Table 2.

141-dimensional feature name and serial number.

Number	Feature	Feature Content
1–30	Mean	Average of the angle of the hip, knee, and ankle; (6 dimensions) Average of the three-axis acceleration of the hip, knee, and ankle; (18 dimensions) Average of pressure on the left and right feet. (6 dimensions)
31–60	Variance	The variance of the hip, knee and ankle angles of the two legs; (6 dimensions) The variance of the triaxial acceleration of hips, knees and ankles of two legs; (18 dimensions) Variance of three pressure points on both feet. (6 dimensions)
61–120	Maximum value	Maximum and range of angles for hips, knees, and ankles; (12 dimensions) Maximum and range values of triaxial acceleration of hip, knee and ankle; (36 dimensions) Maximum and range values of the three pressure points of left and right feet. (12 dimensions)
121–128	Correlation coefficient	Hip and knee angle correlation coefficient of the left leg and right leg; (2 dimensions) Knee and ankle angle correlation coefficient of the left leg and right leg; (2 dimensions) Acceleration coefficient of left foot and right foot in x-z plane; (1 dimension) Angle correlation coefficient between left hip and right hip; (1 dimension) Angle correlation coefficient between left knee and right knee; (1 dimension) Angle correlation coefficient between left ankle and right ankle joint. (1 dimension)
129–138	Fourier series	Fifth-order Fourier series of hip and knee angles of left leg. (10 dimensions)
139–140	SMA	The amplitude of the left and right foot acceleration signals. (2 dimensions)
141	Wavelet energy entropy	Wave energy entropy of left hip joint angle. (1 dimension)