Robust Model-Checking of Timed Automata via Pumping in Channel Machines

Timed automata are governed by a mathematical semantics which assumes perfectly continuous and precise clocks. This requirement is not satisfied by digital hardware on which the models are implemented. In fact, it was shown that the presence of imprecisions, however small they may be, may yield extra behaviours. Therefore correctness proven on the formal model does not imply correctness of the real system. The problem of robust model-checking was then defined to circumvent this inconsistency. It consists in computing a bound on the imprecision under which the system will be correct. In this work, we show that robust model-checking against !-regular properties for timed automata can be reduced to standard model-checking of timed automata, by computing an adequate bound on the imprecision. This yields a new algorithm for robust model-checking of !-regular properties, which is both optimal and valid for general timed automata.