“…Therefore, from the experimental results of the above comparison, the conventional signal analysis methods, such as VMD, CEEMDAN, LMD, and ITD, do not effectively extract the original signal x(t); however, the proposed method is superior. As mentioned previously, some researchers have proposed several intelligent optimization algorithms (i.e., PSO, PIO, and WOA) in [26]- [30]. These methods optimize the performance of VMD, and the premise is to design an appropriate fitness function.…”