极小化加权总完工时间的分批排序问题

本文讨论了分批排序中极小化加权总完工时间的两个问题.就所有工件的加工时间都相等这一特殊情况,分别给出两个算法,并证明了算法的最优性.     

季节性需求产品的预订销售模型

本文研究了采用两阶段定价策略的季节性需求产品的预订销售问题,其中需求受价格影响并随时间季节性变化,允许取消预订且取消预订费随时间变化.通过对模型的分析,给出了最优解的解析式,最后给出了数值例子,并对主要参数进行了灵敏度分析.     

一类求解约束全局优化问题的填充函数

本文构造了一类求解约束全局优化问题的填充函数,并在适当的假设条件下, 证明了其填充性质及其它分析性质; 此外,根据所构造的填充函数设计了相应的算法, 并给出了数值试验结果, 以说明所构造填充函数方法的有效性.     

工件有尺寸且分两批到达的单机分批排序

本文首次研究了工件有尺寸大小,有到达时间的分批排序问题,这里目标函数为工件的极大完工时间．就所有工件有两个到达时间的且工件加工时间与尺寸大小一致的排序给出算法,并证明了算法的性能比不超过33/14．     

最小化加权误工工件数的多代理平行分批排序

考虑多代理的平行分批排序,不同代理的工件不能放在同一批中加工,目标函数是最小化加权误工工件数.本文考虑两种模型,证明了甚至当所有工件具有单位权时,这两个模型都是强NP困难的.但当代理数给定时,这两个问题都可在拟多项式时间解决,并且当工件具有单位权时,可在多项式时间解决.进一步证明当代理数固定时,两个问题都有FPTAS算法.     

销售问题的分解算法

销售问题:一家商店经销某种商品,有一个容量为w件的仓库,每月初订货一次,订货提前时间为0,第i月的订货单价为a_i,售货单价为b_i,a_i>0,b_i>0,i=1,…,n;第1月订货前已有存货c件;0≤c≤w,w>0;第n月末不须存货,试制订出一个从第1月到第n月的购销方案,使总收益最大。为讨论方便,如果某个月售货就假定把当月的总售货量在月底一次售完。     

一类特殊凸对策的求解方法

针对支付函数对每个自变量都是严格凸函数的一类特殊凸对策问题，提出了求解局中人双方最优策略的一种简单方法。     

用罚函数求解线性双层规划的全局优化方法

用罚函数法将线性双层规划转化为带罚函数子项的双线性规划问题，由于其全局最优解可在约束域的极点上找到，利用对偶理论给出了一种求解该双线性规划的方法，并证明当罚因子大于某一正数时，双线性规划的解就是原线性双层规划的全局最优解。     

极小化最大完工时间的单机分批加工问题

本文考虑极小化最大完工时间的单机分批加工问题．设有n个工件和一台批加工机器．每个工件有一个释放时间和一个加工时间．批加工机器可以同时加工b(b相似文献   

集群搜索-规避对抗对策的概念和性质

讨论了集群搜索-规避对抗对策的概念,明确了对策双方的策略与最优策略的定义,给出了对策的支付函数及对策的解,讨论了最优策略及对策值的存在性。     

一类最优组合批处理码

Ishai等人首先提出了批处理码的概念,Peterson等人从纯组合的观点定义了(n,N,k,m)-组合批处理码:即是一个n元集和它的m个子集组成的集合系统,对于整数尼,满足任意k个元素都能从每个子集中至多读取1个元素(可以一般化为t个元素)来取得,此时m个子集中元素的总数为N.对给定的参数n,k,m,确定N的最小值N(n,k,m)是该问题研究的中心内容,它不仅具有理论意义,而且有着重要的使用价值.到目前为止,除了一些极特殊的参数以外,当k≥5,m+3≤n(m k-2)时,N(n,k,m)的值还没有被确定.本文给出了N(m+3,5,m)=m+11(m≥7),N(9,5,6)=18,N(m+3,6,m)=m+13(m≥8),N(10,6,7)=21.得到的结果部分解决了:Peterson等人提出的未解决问题.     

