TABLE 9.

Results of principal components analysis showing the classification results of ten typical noises.

	Variance explained (%)	Mechanical sound	Components
			1	2	3
C1	22.1	Dump truck	0.836	0.086	−0.141
		Loader	0.715	0.199	0.317
		Excavator	0.610	0.077	0.548
		Concrete vibrator	0.476	0.231	0.150
C2	20.2	Jackhammer	0.106	0.767	0.214
		Angle grinder	0.022	0.754	−0.091
		Electric drill	0.144	0.631	0.144
		Electric screwdriver	0.346	0.591	−0.083
C3	15.6	Breaker	0.019	0.045	0.869
		Concrete pump	0.498	0.073	0.529

Most important variables in each component are in Italic.