复杂供水系统优化调度的数学模型与求解方法研究

从供水管网系统整体优化和最小供水费用的角度出发,结合复杂供水系统的生产调度特点,建立了复杂供水系统整体优化调度的数学模型.利用多维编码的遗传算法求解数学模型,对其编码规则、染色体的评估以及遗传操作进行了深入的研究.并给出了详细的求解步骤.采用Matlab软件编写了基于遗传算法的优化调度程序.对某市供水管网系统的生产调度进行了仿真研究.仿真结果表明,应用遗传算法求解管网系统优化调度,可以得到问题的全局最优解,并将调度结果和自来水公司实际生产情况比较,采用优化调度程序进行生产调度可以节省运行费用.     

生鲜类物流配送网络选址-路径优化问题研究

为解决生鲜类物流配送网络选址-路径优化问题,构建了基于服务质量最优化、物流节点建造成本及物流运营服务成本最小化的多目标两层级物流配送网络选址-路径优化问题数学模型,并通过改进遗传算法求解最优方案.对遗传算法中的算子进行优化,解决了传统遗传算法求解过程中无法求得全局最优解以及易陷入局部最优解的现象.通过选取通州区部分区域为背景进行模型验证,得出优化后成本节约了15.71%,说明该模型具有良好的参考价值.     

油田注水系统拓扑布局优化的混合遗传算法

以投资最小为目标函数,建立了注水系统拓扑布局优化数学模型.根据模型特点,将优化问题分为两层,分别采用遗传算法和非线性优化方法进行求解.并对遗传算法的操作过程进行了改进,调整了适应函数,改进了交叉和变异操作,结合了模拟退火算法,在操作过程中使约束条件得到满足,减少了不可行解的产生,使遗传算法的优化性能得到了提高.优化算例说明了该方法的有效性.     

ERW钢管考虑动态库存和交货期的多阶段生产计划优化方法研究北大核心

多阶段生产计划在钢管制造企业中起着重要的作用,在学术研究中也具有一定的复杂性.由于企业库存与生产及计划密切相关、订单交货期对生产和库存又具有很强的关联性,在研究中将库存的动态性和交货期纳入多阶段生产计划中,试图寻求找到优化的生产计划的方法.根据ERW直缝焊管企业的生产特点,对其生产计划的制订方式进行了优化.针对多阶段生产计划建立了考虑库存和交货期的提前/拖期惩罚数学模型,通过遗传算法对其进行求解及优化,从而得到生产计划的较优解.     

ERW钢管考虑动态库存和交货期的多阶段生产计划优化方法研究

多阶段生产计划在钢管制造企业中起着重要的作用,在学术研究中也具有一定的复杂性.由于企业库存与生产及计划密切相关、订单交货期对生产和库存又具有很强的关联性,在研究中将库存的动态性和交货期纳入多阶段生产计划中,试图寻求找到优化的生产计划的方法.根据ERW直缝焊管企业的生产特点,对其生产计划的制订方式进行了优化.针对多阶段生产计划建立了考虑库存和交货期的提前/拖期惩罚数学模型,通过遗传算法对其进行求解及优化,从而得到生产计划的较优解.     

基于VAR风险控制的LOG-最优资产组合模型

在证券收益率服从正态分布的假设下,提出了基于V AR风险控制下的单周期LOG-最优资产组合问题,建立了数学模型,证明了最优解的存在性与唯一性,设计了求解该模型的新兴智能优化算法——遗传算法并进行了实例计算与分析.     

基于圆形件排样问题的遗传算法研究

排样性问题是一类优化求解问题,在遗传算法求解过程中,若所用的算法是不收敛的,则无法得到最优解.给出了一种混合式遗传算法,并证明了算法是完全收敛的,能够得到全局最优解.     

基于改进NSGA-Ⅱ算法的次同步附加阻尼控制器的优化设计

针对直驱永磁同步风电机组中出现的次同步振荡问题,建立引入次同步阻尼控制器(sub-synchronous oscillation damping controller,SSDC)后的直驱风电机组完整数学模型,在此基础上,以振荡模态特征值实部和阻尼比为目标函数建立了SSDC参数多目标优化模型.针对改进非支配解排序遗传算法(improved nondominated sorting genetic algorithm,NSGA-Ⅱ)在参数优化时种群多样性较差的问题,对其选择策略进行了改进,然后将改进后的NSGA-Ⅱ算法引入到SSDC参数优化设计中,利用空间评价方法对解集进行评价,结果表明采用改进算法所获得的Pareto最优解分布更加均匀.最后通过特征值分析和仿真验证,进一步证实了文章所优化设计得到的SSDC对发生在直驱风电机组的次同步振荡抑制具有显著效果.     

有时间窗装卸问题的多策略分组编码遗传算法

根据有时间窗装卸问题(PDPTW)的数学模型,设计了多策略分组编码遗传算法,将禁忌思想用于产生可行解的启发式插入算法之中,对计算实例进行了求解,结果表明,此算法可以有效求得有时间窗装卸问题的近似最优解.     

