A game approach to determinize timed automata

Abstract. We consider the setting of component-based design for realtime systems with critical timing constraints. Based on our earlier work, we propose a compositional specification theory for timed automata with I/O distinction, which supports substitutive refinement. Our theory provides the operations of parallel composition for composing components at run-time, logical conjunction/disjunction for independent development, and quotient for incremental synthesis. The key novelty of our timed theory lies in a weakest congruence preserving safety as well as bounded liveness properties. We show that the congruence can be characterised by two linear-time semantics, timed-traces and timed-strategies, the latter of which is derived from a game-based interpretation of timed interaction.

Section: Discussionmentioning

confidence: 99%

Revisiting Timed Specification Theories: A Linear-Time Perspective

Chilton

Kwiatkowska

Wang

2012

“…The testers are sound, but not in general complete and might accept behavior of the system under test that should be rejected. Bertrand et al [7] develop a game-based method for determinization of eNTA which generates either a language equivalent DTA when possible, or its approximation otherwise. A similar approach is proposed in [6] in the context of model-based testing, where it is shown that their approximate determinization procedure preserves the tioco relation.…”

Section: Related Workmentioning

confidence: 99%

Bounded Determinization of Timed Automata with Silent Transitions

Lorber

Rosenmann

Ničković

et al. 2015

Deterministic timed automata are strictly less expressive than their non-deterministic counterparts, which are again less expressive than those with silent transitions. As a consequence, timed automata are in general non-determinizable. This is unfortunate since deterministic automata play a major role in model-based testing, observability and implementability. However, by bounding the length of the traces in the automaton, effective determinization becomes possible. We propose a novel procedure for bounded determinization of timed automata. The procedure unfolds the automata to bounded trees, removes all silent transitions and determinizes via disjunction of guards. The proposed algorithms are optimized to the bounded setting and thus are more efficient and can handle a larger class of timed automata than the general algorithms. The approach is implemented in a prototype tool and evaluated on several examples. To our best knowledge, this is the first implementation of this type of procedure for timed automata.

“…So far, the most general of those techniques has been introduced in [3] and consists in turning a TA A into a safety game G A,(Y,M ) (parametrised by a set of clocks Y and a maximal constant M ). Then, a deterministic TA overapproximating A (with set of clocks Y and maximal constant M ), can be extracted from any Player A strategy.…”

Section: Ltl Realisability Ltlmentioning

confidence: 99%

“…In this framework, computing a winning strategy for the player amounts to synthesising a control policy that guarantees no bad state will be reached, no matter how the environment behaves. Safety games have also been used as a tool to solve other problems such as LTL realisability [8], real-time scheduler synthesis [4] or timed automata determinisation [3]. We will come back to those applications.…”

Section: Introductionmentioning

confidence: 99%

Synthesising Succinct Strategies in Safety and Reachability Games

Geeraerts

Goossens

Stainer

2014

Self Cite

Finite turn-based safety games have been used for very different problems such as the synthesis of linear temporal logic (LTL) [8], the synthesis of schedulers for computer systems running on multiprocessor platforms [4], and also for the determinisation of timed automata [3]. In these contexts, games are implicitly defined, and their size is at least exponential in the size of the input. Nevertheless, there are natural relations between states of arenas of such games. We first formalise the properties that we expect on the relation between states, thanks to the notion of alternating simulation. Then, we show how such simulations can be exploited to (1) improve the running time of the OTFUR algorithm[6] to compute winning strategies and (2) obtain a succinct representation of a winning strategy. We also show that our general theory applies to the three applications mentioned above.