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F.W.: A theory of normed simulations
 ACM Trans. Comput. Log
, 2004
"... In existing simulation proof techniques, a single step in a lowerlevel specification may be simulated by an extended execution fragment in a higherlevel one. As a result, it is cumbersome to mechanize these techniques using general purpose theorem provers. Moreover, it is undecidable whether a giv ..."
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Cited by 5 (1 self)
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In existing simulation proof techniques, a single step in a lowerlevel specification may be simulated by an extended execution fragment in a higherlevel one. As a result, it is cumbersome to mechanize these techniques using general purpose theorem provers. Moreover, it is undecidable whether a given relation is a simulation, even if tautology checking is decidable for the underlying specification logic. This paper studies various types of normed simulations. In a normed simulation, each step in a lowerlevel specification can be simulated by at most one step in the higherlevel one, for any related pair of states. In earlier work we demonstrated that normed simulations are quite useful as a vehicle for the formalization of refinement proofs via theorem provers. Here we show that normed simulations also have pleasant theoretical properties: (1) under some reasonable assumptions, it is decidable whether a given relation is a normed forward simulation, provided tautology checking is decidable for the underlying logic; (2) at the semantic level, normed forward and backward simulations together form a complete proof method for establishing behavior inclusion, provided that the higherlevel
A linear processalgebraic format with data for probabilistic automata
, 2011
"... This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar te ..."
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Cited by 5 (4 self)
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This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar techniques for traditional process algebras with data, and — more importantly — treats data and datadependent probabilistic choice in a fully symbolic manner, leading to the symbolic analysis of parameterised probabilistic systems. We discuss several reduction techniques that can easily be applied to our models. A validation of our approach on two benchmark leader election protocols shows reductions of more than an order of magnitude.
A Process Algebra Based Verification of a Production System
 Proceedings of the 2nd IEEE international
, 1998
"... Studying industrial systems by simulation enables the designer to study the dynamic behaviour and to determine some characteristics of the system. Unfortunately, simulation also has some disadvantages. These can be overcome by using formal methods. Formal methods allow a thorough analysis of the pos ..."
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Cited by 4 (2 self)
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Studying industrial systems by simulation enables the designer to study the dynamic behaviour and to determine some characteristics of the system. Unfortunately, simulation also has some disadvantages. These can be overcome by using formal methods. Formal methods allow a thorough analysis of the possible behaviours of a system, parameterised system analysis and a modular approach to the analysis of systems. We present a case study in which a model of an industrial system is studied in a formal way. For this purpose, the model is first specified and simulated using the CSPbased executable specification language Ø. The model is translated into a model in the process algebra ACP ø . This enables us to give a correctness proof of the parameterised model and to study the model in isolation. 1. Introduction Nowadays, industry makes higher demands on methodologies used for the design of new factories. Firstly, due to the huge amount of money involved and growing competition on the market...
A linear processalgebraic format for probabilistic systems with data
"... Abstract—This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises si ..."
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Cited by 3 (3 self)
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Abstract—This paper presents a novel linear processalgebraic format for probabilistic automata. The key ingredient is a symbolic transformation of probabilistic process algebra terms that incorporate data into this linear format while preserving strong probabilistic bisimulation. This generalises similar techniques for traditional process algebras with data, and — more importantly — treats data and datadependent probabilistic choice in a fully symbolic manner, paving the way to the symbolic analysis of parameterised probabilistic systems. Keywordsprobabilistic process algebra, linearisation, datadependent probabilistic choice, symbolic transformations I.
Is timed branching bisimilarity an equivalence indeed
 In Formal Modeling and Analysis of Timed Systems, Third International Conference, FORMATS 2005
, 2005
"... Abstract. We show that timed branching bisimilarity as defined by van der Zwaag [14] and Baeten & Middelburg [2] is not an equivalence relation, in case of a dense time domain. We propose an adaptation based on van der Zwaag’s definition, and prove that the resulting timed branching bisimilarity ..."
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Cited by 3 (2 self)
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Abstract. We show that timed branching bisimilarity as defined by van der Zwaag [14] and Baeten & Middelburg [2] is not an equivalence relation, in case of a dense time domain. We propose an adaptation based on van der Zwaag’s definition, and prove that the resulting timed branching bisimilarity is an equivalence indeed. Furthermore, we prove that in case of a discrete time domain, van der Zwaag’s definition and our adaptation coincide. 1
Checking Verifications of Protocols and Distributed Systems By Computer
, 1998
"... We provide a treatise about checking proofs of distributed systems by computer using general purpose proof checkers. In particular, we present two approaches to verifying and checking the verification of the Sequential Line Interface Protocol (SLIP), one using rewriting techniques and one using the ..."
