北京市用水结构预测分析

城市化进程给城市用水量与用水结构带来了显著的改变,通过研究北京市用水结构的发展趋势,为区域水资源的科学管理与合理配置提供依据.用水结构主要包括农业用水、工业用水、生活用水和生态用水四类,可将历年用水量作为一系列按照时间顺序排列的成分数据,运用球坐标变换的成分数据预测方法,研究了北京市用水量结构的动态规律,并对未来两年的用水量结构作出预测.     

基于模糊综合评价模型的赣州市水资源承载力动态评价

水资源的合理利用对区域经济社会发展以及促进人与自然的可持续发展至关重要.通过构建模糊综合评价模型,选取年降水量、人均水资源量、水资源利用率、万元GDP用水量、万元工业增加值用水量、农田灌溉亩均用水量、生态用水等7个指标对赣州市2009-2018年水资源承载力进行动态评价研究,分析近十年该地区水资源承载力演变趋势以及影响该地区水资源承载力的主要因素.结果表明:1)赣州市水资源综合承载力较高,水资源还有进一步开发利用的空间;2)2009-2018年赣州市水资源承载力整体上呈上升趋势,但上升幅度不大,呈现小幅波动状态,其中GDP、工业用水量以及农业用水量对赣州市水资源承载力的具有显著影响;3)赣州市水资源较丰富,但由于时空分配不均,水资源配置体系也不够完善,且供水的基础设施比较薄弱,所以水资源的开发利用程度比较低.该研究结果可为当地水资源的可持续利用提供决策参考和依据.     

基于粒子群算法的水稻用水的优化配置

本文旨在实现水稻用水资源的优化配置.早稻、一季稻和晚稻等不同类型水稻的用水,以及同一类型的水稻在不同的生长阶段,均存在着用水优化配置的问题.粒子群优化算法比较容易操作,在计算方面具有效率和精度高的优点,可以应用于水稻用水的优化配置模型的求解.以衡阳县高炉村的水稻用水优化配置为具体算例,验证了算法的可行性.     

贵州省水资源变化及开发利用时空分布特征研究

开展贵州省水资源的时空变化差异,可为当地水资源可持续利用提供依据和参考,促使贵州省水资源、生态环境与社会经济协调发展.通基于贵州省2012-2018年的水文、社会、经济等数据,运用泰尔系数、变异系数、空间分级分类等数学方法,从人均水资源量,地均水资源量和水资源开发利用率多个角度揭示贵州省水资源开发利用的时空分布特征及区域差异.结果表明:1) 2012-2018年贵州省东部、东南部、北部地区水资源量较多,而西部、西南部地区水资源量较小.各地级市人均和地均水资源量呈波动起伏的变化大.2)从贵州省2012-2018年用水指标的泰尔系数、变异系数来看,除了农业用水量泰尔系数波动幅度大之外,其他用水量变化不明显.3) 1999-2018年期间,农业用水在贵州省各地级市中的比重较大,一直以来长占主导地位,2012年城镇公共用水出现了明显的波动情况,上升幅度较大.4)贵州省各地级市2012-2018年水资源开发利用率总体上表现出稳定上升的变化趋势,整体水资源开发利用率低于30%.经济发展、城市化经济差异、工农业发展状况、资源条件等是影响水资源开发利用的重要因素,合理协调各个因素相关关系,可为未来贵州...     

可变模糊集理论在江西省水资源承载力评价中的应用

结合江西省2009年自然、社会和经济以及水资源资料,选取降水量、灌溉率、水资源开发利用程度、生活用水定额、人均供水量、万元GDP用水量、生态环境用水率、缺水率作为评价指标,应用可变模糊评价模型对江西省11个市的水资源承载力进行了评价研究.能够科学、合理地确定样本指标对各级指标标准区间的相对隶属度、相对隶属函数,并且能够通过变化模型及其参数,合理地确定出样本的评价等级,提高对样本等级评价的可信度.最后与模糊识别理论计算出的结果进行比较,评价等级基本保持一致.研究结果表明,江西省整体水资源承载力等级为1~2级,水资源开发利用已具有一定规模,部分区域水资源开发潜力较大.     

可交易的水权安排对农户灌溉用水行为的影响——基于农户行为模型的理论分析

水资源用水总量控制与定额管理相结合的制度已成为我国水法的重要制度.但目前我国用水定额管理工作仅强调了通过用水定额管理并结合价格机制实行超定额累进加价征收水资源费和水费的办法来激励人们节约用水,没有明确界定这些用水定额的产权归属问题及用水定额的可交易性问题.将通过建立农户灌溉用水行为模型,利用边际分析方法分析可交易的农业用水定额对农户行为的影响.分析表明,当水权可交易时,水价政策与水市场的存在将激励农户节约用水,减少灌溉用水量.农户将通过采用灌溉效率更高的灌溉技术来节约单位面积的灌溉用水量或通过改变种植面积或种植结构的方式来节约总的灌溉用水量,而种植面积或种植结构的变化将进一步促进农地流转市场的发展.但水权交易成本的增加可能削弱出售水权农户的节水积极性并影响农户参与水市场的积极性从而影响水市场的形成与发展.     

