ABSTRACT

References..............................................................................................................304

ABSTRACT

The Hilbert-Huang transform (HHT) provides a new method of analyzing nonstationary and nonlinear time series data. It allows the exploration of intermittent and amplitude-varying motions. The classical signal analysis theory and practice have been dominated by the Fourier transform, which represents the signal system in the frequency domain. The Fourier works well for strictly periodic or stationary random functions of time. To address the issues of nonstationarity and nonperiodic functions, various methods have been introduced in the literature. These include wavelet analysis, the Wigner-Ville distribution, and the evolutionary spectrum. Unfortunately, these methods failed in one way or another [Huang et al., 1998].