An Optimal Mixed Batch Shipment Policy for Multiple Items in a Single-Supplier Multiple-Retailer Integrated System

This study addresses mixed batch shipment policy with common replenishment cycle for multiple items in a single-supplier multiple-retailer integrated system. The supplier produces multiple items on a single facility under a common replenishment cycle and delivers products to retailer utilizing a mixed batch shipment policy. The objective is to determine the optimal replenishment cycle, the number of shipments, and the structure of mixed shipment, all of which minimize the integrated total cost per unit time. The single-item isolation model is constructed first, and the single-item isolation model is then integrated into the single-item integration model. Moreover, the single-item integration model is integrated into the multi-item integration model. The minimum total cost model is transformed into a maximum replenishment cycle model to optimize the structure of the mixed batch shipment. The replenishment cycle division method is then developed to obtain the optimal solutions to the subject problem. Examples are presented to illustrate the procedures involved in the replenishment cycle division method.     

Economic Batch Quantities for Manufactured Parts

The fundamental assumption in the classical Economic Batch Quantity model is that the products which are manufactured by a company have demands which are independent of each other. In an assembly operation, the demand for the components is mainly due to the demand for the parent assembly and hence the classical model is not applicable. In such a situation, requirements planning methodology may be successfully employed. A case study is described in this paper in which a number of factors besides set-up and stock-holding costs are considered. The results have proved to be of considerable benefit to the company.     

Optimal Batch Sizes for a Two-Stage Production System

A 2-stage production model is considered in which items are processed in batches at both stages. Items processed at Stage 1 are stored until needed at Stage 2 and new batches are processed at Stage 1 only when necessary to meet second stage demand. It is shown that in an optimal policy the batch size at the first stage must be an integer multiple of second stage batch size. This can be used in an analytical derivation of the optimum batch sizes.     

Optimal Decision for Selling an Illiquid Stock

This paper is concerned with liquidation of an illiquid stock. The stock price follows a fluid model which is dictated by the rates of selling and buying over time. The objective is to maximize the expected overall return. The method of constrained viscosity solution is used to characterize the dynamics governing the optimal reward function and the associated boundary conditions. Numerical examples are given to illustrate the results.     

存货影响销售率的无形变质物品库存控制模型

为解决存储过程中价值易发生贬值的一类无形变质物品最优订货问题,建立了一种存货影响销售率的无形变质物品库存控制模型.针对零售商期初订货批量的不同水平,以库存总成本最小为优化目标,分别求得了无形变质物品库存总成本函数.鉴于这些函数中的主要部分属于超越函数,函数性质不易探明,最优解难以直接求得.为此,从严格的数学证明出发,深入探讨了函数最优解的存在性和惟一性,为进一步研究提供了理论基础.最后,通过数值算例,系统分析了模型参数对库存总成本、期初订货批量和库存更新周期的影响,并结合实际对其结果的合理性进行了解释说明.     

Optimal Edge-Colourings for a Class of Planar Multigraphs

  Let G be a multigraph containing no minor isomorphic to or (where denotes without one of its edges). We show that the chromatic index of G is given by , where is the maximum valency of G and is defined as

单一生产商单一零售商供应链中最优生产与运输协调策略研究

在供应链背景下,易腐品的生产运输协调决策具有非常重要的现实意义,也是近几年研究的热点问题。本文在前人研究的基础上,通过引入安全库存并将其作为决策变量,拓展了易腐品生产运输协调决策模型;并证明了最佳运输批量序列一定是单调不减的及第一次补货时一定要清空库存;进而证明了最佳运输批量序列的具体形式并提出了一种运输策略。本文的目标是在新的运输策略下最大化单一生产商单一零售商供应链系统的利润,找到最佳运输批量、最佳生产时间以及运输次数。最后,本文进行了算例分析,用来验证本文提出的模型。     

Optimal Decentralized Regulation for a Class of Flow Networks

Optimal decentralized regulation is considered for a class of flow networks where, at each intersection, a selective switch links a single input–output pair at anytime. It is shown that a special case of the above is an urban traffic network with signalized intersection. We analyze first the traffic situation of an isolated intersection based on the point-queuing model of traffic and model the intersection dynamics via two states: either unsaturated or saturated. According to the different traffic characteristics of the two states, we design two intersection controllers and then combine them into one hybrid controller. This hybrid controller is extended to the multi-intersection case and becomes a decentralized hybrid intersection controller. A simulation study is given in this paper and it shows that this decentralized hybrid intersection control method can improve the performance of traffic networks and by extension the performance of more general flow networks.