Improving real-time identification of Petri Nets using timing information

This paper deals with the problem of identifying a Petri net system given an observed sequence of events generated by it and an observed sequence of output vectors associated to the marking of the measurable places. The problem is not new in the literature. The original contribution of this work consists in the use of the timing information associated to the net so as to improve its identification. The fact that a transition has not fired for a time larger than its expected delay is here exploited to obtain a list of counterexamples, i.e. the strings that does not belong to the language, even if a whole language is not known. This accelerates the identification procedure. The problem of identifying a ¿-free labeled Petri net system is here considered, that is the identification of a net where a label may be associated to more than one transition, and no transition may by labelled with the empty string.