网格紧致化存储系统的分区设计和ABC分类分析

基于网格的紧致化存储系统可以密集地存储货物,在充分利用存储空间的同时还能较好地保证货物的可达性。现有研究集中在取货时间最小化算法设计等基本问题上,但如何更好地利用这些研究结果改善系统设计的研究还未展开。本文应用现有算法研究成果分析网格紧致化存储系统的不同分区布局的绩效,构建了一个开放的排队网络,由基于取货时间的分区仓储子系统、仓储分区内基于货物需求频率的ABC分类子系统两个部分组成。以网格面积10×10为实例的计算实验表明,与随机存储分配规则相比,对基于网格的存储系统进行分区所实现的期望取货时间可以减少53.8%;在此基础上再进行ABC分类可以进一步改善系统性能最多可以达到46.5%,同时还可以大幅度减少因排队所产生的等待时间。     

Flying-V型仓储布局货位分配优化方法研究

Flying-V是一种典型的非传统布局方式,根据其布局方式的特性,针对仓储货位分配优化问题,以货物出入库效率最高和货物存放的重心最低为优化目标,建立了货位分配多目标优化模型,并采用自适应策略的遗传算法(GA),以及粒子群算法(PSO)进行求解。根据货位分配的优化特点,在GA算法的选择、交叉和变异环节均采用自适应策略, 同时采用惯性权重线性递减的方法设计了PSO算法,有效地解决了两种算法收敛速度慢和易“早熟”的问题,提高了算法的寻优性能。为了更好地表现两种优化求解算法的有效性和优越性,结合具体的货位分配实例利用MATLAB软件编程实现。通过对比分析优化结果表明,PSO算法在收敛速度和优化效果方面相比于自适应GA算法更具有优势,更加合适于解决Flying-V型仓储布局货位分配优化问题。     

云仓模式下相关利益者演化博弈分析

随着物流经济的快速发展,共享物流为提高仓储管理效率提供了新的途径.通过分析共享仓储中的云仓模式,针对云仓平台使用中的信用监管问题,构建了该模式下云仓平台、仓储供给方以及仓储需求方三方的演化博弈模型,运用演化博弈理论分析了各参与方策略选择的演化稳定性,并使用Matlab进行了数值仿真,分析不同参数变化对演化结果的影响.研...     

基于物料周转率与需求相关性的储位分配优化策略与算法

优化储位分配策略是加快订单拣选速度和提高仓储效率的重要前提。在实际出入库操作中,物料可能具有一定的需求相关性,如螺钉与螺母。若这些需求相关度较高的物料被安排于距离较远的货位,将大大影响其拣选出库的效率。因此,本研究考虑不同储位分配方案的影响,提出将基于物料周转率的存储策略(COI)与物料需求相关度相结合的存储策略,使得周转频率高和相关度大的物料在仓库中的位置接近,且存储于更近仓库出入口的巷道货位。由于模型的计算规模随着参数增长呈指数式增长,本研究开发出一种近似算法,并通过实验证明,相较于商业软件,本算法可更为有效得获取问题的最优或近似解。最后通过实例分析,给出不同COI系数与物料需求度偏好下该仓库的可行储位分配方案     

B2B2C平台中的需求信息隐藏行为及合作模式研究

针对B2B2C模式下电商平台与第三方商户之间既合作又竞争的交互关系及其导致的机会主义行为展开研究.通过构建平台和第三方商户在两种典型模式(自营、它营)下的竞合交互模型,研究了第三方商户隐藏需求信息的动机及影响,并探讨了合营模式在规避机会主义行为及增加渠道收益方面的有效性.研究结果表明:①产品需求量较高的第三方商户在面临平台自营威胁时有隐藏需求信息的动机,最终导致双方收益受损;②合营模式能够解决第三方商户的需求隐藏问题,并为平台和第三方商户带来整体收益的增加;③平台针对销售不同需求量产品的进驻方应该选择不同的销售模式,即高需求产品采用自营模式,中需求采用合营模式,较低需求采用它营模式.     

