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20
Action Transducers and Timed Automata
 Formal Aspects of Computing
, 1996
"... The timed automaton model of [LV92, LV93] is a general model for timingbased systems. A notion of timed action transducer is here defined as an automatatheoretic way of representing operations on timed automata. It is shown that two timed trace inclusion relations are substitutive with respect to ..."
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Cited by 40 (13 self)
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The timed automaton model of [LV92, LV93] is a general model for timingbased systems. A notion of timed action transducer is here defined as an automatatheoretic way of representing operations on timed automata. It is shown that two timed trace inclusion relations are substitutive with respect to operations that can be described by timed action transducers. Examples are given of operations that can be described in this way, and a preliminary proposal is given for an appropriate language of operators for describing timingbased systems.
A general conservative extension theorem in process algebra
 THEORETICAL COMPUTER SCIENCE
, 1994
"... We prove a general conservative extension theorem for transition system based process theories with easytocheck and reasonable conditions. The core of this result is another general theorem which gives sufficient conditions for a system of operational rules and an extension of it in order to ensur ..."
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Cited by 36 (4 self)
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We prove a general conservative extension theorem for transition system based process theories with easytocheck and reasonable conditions. The core of this result is another general theorem which gives sufficient conditions for a system of operational rules and an extension of it in order to ensure conservativity, that is, provable transitions from an original term in the extension are the same as in the original system. As a simple corollary of the conservative extension theorem we prove a completeness theorem. We also prove a general theorem giving sufficient conditions to reduce the question of ground confluence modulo some equations for a large term rewriting system associated with an equational process theory to a small term rewriting system under the condition that the large system is a conservative extension of the small one. We provide many applications to show that our results are useful. The applications include (but are not limited to) various real and discrete time settings in ACP, ATP, and CCS and the notions
Discrete Time Process Algebra with Silent Step
, 2000
"... The axiom system ACP of [10] was extended to discrete time in [6]. Here, we proceed to define the silent step in this theory in branching bisimulation semantics [7, 15] rather than weak bisimulation semantics [11, 20]. The version using relative timing is discussed extensively, versions using absolu ..."
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Cited by 16 (7 self)
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The axiom system ACP of [10] was extended to discrete time in [6]. Here, we proceed to define the silent step in this theory in branching bisimulation semantics [7, 15] rather than weak bisimulation semantics [11, 20]. The version using relative timing is discussed extensively, versions using absolute and parametric timing are presented in brief. A term model and a graph model are presented and soundness and completeness results are given. The time free theories BPA # and BPA # # are embedded in the discrete time theories. Examples of the use of the relative time theory are given by means of some calculations on communicating buffers. Note: Partial support received from ESPRIT Basic Research Action 7166, CONCUR2. This paper supersedes [4]. 1 Introduction Process algebra was introduced by Milner in the form of CCS [19]. The original design of CCS and of subsequent versions of process algebra such as ACP [10] and TCSP [14] involves no explicit notion of time. Time is present in the int...
A Calculus for Timed Automata (Extended Abstract)
"... . A language for representing timed automata is introduced. Its semantics is defined in terms of timed automata. This language is complete in the sense that any timed automaton can be represented by a term in the language. We also define a direct operational semantics for the language in terms of (t ..."
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Cited by 11 (6 self)
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. A language for representing timed automata is introduced. Its semantics is defined in terms of timed automata. This language is complete in the sense that any timed automaton can be represented by a term in the language. We also define a direct operational semantics for the language in terms of (timed) transition systems. This is proven to be equivalent (or, more precisely, timed bisimilar) to the interpretation in terms of timed automata. In addition, a set of axioms is given that is shown to be sound for timed bisimulation. Finally, we introduce several features including the parallel composition and derived time operations like wait, timeout and urgency. We conclude with an example and show that we can eliminate nonreachable states using algebraic techniques. 1 Introduction A realtime system is a system whose behaviour is constrained by requirements on the time in which events can occur. Sometimes, systems are implemented as timed systems in the sense that they fulfil certain t...
The cones and foci proof technique for timed transition systems
 Information Processing Letters
"... ..."
