“…Standard DHMMs have been used in the past in many applications [31,57,42,8,3,26] and in particular for noisy speech and character recognition [7,50,17,12]. In the context of PHM, DHMM has also been widely used, for instance in [25] for predictive modeling dedicated to intelligent maintenance in complex semiconductor manufacturing processes, in [29] for incipient fault detection and diagnosis in turbine engines, in [2] for failure isolation for cognitive robots and in [16] for anomaly detection in electronic systems.…”