An Improved Nonlinear Grey Bernoulli Model Combined with Fourier Series

Table 3

In-sample comparisons among five grey forecasting models.

Model	MAPE (%)	Forecasted accuracy (%)	Performance
GM (1, 1)	2.1113	97.8887	Good
Optimized GM (1, 1)	2.1108	97.8892	Good
Original NGBM (1, 1)	1.7948	98.2052	Good
Optimized NGBM (1, 1)	1.7791	98.2209	Good
F-NGBM (1, 1)	0.0008	99.9992	Excellent