Assessment of River Water Quality Based on Theory of Variable Fuzzy Sets and Fuzzy Binary Comparison Method

There has been an increasing need for the proper evaluation of river water quality in order to safeguard public health and to protect the valuable fresh water resources. In order to overcome the own limitations of the traditional evaluations which can only use a point value instead of an interval for grading standards, on the basis of the fuzzy binary comparison method (FBCM) and the theory of variable fuzzy sets (VFS), an integrated variable fuzzy evaluation model (VFEM) is proposed for the assessment of river water quality in this paper. This model possesses the preciseness of the algorithm and operability in practice, can well solve the grading standards which are interval form. In order to explore and compare the present method with other traditional methods, two cases studies in the Three Gorges and Tseng-Wen River are made. The results show that the proposed VFEM method can convey water cleanliness to certain degree by using the eigenvector of level H, which is much stricter in the superior level, and that it can improve the veracity for the assessment of water quality.     

Introducing Biological Indicators into CCME WQI Using Variable Fuzzy Set Method

Water Resources Management - The biological indicators are rarely used in CCME WQI, for the objective thresholds of most biological indicators are ambiguous. To solve this problem, this study...     

一种模糊变步长自适应谐波检测算法

电力有源滤波器的成功应用依赖于精确的谐波电流检测技术。基于自适应干扰对消理论,提出一种基于模糊变步长推理的最小均方差（LMS）自适应谐波检测算法。通过分析影响LMS自适应谐波算法性能的不利因素,选取均方误差变化量和输入输出信号相关函数作为参量,建立模糊推理系统,自适应地调节算法的步长,实现谐波检测过程中,既能保证较快的动态响应速度和对噪声干扰的抑制,又能保持较高的检测精度,并通过计算机仿真及物理实验验证了该算法的有效性和可行性。     

基于可变模糊集的钢混结构地震损伤评估原理与方法

为提高钢筋混凝土结构地震损伤评估的可靠性,根据陈守煜创建的可变模糊集理论,提出钢筋混凝土结构地震损伤多指标综合评估的可变模糊集模型与方法.经过与集对分析以及同类结构地震损伤综合评估结果进行了比较与分析,表明提出方法的合理性与有效性.     

Flood Control Operations Based on the Theory of Variable Fuzzy Sets

Flood control decisions are often involved with quantitative and qualitative criteria. In this paper, a decision model is presented for flood control operations based on the theory of variable fuzzy sets. Using dual comparison, two models computing relative membership grades with qualitative and quantitative criteria are established, respectively. A method integrating subjective preference and iterative weights is proposed for weight-assessment. First, an initial solution of criteria weights is obtained by using proposed fuzzy optimal iteration model. Then, according to their knowledge related to real time flood operations, operators may modify the initial weights if necessary. When the relative membership grades of alternatives belonging to all rankings are fixed by using multi-criterion variable fuzzy model proposed, the decision alternative is chosen according to the ranking characteristic value computed using a defuzzification equation. The case study of Fengman Reservoir flood operation (in China) is provided to illustrate the application of the proposed method. With the incorporation of operator’s knowledge related to flood operations, the proposed model is flexible and practical.     

Variable Sets and Fuzzy Rating Interval for Water Allocation Options Assessment

Optimal water allocation is an important means of improving water use efficiency. However, since water allocation options are usually characterized by multi-region, multi-principle and multi-criterion factors, decision-makers often have difficulty in making objective decisions using them because the many available water allocation options often make the ratings of the options so close to be ranked. This study present a hierarchy variable sets (VS) model, based on the single-layer variable sets model, for ranking the water allocation options of Jining City, China. The ratings of the options are evaluated using a fuzzy rating interval (FRI) that can overcome homogenization in the ratings. The structure of the model presented in this study is clear with a simple procedure of computation and the result is rational. The case study used illustrates that this model can help decision-makers know the rating of water allocation options partially and overall. The computed result from this model appears more convincing than a previous water allocation approach for the city based on the maximum entropy principle.     

