The timed failures — Stability model for CSP

Reed, G. M.; Roscoe, A. W.

doi:10.1016/s0304-3975(98)00214-x

Cited by 30 publications

(21 citation statements)

References 8 publications

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“…To relate the simulations with differing refinement preorders we need a timed semantics such as provided by timed automaton, e.g., [13], or the semantics for a timed process algebra, e.g., [18,23]. To do so we will augment our LTSs with visible time passing actions, and will not make a fundamental distinction between a transition due to time and one due to another atomic action as is done in some process algebraic semantics (i.e., we do not have two types of transitions).…”

Section: A Timed Behavioural Modelmentioning

confidence: 99%

Relational Concurrent Refinement: Timed Refinement

Derrick

Boiten

2011

Formal Techniques for Distributed Systems

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Abstract. Data refinement in a state-based language such as Z is defined using a relational model in terms of the behaviour of abstract programs. Downward and upward simulation conditions form a sound and jointly complete methodology to verify relational data refinements, which can be checked on an event-byevent basis rather than per trace. In models of concurrency, refinement is often defined in terms of sets of observations, which can include the events a system is prepared to accept or refuse, or depend on explicit properties of states and transitions. By embedding such concurrent semantics into a relational one, eventwise verification methods for such refinement relations can be derived. In this paper we continue our program of deriving simulation conditions for process algebraic refinement by considering how notions of time should be embedded into a relational model, and thereby deriving relational notions of timed refinement.

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Section: A Timed Behavioural Modelmentioning

confidence: 99%

Relational Concurrent Refinement: Timed Refinement

Derrick

Boiten

2011

Formal Techniques for Distributed Systems

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“…There are a number of choices of timed extensions to CSP; we need decide which to follow. The original is the continuous Timed CSP: a detailed analysis can be found in [13]. That gives a model in which all events are given an arbitrary real-number time.…”

Section: Timed Versions Of Cspmentioning

confidence: 99%

Extending noninterference properties to the timed world

Huang

Roscoe

2006

Proceedings of the 2006 ACM Symposium on Applied Computing

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Most previous work on information flow in process algebras has been based on untimed models of concurrency. It is obvious, however, that an observer might well use time to gain information about what a high-level user of the system is doing. We use the priority tock view (a discrete timed model) to extend several traditional untimed noninterference properties to the timed world. These are the determinism-based conditions of [14], [15] and [17], and Forster's local noninterference properties [6], [7].

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“…In this section, we briefly recall the definition of timed failure equivalence [16,3,15], as well as the definition of the traditional timed weak bisimulation equivalence [1,9] and its relation to timed failure equivalence.…”

Section: Timed Equivalencesmentioning

confidence: 99%

“…For timed communicating processes, we have to extend the notion of failure to the corresponding timed one. Several such extensions have been proposed in [7,16,3,15,12]. In this paper, we adopt the definition that is slightly modified from that of [16] for simplicity.…”

Section: Timed Failure Equivalencementioning

confidence: 99%

“…Global timed bisimulation equivalence [4] is weaker than timed weak bisimulation equivalence and is less sensitive to the modification of branching structures. Unfortunately, global timed bisimulation equivalence is still too strong compared to timed failure equivalence [16,3,15]. Timed failure equivalence is considered to be a sufficient criterion of correct refinement of practical communicating systems in the sense that if two (finite state) systems P and Q are timed failure equivalent, then for any (finite state) external environment R, the composed communicating system of P and R behaves equivalently to that of Q and R. Therefore, we adopt timed failure equivalence 1 as the refinement relation between a specification and its refined implementation.…”

Section: Introductionmentioning

confidence: 99%

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A Timed Failure Equivalence Preserving Abstraction for Parametric Time-Interval Automata

Nakata

Tanimoto

Sasaki

et al. 2006

Int. J. Found. Comput. Sci.

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In the development of real-time communicating hardware/embedded-software systems, it is frequently the case that we want to refine/optimize the system's internal behavior while preserving the external timed I/O behavior. In such a design refinement, modification of the systems' internal branching structures, as well as re-scheduling of internal actions, may frequently occur. Our goal is, then, to ensure that such modification of internal branching structures and re-scheduling of internal actions preserve the systems' external timed behavior, which is typically formalized by the notion of (timed) failure equivalence since it is less sensitive to the difference of internal branching structures than (timed) weak bisimulation. In order to know the degree of freedom of such re-scheduling, parametric analysis is useful. One of the models suitable for such an analysis is a parametric timeinterval automaton(PTIA), which is a subclass of the existing model, a parametric timed automaton. It has only a time interval with upper-and lower-bound parameters as a relative timing constraint between consecutive actions. In this paper, at first, we propose an abstraction algorithm of PTIA which preserves timed failure equivalence. Timed failure equivalence is strictly weaker than timed weak bisimulation in the sense that it does not distinguish the difference of the timing when the internal resolution of nondeterminism has occurred, but it does distinguish the difference of the refusals of communicating actions observed by an external environment. Then, we also show that after applying our algorithm, the reduced PTIA has no internal actions, and thus the problem deriving a parameter condition in order that given two models are timed failure equivalent can be reduced to the existing parametric strong bisimulation equivalence checking.

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The timed failures — Stability model for CSP

Cited by 30 publications

References 8 publications

Relational Concurrent Refinement: Timed Refinement

Relational Concurrent Refinement: Timed Refinement

Extending noninterference properties to the timed world

A Timed Failure Equivalence Preserving Abstraction for Parametric Time-Interval Automata

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