共查询到20条相似文献,搜索用时 15 毫秒
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基于排队理论的最优生产线设计 总被引:5,自引:0,他引:5
本研究了在工厂生产线的设计过程中,如何安排生产线上的机器、工人、甚至物料运输设备,以提高生产率的水平,降低生产过程中的原料和半成品存量的最优化问题,用排队论方法建立了该问题的数学模型,并解出了结果和进行经济评价。 相似文献
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通过运用光学成像原理和空间解析几何上向量和平面的一些知识,将立体中的几何问题转化为平面几何问题来解决,对车灯线光源进行优化设计,建立模型.通过数学软件计算线光源长度,使线光源的功率最小.对得到的线光源长度,在有标尺的坐标系中画出测试屏上反射光的亮区,最后本文讨论该设计规范的合理性. 相似文献
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Optimal Control of a Stochastic Assembly Production Line 总被引:1,自引:0,他引:1
The system under consideration comprises n workstations in parallel and one assembly workstation. The workstations are either reliable or unreliable and the product demand is random. The n different type parts are processed first in the parallel workstations and then are joined in the assembly workstation. By minimizing the expected discounted cost, it is shown that the optimal control policy is of the bang–bang type and can be described by a set of switching manifolds. The structural properties of the optimal policy, such as monotonicity and asymptotic behavior, are investigated. These structural properties are very useful to find the optimal policy in large-size systems. Three numerical examples are given to demonstrate the results. 相似文献
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In this paper we address the problem of locating a mobile response unit when demand is distributed according to a random variable on a line. Properties are proven which reduce the problem to locating a non-mobile facility, transforming the original optimization problem into an one-dimensional convex program.In the special case of a discrete demand (a simple probability measure), an algorithm which runs in expected linear time is proposed. 相似文献
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运作实践中,供应商不仅会给予零售商延期付款待遇以刺激其订购量,同时也会为信用期内零售商的应付账款设置上限值(即商业信用额度),从而规避零售商的应付账款对其造成的资金机会成本和违约风险。鉴于此,本文基于商业信用额度构建了零售商关于易腐品的订购决策模型。通过分析零售商资金机会成本的不同形式,可以得到零售商关于易腐品五种不同的成本函数表达式。结合数学证明可以得到零售商五种目标函数的性质,以及在商业信用额度条款下零售商最优的订购决策。算例表明供应商可以通过设置一个合理的商业信用额度条款将零售商的订购量和信用期内的应付账款控制在一个合适范围。同时商业信用额度条款有助于缓解供应商的营运资金压力,但会在一定程度上增加零售商的运营成本。 相似文献
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G. E. Fruchter A. Fligler R. S. Winer 《Journal of Optimization Theory and Applications》2006,131(2):227-244
In this marketing-oriented era where manufacturers maximize profits through customer satisfaction, there is an increasing need to design a product line rather than a single product. By offering a product line, the manufacturer can customize his or her products to the needs of a variety of segments in order to maximize profits by satisfying more customers than a single product would. When the amount of data on customer preferences or possible product configurations is large and no analytical relations can be established, the problem of an optimal product line design becomes very difficult and there are no traditional methods to solve it. In this paper, we show that the usage of genetic algorithms, a mathematical heuristics mimicking the process of biological evolution, can solve efficiently the problem. Special domain operators were developed to help the genetic algorithm mitigate cannibalization and enhance the algorithm’s local search abilities. Using manufacturer’s profits as the criteria for fitness in evaluating chromosomes, the usage of domain specific operators was found to be highly beneficial with better final results. Also, we have hybridized the genetic algorithm with a linear programming postprocessing step to fine tune the prices of products in the product line. Attacking the core difficulty of cannibalization in the algorithm, the operators introduced in this work are unique. 相似文献
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最优公交线路选择问题的数学模型及算法 总被引:1,自引:0,他引:1
公交线路选择问题是城市公共交通信息查询的重要内容,本文建立了满足不同公交线路查询者需求的最优线路选择模型并给出了相应的算法。首先通过引入各条公交线路直达最短距离矩阵构造了公交网络直达关系图(直达矩阵),在直达关系图(直达矩阵)上,利用修改了的最短路算法,即可求得最优换乘路线。根据出行者的不同需求,通过在直达关系图上定义不同的权系数,可以分别求得换乘次数最少的公交出行线路、经过站点最少的公交出行线路;通过修改最短路算法,可以求得出行耗时最少的线路及出行费用最低的线路,另外,本模型还可以综合考虑出行者的需求情况,求得出行者满意度最大的出行路线。 相似文献
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<正>2017年7月14日,以"工业应用数学在中国及其他亚太地区:回顾与展望"为主题的为期一天的研讨会在上海交通大学陈瑞球楼204室成功举办。作为"第十四届国际自由边界问题理论及应用"会议的嵌入会议,本次研讨会旨在探讨如何深化中国学术界与工业界在数学领域的合作,同时也特别回顾了中国工业应用数学工作坊(math-for-industry)的创始人谭永基教授为中国工业应用数学的发展所做出的 相似文献
