基于供水安全性的管网管径优化计算改进遗传算法

分析了目前给水管网遗传优化研究仅考虑管网设计方案的经济性而忽略供水安全性的不足,采用罚函数的思想对遗传算法进行了改进,使其能够完成流量分配情况下的管网优化设计.实例计算对比了改进前后的设计方案,改进后设计方案的经济性和供水安全性得到了保证.     

遗传算法实现农村树状供水管网的优化设计

为改善农村树状供水管网的管径设计方案,应用数学建模和最优化理论,提出在确定管网布置方案的基础上,采用整数编码的遗传算法,建立管径组合方案优化模型。以经济性作为目标函数,并结合实例,编制相应计算程序,对某一农村供水管网进行优化设计,与传统设计方案进行对比。结果表明,该优化设计方案在经济性和水力特性都优于传统的设计方案。     

供水管网优化调度决策支持系统开发与应用

供水管网优化调度的目标是运用数据采集、优化决策支持和调度执行等信息化技术,安全可靠地将符合流量、压力和水质要求的水供应给用户.供水管网优化调度决策支持系统包括供水系统的模拟、用水量预测、优化调度决策和运行状态评估.该决策支持系统包括宏观水力模型、微观水力模型、水质模型、考虑供水经济性和水质安全性的多目标优化决策模型.采用单目标优化决策模型与多目标评估体系相结合的方法来考虑供水经济性和水质安全性,开发了供水管网优化调度决策系统,并进行了实践应用.     

丘陵地区常高压生活及消防系统设计方案浅析

列举了丘陵地区生活给水和消防给水设计中可能采用的几种常高压供水方案,根据各方案供水管网和高位水池的不同设置方法,从安全性、可靠性和经济性3个方面探讨了各方案的优缺点,并根据分析结果推荐了最优方案。     

基于MTSP的给水管网定线优化设计

为优化城市给水管网系统设计以减少工程投资、降低给水泵站扬程、保证供水运行安全、方便维护管理,基于MTSP优化理论,结合城市给水管网设计理论和实际工程中管道定线的要求,针对目前城市给水管网管道定线设计中存在的一些问题,提出了一种基于MTSP的管道定线优化设计方法,并尝试将MTSP基本方法应用于给水管网优化设计中。实例计算表明,该方法能够使管道定线总长度最短,从而达到优化设计的目的。     

基于遗传算法的农村供水管网优化设计

农村饮水安全工程的供水管网优化设计,对于节约工程投资、提高工程社会效益具有重要意义。为了对供水管网进行管径优化,从经济性和可靠性出发,以投资成本最低为目标函数,以水力学指标为约束条件,建立管网优化数学模型。运用遗传算法进行模型求解,针对供水管网优化模型的特点,选取自然数编码,建立合适的适应度函数,设置选择、交叉、变异等遗传算子,并选取工程实例进行优化求解,通过与传统方法的计算结果对比,验证了遗传算法用于供水管网优化的实用性。     

L市多水源给水管网供水范围预测研究

城市供水水源的切换和改变可造成市政给水管网出现化学稳定性等问题,使得给水管网的水质无法得到保障,研究和确定多水源市政给水管网的供水范围,对管网水质保障和运行管理具有重大研究意义和应用价值。针对具有多水源供水特点的华北某大型城市的给水管网,研究了南水北调水对给水管网的水量和供水范围等方面的影响,为城市供水监控和调度提供了依据,为确保给水管网供水范围和水质安全保障提供了支持。     

给水管网的优化布置与设计

在以往的灌溉中为了实现加压输水系统的优化设计,经建立了许多模型,这些模型主要用于水分配网络的分析和设计,其中供水管线的布局大部分是固定的,从而限制了供水管线的布局以及系统的其他特性进一步的优化。本文提出了一种混合优化方法,包括两种计算方法,线性规划(LP)和混合整数规划(MIP),前者适合于线路布局优化,后者则更适合于设计优化。将这两种算法组合起来,建立了给水管网优化布置与设计模型,并且应用于给水管网的优化设计,在所有可行路径中寻找成本最小的路径。     

赤峰市平庄城区给水管网改造工程优化设计研究

提出了以总费用在工程运行期的计算终值为目标函数,以最大自由水头限值等为约束条件,以平均日平均时工况进行设计、对多工况进行安全性校核的管网优化设计方法,并用Matlab编程实现。利用该优化设计程序对赤峰市平庄城区给水管网改造工程设计表明,与传统设计方法相比,优化程序在保证管网安全性的同时可降低30%的建设投资。     

