组合赋权模糊熵-灰云聚类二维河流健康评价

Two dimensional river health evaluation based on fuzzy entropy-gray cloud clustering and combination weighting method

为弥补传统灰色聚类法中白化函数对隶属度的量化取值过于固定,忽视随机性信息而无法兼顾河流健康评价体系中的模糊性、不确定因素的不足,引入云模型理论,实现模糊性、随机性信息的定性定量转换,构造基于正态云模型的灰云聚类白化函数.权重确定采用最小偏差组合赋权法,可实现各指标相对重要度的合理界定;为解决指标等级归属不一致时的综合评判问题,引入模糊熵作为第二维评价系统,反映河流健康复杂度,从而实现模糊熵-灰云聚类二维河流健康评价.选取太湖流域几条河流进行评价,评价结果对比单一等级评价方法更直观全面.结果表明：所提出的改进方法可对健康等级归属不一致、不确定性作出合理解释,从宏观健康等级与微观复杂度两层面有效揭示河流健康状况细节,为河流健康评价研究提供可行思路.

To overcome the problem that quantification for membership function in the traditional grey clustering method is too fixed,ignoring random information without taking into account the fuzzy and uncertain factors in the river health evaluation system,the cloud model theory was introduced to realize the conversion between qualitative and quantitative information of fuzziness and randomness,thus,the gray cloud clustering whiten function was established based on the normal cloud model.The index weight was determined through combination weighting method based on minimum deviation principle to reasonably define the relative importance between indexes.Furthermore,to figure out the comprehensive evaluation problem that where the level each index belonging to was inconsistent,the fuzzy entropy theory was introduced as the second dimension evaluation system to reflect the complexity of river health.Overall,the two dimensional river health evaluation based on fuzzy entropy and gray cloud clustering was realized and several rivers in the Taihu Lake basin were selected as the evaluation cases.The evaluation results were more intuitional and comprehensive than other methods using single health level to evaluate.Results indicate that the proposed method can provide reasonable explanation for the index inconsistency and uncertainty of health level,which can effectively describe the river health details from two aspects of health level and complexity.Therefore,the evaluation model is verified to provide a feasible and efficient thought for river health assessment.