基于模糊证据理论的水质环境状态估计

从信息融合的角度，将湖泊水质环境多因子综合评价过程看成是一个多源数据融合处理与状态估计过程，提出基于相似度的模糊证据理论，评估湖泊水体富营养状况．通过引入模糊集合的相似度，一方面，确定模糊焦元的权值，并修改证据模型；另一方面，确定模糊焦元对类别焦元的信任函数的贡献因子，并建立状态估计与评价模型，使其能够处理湖泊水体富营养状况的突发性带来的某些焦点元素的显著变化问题．对太湖水体富营养状况的评估做了实证分析，并与营养状态指数评价方法进行比较，结果一致，说明基于相似度的模糊证据理论的估计方法可行．

Water environmental quality assessment based on fuzzy evidence theory

The process of assessing lake water quality, as viewed from the perspective of data fusion, is a process involving multi-source data fusion and state estimation. This paper proposes using fuzzy-evidence theory to assess the eutrophication of lake water based on degrees of similarity.. On one hand, by introducing degrees of similarity with fuzzy sets, the weights of fuzzy focal elements are determined and the evidence model is modified. On the other hand, by using the degree of similarity with fuzzy sets, the contribution factors of fuzzy focal elements to the belief functions of focal elements of the class are determined, and models of state estimation and assessment are established which can handle problems due to obvious changes in some focal elements induced by abrupt changes of lake water eutrophication. This proposed method was tested by water eutrophication assessment of Taihu lake in China. Results were analyzed and compared with those obtained by the trophic status index method, indicating that the proposed method based on degree of similarity is feasible for water quality assessment.