遗传算法在水分配系统优化设计中的应用研究

论述了建立遗传算法市政给水管网优化模型的过程 ,阐述了应用遗传算法进行给水管网优化设计的原理、特点 ,并对某小区管网改建工程进行优化求解 ,介绍了遗传算法模型的设计参数选取情况。     

基于整数编码遗传算法的树状灌溉管网优化设计方法

针对树状管网布置中较多依赖设计人员经验的特点,提出了一种基于整数编码遗传算法的树状管网两级优化方法.第一级优化是根据树状管网单点供水的原则,建立了融合工程设计经验的树状管网优化布置整数编码遗传算法模型,克服了传统二进制编码方法易产生不可行解的问题,可快速寻找出一组符合工程实际情况的管网布置方案.第二级优化在确定管网布置方案组的基础上采用整数编码的遗传算法,以投资最小为目标,建立了管径优化模型与算法.编制了灌溉管网两级优化设计Matlab程序,进行了工程实例验证.与单亲遗传算法(SPGA)和管网布置经验设计方法进行了比较,表明本文提出的基于整数编码的管网优化设计方法可方便地将设计经验融合到优化计算过程中.能降低管网优化设汁的复杂性和求解难度,快速有效求解符合工程实际的管网优化方案.     

渠灌区管网输水系统优化设计问题研究

本文通过对农田灌溉管道输水系统的分析，提出了两种管道输水系统辅助优化设计方法，一是借鉴城市给水系统的单目标下管网系统管径优化计算方法，另一个是基于不完全偏好信息的农田管网系统多目标化设计方法，通过一个实际案例的应用表明：本文所提出的方法具有一定的实用性.     

考虑全寿命周期成本的供水管网优化设计

针对城市管网的传统优化设计中仅考虑初始投资而没有考虑运行过程中维修管理成本的问题,提出了基于全寿命周期成本(LCC)的管网优化模型和计算方法。通过对管网建造成本及运行阶段维修管理成本的定量分析,建立了以全寿命周期总费用最低为目标的优化模型,并利用PSO算法对管径进行优化设计。通过实例分析,分别得到两种常用管材的最优管径,并基于寿命周期成本对比分析为管网设计阶段的方案选择和优化设计提供了依据。     

用聚类算法及Hopfield神经网络布置环状管网

为了降低供水管网的工程投资,提出了一种环状给水管网优化设计的方法,把环状管网布置问题用K-Means算法分解成许多小规模的环状问题,对于每一个小规模的环状管网用Hopfiled连续型神经网络求解环状的最短距离,然后把各个基环当成一个点,再用Hopfield神经网络以较大的概率求出最优路径。对某小区58个供水点进行了供水管网实例计算,结果表明:该供水管网的质心间最短距离为2.893 7 km,能量函数为递减状态且最终的能量函数值为1.447,再连接相邻聚类中的最接近的两个点就形成供水管网的环状布置。     

Modelling Intelligent Water Resources Allocation for Multi-users

This study proposes intelligent water resources allocation strategies for multiple users through hybrid artificial intelligence techniques implemented for reservoir operation optimization and water shortage rate estimation. A two-fold scheme is developed for (1) knowledge acquisition through searching input–output patterns of optimal reservoir operation by optimization methods and (2) the inference system through mapping the current input pattern to estimate the water shortage rate by artificial neural networks (ANNs). The Shihmen Reservoir in northern Taiwan is the study case. We first design nine possible water demand conditions by investigating the changes in historical water supply. With the nine designed conditions and 44-year historical 10-day reservoir inflow data collected during the growth season (3 months) of the first paddy crop, we first conduct the optimization search of reservoir operation by using the non-dominated sorting genetic algorithm-II (NSGA-II) in consideration of agricultural and public water demands simultaneously. The simulation method is used as a comparative model to the NSGA-II. Results demonstrate that the NSGA-II can suitably search the optimal water allocation series and obtain much lower seasonal water shortage rates than those of the simulation method. Then seasonal water shortage rates in response to future water demands for both sectors are estimated by using the adaptive network fuzzy inference system (ANFIS). The back-propagation neural network (BPNN) is adopted as a comparative model to the ANFIS. During model construction, future water demands, predicted monthly inflows (or seasonal inflow) of the reservoir in the next coming quarter and historical initial reservoir storages configure the input patterns while the optimal seasonal water shortage rates obtained from the NSGA-II serve as output targets (training targets) for both neural networks. Results indicate that the ANFIS and the BPNN models produce almost equally good performance in estimating water shortage rates, yet the ANFIS model produces even better stability. The reliability of the proposed scheme is further examined by scenario analysis. The scenario analysis indicates that an increase in public water demand or a decrease in agricultural water demand would bring more impacts of water supply on agricultural sectors than public sectors. Similarly, a bigger decrease in inflow amount would obviously bring more influence on agricultural sectors than public one. Consequently, given predicted inflow, decision makers can pre-experience the possible outcomes in response to competing water demands through the estimation models in order to determine adequate water supply as well as preparedness measures, if needed, for drought mitigation.     

