“…The first was the popular ground reaction force (GRF) used previously in [2], [4], [8], [11], [15], in this case an average across all sensors was carried out to obtain a global profile for the GRF. The other two features were the spatial average of the sensors, which results in a single average profile of all sensors of the footstep signal; and finally the upper and lower contour profiles of the time domain signal.…”