Comparison Analysis of Different Time-Scale Heart Rate Variability Signals for Mental Workload Assessment in Human-Robot Interaction

Table 2

Statistical analysis results of features under multiple time scales.

		M-1 and R-1	M-3 and R-3	M-5 and R-5
Time domain	HRVTi	0	0	0
	Mean	0	0	0
	SDNN	0	0	0
	Median	0	0	0
	pNN50	0	0	0
	RMSSD	0	0	0
Frequency domain	aHF	0	0	0
	aLF	0	0	0
	aTotal	0	0	0
	aVLF	0	0	0
	LF/HF	0	0.054	0
	nHF	0	0	0.001
	nLF	0	0	0.002
	pHF	0.80	0	0
	pLF	0.003	0.60	0.194
	pVLF	0.006	0	0
Nonlinear	SaEn	0	0	0
	Alpha	0	0	0
	Alpha1	0	0	0
	Alpha2	0	0	0

, , and represent , , and , respectively. M-1 : 1 min signals of the task-performing state; R-1 : 1 min signals of the rest state; M-3 : 3 min signals of the task-performing state; R-3 : 3 min signals of the rest state; M-5: 3 min signals of the task-performing state; R-5 : 5 min signals of the rest state.