District Metered Areas Design Under Different Decision Makers’ Options: Cost Analysis

Water loss is a big challenge for water supply companies worldwide, and the Water Network Partitioning (WNP) is an excellent tool for water loss management–particularly in the current difficult economic and financial conditions. WNP is a recent research line and consists in dividing the water distribution network into smaller zones called District Metered Areas (DMAs) with one (or more, in exceptional cases) supply point, to reduce the network complexity and/or allow pressure management. Since there are several possible future scenarios, such as the water demand and/or the infrastructure degradation forecasts, which may have different impacts on the hydraulic behaviour, in this paper a computational application, based on an optimization model, is proposed to achieve a compromise between robustness required for the DMAs design (using a baseline scenario) and different decision makers’ options (using other scenarios with a lower “probability” of occurrence), to reduce the total cost. The objective function reflects the minimization of the squared deviations between the total cost of the DMAs design and the minimum cost for each scenario forecasted for the project plan, multiplied by the weight or “probability” of occurrence for each of the scenarios. The performance of the computational application is illustrated with a case study, and the results are encouraging.     

泵站加压式树状供水管网优化设计研究

针对传统供水管网优化设计时未考虑整个管网的首末水头约束问题,提出了以管网系统年折算费用最小为目标函数,以水泵扬程和具有标准管径的干、支管管道长度为决策变量的泵站加压式树状供水管网优化设计数学模型。在该模型中,假定水泵扬程已知,将管网优化问题转化成管网投资线性子模型问题,并采用大系统分解-动态聚合方法对该子模型进行求解。研究结果表明,该方法寻优能力强,且计算时间短,计算结果精度较高,为泵站加压式树状供水管网系统优化设计提供了一种可行而有效的新方法。     

Optimization Approach to Designing Water Supply Systems in Non-Coastal Areas Suffering from Water Scarcity

This article presents a novel optimization approach to designing water supply systems in non-coastal areas with water scarcity. In such areas, high water demand caused by population increases and economic development can only be satisfied with seawater supply. Furthermore, most of the non-coastal users are located at long distances and sometimes at altitudes very diverse from the coastline, meaning long pipelines and several pumping stations will be required to effectively supply water. The proposed optimization approach based on a mixed integer nonlinear programming model offers optimal designs of water supply systems from an economic and technical perspective. It determines the location and size of desalination plants and the design of the water transport network including pipelines of specified length and diameter and pumping stations that minimize capital and operational costs of the whole system. A case study in a hyper-arid region of Chile was used to validate the applicability of the proposed model and the results show its aptitude for determining global optimal solutions to real-scale problems.     

Resilience Indexes for Water Distribution Network Design: A Performance Analysis Under Demand Uncertainty

Traditionally, the optimal design of water distrubution networks has been dealt with using single-objective constrained approaches, where the aim is to minimize the network investment cost while maintaining minimum pressure head constraints at all nodes. However, in the last decade some authors have proposed multi-objective approaches which optimize other objectives than network investment cost. In most cases, these objectives have been formulated using the concept of resilience index, which mimics the design aim of providing excess head above the minimum allowable head at the nodes and of designing reliable loops with practicable pipe diameters. Although several authors have proposed different resilience indexes for this pupose, to date there is no empirical study that analyzes the advantages and disadvantages of these proposals. This paper evaluates the performance of a well-known multi-objective evolutionary algorithm, the Strength Pareto Evolutionary Algorithm 2, using three different resilience indexes. The results obtained in two water supply networks under a large number of simulated over-demand scenarios show the advantages and disadvantages of these measures.     

农村供水管网延伸设计与ExceI计算的应用

在农村饮水管网延伸工程中，采取因地制宜的设计方案，可以充分发挥现有供水工程潜力。在满足现行标准和用户要求的前提下，兼顾方案的经济合理，使工程充分发挥效益，是工程设计人员应当研究的问题。该文主要介绍供水管网延伸方案设计的设计依据、基本内容和计算方法，以供类似工程借鉴。