Diagnosability of intermittent sensor faults in discrete event systems

We address in this paper the problem of diagnosing intermittent sensor faults. In order to do so, we modify the model of intermittent loss of observations proposed in the literature to account for sensor malfunction only. Using this model together with a modified label automaton, it will be possible to change the problem of detecting intermittent sensor faults into a problem of diagnosing a language generated by an automaton in the presence of intermittent faults, where the fault event will be an unobservable event that models the non-detection of the event to be registered by the sensor under consideration. In this regard, we present necessary and sufficient conditions for diagnosability of intermittent sensor faults and propose a test based on diagnoser automaton to verify intermittent sensor fault diagnosability.