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1.
对水资源进行优化配置是解决社会经济发展与水资源可用量紧张的有效手段.采用区域水质—水量耦合水资源优化配置模型,以吉林省辽源市2010年数据为基准,对2020年水资源配置进行优化预测.研究结果表明,辽源市在规划期内"三生"用水结构由89:10:1调整到81:18:1.其中生产用水中第一产业用水量下降2.17%,第二产业用水总量下降2.78%.第三产业用水量提升4.29%,同时降低了水污染的排放.优化方案可有效降低辽源市水资源消耗与水环境污染,为水资源的可持续利用提供了有效的技术支持.  相似文献   

2.
针对用水结构这一成分数据,采用球坐标变换,灰色模型与指数平滑模型相组合,Aitchison距离最小确定权重,构建了河北省用水结构组合预测模型.研究表明,构建的组合预测模型能够较好的反映用水结构的变化特征,拟合精度较单一预测模型有明显改善.应用该模型对河北省用水结构进行预测,可为区域水资源管理和高效利用提供科学参考依据.  相似文献   

3.
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.  相似文献   

4.
首先运用主成分分析方法对北京市经济指标数据进行降维处理,然后基于降维后的数据拟合部分线性模型.将拟合后的模型对2008年北京市税收进行预测,所得结果优于常用的逐步线性回归分析方法的预测结果.  相似文献   

5.
多元成分数据的对数衬度偏最小二乘通径分析模型   总被引:2,自引:1,他引:1  
本文研究多元成分数据的路径关联关系的建模问题,提出多元成分数据的对数衬度PLS通径分析模型.将中心化对数比变换与PLS通径分析方法相结合建立模型,其主要优势在于:①PLS通径分析模型对数据没有严格的分布假设要求,特别适于成分数据这类分布复杂的数据建模;②成分数据中心化对数比变换后的变量完全多重相关,PLS方法能够有效解决这一问题;③PLS通径分析模型特别适于多元成分数据这类具有层次关系的数据结构的建模,通过结构模型揭示多元成分数据之间的整体性路径关联关系,通过测量模型揭示成分数据与其成分分量之间的构成关系.更重要的是,本文的方法研究遵循成分数据所特有的代数基本理论,推导出模型的成分数据对数衬度隐变量的表达形式,从理论上证明了该建模方法的科学合理性.最后,将本方法用于北京市三次产业的投资结构、GDP结构、就业结构的路径关联关系的分析中,通过实证研究验证模型的可行性和应用价值.  相似文献   

6.
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.  相似文献   

7.
成分数据是一类具有复杂性质的数据,特别是它的预测研究在管理学与经济学中占有很重要的地位.组合预测则是近年来在预测中应用比较广泛的一种方法,它能够充分利用单预测模型的信息,提高预测精度,增强预测的稳定性,且具有较高的适应能力.本文首次把组合预测方法应用到成分数据的预测分析中,基于成分数据的一些基本性质,利用组合预测得到了较好的预测结果.  相似文献   

8.
利用灰色预测理论,根据北京市1999~2006年道路交通事故的统计资料,建立了北京市道路交通事故发生次数的灰色GM(1,1)预测模型,并根据实际数据的特点,对所建立的模型进行了改进.经证实,改进后的GM(1,1)模型预测精度高,预测结果与实际相符.GM(1,1)模型的预测结果可为北京市道路交通管理部门制定预防交通事故的措施提供重要的数据支持和理论依据,这对加强北京市的道路交通管理、改善北京市的道路交通安全状况将具有一定的现实意义.  相似文献   

9.
山口商品结构是指-国对外贸易中各商品组成部分在贸易总体中比例关系,它可以反映国家经济发展水平和商品的国际市场竞争力.本文运用球坐标变换的成分数据预测方法,研究我国出口商品结构的动态变化规律,对中国出口商品结构的发展趋势进行分析与预测.研究表明,近年来我国的出口商品结构正快速由劳动密集型商品向资本密集型和技术密集型商品过渡,初级产品的比重不断下降,高新技术产品的比重迅速提高.本论文研究结果为进一步分析我国产业结构的调整方向、优化我国的出口商品结构提供参考信息.  相似文献   

