“…The signal analysis has been set up as one of the useful methods for fault diagnosis. Many useful techniques for signal analysis have been proposed such as fast Fourier transform (FFT) (Corinthios, 1971), higher-order statistics (HOS) (Swami, Giannakis, & Zhou, 1997), and adaptive order-tracking (Bai, Huang, Hong, & Su, 2005;Wu, Huang, & Huang, 2004). Nonetheless, the fault diagnosis system of sound emission or vibration signals analysis is stressed in the time-frequency domain information.…”