ABSTRACT
The covariance is a measure of the joint variability of two random variables forming a Cartesian coordinate. Variance is a special case of covariance, when two variables are the same. The root of variance is the standard deviation. The normalization of covariance to standard deviation is called Pearson correlation coefficient. The covariance for the region of first and third quadrant is called upper semi-covariance. The covariance for the region of second and fourth quadrant is called down semi-covariance. Here we present semi-covariance, an accurate ReLU (Rectified Linear Unit) way of measuring the non-linear correlation between variables. Our framework is applied to successfully analyze the association between alternative environment social life factors and the pandemic toll recovery health. The results of our analyses of the 2021 pandemic toll suggest that pesticide residual, annual precipitation, forest coverage, economy development, lifestyle, etc. have different impacts on toll of each country. The pesticide may kill immune system, pandemic lifestyle is impacted. We picked total 8 related factors from 22 countries in order to set up future model for digital twin that predicting pandemic trend. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.