随机需求条件下的延迟发运策略模型及性质

本针对随机需求条件下物流配送中心的库存和运输联合决策问题，在基本库存和自身运输能力不足的情况下，提出对剩余客户订货需求采取部分延迟到下一期与部分利用第三方物流立即发运两相结合的策略，并在具有一般惩罚(损失)费延迟发运量限制的条件下，建立运输和库存相关总成本数学期望最小的优化模型，论证了该模型的主要性质，在此基础上很容易构造求解该类问题的优化方法。     

需求导向的容量设施竞争选址问题研究

客户意愿与容量限制是竞争设施选址问题中两个重要的影响因素,在考虑客户意愿与设施容量共同作用条件下,建立了最小化企业总成本以及每个客户费用为目标的竞争设施选址问题优化模型,通过设计需求导向服务分配机制解决设施与客户之间服务关系分配问题,结合模拟退火思想提出了求解模型的算法。最后利用数值例子分析了需求导向服务分配机制以及目标权重、预算限额等参数对于选址决策的影响,其中考虑需求导向因素会适当增加企业的总成本,但可以减少客户所付出的费用从而增强对客户的吸引力;另外企业的预算限额对于企业的设施选址决策有着重要的影响,企业所能获取的市场份额与其选址预算限额呈正相关的关系;而客户所需付出的总费用与企业提供服务的总成本两者之间则呈负相关的关系,因此需要通过服务质量与成本之间的权衡实现最理想的选址决策。     

基于移动机器人的拣选系统货架动态储位分配研究

为了提高基于移动机器人的拣选系统拣货效率,更好地满足客户动态需求和订单时效要求,提出了考虑货架后续需求频次、需求紧迫程度以及拥堵因素的货架动态储位分配策略,构建了最小化货架搬运距离的动态储位分配模型,并设计了启发式算法进行模型求解.首先,基于货架需求紧迫程度,构造贪婪算法生成动态货架储位分配的初始解;然后,基于货架在后续批次订单的需求频次及通道间负载均衡,采用邻域搜索算法进行动态货架储位优化.最后,通过与其他静态和动态储位分配方法对比,验证文章提出的模型和算法的有效性.     

产品服务能力与定价联合优化策略机制研究——基于动态性和非线性视角

为了快速响应客户需求的动态变化和提高产品服务能力的管理效率,运用状态相关需求率函数和成本收益率函数,建立用以解决产品服务需求动态性和非线性难题的排队优化模型。通过考虑产品服务化过程中客户需求变化特征,从服务能力和价格两个维度将客户划分为实惠型、经济型、专业型和品质型四个不同类别。依据客户产品服务需求动态演变阶段,针对服务能力与价格的内在关联性,运用排队优化模型分别构建了成本领先策略、服务能力领先策略、价格领先策略和产品服务能力定价联合策略。最后,借助南阳泵业企业运营实例,验证了产品服务能力定价联合策略的优越性,并给出产品服务能力定价联合策略演化路径及其实施对策。     

基于两阶段混合整数规划模型的洪涝灾害应急管理研究

本文以洪涝自然灾害为现实背景, 考虑多种应急物资、灾情的不确定性和应急救灾的多目标性, 集成优化灾前准备和灾后响应两阶段, 建立了一定最大救援时间下的两阶段多目标混合整数规划模型。模型的目标一是使得不同灾害情景下灾后响应阶段总物资不足惩罚和延误损失的期望最小, 目标二是使得灾前准备阶段应急物资存储点建造成本、物资存储成本及灾后响应阶段物资分配成本之和最小。该模型保证了应急救灾的及时有效以及物资的公平分配。本文设计了一种多目标遗传算法用于模型求解, 结合具体算例, 得到了模型在最大救援时间为4到9区间内任意数值下的pareto最优解, 很好地适应了决策者不同的决策需求, 并根据pareto应急方案的数目, 灾后响应阶段成本期望和两阶段总成本等模型的三个关键产出随最大救援时间的变化趋势, 得出最优的最大救援时间为5.7。     

Deterministic inventory model for deteriorating items with capacity constraint and time-proportional backlogging rate

In this paper, a deterministic inventory model for deteriorating items with two warehouses is developed. A rented warehouse is used when the ordering quantity exceeds the limited capacity of the owned warehouse, and it is assumed that deterioration rates of items in the two warehouses may be different. In addition, we allow for shortages in the owned warehouse and assume that the backlogging demand rate is dependent on the duration of the stockout. We obtain the condition when to rent the warehouse and provide simple solution procedures for finding the maximum total profit per unit time. Further, we use a numerical example to illustrate the model and conclude the paper with suggestions for possible future research.     

