遗传算法优化神经网络用于大气污染预报

    Optimizing BP Networks by Means of Genetic Algorithms in Air Pollution Prediction

    • 摘要: 大气污染预报可以对大气污染提出警示,保护人体健康和生活环境.为了对北京市PM10的质量浓度进行预报,建立了用于大气污染预报的遗传神经网络模型,该模型运用遗传算法优化神经网络的权值和阈值,有效提高了网络的收敛性和预报准确率.用改进后的神经网络对北京市PM10的质量浓度进行了模拟,并将模型模拟结果与美国第3代空气质量模型Models-3(CMAQ)的数值模拟结果进行了比较.实验结果表明:遗传神经网络模型和数值模型的模拟结果的平均相对误差分别为0.21和0.26,用于空气污染物质量浓度短期预报时,神经网络模型的预测精度与数值模型的预测精度相当.对于没有条件开展空气污染数值预报的城市或地区,神经网络是一种有效的替代方法.

       

      Abstract: Air pollution forecasting provides early warning before air pollution issue occurs,thus protects human health and living environment.A neural network model optimized by genetic algorithm was developed in order to predict PM10 concentrations in Beijing.The genetic algorithm was used to optimize the initial weights and threshold of the BP neural network in simulation.Astringency of network and accuracy of prediction were effectively improved.The improved network and Models-3 Community Multi-scale Air Quality(CMAQ) modeling system were both applied in the prediction of short-term PM10 concentration in autumn 2002 in Beijing.Resultsshowed good prediction capability of both models,and the mean relative errors were separately 0.21 and 0.26.When applied in short-term air pollution forecasting,neural network is of similar prediction accuracy compared with CMAQ.It is an effective alternate method for air pollution forecasting in areas where mathematical model on air pollution can't be widely applied.

       

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