Simplex-chaos Optimization Algorithm For Parameter Estimation Of Water Quality Model Of River

Water quality parameters are the important date to establish water quality model of riverand the important basis to forecast river water quality changes. Water quality parameters areextremely vital significant to the use of river and environmental planning and environmentalimpact assessment. Now，using optimization algorithm to solve the function optimizationproblem that is on the basis of analyzing the experiment data of water quality of river streamto estimate the water quality parameters is one of main methods.With chaotic optimization algorithm and simplex algorithm and simplex-chaosoptimization algorithm，the function problem for one-dimensional river water quality modeland two-dimensional river water quality model that are nonlinear and difficult is presented inthis paper. Basing on the results of the numerical experiment，the advantages of simplex-chaosoptimization algorithm are analyzed and discussed. The important research work is asfollows：1、Firstly，The advantages and disadvantages of chaos optimization algorithm andsimplex algorithm are analyzed. Then，such measures as adding Simplex algorithm into chaosoptimization algorithm are taken to improve convergence of algorithm. It is simplex-chaosoptimization algorithm that has strong global and local search ability.2、With Simplex-chaos optimization algorithm，the function optimization problem foranalyzing the one-dimensional experiment data of water quality of river stream to estimate thelongitudinal dispersion coefficient and average stream velocity and the other parameter ispresented in this paper. The results of simulation show that the method can be successfullyused in analyzing the one-dimensional experiment data of water quality of river stream toestimate Water quality parameters. The convergence of algorithm can not improved by thelarger chaotic sequence and time of coarse search. The range of initial guess value of aquiferparameters has influence on the convergence speed of the algorithm, but has no effect on thefinal result of computation；Comparing to the simplex algorithm and the chaos optimizationalgorithm，the combined algorithm has the advantage of convergence and the rate ofconvergence. So an effective way for parameter estimation of water quality model of river isprovided. 3、With Simplex-chaos optimization algorithm，the function optimization problem foranalyzing the two-dimensional experiment data of water quality of river stream to estimate thetransverse diffusion coefficient and the mean velocity of a river stream and the location ofcontinuous pollutant injection is presented in this paper. The results of simulation show thatthe method can be successfully used in analyzing the two-dimensional experiment data ofwater quality of river stream to estimate Water quality parameters. The convergence ofalgorithm can not improved by the larger chaotic sequence. The range of initial guess value ofaquifer parameters has influence on the convergence speed of the algorithm, but has no effecton the final result of computation；Comparing to the simplex algorithm and the chaosoptimization algorithm，the combined algorithm has the advantage of convergence and therate of convergence. So an effective way for two-dimensional parameter estimation of waterquality model of river is provided.