A heuristic algorithm for the truckload and less-than-truckload problem

The delivery of goods from a warehouse to local customers is an important and practical problem of a logistics manager. In reality, we are facing the fluctuation of demand. When the total demand is greater than the whole capacity of owned trucks, the logistics managers may consider using an outsider carrier.Logistics managers can make a selection between a truckload (a private truck) and a less-than-truckload carrier (an outsider carrier). Selecting the right mode to transport a shipment may bring significant cost savings to the company.In this paper, we address the problem of routing a fixed number of trucks with limited capacity from a central warehouse to customers with known demand. The objective of this paper is developing a heuristic algorithm to route the private trucks and to make a selection of less-than-truckload carriers by minimizing a total cost function. Both the mathematical model and the heuristic algorithm are developed. Finally, some computational results and suggestions for future research are presented.     

Credit financing in a two-warehouse environment for deteriorating items with price-sensitive demand and fully backlogged shortages

In the current global market, organizations use many promotional tools in order to increase their sales. One such tool is permissible delay in payments, i.e., the buyer does not have to pay for the goods purchased immediately rather can defer the payment for a prescribed period given by the supplier. This phenomenon motivates the retailer/buyer to order a large inventory lot so as to take full benefit of credit period. But the well decorated showroom (OW) with modern facilities has a limited storage capacity. Thus the retailer has to hire a rented warehouse to store the excess units. In this scenario, retailer usually adopts two types of dispatch policy: FIFO & LIFO, depending upon the situation, e.g., nature of items/deteriorating items, location of warehouse. Further in order to survive in the market, the retailer dynamically adjusts the prices of the goods to boost the demand and enhance the revenues.In the light of these facts, this paper develops an inventory model for deteriorating items with price-sensitive demand under permissible delay in payment in a two warehouse environment. Shortages are allowed and fully backlogged. The objective of this study is to find the optimal inventory and pricing policies so as to maximize the total average profit. Further, the different trade credit scenario has been exhibited with the help of a numerical example. A comprehensive sensitivity analysis has also been carried out to advocate the implication of FIFO and LIFO dispatch policy.     

仓库容量有限条件下的随机存贮管理模型

以商场的商品销售与存贮为研究对象,建立了一类在仓库容量有限条件下的存贮管理决策模型,并给出了最优存贮策略.针对某个大型超市的三种商品的真实销售数据,我们运用该模型分析求解得出了三种商品的最优订货点L*分别为35、39和40.结合销售存贮管理中的实际情况,我们针对商场同时订购多种商品时的情况对模型进行了初步推广,并依据此推广模型得出了在同时订购三种商品时的最优订货点L*为7.2.最后我们进一步讨论了在商品销售率随存贮时间发生变化及存贮变质性商品时的存贮管理决策模型,以便满足不同商家的订货和存贮策略.     

A two-echelon inventory model for a deteriorating item with stock-dependent demand,partial backlogging and capacity constraints

This study investigates a two-echelon supply chain model for deteriorating inventory in which the retailer’s warehouse has a limited capacity. The system includes one wholesaler and one retailer and aims to minimise the total cost. The demand rate in retailer is stock-dependent and in case of any shortages, the demand is partially backlogged. The warehouse capacity in the retailer (OW) is limited; therefore the retailer can rent a warehouse (RW) if needed with a higher cost compared to OW. The optimisation is done from both the wholesaler’s and retailer’s perspectives simultaneously. In order to solve the problem a genetic algorithm is devised. After developing a heuristic a numerical example together with sensitivity analysis are presented. Finally, some recommendations for future research are presented.     

