGS OF THE 3RD WORKSHOP ON PROCESS ALGEBRA AND PERFORMANCE MODELLING
, 1995
"... ..."
Branching bisimilarity is an equivalence indeed
 Inform. Process. Lett
, 1996
"... Communicated by P.M.B. Vitiyi This note presents a detailed proof of a result in the theory of concurrency semantics that is already considered folklore, namely that branching bisimilarity is an equivalence relation. The “simple proof ‘, which in the literature is always assumed to exist, is shown t ..."
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Cited by 33 (3 self)
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Communicated by P.M.B. Vitiyi This note presents a detailed proof of a result in the theory of concurrency semantics that is already considered folklore, namely that branching bisimilarity is an equivalence relation. The “simple proof ‘, which in the literature is always assumed to exist, is shown to be incorrect. The proof in this note is based on the notion of a semibranching bisimulation taken from (Van Glabbeek and Weijland, 1991). Branching bisimilarity can equivalently be defined in terms of semibranching bisimulations; the results suggest that such a definition is more intuitive than the original definition of Van Glabbeek and Weijland ( 1989).
The Formal Specification Language mCRL2
 In Proceedings of the Dagstuhl Seminar
, 2007
"... Abstract. We introduce mCRL2, a specification language that can be used to specify and analyse the behaviour of distributed systems. This language is the successor of the µCRL specification language. The mCRL2 language extends a timed basic process algebra with the possibility to define and use abst ..."
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Cited by 31 (8 self)
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Abstract. We introduce mCRL2, a specification language that can be used to specify and analyse the behaviour of distributed systems. This language is the successor of the µCRL specification language. The mCRL2 language extends a timed basic process algebra with the possibility to define and use abstract data types. The mCRL2 data language features predefined and higherorder data types. The process algebraic part of mCRL2 allows a faithful translation of coloured Petri nets and component based systems: we have introduced multiactions and we have separated communication and parallelism.
Web Services : a Process Algebra Approach
"... It is now welladmitted that formal methods are helpful for many issues raised in the Web service area. In this paper we present a framework for the design and the verification of WSs using process algebras and their tools. We define a twoway mapping between abstract specifications written using th ..."
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Cited by 31 (0 self)
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It is now welladmitted that formal methods are helpful for many issues raised in the Web service area. In this paper we present a framework for the design and the verification of WSs using process algebras and their tools. We define a twoway mapping between abstract specifications written using these calculi and executable Web services written in BPEL4WS; the translation includes also compensation, event, and fault handlers. The following choices are available: design and verification in BPEL4WS, using process algebra tools, or design and verification in process algebra and automatically obtaining the corresponding BPEL4WS code. The approaches can be combined. Process algebras are not useful only for temporal logic verification: we remark the use of simulation/bisimulation for verification, for the hierarchical refinement design method, for the service redundancy analysis in a community, and for replacing a service with another one in a composition.
Petri Net Transformations for Business Processes – A Survey
"... Abstract. In ProcessAware Information Systems, business processes are often modeled in an explicit way. Roughly speaking, the available business process modeling languages can be divided into two groups. Languages from the first group are preferred by academic people but shunned by business people, ..."
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Cited by 21 (3 self)
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Abstract. In ProcessAware Information Systems, business processes are often modeled in an explicit way. Roughly speaking, the available business process modeling languages can be divided into two groups. Languages from the first group are preferred by academic people but shunned by business people, and include Petri nets and process algebras. These academic languages have a proper formal semantics, which allows the corresponding academic models to be verified in a formal way. Languages from the second group are preferred by business people but disliked by academic people, and include BPEL, BPMN, and EPCs. These business languages often lack any proper semantics, which often leads to debates on how to interpret certain business models. Nevertheless, business models are used in practice, whereas academic models are hardly used. To be able to use, for example, the abundance of Petri net verification techniques on business models, we need to be able to transform these models to Petri nets. In this paper, we investigate a number of Petri net transformations that already exist. For every transformation, we investigate the transformation itself, the constructs in the business models that are problematic for the transformation and the main applications for the transformation. 1