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

Table 7

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 (%)
28	28	0	27.2	−3.6	26.3	−7.1
30	33.4	11.3	33.1	10.3	33.6	12
32	39.2	22.5	38.7	20.9	35.4	10.6
35	41.3	18	40.7	16.2	40.5	15.7
36	43.5	17.5	42.7	15.4	40.9	9.4
42	44.5	5.9	43.5	3.6	42.6	1.4
46	48.8	6.1	44.7	−2.8	45.5	−1.1
51	53.6	5.1	53.3	4.5	52.2	2.3
57	60.3	5.8	60.5	6.1	59.4	4.2
65	67.6	4	67.2	3.3	66.5	2.3
74	77.8	5.1	73.1	1.2	75.3	1.8
83	85.9	3.5	86.1	3.7	84.8	2.1
90	93.6	4	93.2	3.4	92.3	2.6
95	98.5	3.7	97.6	2.7	96.7	1.8
99	100.7	1.7	101.3	2.3	100.3	1.3
102	103.2	1.1	102.4	0.4	102.5	0.5
Average relative error (%)	7.2		5.4		3.8
Extrapolation values	104.7		103.3		102.4
	103.6		103.1		102.2