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86
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.
An overview and synthesis on timed process algebras
, 1991
"... We present anoverview and synthesis of existing results about process algebras for the speci cation and analysis of timed systems. The motivation is double: present anoverview of some relevant and representative approaches and suggest a unifying framework for them. time, we propose a general model f ..."
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Cited by 140 (4 self)
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We present anoverview and synthesis of existing results about process algebras for the speci cation and analysis of timed systems. The motivation is double: present anoverview of some relevant and representative approaches and suggest a unifying framework for them. time, we propose a general model for them: transition systems whose labels are either elements ofavocabulary of actions or elements of a time domain. Many properties of this model are studied concerning their impact on description capabilities and on realisability issues. An overview of the language features of the process algebras considered is presented, by focusing on constructs used to express time constraints. The presentation is organised as an exercise of building a timed process algebra from a standard process algebra for untimed systems. The overview is completed by a discussion about description capabilities according to semantic and pragmatic criteria. 1
A tutorial on EMPA: A theory of concurrent processes with nondeterminism, priorities, probabilities and time
 Theoretical Computer Science
, 1998
"... In this tutorial we give an overview of the process algebra EMPA, a calculus devised in order to model and analyze features of realworld concurrent systems such as nondeterminism, priorities, probabilities and time, with a particular emphasis on performance evaluation. The purpose of this tutorial ..."
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Cited by 95 (9 self)
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In this tutorial we give an overview of the process algebra EMPA, a calculus devised in order to model and analyze features of realworld concurrent systems such as nondeterminism, priorities, probabilities and time, with a particular emphasis on performance evaluation. The purpose of this tutorial is to explain the design choices behind the development of EMPA and how the four features above interact, and to show that a reasonable trade off between the expressive power of the calculus and the complexity of its underlying theory has been achieved.
A Process Algebraic Approach to the Specification and Analysis of ResourceBound RealTime Systems
 PROCEEDINGS OF THE IEEE
, 1994
"... Recently, significant progress has been made in the development of timed process algebras for the specification and analysis of realtime systems. This paper describes a timed process algebra called ACSR, which supports synchronous timed actions and asynchronous instantaneous events. Timed actions a ..."
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Cited by 59 (41 self)
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Recently, significant progress has been made in the development of timed process algebras for the specification and analysis of realtime systems. This paper describes a timed process algebra called ACSR, which supports synchronous timed actions and asynchronous instantaneous events. Timed actions are used to represent the usage of resources and to model the passage of time. Events are used to capture synchronization between processes. To be able to specify real systems accurately, ACSR supports a notion of priority that can be used to arbitrate among timed actions competing for the use of resources and among events that are ready for synchronization. The paper also includes a brief overview of other timed process algebras and discusses similarities and differences between them and ACSR.
An Operational Semantics for Timed CSP
, 1995
"... An operational semantics is defined for the language of timed CSP, in terms of two relations: an evolution relation, which describes when a process becomes another simply by allowing time to pass; and a timed transition relation, which describes when a process may become another by performing an act ..."
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Cited by 55 (6 self)
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An operational semantics is defined for the language of timed CSP, in terms of two relations: an evolution relation, which describes when a process becomes another simply by allowing time to pass; and a timed transition relation, which describes when a process may become another by performing an action at a particular time. It is shown how the timed behaviours used as the basis for the denotational models of the language may be extracted from the operational semantics. Finally, the failures model for timed CSP is shown to be equivalent to maytesting, and thus to trace congruence. 1 Introduction An operational semantics for a computer programming language defines the meaning of programs written in that language in terms of how a machine is intended to execute them step by step. It therefore offers a direct intuition of how program constructs are intended to behave, in contrast with denotational approaches, which often abstract away from such considerations, and with algebraic approach...
A Process Algebra of Communicating Shared Resources with Dense Time and Priorities
 THEORETICAL COMPUTER SCIENCE
, 1997
"... ..."
Process Algebra for Discrete Event Simulation
 In Quantitative Methods in Parallel Systems
, 1993
"... We present a process algebra or programming language, based on CCS, which may be used to describe discrete event simulations with parallelism. It has extensions to describe the passing of time and probabilistic choice, either discrete, between a countable number of processes, or continuous to choose ..."