10.
将主成分分析和支持向量机回归相结合,以广西5、6月区域平均日降水量作为预报对象,进行区域日降水量预测研究.首先,整理分析大量的T213数值预报产品信息数据进行主成分分析,得到主成分数据序列;其次,根据主成分数据序列建立训练集训练支持向量机,并利用遗传算法优化参数;最后,输入支持向量机所需数据,得到主成分预测结果,建立广西日降水预报模型.实例计算结果表明,支持向量机回归模型比逐步回归模型有更好的预测能力.  相似文献   

11.
Dynamic pricing has become a common form of electricity tariff, where the price of electricity varies in real time based on the realized electricity supply and demand. Hence, optimizing industrial operations to benefit from periods with low electricity prices is vital to maximizing the benefits of dynamic pricing. In the case of water networks, energy consumed by pumping is a substantial cost for water utilities, and optimizing pump schedules to accommodate for the changing price of energy while ensuring a continuous supply of water is essential. In this paper, a Mixed-Integer Non-linear Programming (MINLP) formulation of the optimal pump scheduling problem is presented. Due to the non-linearities, the typical size of water networks, and the discretization of the planning horizon, the problem is not solvable within reasonable time using standard optimization software. We present a Lagrangian decomposition approach that exploits the structure of the problem leading to smaller problems that are solved independently. The Lagrangian decomposition is coupled with a simulation-based, improved limited discrepancy search algorithm that is capable of finding high quality feasible solutions. The proposed approach finds solutions with guaranteed upper and lower bounds. These solutions are compared to those found by a mixed-integer linear programming approach, which uses a piecewise-linearization of the non-linear constraints to find a global optimal solution of the relaxation. Numerical testing is conducted on two real water networks and the results illustrate the significant costs savings due to optimizing pump schedules.  相似文献   

12.
以铀材料腐蚀理论、Henry定律、渗透与泄漏理论为基础,建立了铀包装容器的含水量理论计算方法,分析了铀包装容器在不同状态下的水分含量及其变化规律.结果表明,水分的泄漏量、渗透量和泄漏渗透处两端的压力差成正比,渗透与材料本身的渗透系数有关;有机材料吸附水不仅与材料自身的饱和含水率有关,而且和有机材料所处的水分分压有关;铀水反应消耗水量与铀材料质量、表面积及时间成正比.水分的渗透、环境湿度及有机材料吸附水是影响铀包装容器中水分的主要因素.  相似文献   

13.
The purpose of this paper is to study the periodic arc-routing problem when the arcs of a network behave as customers, and sufficient material is delivered so that each achieves its desired inventory level. Therefore, routing and inventory decisions are made simultaneously. Applications include dust suppression in open-pit mines or forest roads and plant watering along sidewalks or street medians. A truck periodically sprays water along the edges of a network. The humidity reaches a desired level and is then consumed over time until water is delivered again. The quantity of water delivered can be fixed or variable; we consider both scenarios and propose a mathematical model for each. Results are reported to validate the model. The contribution of this paper is the first mathematical model that combines inventory and routing decisions in the arc-routing domain.  相似文献   

14.

A structure and implementation principles of a photon computer are proposed. Its functioning is based on effects of the interaction between coherent light wave systems generated by a laser source. The performance of photon computers, consumed energy, and physical sizes are estimated. These estimates show possible advantages of photon computers over electronic ones.

  相似文献   

15.
Conclusion Relative to its major function, pumping, the heart should be considered as an integral musculovascular organ. It is precisely this integration in the structural and functional sense which permits the heart not only to perform its pump function as a converter of chemical energy supplied by the blood into mechanical flow energy but also to combine the supply and conversion of energy into a single cycle, produce the hydrodynamics of cardiac output in definite fashion, and introduce a correction into the filling phase according to current arterial pressure as the most dynamic index of systemic hemodynamics. The breakdown of the structure of the cardiac pump into elements differing in their functional significance permits us to delineate at least three channels for the utilization of energy supplied to the heart and consumed in the major pumping function: the mechanical work performed by the lower part of the cardiac muscle that is displaced into the ventricular space, the energy consumed on maintaining the systolic pressure of the myocardial fibers which form the relatively immobile upper and side walls of the heart, and the energy consumed on maintaining the high tone of the muscular walls of the coronary arteries and arterioles which form the hydraulic frame of the heart.A representation of the heart which includes muscular and vascular components, in our view, is the basic prerequisite for the development of mathematical models for the cardiac pump based on energy balance equations and suitable for solving the problems posed by clinical medicine in regard to auxiliary blood circulation.Translated from Mekhanika Kompozitnykh Materialov, No. 4, pp. 699–702, July–August, 1980.  相似文献   

