Table 1.

Activity recognition model features from accelerometer and gyroscope signals.

Description	Number of features
Mean, range, and interquartile range	3 (per axis)
Moments: standard deviation, skew, and kurtosis	3 (per axis)
Histogram: bin counts of z-scores from -2 to 2	4 (per axis)
Moments of derivative: mean, standard deviation (SD), skew, and kurtosis	4 (per axis)
Mean of the squared norm	1
Sum of axial standard deviations	1
Pearson correlation coefficient, r(xy), r(xz), r(yz)	1 (per axis)
Mean cross products (raw and normalized), xy, xz, yz	2 (per axis)
Absolute mean of cross products (raw and normalized)	2 (per axis)
Power spectra: mean, standard deviation, skew, and kurtosis	4 (per axis)
Mean power in 0.5 Hz bins from 0-10 Hz	20 (per axis)