Pattern diagnosis for stochastic discrete event systems

In this paper, pattern diagnosis problem in stochastic discrete event system (SDES) is investigated. In a system, an abnormal state may be caused by the occurrence of several normal events. This kind of fault is called fault pattern. The diagnosis problem of fault pattern is defined as pattern diagnosis. Based on the notions of Adiagnosability and A-A-diagnosability in SDES, the definitions of PA-diagnosability and PAA-diagnosability for pattern diagnosability in SDES are presented in this paper. In addition, a necessary and sufficient condition for an SDES to be PA-diagnosable is proposed. The goal of this paper is diagnosing fault pattern in the real systems. Three-Tank Water Level Control System and Heating, Ventilation, and Air-conditioning System are described to illustrate our algorithm. Experimental results demonstrate that pattern diagnosability in SDES is more accurate than that in DES.