Multidimensional Connection Cloud Model Coupled with Improved CRITIC Method for Evaluation of Eutrophic Water

Daguo Wu,Juliang Jin,Mingwu Wang,Jiahui Yan,Guangyao Chen,Fengqiang Shen,Krishna Murari Pandey

doi:10.1155/2022/4753261

Abstract

The degree of eutrophication in the water environment is deepening. For the appropriate treatment of eutrophication, it is essential to evaluate it accurately. However, the evaluation of eutrophication has not been well solved because it is full of uncertainty. Herein, a multidimensional connection cloud model, combined with the improved CRITIC (Criteria Importance Through Inter-criteria Correlation) method, was put forward here to assess water eutrophication and depict the randomness, ambiguity, and interaction of evaluation factors. First, an improved CRITIC was adopted to determine indicator weight so that the correlation among different indicators and more information were depicted. Secondly, a multidimensional connection cloud was simulated to characterize fuzzy indicators and ambiguous classification boundary values according to classification criteria. Next, the connection degree was calculated relative to the evaluation standard. The eutrophication grade was specified under the “maximum connection degree” principle. At last, the effectiveness and practicality of the model proposed here were affirmed by two cases and comparisons with supplementary methods. The results suggest that the proposed model can avoid shortcomings of the original CRITIC method and cloud model, and make the assessment result more realistic.

Highlights

Eutrophication is becoming more severe because many untreated wastewaters enter the water directly in nature [1]
Judge the eutrophication grade of the sample Figure 1: Evaluation process of eutrophication carried out by multidimensional connection cloud model coupled with improved CRITIC
Note: A represents the multidimensional connection cloud model based on traditional CRITIC method; B represents the one-dimensional connection cloud model combined with game theory; C represents the comprehensive connection cloud model while the analytic hierarchy process calculates the weight; D denotes the improved fuzzy evaluation method; E represents the projection and pursuit model; F represents the multidimensional connection cloud model

Summary

Introduction

Eutrophication is becoming more severe because many untreated wastewaters enter the water directly in nature [1]. E single factor evaluation method with a few indicators could not fully reflect the level of water eutrophication [16]. Because experts have rich experience in this field, the subjective weighting method effectively reflects the importance of different standards It leads to reasonable judgments based on the actual situation. E CRITIC method assigns the weight in the light of the contrast intensity characterizing each separate factor and the conflict between two factors [44] It can consider the trend of a single indicator and analyze the correlation among different indicators [45]. A new multidimensional connection cloud model combined with an improved CRITIC was provided for water eutrophication evaluation. Numerical characteristics are obtained through the “identity-discrepancy-contrary” of set pair analysis, which simultaneously characterizes the certainty and uncertainty relationship among different indicators and standards. Two cases containing 54 sets of samples and comparisons with supplementary methods were executed to prove the rationality of the proposed method

Methodology

Case Study

Findings

II III