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Generalized balanced tournament packings (GBTPs) extend the concept of generalized balanced tournament designs introduced by Lamken and Vanstone (1989). In this paper, we establish the connection between GBTPs and a class of codes called equitable symbol weight codes (ESWCs). The latter were recently demonstrated to optimize the performance against narrowband noise in a general coded modulation scheme for power line communications. By constructing classes of GBTPs, we establish infinite families of optimal ESWCs with code lengths greater than alphabet size and whose narrowband noise error‐correcting capability to code length ratios do not diminish to zero as the length grows. 相似文献
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陈军飞 《数学的实践与认识》2004,34(7):56-60
调水工程为解决区域间水资源分布不均衡问题提供了一种有效途径 .调水工程线路方案的优选问题涉及社会、经济、环境、技术等多方面的因素 ,是一个复杂的多目标决策问题 .本文建立了其评价指标体系 ,应用 AHP法和信息熵方法相结合确定评价指标权重 ,建立了调水工程线路方案优选的灰色系统评价模型 .算例显示方法的有效性 . 相似文献
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徐云 《数学的实践与认识》2006,36(7):262-266
证券市场的将来是未知的.投资者只能依据所掌握的信息作出相应的投资策略.事实上,信息对投资组合的影响是各种各样的.考虑多个时期有信息作用的投资组合策略问题,建立了有信息影响的最优投资组合的凸规划模型,得到了模型的最优解及其极限,并给出了一些投资组合受信息作用的情形. 相似文献
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Giorgio Davide Di; Lunardi Alessandra; Schnaubelt Roland 《Proceedings London Mathematical Society》2005,91(3):703-737
We study the operator Lu(t):= u'(t) A(t) u(t) on Lp(R; X) for sectorial operators A(t), with t R, on a Banachspace X that are asymptotically hyperbolic, satisfy the AcquistapaceTerreniconditions, and have the property of maximal Lp-regularity.We establish optimal regularity on the time interval R showingthat L is closed on its minimal domain. We further give conditionsfor ensuring that L is a semi-Fredholm operator. The Fredholmproperty is shown to persist under A(t)-bounded perturbations,provided they are compact or have small A(t)-bounds. We applyour results to parabolic systems and to generalized OrnsteinUhlenbeckoperators. 2000 Mathematics Subject Classification 35K20, 35K90,47A53. 相似文献
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The problem of finding the optimal tapering of a free (nonsupported) javelin is described and solved. For the optimal javelin, the lowest mode of vibration has the highest possible frequency. With this tapering inner damping will lead to the cessation of the vibration at the fastest possible rate. The javelin is modeled as a beam of uniform material. The differential equations governing the vibration and the tapering of the beam are derived. These equations have a difficult singularity at the tips of the beam. A procedure using a similarity solution, as in [ 1 ], is used to solve this singular system, and the solution is found. The maximal frequency is found to be almost five times larger than the frequency of a cylindrical rod. 相似文献
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Phil Howlett 《Annals of Operations Research》2000,98(1-4):65-87
We consider the problem of determining an optimal driving strategy in a train control problem with a generalised equation of motion. We assume that the journey must be completed within a given time and seek a strategy that minimises fuel consumption. On the one hand we consider the case where continuous control can be used and on the other hand we consider the case where only discrete control is available. We pay particular attention to a unified development of the two cases. For the continuous control problem we use the Pontryagin principle to find necessary conditions on an optimal strategy and show that these conditions yield key equations that determine the optimal switching points. In the discrete control problem, which is the typical situation with diesel-electric locomotives, we show that for each fixed control sequence the cost of fuel can be minimised by finding the optimal switching times. The corresponding strategies are called strategies of optimal type and in this case we use the Kuhn–Tucker equations to find key equations that determine the optimal switching times. We note that the strategies of optimal type can be used to approximate as closely as we please the optimal strategy obtained using continuous control and we present two new derivations of the key equations. We illustrate our general remarks by reference to a typical train control problem. 相似文献