Fischer's Protocol in Timed Process Algebra
, 1994
"... Timed algebraic process theories can be developed with quite different purposes in mind. One can aim for theoretical results about the theory itself (completeness, expressiveness, decidability), or one can aim for practical applicability to nontrivial protocols. Unfortunately, these aims do not go ..."
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Cited by 8 (2 self)
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Timed algebraic process theories can be developed with quite different purposes in mind. One can aim for theoretical results about the theory itself (completeness, expressiveness, decidability), or one can aim for practical applicability to nontrivial protocols. Unfortunately, these aims do not go well together. In this paper we take two theories, which are probably of the first kind, and try to find out how well suited they are for practical verifications. We verify Fischer's protocol for mutual exclusion in the settings of discretetime process algebra (ACP dt ) and realtime process algebra (ACP ur ). We do this by transforming the recursive specification into an equivalent linear specification, and then dividing out the maximal bisimulation relation. The required mutual exclusion result can then be found by reasoning about the obtained process graph. Finally, we consider the ease of the verification, and ways to adapt the theory to make it more practical. It will turn out that the...
Analysis of Three Hybrid Systems in Time µCRL
 VISUALISATION OF STATE TRANSITION GRAPHS, MASTER THESIS, EINDHOVEN UNIVERSITY OF TECHNOLOGY,2000. [41] HENNESSY, M., LIN, H.: SYMBOLIC BISIMULATIONS, THEORETICAL COMPUTER SCIENCE
, 1998
"... We study three simple hybrid control systems in timed µCRL [6]. A temperature regulation system, a bottle filling system and a railway gate control system are specified componentwise and expanded to linear process equations. Some basic properties of the systems are analysed and a few correctness re ..."
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Cited by 7 (0 self)
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We study three simple hybrid control systems in timed µCRL [6]. A temperature regulation system, a bottle filling system and a railway gate control system are specified componentwise and expanded to linear process equations. Some basic properties of the systems are analysed and a few correctness requirements are proven to be satisfied. Although not designed for this purpose, timed CRL seems to allow detailed analysis and verification of hybrid systems. The operators for parallelism and encapsulation are handled using some basic results from [9]. It turns out that the expansion and encapsulation of a parallel composition of processes generally leads to a considerable number of potential time deadlocks, which generally turn out to be harmless. Also inherent to parallelism are the multiple time dependencies between the summands of the separate components. As a consequence, expansions tend to lead to large numbers of terms. Various techniques, such as the use of invariants [5], have to be ...
A New Equivalence for Processes with Timing With an Application to Protocol Verification
 Department of Mathematics and Computer Science, Eindhoven University of Technology
, 2002
"... We propose a variant of the version of branching bisimulation equivalence for processes with discrete relative timing from Baeten, Bergstra, and Reniers. We show that this new equivalence allows for the functional correctness of the PAR protocol as well as its performance properties to be analyz ..."
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Cited by 5 (3 self)
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We propose a variant of the version of branching bisimulation equivalence for processes with discrete relative timing from Baeten, Bergstra, and Reniers. We show that this new equivalence allows for the functional correctness of the PAR protocol as well as its performance properties to be analyzed. The new equivalence still coincides with the original version of branching bisimulation equivalence from van Glabbeek and Weijland in the case without timing.
Structural operational semantics and bounded nondeterminism
 Acta Informatica
, 2003
"... Abstract. We present a rule format for structural operational semantics to guarantee that the associated labelled transition system is bounded nondeterministic. 1 ..."
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Cited by 3 (0 self)
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Abstract. We present a rule format for structural operational semantics to guarantee that the associated labelled transition system is bounded nondeterministic. 1
personal communication
, 1993
"... Abstract. We show that timed branching bisimilarity as defined by Van der Zwaag [17] and Baeten and 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 i ..."
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Abstract. We show that timed branching bisimilarity as defined by Van der Zwaag [17] and Baeten and 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. Finally, we prove that a rooted version of timed branching bisimilarity is a congruence over a basic timed process algebra containing parallelism, successful termination and deadlock. 1.