A New Approach to Improve Accuracy of Grey Model GMC in Time Series Prediction

Table 2

Comparison of actual values, model values, and APEs of D-GMC and modified GMC models.

Years		CO2 emission data	D-GMC		Modified GMC
			Model value	APE	Model value	APE
1994	1	122,876.13	122,876.13	0.00	122,876.13	0.00
1995	2	137,691.67	142,056.72	3.17	138,089.13	0.29
1996	3	155,553.15	148,750.34	4.37	154,325.20	0.79
1997	4	161,057.54	154,933.62	3.80	162,115.22	0.66
1998	5	145,451.52	161,292.65	10.89	146,188.49	0.51
1999	6	149,881.53	140,012.17	6.58	148,098.26	1.19
2000	7	150,832.00	150,968.83	0.09	150,578.46	0.17
2001	8	153,545.22	157,968.41	2.88	156,157.34	1.70
2002	9	163,558.08	164,645.66	0.66	161,506.52	1.25
2003	10	172,053.83	176,232.82	2.43	172,557.16	0.29
2004	11	187,418.22	176,180.65	6.00	189,201.76	0.95
2005	12	192,574.90	193,410.05	0.43	188,058.52	2.35
2006	13	193,233.99	197,621.97	2.27	196,939.39	1.92
2007	14	200,494.35	194,241.16	3.12	199,340.27	0.58
2008	15	203,261.89	208,243.34	2.45	204,008.47	0.37
2009	16	208,267.86	211,387.03	1.50	207,577.79	0.33
2010	17	220,467.16	217,488.33	1.35	220,488.97	0.01
2011	18	224,465.07	236,377.49	5.31	222,859.77	0.72
2012	19	240,583.97	234,631.65	2.47	240,026.56	0.23
2013	20	240,802.07	248,902.18	3.36	241,530.87	0.30

Prediction.