我国工业需水量预测模型研究及应用

工业需水量预测是水资源管理和规划的重要内容之一.首先判断了工业用水量的主要影响因素.数据分析表明,工业用水量与工业增加值之间存在明显的倒"U"型关系,与工业用水重复利用率之间存在很强的负相关关系.然后建立了以工业增加值,工业增加值的平方及工业用水重复利用率为解释变量的多元回归模型.在情景假定下,应用模型预测2014年、2015年我国的工业需水量.预测结果为2014年工业需水量为1416.4亿立方米,比2013年增加0.5%.2015年工业需水量为1418.6亿立方米,比2013年增加0.6%.     

中考复习中的“变式”价值

1 问题提出 先看一道2012年广州市中考数学题: 某城市居民用水实行阶梯收费,每户每月用水量如果未超过20吨,按每吨1.9元收费;每户每月用水量如果超过20吨,未超过的部分仍按每吨1.9元收费,超过部分则按每吨2.8元收费.设某户每月用水量为x吨,应收水费为y元. (1)分别写出每月用水量未超过20吨和超过20吨时,y与x的函数关系式.     

北京市水资源利用建模分析研究

以北京市为例,分别应用无偏灰色GM(1,1)模型和非线性模型对北京市2001年-2010年的用水量进行了建模,利用最优化方法,计算了上述两种模型的最优组合模型,通过三种模型分别计算了北京市2001年-2010年的水资源利用量,并与北京市2001年-2010年的实际用水量进行了对比,采用精度检验方法,分别对无偏灰色模型,非线性模型和组合模型进行了精度检验,计算结果表明,加权组合模型是三种模型中精度最高的模型,通过组合模型计算得出的用水量值与实际水资源利用量相比误差最小,由此得出,可以利用组合模型对北京市未来的水资源利用量进行预测,预测结果可为其他相关研究提供参考.     

免疫粒子群优化算法在农业水资源优化配置中的应用

求解农业水资源优化配置模型(高维非线性优化模型),较常采用大系统分解协调原理和动态规划相结合的方法,这样减少了变量个数,便于优化求解,但协调的过程需要多次从低阶模型中返回信息,而且对于每层的寻优求解过程存在难以克服的矛盾.采用标准的粒子群优化算法则优化程度不易保证并容易陷入局部最优,优化结果对初始种群依赖性较强.因此应用免疫进化算法对标准粒子群优化算法进行改进并应用于灌区农业水资源优化配置模型的求解.算例分析表明,免疫粒子群算法为求解高维复杂的优化配置问题提供了新思路.     

基于二层规划的流域水资源交易决策模型

对于一个流域而言,解决水资源短缺及污染最为有效的经济手段是建立以流域统一管理为基础,兼顾水权交易和排污权交易的市场体系.在水交易市场运作过程中存在着流域管理机构和具体用户之间的利益矛盾,为此本文构建了以流域管理机构作为流域水资源系统整体计划、控制和协调中心的上层决策者,各用户作为具有相对自主权的下层决策者的决策管理机制,并利用二层规划方法对流域水资源的交易进行建模研究,期望实现流域水资源的最优分配.最后,应用算例验证了模型及求解方法的可行性和有效性.     

Water resources planning based on complex system dynamics: A case study of Tianjin city

A complex system dynamic (SD) model focusing on water resources, termed as TianjinSD, is developed for the integrated and scientific management of the water resources of Tianjin, which contains information feedback that governs interactions in the system and is capable of synthesizing component-level knowledge into system behavior simulation at an integrated level, thus presenting reasonable predictive results for policy-making on water resources allocation and management. As for the Tianjin city, interactions among 96 components for 12 years are explored and four planning alternatives are chosen, one of which is based on the conventional mode assuming that the existing pattern of human activities will be prevailed, while the others are alternative planning designs based on the interaction of local authorities and planning researchers. Optimal mode is therefore obtained according to different scenarios when compared the simulation results for evaluation of different decisions and dynamic consequences.     

产业结构与水资源相关分析理论及其实证

由于不同的产业部门和生活方式对水资源的消耗是不同的，经济的不同发展格局会在很大程度上改变水的需求，因此对宏观经济系统和水资源系统同时进行动态分析，才能揭示它们之间的内在联系。本以北京市为实例，利用相关分析理论和方法，系统地研究了产业结构调整与水资源需求变化之间的关系，同时通过计算，指出北京市产业结构与用水量之间存在着高度相关关系，发展第三产业，调整第二产业是解决首都水资源紧缺的重要方法。     

基于主成分分析的水质评价方法

主成分分析法能够在保证原始数据信息损失最小的情况下,以少数的综合变量取代原有的多维变量,使数据结构大为简化,并且客观地确定变量权数,避免了主观随意性.应用主成分分析法对长春市地面水环境进行评价,且与其它评价方法相比较,结果显示主成分分析法更客观且指导性较强,是一种行之有效的水质评价方法.通过主成分分析进行水质评价,可为水资源规划、利用、开发和环境系统优化提供更为客观的参考依据.     

