Figure 2

An instance of activity signal representations both in the time domain and in the transform domain: (a, b) The original data in some window respectively related to the walking forward and the Jump activity, recorded by the accelerometer located at the waist along z -axis. (c, d) Resultant FFT of the signal in (a, b), respectively (with the maximum five peaks of FFT marked with 'O'). (e, f) Resultant cepstrum of the signal in (a, b), respectively (with the maximum five peaks of cepstral coefficients marked with 'O').