Updatable timed automata

نویسندگان

Patricia Bouyer

Catherine Dufourd

Emmanuel Fleury

Antoine Petit

چکیده

We investigate extensions of Alur and Dill’s timed automata, based on the possibility to update the clocks in a more elaborate way than simply reset them to zero. We call these automata updatable timed automata. They form an undecidable class of models, in the sense that emptiness checking is not decidable. However, using an extension of the region graph construction, we exhibit interesting decidable subclasses. In a surprising way, decidability depends on the nature of the clock constraints which are used, diagonal-free or not, whereas these constraints play identical roles in timed automata. We thus describe in a quite precise way the thin frontier between decidable and undecidable classes of updatable timed automata. We also study the expressive power of updatable timed automata. It turns out that any updatable automaton belonging to some decidable subclass can be effectively transformed into an equivalent timed automaton without updates but with silent transitions. The transformation suffers from an enormous combinatorics blow-up which seems unavoidable. Therefore, updatable timed automata appear to be a concise model for representing and analyzing large classes of timed systems.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

P . Bouyer Updatable Timed Automata , an Algorithmic Approach

The notion of updatable timed automata has been introduced as a natural syntactic extension of classical timed automata. These updatable timed automata allow in particular to represent large classes of real-time systems in a much more concise way. For numerous families of updatable timed automata, the decidability of the emptiness problem has been proved with a suitable extension of Alur and Di...

متن کامل

On Termination and Boundedness of Nested Updatable Timed Automata

We introduce a model named nested updatable timed automata (NeUTAs), which can be regarded as a combination of nested timed automata (NeTAs) and updatable timed automata with one updatable clock (UTA1s). The model is suitable for soft real-time system analysis, since the updatable clock representing a deadline can be updated due to environments. A NeUTA behaves as a UTA1, in which all clocks ca...

متن کامل

Forward Analysis of Updatable Timed Automata

Timed automata are a widely studied model. Its decidability has been proved using the so-called region automaton construction. This construction provides a correct abstraction for the behaviours of timed automata, but it suffers from a state explosion and is thus not used in practice. Instead, algorithms based on the notion of zones are implemented using adapted data structures like DBMs. When ...

متن کامل