An Improved Nonlinear Grey Bernoulli Model Based on the Whale Optimization Algorithm and Its Application

Table 2

Parameter values for five grey models.

Parameters
GM (1, 1)	−0.164	748.161	0.500
DGM (1, 1)					1.179	817.126
NGBM (1, 1)	−0.213	19390.960	0.500	−0.440
ONGBM (1, 1)	−0.211	20938.930	0.460	−0.450
INGBM (1, 1)	−0.220	39847.500	0.500	−0.542			−0.222	42037.640

Note: represents the weighted parameter of background value and it is taken as 0.5 generally. It is, however, recommended to search for the optimal value in ONGBM (1, 1). In addition, and are parameters of DGM (1, 1) in this case.