Table 5. PCA analysis and principle factors extraction.

Initial factor	Initial whole factors				Extracted factors features				Extracted factors (in 4 dimension)
	λ	Variance%	Total %		λ	Variance%	Total %		a1	a2	a3	a4
1	1.857	30.956	30.956		1.857	30.956	30.956		0.460	−0.417	0.528	−0.489
2	1.059	17.642	48.598		1.059	17.642	48.598		0.538	−0.373	−0.119	0.661
3	0.944	15.739	64.337		0.944	15.739	64.337		0.750	−0.131	0.105	0.109
4	0.867	14.458	78.795		0.867	14.458	78.795		0.509	0.257	−0.636	−0.321
5	0.668	11.129	89.923		–	–	–		0.694	0.265	−0.064	−0.149
6	0.605	10.077	100.000		–	–	–		0.229	0.769	0.481	0.232

Notes: a₁–a₄, extracted factors; λ, Load coefficient. PCA, principle components analysis.