“…Then, we generalized the DFA algorithm (six steps described above in DFA algorithm) to find (covariance of the residuals) and the detrended function by: But, for quantify the level of cross-correlation, the DCCA cross-correlation coefficient can defined as the ratio between the detrended cross-correlation function, , and the detrended auto-correlation function, and , for the time-series and , respectively: Some properties of naturally appear, the most important is that: In this case, means there is no cross-correlation between and , and it splits the level of cross-correlation between positive and the negative case. This coefficient has been tested on selected time-series [21] , [42] and proved to be quite robust, mainly for statistical analysis between non-stationary time-series [43] , [44] , [45] , [46] , [47] , [48] , among other cases. It is noteworthy that there is the generalization, for more than two time-series analysis, what we call multiple DCCA coefficient, …”