Process Algebra with Timing: Real Time and Discrete Time

Baeten, J.C.M.; Middelburg, Cornelis A.

doi:10.1016/b978-044482830-9/50028-x

Cited by 35 publications

(38 citation statements)

References 31 publications

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“…For details on continuous-time process algebras, the interested reader is referred to [1,25,21]. We consider real-time process algebras that assume a global clock, shared by all concurrent processes, which advances in discrete increments.…”

Section: Discrete-time Modelingmentioning

confidence: 99%

See 1 more Smart Citation

Process-Algebraic Analysis of Timing and Schedulability Properties

Philippou¹,

Sokolsky²

2007

Chapman &Amp; Hall/CRC Computer &Amp; Information Science Series

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In this chapter, we present an overview of how timing information can be embedded in process-algebraic frameworks. We concentrate on the case of discrete-time modeling. We begin by discussing design approaches that have been adopted in different formalisms to model time and time passage, and how the resulting mechanisms interact with one another and with standard untimed process-algebraic operators. We proceed to give an overview of ACSR, a timed process algebra developed for modeling and reasoning about timed, resource-constrained systems. In doing this, ACSR adopts the notion of a resource as a first-class entity, and it replaces maximal progress, employed by other timed process algebras, by the notion of resource-constrained progress. ACSR associates resource-usage with time passage, and implements appropriate semantic rules to ensure that progress in the system is enforced as far as possible while simultaneous usage of a resource by distinct processes is excluded. In addition, ACSR employs the notion of priorities to arbitrate access to resources by competing processes. Finally, we illustrate the use of ACSR for the schedulability analysis of a realistic real-time system problem. CommentsReprinted AbstractIn this chapter, we present an overview of how timing information can be embedded in processalgebraic frameworks. We concentrate on the case of discrete-time modeling. We begin by discussing design approaches that have been adopted in different formalisms to model time and time passage, and how the resulting mechanisms interact with one another and with standard untimed process-algebraic operators. We proceed to give an overview of ACSR, a timed process algebra developed for modeling and reasoning about timed, resource-constrained systems. In doing this, ACSR adopts the notion of a resource as a first-class entity, and it replaces maximal progress, employed by other timed process algebras, by the notion of resource-constrained progress. ACSR associates resource-usage with time passage, and implements appropriate semantic rules to ensure that progress in the system is enforced as far as possible while simultaneous usage of a resource by distinct processes is excluded. In addition, ACSR employs the notion of priorities to arbitrate access to resources by competing processes. Finally, we illustrate the use of ACSR for the schedulability analysis of a realistic real-time system problem.

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Section: Discrete-time Modelingmentioning

confidence: 99%

“…Another commonly-used operator is the choice operator, P 1 + P 2 , which yields a process that spontaneously evolves into P 1 or P 2 . The rules for the choice operator are (SUM) P 1 e −→ P 1 P 1 + P 2 e −→ P 1 , and a symmetric rule for P 2 . We say that the first event performed by P 1 or P 2 resolves the choice.…”

Section: Conventional Process Algebrasmentioning

confidence: 99%

Process-Algebraic Analysis of Timing and Schedulability Properties

Philippou¹,

Sokolsky²

2007

Chapman &Amp; Hall/CRC Computer &Amp; Information Science Series

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“…Although there is a wealth of literature on timed process algebras [6], little work has been done in developing theories for relating processes with respect to speed. The approaches closest to ours are obviously the one by Moller and Tofts regarding processes equipped with lower time bounds [20], and our own one regarding processes equipped with upper time bounds [17].…”

Section: Related Workmentioning

confidence: 99%

“…Early process algebras, such as Milner's CCS [18] and Hoare's CSP [15], have been augmented to capture other important system aspects as well, including timing behavior [6]. Many variants of timed process algebra that employ either discrete or continuous notions of time have been proposed, whose semantic theories are usually based on the well-studied concepts of bisimulation [19], failures [22], or testing [14].…”

Section: Introductionmentioning

confidence: 99%

Bisimulation on speed: Lower time bounds

Lüttgen

Vogler

2005

RAIRO-Theor. Inf. Appl.

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Abstract. More than a decade ago, Moller and Tofts published their seminal work on relating processes that are annotated with lower time bounds, with respect to speed. Their paper has left open many questions concerning the semantic theory for their suggested bisimulation-based faster-than preorder, the MT-preorder, which have not been addressed since. The encountered difficulties concern a general compositionality result, a complete axiom system for finite processes, and a convincing intuitive justification of the MT-preorder. This paper solves these difficulties by developing and employing novel tools for reasoning in discrete-time process algebra, in particular a general commutation lemma relating the sequencing of action and clock transitions. Most importantly, it is proved that the MT-preorder is fullyabstract with respect to a natural amortized preorder that uses a simple bookkeeping mechanism for deciding whether one process is faster than another. Together these results reveal the intuitive roots of the MTpreorder as a faster-than relation, while testifying to its semantic elegance. This lifts some of the barriers that have so far hampered progress in semantic theories for comparing the speed of processes.

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“…It enables us to specify both the discrete behavior of control and the continuous behavior of time. Process calculi models including time [21,2,6] have also been proposed, adding a set of timing operators to process algebras. They offer a level of abstraction based on processes: a system is viewed as a composition of (interacting) processes.…”

Section: Formal Specification Of Real-time Sys-temsmentioning

confidence: 99%