Table 2. Features derived from raw sensor data.

Feature #	Feature Description
1	Sum of range of linear acceleration
2	Sum of standard deviation of linear acceleration
3	Simple moving average of sum of range of linear acceleration
4	Difference to y (y gravity—z gravity—x gravity)
5, 6, 7	Range of gravity vector (x, y, z)
8,9,10	Mean of gravity vector (x, y, z)
11,12,13	Range of linear acceleration (x, y, z)
14,15,16	Mean of linear acceleration (x, y, z)
17,18,19	Kurtosis of gravity vector (x, y, z)
20	Sum of Kurtosis of gravity vector
21	Sum of standard deviation of linear acceleration
22	Sum of variances gravity (summed diagonal of covariance matrix)
23	Simple moving average of sum of variances
24	Maximum slope of simple moving average of sum of variances
25–30	Covariance matrix elements of gravity vector
31–36	Covariance matrix elements of linear acceleration vector
37–42	Covariance matrix elements of rotated linear acceleration vector [25]
43	Velocity from integral of rotated linear acceleration1 (excluding y-axis)
44	Velocity for y-axis
45,46,47	Mean Euclidean norm (Linear, rotated linear1, raw acceleration)
48,49,50	Skewness of rotated linear acceleration (x, y, z)1
51,52,53	Moving average of skewness of rotated linear acceleration (x, y, z)1
54	Sum of moving average of skewness (x, y)
55	Range of rotated linear acceleration (x)
56	Moving average of distance from rotated linear acceleration1
57,58,59	Mean absolute linear acceleration (x, y, z)
60,61,62	Harmonic mean linear acceleration (x, y, z)
63,64,65	Cumulative sum linear acceleration (x, y, z)
66	Correlation between acceleration along gravity and heading
67	Average velocity in gravity direction
68	Average velocity in heading direction
69,70,71	Gyroscope mean (x, y, z)
72,73,74	Interquartile range linear acceleration (x, y, z)
75	Zero cross rate
76	Mean cross rate