Abstract
In the conventional framework for failure diagnosis of partially observed discrete event systems, it is assumed that, for each event, the corresponding output symbol is determined uniquely. However, this assumption does not hold in discrete event systems such as a mobile system, where an output symbol depends on not only an event but also a state at which the event occurs. In this paper, we model such a discrete event system by a Mealy automaton with a nondeterministic output function, and consider a diagnosis problem that requires any occurrence of a failure should be detected within a uniformly bounded number of steps. We present a necessary and sufficient condition for the existence of a diagnoser. We then present an algorithm for verifying this condition.