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Cited by 44 (2 self)
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We present a process algebra or programming language, based on CCS, which may be used to describe discrete event simulations with parallelism. It has extensions to describe the passing of time and probabilistic choice, either discrete, between a countable number of processes, or continuous to choose a random amount of time to wait. It has a clear operational semantics and we give approaches to denotational semantics given in terms of an algebra of equivalences over processes. It raises questions about when two simulations are equivalent and what we mean by nondeterminism in the context of the specification of a simulation. It also exemplifies some current approaches to adding time and probability to process algebras. 1 Introduction Imagine we wish to simulate the behaviour of a complex system with computerised components, such as a telephone network. First, let us look at the implementation of such a complex system. When it is implemented, typically work will start with some type of ...
Automatic Verification of RealTime Communicating Systems by ConstraintSolving
 In Proc. of the 7th International Conference on Formal Description Techniques
, 1994
"... this paper, an algebra of timed processes with realvalued clocks is presented, which serves as a formal description language for realtime communicating systems. We show that requirements such as "a process will never reach an undesired state" can be verified by solving a simple class of constrai ..."
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Cited by 43 (15 self)
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this paper, an algebra of timed processes with realvalued clocks is presented, which serves as a formal description language for realtime communicating systems. We show that requirements such as "a process will never reach an undesired state" can be verified by solving a simple class of constraint systems on the clockvariables. A complete method for reachability analysis associated with the language is developed, and implemented as an automatic verification tool based on constraintsolving techniques. Finally as examples, we study and verify the safetyproperties of Fischer's mutual exclusion protocol and a railway crossing controller.
Time Abstracted Bisimulation: Implicit Specifications and Decidability
, 1997
"... ed Bisimulation: Implicit Specifications and Decidability Kim G. Larsen y and Yi Wang z January 8, 1997 Abstract In the last few years a number of realtime process calculi have emerged with the purpose of capturing important quantitative aspects of realtime systems. In addition, a number o ..."
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Cited by 39 (9 self)
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ed Bisimulation: Implicit Specifications and Decidability Kim G. Larsen y and Yi Wang z January 8, 1997 Abstract In the last few years a number of realtime process calculi have emerged with the purpose of capturing important quantitative aspects of realtime systems. In addition, a number of process equivalences sensitive to timequantities have been proposed, among these the notion of timed (bisimulation) equivalence in In this paper, we introduce a timeabstracting (bisimulation) equivalence, and investigate its properties with respect to the realtime process calculus of [Wan90]. Seemingly, such an equivalence would yield very little information (if any) about the timing properties of a process. However, timeabstracted reasoning about a composite process may yield important information about the relative timingproperties of the components of the system. In fact, we show as a main theorem that such implicit reasoning will reveal all timing aspects of a process. More p...
VERSA: A Tool for the Specification and Analysis of ResourceBound RealTime Systems
 Journal of Computer and Software Engineering
, 1995
"... VERSA is a tool that assists in the algebraic analysis of realtime systems. It is based on ACSR, a timed process algebra designed to express resourcebound realtime distributed systems. VERSA is designed to be both a usable and useful tool for the analysis of ACSR specifications. Usability is a ..."
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Cited by 36 (26 self)
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VERSA is a tool that assists in the algebraic analysis of realtime systems. It is based on ACSR, a timed process algebra designed to express resourcebound realtime distributed systems. VERSA is designed to be both a usable and useful tool for the analysis of ACSR specifications. Usability is assured by a flexible user interface that uses ACSR's traditional notation augmented with conventions from programming languages and mathematics that allow concise specification of realistic systems. Usefulness is the result of the breadth of analysis techniques planned and currently implemented, including algebraic term rewriting and statespace exploration based techniques. 1 Introduction Reliability in realtime systems can be improved through the use of formal methods for the specification and analysis of realtime systems. Formal methods treat system components as mathematical objects and provide mathematical models to describe and predict the observable properties and behaviors of...