참고문헌 (시계열 분해 관련)
[1] N, Huang et al., "The empirical mode decomposition and hilbert spectrum for nonlinear and nonstationary time series analysis", Proceedings of the Royal Society of London. Series A: mathematical, physical and engineering sciences, Vol. 454, pp. 903-995, 1971.
[2] M, Zaichao et al., "EEMD Independent Extraction for Mixing Features of Rotating Machinery Reconstructed in Phase Space", Vol. 15, no. 4, pp. 8550-8569, 2015.
[3] Z, Wu and N, Huang, "Ensemble empirical mode decomposition: a noise-assisted data analysis method", World Scientific, Vol. 1, no. 1, pp. 1-41, 2009.