Table 1.

Proposed set of statistical time domain features estimated during the signal processing in the TD analysis, where each y(j) value belongs to each sample point of the processed signal for j = 1, 2, 3…P, with a total number P samples.

Statistical Feature	Mathematical Equation
Mean	$t_1=\frac{1}{P} {\displaystyle \sum }_{j=1}^P\left|y_j\right|$	(9)
Maximum value	$t_2=max\left(x\right)$	(10)
Root mean square	$t_3=\sqrt{\frac{1}{P} {\displaystyle \sum }_{j=1}^P{\left(y_j\right)}^2}$	(11)
Square root mean	$t_4={\left(\frac{1}{P} {\displaystyle \sum }_{j=1}^P\sqrt{\left|y_j\right|}\right)}^2$	(12)
Standard deviation	$t_5=\sqrt{\frac{1}{P} {\displaystyle \sum }_{j=1}^P{\left(y_j-t_1\right)}^2}$	(13)
Variance	$t_6=\frac{1}{P} {\displaystyle \sum }_{j=1}^P{\left(y_j-t_1\right)}^2$	(14)
RMS Shape factor	$t_7=\frac{t_3}{\frac{1}{P} {{\displaystyle \sum }}_{j=1}^P\left|y_j\right|}$	(15)
SRM Shape factor	$t_8=\frac{t_4}{\frac{1}{P} {{\displaystyle \sum }}_{j=1}^P\left|y_j\right|}$	(16)
Crest factor	$t_9=\frac{t_2}{t_3}$	(17)
Latitude factor	$t_{10}=\frac{t_2}{t_4}$	(18)
Impulse factor	$t_{11}=\frac{t_2}{\frac{1}{P} {{\displaystyle \sum }}_{j=1}^P\left|y_j\right|}$	(19)
Skewness	$t_{12}=\frac{{{\displaystyle \sum }}^{ }\left[{\left(y_j-t_1\right)}^3\right]}{t_5{}^3}$	(20)
Kurtosis	$t_{13}=\frac{{{\displaystyle \sum }}^{ }\left[{\left(y_j-t_1\right)}^4\right]}{t_5{}^4}$	(21)
Fifth moment	$t_{14}=\frac{{{\displaystyle \sum }}^{ }\left[{\left(y_j-t_1\right)}^5\right]}{t_5{}^5}$	(22)
Sixth moment	$t_{15}=\frac{{{\displaystyle \sum }}^{ }\left[{\left(y_j-t_1\right)}^6\right]}{t_5{}^6}$	(23)