9Heng A, Zhang S, Tan A C C, et al. Rotating machinery prognostics: State of the art, challenges and opportunities [J]. Mechanical Systems and Signal Processing, 2009, 23 (3) : 724 -739.
10Li N, Zhou R, Hu Q, et al. Mechanical fault diagnosis based on redundant second generation wavelet packet transform neighborhood rough set and support vector machine [ J ]. Mechanical Systems and Signal Processing, 2012, 28: 608 - 621.
