Model analysis
We observed how ESV (Y) responded to the change in each influence factor
(X) by sampling continuously in the range of each input X. In the course
of the concrete analysis, other factors were kept as the mean of
samples, and the values of the target factors were changed by adopting
control variables. In addition, the range of target X was regarded as
its definition domain, called the sampling domain. The range of ESV is
called the response domain. The influence intensity of every X factor
can be judged according to the corresponding response domain, and the
influence mode and potential mechanism can be judged according to the
variation trend of the function.
Results and discussion