Table 3.
List of features extracted from E4 physiological sensor signals.
| Domain | Sensor data stream | Feature |
|---|---|---|
| Time-Domain | Accelerometry | Minimum |
| Electrodermal Activity | Maximum | |
| Skin temperature | Mean | |
| Heart rate | Median | |
| SD | ||
| Skewness | ||
| Kurtosis | ||
| Interquartile range | ||
| Interbeat interval | MeanNN | |
| SDNN | ||
| RMSSD | ||
| SDSD | ||
| NN50 | ||
| pNN50 | ||
| Frequency-Domain | Accelerometry | Dominant frequency |
| Spectral entropy | ||
| Spectral energy | ||
| Minimum | ||
| Maximum | ||
| Mean | ||
| SD | ||
| Interbeat interval | VLF | |
| LF | ||
| HF | ||
| LF/HF ratio | ||
| LF (nu) | ||
| HF (nu) |
SD Standard deviation, SDNN Standard deviation of NN intervals obtained from the time-window, RMSSD Root mean square of successive differences between heartbeats in the time-window, SDSD Standard deviation of differences between consecutive NN intervals, NN50 The number of successive NN interval that differ by more than 50 ms in the time-window, pNN50 The percentage of successive NN interval that differ by more than 50 ms in the time-window, VLF Logarithmic of absolute power of very low frequency band (0–0.04 hz), LF Logarithmic of absolute power of low frequency band, LF(nu) Normalized absolute power of low frequency band, HF(nu) Normalized absolute power of High frequency band.