3,152 research outputs found
Parameterized Model-Checking for Timed-Systems with Conjunctive Guards (Extended Version)
In this work we extend the Emerson and Kahlon's cutoff theorems for process
skeletons with conjunctive guards to Parameterized Networks of Timed Automata,
i.e. systems obtained by an \emph{apriori} unknown number of Timed Automata
instantiated from a finite set of Timed Automata templates.
In this way we aim at giving a tool to universally verify software systems
where an unknown number of software components (i.e. processes) interact with
continuous time temporal constraints. It is often the case, indeed, that
distributed algorithms show an heterogeneous nature, combining dynamic aspects
with real-time aspects. In the paper we will also show how to model check a
protocol that uses special variables storing identifiers of the participating
processes (i.e. PIDs) in Timed Automata with conjunctive guards. This is
non-trivial, since solutions to the parameterized verification problem often
relies on the processes to be symmetric, i.e. indistinguishable. On the other
side, many popular distributed algorithms make use of PIDs and thus cannot
directly apply those solutions
Robust Model-Checking of Linear-Time Properties in Timed Automata
International audienceFormal verification of timed systems is well understood, but their \emphimplementation is still challenging. Recent works by Raskin \emphet al. have brought out a model of parameterized timed automata that can be used to prove \emphimplementability of timed systems for safety properties. We define here a more general notion of robust model-checking for linear-time properties, which consists in verifying whether a property still holds even if the transitions are slightly delayed or expedited. We provide PSPACE algorithms for the robust model-checking of BĆ¼chi-like and LTL properties. We also verify bounded-response-time properties
A test generation framework for quiescent real-time systems
We present an extension of Tretmans theory and algorithm for test generation for input-output transition systems to real-time systems. Our treatment is based on an operational interpretation of the notion of quiescence in the context of real-time behaviour. This gives rise to a family of implementation relations parameterized by observation durations for quiescence. We define a nondeterministic (parameterized) test generation algorithm that generates test cases that are sound with respect to the corresponding implementation relation. Also, the test generation is exhaustive in the sense that for each non-conforming implementation a test case can be generated that detects the non-conformance
Testing real-time multi input-output systems
In formal testing, the assumption of input enabling is typically made. This assumption requires all inputs to be enabled anytime. In addition, the useful concept of quiescence is sometimes applied. Briefly, a system is in a quiescent state when it cannot produce outputs. In this paper, we relax the input enabling assumption, and allow some input sets to be enabled while others remain disabled. Moreover, we also relax the general bound M used in timed systems to detect quiescence, and allow different bounds for different sets of outputs. By considering the tioco-M theory, an enriched theory for timed testing with repetitive quiescence, and allowing the partition of input sets and output sets, we introduce the mtioco^M relation. A test derivation procedure which is nondeterministic and parameterized is further developed, and shown to be sound and complete wrt mtioco^
Testing multi input-output real-time systems (Extended version)
In formal testing, the assumption of input enabling is typically made. This assumption requires all inputs to be enabled anytime. In addition, the useful concept of quiescence is sometimes applied. Briefly, a system is in a quiescent state when it cannot produce outputs. In this paper, we relax the input enabling assumption, and allow some input sets to be enabled while others remain disabled. Moreover, we also relax the general bound M used in timed systems to detect quiescence, and allow different bounds for different sets of outputs. By considering the tiocoM theory, an enriched theory for timed testing with repetitive quiescence, and allowing the partition of input sets and output sets, we introduce the mtiocoM relation. A test derivation procedure which is nondeterministic and parameterized is further developed, and shown to be sound and complete wrt mtiocoM
MTL-Model Checking of One-Clock Parametric Timed Automata is Undecidable
Parametric timed automata extend timed automata (Alur and Dill, 1991) in that
they allow the specification of parametric bounds on the clock values. Since
their introduction in 1993 by Alur, Henzinger, and Vardi, it is known that the
emptiness problem for parametric timed automata with one clock is decidable,
whereas it is undecidable if the automaton uses three or more parametric
clocks. The problem is open for parametric timed automata with two parametric
clocks. Metric temporal logic, MTL for short, is a widely used specification
language for real-time systems. MTL-model checking of timed automata is
decidable, no matter how many clocks are used in the timed automaton. In this
paper, we prove that MTL-model checking for parametric timed automata is
undecidable, even if the automaton uses only one clock and one parameter and is
deterministic.Comment: In Proceedings SynCoP 2014, arXiv:1403.784
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