基于分形维数权重的南水北调东线源头水质评价研究

水质评价问题的实质是对水质现状和各评价因素间的函数关系的逼近,是一种复杂的非线性问题.针对水质评价指标之间的非线性关系,提出了基于分形维数权重的水质评价方法.为有效地评估南水北调东线源头的水质现状,首先选取影响水质评价的7个主要因素,根据标准等级水体分类标准,采用在等级标准中随机内插的方法,得到50个标准等级样本,并根据样本综合评估值与经验等级之间的关系建立分形插值评价模型;最后,以长江江都市芒稻河断面2001—2008年的年平均水质监测数据为例对模型进行验证.结果表明,该方法可以通过分段函数得到每个样本的具体得分值,因而具有较高的分类精度,为水质评价提供了一种较好的新方法.

Water quality assessment of the east route of south-to-north water diversion based on fractal dimension weight

Water quality evaluation is essentially a function approximation problem between water quality status and various evaluation factors, therefore is a complex nonlinear problem. The water quality evaluation method based on fractal dimension weight is developed according to the nonlinear relationship of water quality evaluation index. In order to evaluate the water quality condition of the east route of South-to-North Water Diversion, seven key factors are chosen to construct the model. According to the classification standard of water quality, fifty standard samples are produced by the way of stochastic interpolation on the basis of classification standard. The fractal interpolation evaluation model is established according to the relationship between the value of comprehensive evaluation of the samples and the experience level. Finally, a case study using the method is implemented according to monitoring data of Mangdaohe section in Yangtze River from 2001 to 2008. The result shows that the method can be obtained through specific scores value of each sample by piecewise function, therefore it has high classification accuracy and provides a better method for water quality assessment.