16.
This paper considers a new class of network flows, called dynamic generative network flows in which, the flow commodity is dynamically generated at a source node and dynamically consumed at a sink node and the arc-flow bounds are time dependent. Then the maximum dynamic flow problem in such networks for a pre-specified time horizon T is defined and mathematically formulated in both arc flow and path flow presentations. By exploiting the special structure of the problem, an efficient algorithm is developed to solve the general form of the dynamic problem as a minimum cost static flow problem.  相似文献   

17.
Feedback supply chain is a key structure in the supply chain system, and the development of feedback supply chain for biogas biomass energy is one of the important ways of the rural ecological civilization construction. Presently, the efficiency problem of biogas supply chain in rural China has been restricting the development of biogas biomass energy business. This article, on the basis of combination of regulation parameters, describes the dynamic changes in the system, using differential equations integrated with simulation to reveal the rules of regulation parameters to investigate the efficiency problem in the biogas supply chain. First of all, on the basis of the actual situation, the flow level and flow rate system structure model and simulation equation set are established for the biogas energy feedback supply chain from a scale livestock farm to peasant households; On the basis of the differentiability of the simulation equation a third order inhomogeneous differential equation with constant coefficients containing regulative parameters is established for the quantity of biogas stored in the feedback supply chain. A theorem and its corollaries are established for the operating efficiency of supply chain to reveal the change law of the quantity of biogas, the quantity of biogas consumed daily by peasant households and its standard-reaching rate as well as other variables.  相似文献   

18.
产业结构与水资源相关分析理论及其实证   总被引:17,自引:0,他引:17  
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。  相似文献   

19.
This article deals with optimal spatio-temporal development of capital and labour stocks in a production economy with spatial extension. Current stocks of capital and labour are used to produce a commodity, partly invested to replace worn capital, partly consumed. These stocks can be relocated in space, but relocation uses up some of the inputs themselves. Under these constraints the objective is to maximize a utility measure derived from per capita consumption and aggregated over individuals, space and time.The necessary conditions for optimum are derived as Euler equations of a continuous variational problem. They concern choice of production scale and technology, rate of reinvestment, and optimal flows of labour and produced commodities through space. The Lagrangian multipliers of the constraints are interpreted as imputed wages and commodity prices.The whole structure of optimum depends on these imputed wages and prices, and their solution can be derived from a pair of dependent non-linear partial differential equations. The spatial flow portrait at each moment depends on the time parameter and on the parameters of the model (net reproduction and capital depreciation rates). It can undergo sudden changes described by the elliptic and hyperbolic umbilic catastrophes.  相似文献   

20.
The transport of substances across cell membranes may be the most fundamental activity of living things. When the substance transported is any ion there can be a change in the concentration of hydrogen ions on the two sides of the membrane. These hydrogen ion concentration changes are not caused by fluxes of hydrogen ions although fluxes of hydrogen ions may sometimes be involved. The reason for the apparent contradiction is quite simple. All aqueous systems are subject to two constraints: (1) to maintain the charge balance, the sum of the cationic charges must equal the sum of the anionic charges and (2) the product of the molar concentration of H+ and the molar concentration of OH, established and maintained by the association and the dissociation of water, remains always at 10–14. As a consequence the concentrations of H+ and OH are determined uniquely by differences between the concentrations of the other cations and anions, with [H+] and [OH] being dependent variables. Hydrogen ions and hydroxyl ions can be produced or consumed in local reactions whereas any strong ions such as Cl, Mg2+, or K+ can be neither produced nor consumed in biological reactions. Further consequences of these truisms are outlined here in terms of the chemistry of the kinds of reactions which can lead to pH changes.  相似文献   

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