遗传算法与蚂蚁算法的融合在带时间窗的车辆路径问题中的应用

对带时间窗的车辆路径问题(VRPTW)的求解分为两个过程,先由遗传算法求解出初步的可行解,由此生成信息素初始分布,而后采用蚂蚁算法找出问题的最优解或近似最优解.通过具体算例,从数值计算上探索了遗传算法和蚂蚁算法融合后的优化能力,获得了满意的效果.     

A Lagrangian decomposition approach for the pump scheduling problem in water networks

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.     

生物芯片无阀压电微流体泵流场数值研究

采用浅水波模型把浅薄形微泵的三维流动近似为二维厚度平均流动, 并采用有限元/压强修正法求解水平流场和计算微泵流量A·D2数值结果表明:1) 在微泵扩散管的过流截面上流速有时间相位差和回流现象．2) 微泵在吸流末期泵腔出现对称旋涡．3) 微流体泵的定向净流量来自于Navier-Stokes方程的非线性．还给出微泵流量与扩散管长宽比、厚宽比、液体粘度和进出口反压差的定量关系．通过参数优化可以使微泵得到尽可能大的流量．     

基于相关系数指标筛选法的油田集输泵机组用能评价体系研究

针对不同油田泵机组的用能情况不同而导致的泵机组评价指标种类和权重产生差异的问题,提出一种确定指标的方法,根据西北油田泵机组的实际工况,采用相关系数法筛选评价指标,再结合主成分分析法与灰色关联法综合评价泵机组的用能情况.结果表明筛选出了5个评价指标,按权重大小排序依次为泵机组效率、节流损失率、外输负载率、集输单耗、功率因...     

The numerical modelling of DC electromagnetic pump and brake flow

The interaction of an externally imposed magnetic and electric field on the laminar flow of a conducting fluid in a channel is studied using computational techniques. The Navier-Stokes equations and the equations describing the electromagnetic field are solved simultaneously in a single control volume-type computational fluid dynamic code, in a moderate Hartmann number and interaction parameter regime. The flow considered is two-dimensional, with an imposed magnetic field acting in the third dimension over the central region of the channel and decaying exponentially in the remainder. A pair of electrodes placed at right angles to the magnetic field exercises control over the resultant Lorentz force and hence the velocity profile shape. This configuration has application in direct-current electromagnetic pumps or, conversely, electromagnetic brakes. The initial parabolic flow profile acquires an M-shape / W-shape mode in the magnetic field fringe regions, corresponding to a pump / brake. A novel coupled procedure is described to model magnetohydrodynamic phenomena and is used to explore the effects of the Reynolds number, interaction parameter, and applied voltage on the pump / brake configuration.     

Scheme choice for optimal allocation of water resources based on fuzzy language evaluation and the generalized induced ordered weighted averaging operator

The choice of scheme for the optimal allocation of water resource (OAW R) is a fuzzy multiple-attribution decision that is determined using information from many figures and fuzzy language regarding several evaluated factors, such as investment, daily water supplying, fee of contaminated water disposal, water conservation, and the development of economy.     

均匀设计配制水泥基超细粉煤灰灌浆材料的研究

唐明，王继相．均匀设计配制水泥基超细粉煤灰灌浆材料的研究．数理统计与管理，１９９８，１７（４），１０～１９．唐明，王继相．均匀设计配制水泥基超细粉煤灰灌浆材料的研究．数理统计与管理，１９９８，１７（４），１０～１９．本研究用三因子多水平的均匀设计方法，研究了水泥基超细粉煤灰灌浆材料的性能，探索了组成材料对保水性和强度特性的影响规律，建立了相应的数学模型，优化求解对进一步开发该类材料，满足各种工程要求，提供了重要依据     

Optimal control of heat-pump/heat-storage systems with time-of-day energy price incentive

The maximum principle of optimal control theory is applied to the problem of optimizing the operation of a heat pump, when a storage capability is available and the electrical utility offers time-of-day price incentives in order to help level its diurnal load profile. The cost functional for optimal control is the monetary cost of purchased electrical energy. A bilinear model for the heat pump is assumed. When the ambient temperature is cyclic over the 24-hour period of the price pattern, periodic boundary conditions apply and the closed extremal trajectories are found to be unique and easily determined with a one-dimensional numerical search. These extremals have simple characteristics and reveal plausible strategies for minimizing the cost of purchased energy. They are potentially implementable with a simple, micro-processor-based controller.This work was supported in part by Energy, Mines, and Resources, Canada, Research Agreement No. 89.     

多层次模糊综合评判法在宗地估价中的应用

宗地估价中存在着大量的不确定性和模糊性 ,本文以九江市为例应用多层次模糊综合评判法对宗地价格进行评估 ,着重探讨了应用的步骤和数学模型 ,提出它是一种新的土地估价应用方法。     

基于DEA的污染物排放配额分配方法研究

文章首先提出一种典型的通过分配污染物排放配额改善环境状况的环境管理问题,在分析问题特性的基础上,提出一种基于DEA的污染物排放配额的分配方法,该方法将污染物排放配额作为一种决策变量,在求解系统整体效率的同时得到各决策单元的配额分配量。然后采用淮河流域造纸厂的实例说明了该方法的合理性和可行性。由于本文提出的方法考虑环境管理实际情况,在分配配额时能有效提高整个系统的环境效率,能为环境管理政策的制定提供有效的参考信息,具有很大的应用价值.