Table 2.
List of the extracted features.
| Type | Features | Description |
|---|---|---|
| TD 1 | Mean | The mean value of RR intervals |
| SDNN | The standard of successive RR intervals | |
| RMSSD | The root mean square of successive RR intervals | |
| PNN50 | The percentage of RR intervals longer than 50ms | |
| FD 2 | vLF | The power in 0.0033 Hz–0.04 Hz band |
| LF | The power in 0.04 Hz–0.15 Hz band | |
| HF | The power in 0.15 Hz–0.4 Hz band | |
| LF/HF | The ratio of power in LF and HF band | |
| ND 3 | SampEn | The sample value with r = 0.15 * STD |
| DFA | The short-term coefficient of detrended fluctuation analysis | |
| BF 4 | ZCR | The zero crossing rate of BCG signal |
| ACAC | The average cumulative amplitude change in unit length | |
| ANEP | The average number of extreme points in unit time | |
| ASTC | The average signal turn counts in unit time |
1 Time domain features. 2 Frequency domain features. 3 Non-linear domain features. 4 BCG fluctuation features.