Table 2.

Selection of Features.

Description	Name	Equations
1. Index of minimum	arg_min	${\varphi }_{min}=argmin\left(c\right)$
2. Index of maximum	arg_max	${\varphi }_{max}=argmax\left(c\right)$
3. Variance	var	${\sigma }^2={\sum }_{i=1}^n(\frac{{(c_i-\overline{c})}^2}{n-1}$)
4. Maximum	max	$c_{max}=max\left(c\right)$
5. Minimum	min	$c_{min}=min\left(c\right)$
6. Maximum gradient	max_grad	$\frac{\partial c}{\partial \varphi }{|}_{max}=max\left(\frac{\partial c}{\partial \varphi }\right)$
7. Mean difference	mean_diff	$\overline{d}=\overline{c_{i+1}-c_i}$
8. Root mean square	rms	$c_{rms}=\frac{\sqrt{{\sum }_{i=1}^n{c_i}^2}}{n}$