title: A cloud model-based approach for water quality assessment.
abstract: Water quality assessment entails essentially a multi-criteria decision-making process accounting for qualitative and quantitative uncertainties and their transformation. Considering uncertainties of randomness and fuzziness in water quality evaluation, a cloud model-based assessment approach is proposed. The cognitive cloud model, derived from information science, can realize the transformation between qualitative concept and quantitative data, based on probability and statistics and fuzzy set theory. When applying the cloud model to practical assessment, three technical issues are considered before the development of a complete cloud model-based approach: (1) bilateral boundary formula with nonlinear boundary regression for parameter estimation, (2) hybrid entropy-analytic hierarchy process technique for calculation of weights, and (3) mean of repeated simulations for determining the degree of final certainty. The cloud model-based approach is tested by evaluating the eutrophication status of 12 typical lakes and reservoirs in China and comparing with other four methods, which are Scoring Index method, Variable Fuzzy Sets method, Hybrid Fuzzy and Optimal model, and Neural Networks method. The proposed approach yields information concerning membership for each water quality status which leads to the final status. The approach is found to be representative of other alternative methods and accurate.
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China. Electronic address: wangdong@nju.edu.cn.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China.
authors.forename: Dengfeng
authors.initials: D
authors.lastname: Liu
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Ding
authors.affiliation: Department of Biological and Agricultural Engineering and Zachry Department of Civil Engineering, Texas A&M University, College Station TX77843, USA.
authors.forename: Vijay P
authors.initials: VP
authors.lastname: Singh
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China.
authors.forename: Yuankun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China.
authors.forename: Xiankui
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210046, China.
authors.forename: Jichun
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Geographic and Oceanographic sciences, Nanjing University, Nanjing, China.
authors.forename: Lachun
authors.initials: L
authors.lastname: Wang
mesh_terms: D005068:Eutrophication; D060106:Lakes; D008962:Models, Theoretical; D060753:Water Quality; D014881:Water Supply
keywords: Analytic hierarchy process; Cloud model; Fuzziness; Information entropy; Multi-criteria decision-making; Randomness