2Huang N E, Shen Zheng and Steven R L, et al. The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis.Proc. R. Soc. Lond. A, 1998;454: 903--995.
3Huang N E, Shen Zheng and Steven R L. A new view of nonlinear water waves: the Hilbert spectrum. Annu.Rev. Fluid Mech. , 1999 ;31: 417--457.
