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

Table 6

Accuracy comparison of GVM, TPGVM, and TRGVM models.

Measured raw data	GVM		TPGVM		TRGVM
	Prediction value	The relative error (%)	Prediction value	The relative error (%)	Prediction value	The relative error (%)
28	28	0	27.3	−2.5	26.1	−6.8
30	33.4	11.3	33.5	11.6	33.8	12.7
32	39.2	22.5	38.2	19	34.8	8.8
35	41.3	18	41.3	18	40.7	16
36	43.5	17.5	42.2	14.1	39.2	6.0
42	44.5	5.9	43.9	4.5	42.2	0.5
46	48.8	6.1	45.3	−1.5	44.9	−2.4
51	53.6	5.1	52.8	3.5	53.2	4.3
57	60.3	5.8	60.2	5.6	58.9	3.3
65	67.6	4	68.1	4.7	66.7	2.6
74	77.8	5.1	72.6	−1.9	75.6	2.2
83	85.9	3.5	85.3	2.8	83.5	0.6
90	93.6	4	92.5	2.8	92.1	2.3
95	98.5	3.7	97.2	2.3	96.3	1.3
99	100.7	1.7	101.1	2.1	100.5	1.5
102	103.2	1.1	102.7	0.7	101.4	0.6
Average relative error (%)	7.2		5.3		3.3
Extrapolation values	104.2		102.2		101.5
	104.7		103.8		102.1