Table 2.

Symbol illustrations.

Parameter	Illustration
${\mathrm{C}}_{\mathrm{in}}$	input concentration of each gas
${\mathrm{C}}_{\mathrm{sout}}$	gas sensor output
${\mathrm{S}}_1$	${\mathrm{CH}}_4$ sensor output
${\mathrm{S}}_2$	${\mathrm{C}}_2{\mathrm{H}}_6$sensor output
${\mathrm{S}}_3$	${\mathrm{C}}_3{\mathrm{H}}_8$ sensor output
${\mathrm{C}}_{\mathrm{nout}}$	NN output of gas concentration
${\mathrm{C}}_{\mathrm{corr}}$	final output of gas concentration