Nii O. (University of Delaware, Newark, USA) Attoh-Okine & Norden E. (NASA Goddard Space Flight Center, Greenbelt, Maryland, USA) Huang 
The Hilbert-Huang Transform in Engineering [PDF ebook] 

Data used to develop and confirm models suffer from several shortcomings: the total data is too limited, the data are non-stationary, and the data represent nonlinear processes. The Hilbert-Huang transform (HHT) is a relatively new method that has grown into a robust tool for data analysis and is ready for a wide variety of applications.
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