基于log-logistic概率分布的近海水质组合预测方法研究  

Study on Integrated Prediction Model of Coastal Water Quality Based on Log-logistic Probability Distribution

作　　者：牛志广[1] 张宏伟[1] 辛志伟[2] 

机构地区：[1]天津大学环境科学与工程学院,天津300072 [2]天津市环境保护局,天津300191

出　　处：《系统工程理论与实践》2006年第5期111-116,共6页Systems Engineering-Theory & Practice

基　　金：天津市科技发展计划(033113811);天津市自然科学基金(043606511);天津大学青年教师基金(985200540)

摘　　要：通过多种预测方法的综合运用,提出一种依据环境监测数据的近海水质组合预测方法,力求在降低计算难度的同时,提高预测精度.首先,依据入海水体的情况,采用BP神经网络法对近海水质进行因果型预测,预测平均误差为26.46%;其次,采用傅立叶8次级数对近海水质历史数据进行拟合,并将其延伸对近海水质进行类比型预测,平均误差为38.33%;最后,确定近海水质数据符合log-logistic的概率密度函数,提出将上述两种预测结果的概率密度作为其组合权重的近海水质组合预测方法,平均误差降低为21.20%.应用表明,该组合预测方法避免了机理性研究对众多基础数据的要求,原理简单、实用性强,能够为环境管理提供决策支持.Through the using of different prediction methods, a new integrated prediction model for coastal water quality based on monitoring data was proposed, which aimed to reducing calculation difficulty and prediction errors. Firstly, the cause-effect prediction was taken using BP NN （ back-propagation neural network）, whose inputs were data about the incoming water. The average prediction error of this method was 26.46 %. Secondly, the monitoring data serial of each monitoring point was fitted by Fourier serial, after which the fitted Fourier serial was also used for prediction and the error was 38.33%. Finally, the integrated prediction was taken based on the above two prediction results, whose weights were calculated by its log-logistic probability density and average prediction error was reduced to 21.20% . Through application it could be found that the extreme demand on basic data in mechanism studies could be avoided, which made the method in this paper simple, practicable and could be the decision support for environmental management.

关 键 词：近海 水质 组合预测 log-logistic概率分布 

分 类 号：X3[环境科学与工程—环境工程]