“…For reducing non-stationary and nonlinear signal noises, empirical mode decomposition (EMD) method (Cheng, Wang, Chen, Zhang, & Huang, 2019;Tao, 2019;Zhang, Zhao, & Deng, 2018) is a common method, but in principle there are problems with modal aliasing and endpoint effects. For noise reduction, singular value decomposition (SVD) method (An, Zeng, Yang, & An, 2017;Cai & Xiao, 2019;Wang et al, 2019) has good performance, but the number of singular values depends on the manmade. If the singular value is too large, it will influence the noise reduction effect.…”