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Cited by 2 (1 self)
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We provide a treatise about checking proofs of distributed systems by computer using general purpose proof checkers. In particular, we present two approaches to verifying and checking the verification of the Sequential Line Interface Protocol (SLIP), one using rewriting techniques and one using the socalled cones and foci theorem. Both verifications are carried out in the setting of process algebra. Finally, we present an overview of literature containing checked proofs. Note: The research of the second author is supported by Human Capital Mobility (HCM). 1 Proof checkers Anyone trying to use a proof checker, e.g. Isabelle [67, 68], HOL [29], Coq [20], PVS [78], BoyerMoore [14] or many others that exist today has experienced the same frustration. It is very difficult to prove even the simplest theorem. In the first place it is difficult to get acquainted to the logical language of the system. Most systems employ higher order logics that are extremely versatile and expressive. Howev...
Cones and foci: A mechanical framework for protocol verification
, 2006
"... We define a cones and foci proof method, which rephrases the question whether two system specifications are branching bisimilar in terms of proof obligations on relations between data objects. Compared to the original cones and foci method from Groote and Springintveld, our method is more generall ..."
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We define a cones and foci proof method, which rephrases the question whether two system specifications are branching bisimilar in terms of proof obligations on relations between data objects. Compared to the original cones and foci method from Groote and Springintveld, our method is more generally applicable, because it does not require a preprocessing step to eliminate τloops. We prove soundness of our approach and present a set of rules to prove the reachability of focus points. Our method has been formalized and proved correct using PVS. Thus we have established a framework for mechanical protocol verification. We apply this framework to the Concurrent Alternating Bit Protocol.
Designing and understanding the behaviour of systems
, 2007
"... Robin Milner observed in 1973 that the primary task of computers appeared to be interacting with their environment, yet the theory of programs and programming at that time seemed to ignore this fact completely [36, 37]. As a consequence, he set out working on his seminal book [38, 40] in which he de ..."
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Cited by 1 (0 self)
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Robin Milner observed in 1973 that the primary task of computers appeared to be interacting with their environment, yet the theory of programs and programming at that time seemed to ignore this fact completely [36, 37]. As a consequence, he set out working on his seminal book [38, 40] in which he developed the CCS, the Calculus of Communicating Systems. At the same time two other main process algebras were developed, namely ACP (Algebra of Communicating Processes, [5]) and CSP (Communicating Sequential Processes, [27, 28]). Interesting as they were, these process algebras were too bare to be used for the description of actual systems, mainly because they lacked a proper integration of data. In order to solve this, process algebraic specification languages have been designed (most notably LOTOS [29] and PSF [35]) which contained both data and processes. A problem with these languages was that they were too complex to act as a basic carrier for the development of behavioural analysis techniques. We designed an intermediate language, namely mCRL2 (and its direct predecessor µCRL [21, 19]) as a stripped down process specification language or an extended process algebra. It contains exactly those ingredients needed for a complete behavioural specification, and its (relative) simplicity allows to concentrate on proof and analysis techniques for process behaviour. Throughout the years many of these techniques have been developed. To mention a few: the
Formal verification of timed systems using cones and foci
 PROCEEDINGS OF THE 6TH WORKSHOP ON REALTIME SYSTEMS (ARTS’04
, 1998
"... The cones and foci verification method from Groote and Springintveld [9] was extended to timed systems by van der Zwaag [17]. We present an extension of this cones and foci method for timed systems, which can cope with infinite τsequences. We prove soundness of our approach and give small verifica ..."
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Cited by 1 (1 self)
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The cones and foci verification method from Groote and Springintveld [9] was extended to timed systems by van der Zwaag [17]. We present an extension of this cones and foci method for timed systems, which can cope with infinite τsequences. We prove soundness of our approach and give small verification examples.
A Theory for Normed Situations
 ACM TRANSACTIONS ON COMPUTATIONAL LOGIC
, 2000
"... ... This paper studies various types of normed simulations. In a normed simulation, each step in a lowerlevel specification can be simulated by at most one step in the higherlevel one, for any related pair of states. In earlier work we demonstrated that normed simulations are quite useful as a veh ..."
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... This paper studies various types of normed simulations. In a normed simulation, each step in a lowerlevel specification can be simulated by at most one step in the higherlevel one, for any related pair of states. In earlier work we demonstrated that normed simulations are quite useful as a vehicle for the formalization of refinement proofs via theorem provers. Here we show that normed simulations also have pleasant theoretical properties: (1) under some reasonable assumptions, it is decidable whether a given relation is a normed forward simulation, provided tautology checking is decidable for the underlying logic; (2) at the semantic level, normed forward and backward simulations together form a complete proof method for establishing behavior inclusion, provided that the higherlevel specification has finite invisible nondeterminism