Table 7.

Summary of feature extraction methods.

	Method	Properties	Applications
Features selection	GA	– High resource consumption – Possible premature convergence	[188,189]
	SFS/SBS	– Suboptimal methods	[191,192]
	SFFS/SBFS	– Modified versions of SFS/SBS methods – Based on plus l-take away r algorithm – Partially overcome the deficiencies of SFS/SBS	[194–196]