Application of genetic algorithms to calibration and verification of QUAL2E

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2004

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Göktaş, Recep Kaya

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The objective of this study is to develop a calibration and verification tool for the QUAL2E Model by using Genetic Algorithms. In the developed optimization model, an objective function that is formulated on the basis of the sum-of-least squares approach aiming at minimizing the difference between the observed and simulated quantities was used. In order to perform simultaneous calibration and verification, verification of the calibrated results was treated as a constraint and inserted into the objective function as a penalty function. The performance of the optimization model was tested for different observation data qualities represented by the synthetic perfect and biased data sets. Although it was not possible to obtain the exact values of the kinetic coefficients for any of the tests performed, the coefficient estimates were successful in reflecting the water quality variable profiles in the river. The results of the tests showed that the performance of the optimization model is generally sensitive to the error in the observed data sets, to the number and location of sampling points, and to the objective function formulation. For the problems that involve multiple water quality variables, a weighting approach used in the objective function formulation resulted in better performances. The optimization model was also applied for a case study. For the same input data, calibration obtained with the genetic algorithm optimization ا simulation was better compared to the trial-and-error approach.

Subject Keywords

Water Pollution.

URI

http://etd.lib.metu.edu.tr/upload/12605591/index.pdf
https://hdl.handle.net/11511/14965

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Graduate School of Natural and Applied Sciences, Thesis

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Application of genetic algorithms for calibration and verification of QUAL2E model Göktaş, Recep Kaya; Aksoy, Ayşegül (null; 2004-07-01) Traditional trial-and-error methods make the calibration and verification of a model considerably time consuming. In addition, it is doubtful whether the best results will be achieved. However, by use of optimization techniques in calibration and verification, the best kinetic parameter estimates can be obtained in a shorter time period. In this study, a genetic algorithm (GA) is used to determine the reaeration coefficients for QUAL2E. An objective function, defined by sum-of-least-squares, is used in orde...
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Citation Formats

R. K. Göktaş, “Application of genetic algorithms to calibration and verification of QUAL2E,” M.S. - Master of Science, Middle East Technical University, 2004.