Table 3.

Success rate in vapour identification (%) using flow modulation. Validation results are reported. The optimal value of parameter C is also shown.

Frequency	Pre-processing	TGS 800	TGS 822	TGS 826	All sensors
10 mHz	None	86.7 C = 10	95.1 C = 10	97.7 C = 10	84.4 C = 10
	Mean-centring	79.2 C = 102	88.3 C = 10	84.4 C = 103	82.2 C = 10
	Auto scaling	82.2 C = 10	90.6 C = 10	90.6 C = 103	88.9 C = 10
20 mHz	None	92.9 C = 10	97.0 C = 10	97.5 C = 10	99.7 C = 10
	Mean-centring	93.3 C = 102	91.1 C = 10	97.8 C = 102	100 C = 10
	Auto scaling	88.3 C = 104	97.0 C = 102	100 C = 102	100 C = 10
30 mHz	None	91.1 C = 10	95.6 C = 102	95.6 C = 10	97.8 C = 10
	Mean-centring	97.4 C = 10	95.9 C = 102	99.7 C = 102	100 C = 102
	Auto scaling	95.6 C = 102	88.6 C = 102	95.4 C = 102	97.8 C = 102
40 mHz	None	90.6 C = 10	88.3 C = 10	79.2 C = 10	93.3 C = 10
	Mean-centring	74.7 C = 10	83.7 C = 10	83.1 C = 104	95.6 C = 10
	Auto scaling	83.7 C = 104	86.5 C = 104	75.2 C = 102	93.3 C = 10
60 mHz	None	83.1 C = 10	87.6 C = 10	92.8 C = 10	88.9 C = 10
	Mean-centring	78.3 C = 102	73.8 C = 104	85.3 C = 102	84.4 C = 102
	Auto scaling	72.4 C = 105	76.8 C = 105	79.2 C = 105	84.4 C = 102
80 mHz	None	70.2 C = 10	91.1 C = 10	83.7 C = 102	97.7 C = 10
	Mean-centring	70.5 C = 102	80.0 C = 10	84.4 C = 102	95.5 C = 10
	Auto scaling	53.3 C = 10	88.9 C = 102	78.1 C = 103	97.7 C = 10