Coordinated replenishments from multiple suppliers with price discounts

In this study we present an integer programming model for determining an optimal inbound consolidation strategy for a purchasing manager who receives items from several suppliers. The model considers multiple suppliers with limited capacity, transportation economies, and quantity discounts. We propose an integrated branch and bound procedure for solving the model. This procedure, applied to a Lagrangean dual at every node of the search tree, combines the subgradient method with a primal heuristic that interact to change the Lagrangean multipliers and tighten the upper and lower bounds. An enhancement to the branch and bound procedure is developed using surrogate constraints, which is found to be beneficial for solving large problems. We report computational results for a variety of problems, with as many as 70,200 variables and 3665 constraints. Computational testing indicates that our procedure is significantly faster than the general purpose integer programming code OSL. A regression analysis is performed to determine the most significant parameters of our model. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 579–598, 1998     

基于测试码并行的同步时序电路故障模拟方法

将组合电路故障模拟的一些加速技术推广到时序电路故障模拟中,提出并实现了一个功能块级的基于测试码并行的同步时序电路故障模拟方法,对部分ISCAS89 Benchmark电路的模拟结果表明,该故障模拟方法有较好的性能.     

Impacts of logistics information on sales: Evidence from Alibaba

Facing fierce competition from rivals, sellers in online marketplaces are eager to improve their sales by delivering items faster and more reliably. Because logistics quality can be known only after a transaction, sellers must identify effective ways to communicate logistics information to consumers. Drawing on the accessibility-diagnosticity framework, we theorize that the sales impacts of logistics information depend on its relative diagnostic value. Using data on 1493 items with 505,785 consumer reviews from an online marketplace, we examine how sales are affected by three information sources for logistics services: online word of mouth (WOM) about logistics, self-reported logistics services, and expected delivery time. We use an instrumental variable method to address the endogeneity issue between sales and WOM. We find that, ceteris paribus, consumers give more weight to WOM about logistics and delivery time when they make purchase decisions but less weight to self-reported logistics service. The effects of logistics information on sales are asymmetric for large and small sellers.     

一种从二维照片反求三维CAD模型的稳健方法

研究了从物体二维照片重构其三维CAD模型的算法。通过物体在不同方位的一组照片 ,选取一定数量的配准点 ,该算法能够计算出照相机的运动参数 ,进而得到物体表面的 3D几何信息及CAD模型。算法充分考虑到了CAD建模的可制造性约束 ,具有精确、稳健的特点 ,在逆向工程建模、计算机视觉、机器人领域有应用前景。     

反渗透系统水的回收率研究

反渗透技术是海水淡化技术的重要组成部分,其中水的回收率设计问题是反渗透系统设计的重要方面。在不影响反渗透膜寿命的前提下,回收率设计最基本的依据是提高整个系统的经济性。在综合分析回收率对系统规模、运行成本以及传质过程三个方面的影响之后,认为提高回收率有利于降低系统规模的建设成本以及运行成本,但是由于膜的传质过程的条件限制,回收率的提高必须限定在一个范围内。     

网格环境下虚拟物流企业模型描述及设计研究

虚拟物流企业设计的目的是获取最佳的物流效能,而最佳物流效能必须通过最佳的组织效能来体现,表现在物流使命与企业架构的匹配。由于网格环境下虚拟物流企业设计较为复杂,基于组织权变理论,首先给出了相关的基本概念,指出虚拟物流企业设计包括工作流程和企业架构设计两个方面,设计过程就是二者的平衡过程。此外,按照在物流资源约束的情况下能够产生最佳组织状态为要求,进行了虚拟物流企业设计,以数学模型表示了设计过程,并明确了求解任务,对虚拟物流企业设计研究由定性分析向定量研究转变进行了初步尝试。     

高压静电场在反渗透预处理中的试验研究

试验研究了高压静电场对反渗透进水的温度、总硬度、电导率、pH值和细菌数的影响,以及高压静电场对反渗透膜通透量和回收率的影响。结果表明,高压静电场可有效改进反渗透预处理。经高压静电场处理后,原水的温度、总硬度、电导率升高,pH值降低。高压静电场的杀菌率随作用时间的增加而增大,随电压的上升而增大。采用高压静电场对反渗透进水进行预处理,可提高反渗透的通透量和回收率。     

自由曲面逆向工程系统的设计

以通用CAD软件AutoCAD为平台,设计开发了自由曲面逆向工程系统,给出了系统总体方案和组成结构,并阐述了系统关键技术及具体实现方法。该设计对基于通用软件平台的曲面CAD系统的开发具有较好的参考意义。     

战区弹药保障敏捷供应链优化模型及实现算法

针对现有的供需矛盾,在分析战区弹药保障供应链管理任务需求的基础上,初步构建了战区弹药保障敏捷供应链管理框架及运行机制,分析了战区弹药保障敏捷供应链的供需协同机制,重点对多级库存优化控制模型、多级弹药配送决策优化模型及实现算法进行了研究,提出了战区弹药保障敏捷供应链建设的具体对策。     

基于遗传算法的虚拟物流联合库存控制研究

针对随机需求条件下的虚拟物流库存控制问题进行了深入研究,提出了一种新的联合库存控制策略——（T,S,s）策略,建立了相应的库存成本模型,并构造遗传算法对模型进行求解。结果分析表明,所提出的（T,S,S）联合库存控制策略是有效的。