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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 161 (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.
Reniers. Timed process algebra (with a focus on explicit termination and relativetiming
 Proceedings of the International School on Formal Methods for the Design of RealTime Systems (SFMRT’04), volume 3185 of Lecture Notes in Computer Science
, 2004
"... Abstract. We treat theory and application of timed process algebra. We focus on a variant that uses explicit termination and action prefixing. This variant has some advantages over other variants. We concentrate on relative timing, but the treatment of absolute timing is similar. We treat both discr ..."
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Cited by 5 (2 self)
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Abstract. We treat theory and application of timed process algebra. We focus on a variant that uses explicit termination and action prefixing. This variant has some advantages over other variants. We concentrate on relative timing, but the treatment of absolute timing is similar. We treat both discrete and dense timing. We build up the theory incrementally. The different algebras are interrelated by embeddings and conservative extensions. As an example, we consider the PAR communication protocol. 1
Chaos in Discrete Production Systems?
, 2002
"... In literature, several cases are reported of models of discrete nonstochastic production systems that show irregular, apparently chaotic behavior. In this paper a number of these cases are analyzed, and the irregular behavior is attributed to (1) chaotic behavior in hybrid models, (2) chaotic be ..."
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Cited by 2 (0 self)
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In literature, several cases are reported of models of discrete nonstochastic production systems that show irregular, apparently chaotic behavior. In this paper a number of these cases are analyzed, and the irregular behavior is attributed to (1) chaotic behavior in hybrid models, (2) chaotic behavior in discreteevent models that use a chaotic map, or (3) periodic behavior with a period longer than the observation window. The irregular behavior of a discreteevent model of a twomachine production system is analyzed by means of nonlinear time series analysis and sensitivity analysis. This case reveals the possibilities and limitations of the application of chaos theory to discreteevent models of production systems. Also, a new method for determining the sensitivity of discreteevent models to truly small changes is introduced. Realistic, nonartificial discreteevent models of discrete production systems that show chaotic behavior were not found in this study.
Variables And Equations In Hybrid Systems With Structural Changes
 Proc. 13 th European Simulation Symposium
, 2001
"... In many models of physical systems, structural changes are common. Such structural changes may cause a variable to change from a differential variable to an algebraic variable, or to a variable that is not defined by an equation at all. Most hybrid modelling languages either restrict the kind of str ..."
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Cited by 2 (0 self)
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In many models of physical systems, structural changes are common. Such structural changes may cause a variable to change from a differential variable to an algebraic variable, or to a variable that is not defined by an equation at all. Most hybrid modelling languages either restrict the kind of structural changes that may be modelled, or they require several different language elements to model the different kinds of structural changes. This paper proposes a new language element that can be used in combination with conditional equations to model structural changes. The language element is used to declare unknowns in equations, and thus makes a distinction between variables that are unknown in the equations and variables that are not determined by the equations. Examples are given in which unknown declarations are used for modelling steady state initialization, multibody collision, and higher index systems. Unknown declarations can also be used to clarify the structure of the system of equations, and they can help the modeller detect structurally singular systems of equations.
VARIABLES AND EQUATIONS IN HYBRID SYSTEMS WITH STRUCTURAL CHANGES
"... In many models of physical systems, structural changes are common. Such structural changes may cause a variable to change from a differential variable to an algebraic variable, or to a variable that is not defined by an equation at all. Most hybrid modelling languages either restrict the kind of str ..."
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In many models of physical systems, structural changes are common. Such structural changes may cause a variable to change from a differential variable to an algebraic variable, or to a variable that is not defined by an equation at all. Most hybrid modelling languages either restrict the kind of structural changes that may be modelled, or they require several different language elements to model the different kinds of structural changes. This paper proposes a new language element that can be used in combination with conditional equations to model structural changes. The language element is used to declare unknowns in equations, and thus makes a distinction between variables that are unknown in the equations and variables that are not determined by the equations. Examples are given in which unknown declarations are used for modelling steady state initialization, multibody collision, and higher index systems. Unknown declarations can also be used to clarify the structure of the system of equations, and they can help the modeller detect structurally singular systems of equations.
Declaration of Unknowns in DAEBased Hybrid System Specification
, 2003
"... This paper shows that only one language element is needed for this purpose: an unknown declaration, that allows the explicit declaration of a variable as unknown. The syntax and semantics of unknown declarations are discussed. Examples are given, using the Chi language, in which unknown declarations ..."
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This paper shows that only one language element is needed for this purpose: an unknown declaration, that allows the explicit declaration of a variable as unknown. The syntax and semantics of unknown declarations are discussed. Examples are given, using the Chi language, in which unknown declarations are used for modeling multibody collision, steadystate initialization, and consistent initialization of higher index systems. It is also illustrated how the declaration of unknowns can help to clarify the structure of the system of equations, and how it can help the modeler detect structurally singular systems of equations
MultiDomain Modelling, Simulation, and Control
, 2000
"... For the design of large industrial systems, usually many different modelling languages are required. Currently, different projects aim at the development of standards that enable interaction between simulation models written in different languages. The Chi project aims at providing one language suit ..."
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For the design of large industrial systems, usually many different modelling languages are required. Currently, different projects aim at the development of standards that enable interaction between simulation models written in different languages. The Chi project aims at providing one language suited to modelling, simulation and control of systems from different application domains. Models may range from pure continuoustime models to pure discreteevent models, and any combination of the two. Due to the orthogonal design of the Chi language and careful selection of the language primitives, the core of the language is small. At the same time, the highlevel data modelling constructs and highlevel behaviour modelling constructs provide the modeller with expressive power. Verification of Chi models is currently limited to discreteevent models. The Chi language and simulator have proved themselves in many industrial projects involving discreteevent modelling and simulation. For contin...