A Fuzzy Variable Least Core Game for Inter-basin Water Resources Allocation Under Uncertainty

In this paper, a new solution concept, called Fuzzy Variable Least Core (FVLC), is developed for fuzzy cooperative games. The FVLC is able to incorporate fuzzy input variables and result in fuzzy benefit shares of players participating in a coalition. This solution concept is used for water and benefit allocation to water users in inter-basin water transfer systems considering the uncertainties associated with their benefit coefficients. In the proposed water allocation methodology, an Integrated Stochastic Dynamic Programming (ISDP) model is developed to obtain the water rights of players and economic water allocation policies. In the next step, the total net fuzzy benefit of the system is reallocated to water users in an equitable and rational way using a FVLC-based model. In this model, a new algorithm is proposed for converting a multilateral cooperative game with fuzzy variables to some fuzzy bilateral cooperative games, which are solved using the FLVC solution concept. The applicability and efficiency of the proposed methodology is examined by applying it to a large scale inter-basin water transfer project in Iran.     

基于改进可变模糊集的延河水质评价

为了合理评价延河水质,基于集对分析法、熵值理论和可变模糊集,构建了水质评价模型。该模型利用可变模糊集的思想,将熵权集对分析法得出的加权平均联系度作为相对差异度,计算水质的最终评价等级。利用该模型对延河5个监测断面的6项水质指标进行了综合评价,结果表明:延河整体水质较好,4个监测断面属于Ⅲ类水体,1个监测断面属于Ⅱ类水体;与其他方法比较,该模型评价结果合理,计算简便,同时还可以比较处于同一水质等级下不同监测断面的污染情况,对研究河流沿程污染和确定河流纳污能力有一定指导意义。     

可变模糊集理论在怀集山洪灾害风险分析中的应用

山洪灾害系统的自然社会属性和指标多维度、模糊性是影响科学评估山洪灾害风险性的主要原因,该文应用灾害系统理论构建南方山区丘陵区山洪灾害风险性评价体系,结合可变模糊集理论模型,选取绥江流域上游怀集县为例,以19个乡镇为评价单元,充分评价各指标危险性和易损性的基础上,利用山洪灾害风险性矩阵得出每个乡镇的风险性等级。     

基于证据理论和可变模糊集的地下水环境风险评价

地下水系统的高维性和不确定性,给地下水环境风险评价带来较多困难,为提高评价的准确性和合理性,实现地下水的科学管理,该文将DS证据理论应用到地下水环境风险评价中,同时利用可变模糊集理论来构造证据理论基本信任分配,实现了客观合理的证据建模,最后利用经典组合原理进行证据组合。以希尼尔水库周边区域为例,地下水环境风险为中等时的信任区间为[0,0.33],似然区间为[0,0.35],不确定大小为0.02,根据判断规则,确定研究区地下水环境风险等级为中等。结果表明,该方法能够较好地融合地下水环境各方面信息以及处理风险评价中的不确定性,实现了地下水环境风险的准确评价。     

一种新的扫描点云自动配准方法

点云数据配准是三维激光数据处理的关键问题,结合曲率进行配准是点云配准非常有效的一种方式。为了提高配准的速度和精度,针对点云曲率和RANSAC算法的特点和应用,分析了两种方法之间的优缺点。研究了一种结合曲率的RANSAC点云配准算法,并利用改进的ICP算法对点云进行精确配准。结果表明:基于曲率的RANSAC算法能够显著提高初始配准的速度和精度,同时改进的ICP算法比原有ICP算法提高了二次配准的速度和精度。     

可变模糊优选理论及在水电站联合调度方案优选中的应用

根据可变模糊集理论，提出可变模糊优选模型与方法，并将其应用于松山、小山水库联合电力调度方案优选，提高了优选决策的可信度。提出的可变模糊优选理论、模型与方法，不仅能用于水电站联合电力调度系统的方案优选，也可应用于其他系统的优选决策。     

A Method for Predicting Long-Term Municipal Water Demands Under Climate Change

Water Resources Management - The accurate forecast of water demand is challenging for water utilities, specifically when considering the implications of climate change. As such, this is the first...     

基于熵权权重的可变模糊理论在大连市地下水水质评价中的应用

针对地下水质评价中存在的多目标性和模糊性特点,采用可变模糊集理论模型进行评价;同时基于指标权重确定的客观性,采用熵权法确定指标权重。以大连市甘井子区2007年-2011年4月的水质调查资料为评价指标集,构筑多目标可变模糊识别模型,用熵权法确定评价指标的权重。评价结果显示,研究区内整体水质处于II～III等级之间,与传统的综合指数法评价结果相对比,将熵权法与可变模糊集理论模型相结合的评价结果比较合理,可为大连市的地下水资源综合利用与管理提供水质依据。     