A deterministic order level inventory model for deteriorating items with two storage facilities

In this paper a deterministic inventory model is developed for a single deteriorating item which is stored in two different warehouses. A rented warehouse is used to store the excess units over the fixed capacity W of the own warehouse. The rented warehouse is assumed to charge higher unit holding cost than the own warehouse, but to offer a better preserving facility resulting in a lower rate of deterioration for the goods than the own warehouse. The optimal stock level for the beginning of the period is found and the model developed is shown to agree with the order level model for non deteriorating items with a single storage facility. An illustration to show the applicability of the model is also presented.     

Congruential Inventory Model for Two-Echelon Distribution Systems

Large-scale inventory-distribution systems typically comprise a hierarchy of warehouses that stock goods for distribution to retailers at which demand for these goods originates. This paper develops an inventory model for two-echelon distribution systems under the assumption that the central warehouse and retailers order periodically. Characteristics of the optimal policy are described. An iterative solution procedure is presented to find optimal or near optimal operating-policy variables. Solutions of the model to a large number of test examples show that the model outperforms other existing models in the literature without sacrificing the computation time. Tested against the lower bounds on the optimal average annual variable cost obtained by removing some of the ordering costs, the solutions of the present model are found to be near optimal.     

A Dynamic Distribution Model with Warehouse and Customer Replenishment Requirements

This paper addresses a multiperiod integrated model that plans deliveries to customers based upon inventories (at warehouse and customer locations) and vehicle routes. The model determines replenishment quantities and intervals at the warehouse, and distribution lots and delivery routes at customer locations. We investigate coordination of customer and warehouse replenishment decisions and illustrate their interdependence. Computational experience on randomly generated problems is reported. We show that ordering policy at the warehouse is a function of how goods are distributed to lower echelons and that coordination leads to cost reduction.     

Elementary Theory of Optimal Silo Storage Design

This study indicates a method for calculating an economic division of warehouses into compartments when different varieties have to be stored simultaneously and separately. The study deals with cases where the total storage capacity demand and the number of varieties are known and fixed, but where the storage capacity demand of each variety is unknown. Problems of this nature exist in the preliminary designing of grain silos, fleets of transport vehicles, utensils in public kitchens, etc. If the warehouse capacity can cope with the total storage capacity demand, but the number of compartments is insufficient, it is possible that part of the material to be stored cannot be accommodated, although certain compartments may only be partly filled; this will be due to the impossibility of storing different varieties together. The materials will have to be stored in other warehouses, at a higher charge per capacity unit than that of the warehouse in question.The division of the warehouse into a large number of compartments will assure storage of most, if not all, the material. On the other hand, increase in the number of compartments (and installations) makes for increased investment in transport installation, partitions and additional storage capacity to compensate for space taken up by these partitions and installations.The object of this study is to introduce a method for calculating the optimal division of a warehouse into compartments, so that the annual costs of storage and capital investment are minimized.It is possible-by introducing not very restrictive statistical assumptions-to calculate the annual costs of storing excluded material elsewhere for different modes of partitioning a warehouse into compartments. The annual building cost of the warehouse is calculated in the ordinary way.In this study a solution is offered for the partitioning of a warehouse into equal compartments. It is to be expected that the extension of this solution to cases of the partition into compartments, differing from each other as to storage capacity, will tend to lower costs.     

Computationally Efficient Solution of a Multiproduct,Two-Stage Distribution—Location Problem

A two-stage distribution planning problem, in which customers are to be served with different commodities from a number of plants, through a number of intermediate warehouses is addressed. The possible locations for the warehouses are given. For each location, there is an associated fixed cost for opening the warehouse concerned, as well as an operating cost and a maximum capacity. The demand of each customer for each commodity is known, as are the shipping costs from a plant to a possible warehouse and thereafter to a customer. It is required to choose the locations for opening warehouses and to find the shipping schedule such that the total cost is minimized. The problem is modelled as a mixed-integer programming problem and solved by branch and bound. The lower bounds are calculated through solving a minimum-cost, multicommodity network flow problem with capacity constraints. Results of extensive computational experiments are given.