A fuzzy inventory model without shortages using triangular fuzzy number

In business and industry it becomes very difficult for a manager to take concrete decision regarding inventory, as the data available to him are not always certain. Because uncertainty arises in demand, set-up resources & capacity constraints of an inventory planning system, it could be more justified to consider these factors in an elastic form. Therefore, with these uncertain data, fuzziness can be applied and the problem of inventory can be controlled. In the present paper, an inventory model without shortage has been considered in a fuzzy environment, by considering real-life data from the LPG store of Banasthali University. Triangular fuzzy numbers have been used to consider the ordering and holding costs. For defuzzification, signed-distance method has been used to compute the optimum order quantity.     

基于主成分分析的需水量预测模型研究

用水是整个水资源系统中的一个重要环节,需水预测是制定水资源规划、管理以及国民经济计划的基础和依据.提出了基于主成分分析法分析的需水量预测模型,试图能探讨需水定额与经济社会各影响关系响应,以郑州市为例对2010年、2020年和2030年的工业、农业和生活的需水量进行了预测,并与郑州市水资源规划的预测结果进行了比较,分析及比较结果表明:该模型预测结果比规划结果偏低,2010年、2020年和2030年平水年分别需水162295×104m3、179966×104m3和194696×104m3,需水结构的变化基本反映了郑州市产业结构调整和社会经济良性发展的趋势.     

Production Scheduling with Multiple Criteria Objectives

For many years the L.P. transportation technique has been proved to be an effective means of tackling production planning in the food industry. As the plan approaches implementation however, the objectives can change from ones of cost minimisation to those of utilising existing company resources. This paper describes the modifications which are required to the formulation in order to satisfy these new objectives, and is based on a study of production scheduling undertaken for a large food manufacturer.     

Water resources in unified accounting for natural resources

The aim of this paper is to incorporate the water resources into the unified resources accounting based on scientific objectivity so as to present a brief portrait of the significance of water for the resource conversion and management of the national-scale society in a systems ecological perspective. The water resources in sustaining the human society are incorporated into the total exergy budget and national-scale social exergy accounting framework, not only by accounting the conventionally usable water flowing through society regarding seawater as reference environment, but also by introducing the evaporation exergy of freshwater as essential investment from the hydrological cycle. A case study of the Chinese society 2001–2005 is conducted, with the societal system broken down into seven sectors, i.e., extraction, conversion, agriculture, industry, transportation, tertiary and households sectors, to explore the resource utilization structure based on the proposed accounting method. Typical results for China 2005 showed that the total net input of the societal conventional resource exergy was 87.9 EJ, of which 75.4 EJ was from mineral resources and 22.6 EJ from other resources, while the water resource exergy input amounted to 105.1 EJ, which contributed 54.5% of the total resources exergy investment to the total society. Finally, the exergetic resource use intensities (RUIs) for six sectors were calculated, with the results that RUIs of agriculture and conversion sectors are much higher than those derived from conventional resource accounting.     

A decision tool for optimal irrigated crop planning and water resources sustainability

In the present study, the conjunctive use policies of surface and ground water resources are developed for minimizing water shortage in an irrigation district subject to constraints on groundwater withdrawals and crop planning capacities. An integrated soil water balance algorithm is coupled to a non-linear optimization model in order to carry out water allocation planning in complex deficit agricultural water resources systems based on an economic efficiency criterion. Various options of conjunctive use water resources along with current and proposed cropping patterns have been explored by Koohdasht Irrigation District (KID), a semi-arid region in I.R. Iran. The analysis provides various scenarios, which can help managers in decision-making for the optimum allocation plans of water resources within the irrigation area. The results reveal that the proposed model, as a decision tool for optimal irrigated crop planning and water resources sustainability, may be used for maximizing the overall net benefits and global water productivity of an irrigation district considering an allowable annual recharge of groundwater. Findings indicate the importance of the conjunctive water management modeling, which can be easily implemented and would enhance the overall benefits from cropping activities in the study area.     

Multiobjective Linear Model Optimize Water Distribution in Mexican Valley

A multiobjective optimization model is developed for the Mexican Valley to find optimal water distribution scenarios for three water users: agriculture, industry and domestic. Surface, ground, treated and imported water supplies are considered. The model with three objectives and 15 constraints was solved by the distance based method with distance l ₁. Three scenarios and two priorities were analyzed for this problem. In Scenario 1, actual aquifer overexploitation and treated water usage were allowed. Scenario 2 considered the reduction of water extraction from the aquifer to one billion m³ (59%), and increased usage of treated water in agriculture by 50%. In Scenario 3, we assume aquifer sustainability and increasing surface water usage by 857 mill m³/year. The last scenario is the best because, in the worst case, the farmers can cover one season and also some crops in the second season, and the domestic users can get more water than their minimum demand. In addition, aquifer sustainability is implemented, which can reduce aquifer overexploitation. The waste water disposal problem, which is critical in this area, also can be reduced.