基于可变模糊集的东莞市水资源可持续利用协调能力评价研究

水资源可持续利用是当今社会关注的热点问题。应用可变模糊集理论中的质量互变定理,研究评价了广东省东莞市不同水平年水资源可持续利用协调能力。结果表明,东莞市水资源可持续利用协调能力从2000年至规划水平年(2030年)有了质的变化与提高。经过与集对评价法评价结果比较,表明本文评价成果的合理性和可靠性。     

模糊数学法在水环境质量评价中的应用——以滦河迁安段为例

在自然科学或社会科学研究中,存在着许多定义不很严格或者说具有模糊性的概念。这里所谓的模糊性,主要是指客观事物的差异在中间过渡中的不分明性。这些通常是本来就属于模糊的概念,为处理这些模糊概念而进行的种种努力,催生了模糊数学。通过对环境质量指标的综合分析,确定了模糊综合评价方法,并将其应用到滦河迁安段水环境质量评价中。结果表明,该方法较传统的方法能提供更多的信息,从而提高了评价结果的科学性。     

Management of Multipurpose Multireservoir Using Fuzzy Interactive Method

In this paper a fuzzy interactive method is proposed for efficient management of multipurpose multireservoir problems. The proposed method provides an option to decision maker (DM) to work in an interactive manner to achieve the conflicting objectives as close to their desired values as is practically feasible. In each iteration, fuzzy membership functions of various objectives are framed and combined into a single objective using the product operator. The single objective nonlinear optimization model thus framed in each iteration is numerically solved using genetic algorithm. The solution provides the values of the objectives which can be actually achieved keeping in view their aspired values as provided by DM. At the end of each iteration, DM has the option to modify the aspired values of one or more objectives keeping in view the results obtained by the algorithm thus far. The algorithm is stopped when DM feels satisfied with the results. The working of the proposed method has been demonstrated on the mathematical model of a realistic multipurpose multireservoir system taken from literature.     

可变模糊评价法在大连市干旱等级评定中的应用

将可变模糊评价模型应用于大连市的干旱等级评价研究中,通过变化指标权重及模型参数得出的大连市2002年干旱状况的级别特征值比较稳定,总体评价结果为重度干旱。结果表明,应用可变模糊评价法评价区域干旱等级的方法可靠,为干旱等级评价提供了一种考虑多因素的综合方法。     

A Multi-Criteria Group Decision Making Methodology Using Interval Type-2 Fuzzy Sets: Application to Water Resources Management

In this paper, a new fuzzy group decision-making methodology which determines and incorporates negotiation powers of decision makers is developed. The proposed method is based on a combination of interval type-2 fuzzy sets and a multi-criteria decision making (MCDM) model, namely TOPSIS. To examine the applicability of the proposed methodology, it is used for finding the best scenario of allocating water and reclaimed wastewater to domestic, agricultural, and industrial water sectors and restoring groundwater quantity and quality in the Varamin region located in Tehran metropolitan area in Iran. The results show that the selected scenario leads to an acceptable groundwater conservation level during a long-term planning horizon. Although the capital cost of this scenario is high, which leads to groundwater restoration during the 34-year planning horizon, it is determined as the best allocation scenario. This scenario also entails the second least pumping cost, due to less water allocation from the groundwater. To evaluate the results of the proposed methodology, they are compared with those obtained using some well-known interval type-2 decision-making approaches including arithmetic-based, TOPSIS-based, and likelihood-based comparison methods. The Spearman correlation coefficient shows that the obtained results generally concur with those of the other methods. It is also concluded that the proposed methodology gives more reasonable results by calculating and considering the negotiation powers of decision makers in an extended TOPSIS-based group decision-making model.

     

Valuation of Drainage Infrastructure Improvement Under Climate Change Using Real Options

Valuation of infrastructure systems under climate change is a challenging issue because climate changes constantly and the influence of climate change is hardly predictable. Serious climate change effects can often be represented by frequent heavy rainfall events and floods. In response, municipalities should improve existing drainage systems to adapt to climate change. However, it is difficult to properly determine when or how to improve these systems because different investment strategies could result in entirely different outcomes. This study proposes a decision framework that can assist municipalities in identifying an optimal infrastructure investment strategy under climate change using a real option approach. The framework considers the uncertainties of climate change based on the volatility of flood damage and estimates the value of wait option for the improvement investment using binomial model. A case study is conducted to verify the proposed framework and assess how different investment strategies affect the value of a drainage system. The results showed that the system improvement with 100 year-flood design in 2019 was the most beneficial among available alternatives.