An Improved Grey Model with Time Power and Its Application

Table 1

The simulated results and indices by five grey models.

Year	Raw data	GM(1,1)	DGM(1,1)	NHGM(1,1)	GM(1,1, )	OGM(1,1, )
2005	3.39
2006	4.16	4.06	4.07	4.51	4.16	4.37
2007	4.97	4.72	4.73	5.11	4.73	4.94
2008	5.57	5.49	5.51	5.85	5.48	5.42
2009	5.96	6.39	6.41	6.78	6.40	6.25
2010	7.45	7.44	7.46	7.94	7.48	7.42
2011	8.75	8.66	8.69	9.39	8.72	8.77
2012	10.23	10.07	10.11	11.20	10.11	10.19
RMSE		0.21	0.20	0.60	0.20	0.15
MAPE(%)		2.70	2.53	7.66	2.27	2.03
2013	11.6	11.72	11.77	13.46	11.65	11.62
2014	12.74	13.64	13.69	16.28	13.34	13.05
RMSE		0.64	0.68	2.83	0.43	0.22
MAPE(%)		4.06	4.46	21.89	2.58	1.32

The bold values represent the RMSE and MAPE (%) of the model proposed in this paper for model evaluation in the example.