TY - JOUR
TI - An application of chaos gray-encoded genetic algorithm for Philip infiltration model
AU - Wang Kai-Wen
AU - Yang Xiao-Hua
AU - Li Yu-Qi
AU - Liu Chang-Ming
AU - Guo Xing-Jian
JN - Thermal Science
PY - 2018
VL - 22
IS - 4
SP - 1581
EP - 1588
PT - Article
AB - To improve the precision of parameters' estimation in Philip infiltration  model, chaos gray-coded genetic algorithm was introduced. The optimization  algorithm made it possible to change from the discrete form of time  perturbation function to a more flexible continuous form. The software RETC  and Hydrus-1D were applied to estimate the soil physical parameters and  referenced cumulative infiltration for seven different soils in the USDA soil  texture triangle. The comparisons among Philip infiltration model with  different numerical calculation methods showed that using optimization  technique can increase the Nash and Sutcliffe efficiency from 0.82 to 0.97,  and decrease the percent bias from 14% to 2%. The results indicated that  using the discrete relationship of time perturbation function in Philip  infiltration model's numerical calculation underestimated model's parameters,  but this problem can be corrected a lot by using optimization algorithm. We  acknowledge that in this study the fitting of time perturbation function,  Chebyshev polynomial with order 20, did not perform perfectly near saturated  and residue water content. So exploring a more appropriate function for  representing time perturbation function is valuable in the future.