Boundary-processing-technicque in EMD method and Hilbert transform

Bg virtue of neural network, a series of signals is extended forward and ba ckward, as a result, two additional maxima and two additional minima are ob tained at both ends of the original data set, with which the EMD decomposit ion can be exactly achieved with cubic spline interpolation. Meanwhile, by using of neural network every IMF component can also be extended forward an d backward, which effectively restrains the end effect, thus the veracious Hilbert spectra are achieved. Verifications of the sample signals and the a ctual surface elevation of sea waves show that the present extension method is relatively accurate.