Research on the Concentration Prediction of Nitrogen in Red Tide Based on an Optimal Grey Verhulst Model

Table 4

Accuracy comparison of GVM, BPGVM, and BRGVM models.

Measured raw data	GVM		BPGVM		BRGVM
	Prediction value	The relative error (%)	Prediction value	The relative error (%)	Prediction value	The relative error (%)
30	30	0	30	0	29.1	−2.9
33	36.5	10.6	36.1	9.2	35.1	6.3
37	43.2	16.9	42.7	15.3	41.7	12.5
45	50.5	12.1	49.6	10.2	48.5	7.9
55	57.8	5.1	56.7	3.1	55.6	1.2
65	65.1	0.2	63.7	−1.9	62.7	−3.5
72	72.1	0.09	70.4	−2.2	69.4	−3.6
76	78.4	3.3	76.5	0.7	75.5	0.0
Average relative error (%)	6.9		5.3		4.8
Extrapolation values	84.2		82.0		81.0