分割配送的生鲜产品库存-路径优化研究

目的 基于供应商管理库存策略,优化协调第三方物流（3rd Party Logistics,3PL）参与的二级供应链系统中库存补充与补货配送的关系,在满足配送需求的同时降低系统的库存和运输成本。方法 综合考虑3PL物流模式下的库存-路径系统中生鲜产品的运输距离、质量时间窗以及需求分割配送策略在时间上的调整等因素,以异质车队车辆行驶燃油成本、车辆调用固定成本、配送超时腐坏成本以及各零售商的库存成本为目标函数,建立多品种生鲜产品库存-路径优化模型。结果 通过改进的遗传算法计算并进行配送量调整优化,得到最终的生鲜配送方案,其系统总成本比配送量调整前减少了9.98%。结论 通过在时间上对配送量进行拆分调整可以有效地节约供应链系统总成本。     

供应链协调机制的库存成本优化能力分析

本文在一个供应商和一个采购商的二阶供应链条件下,对传统供应链、寄售、供应商管理库存三种协调机制在集中决策和分散决策情况下的库存成本优化能力进行对比分析.得出结论:在集中决策情况下,供应链总成本是相同的;在分散决策情况下,任何协调机制的供应链总成本总不会优于集中决策下的供应链总成本;VMI是各种协调机制中最优的;传统供应链和寄售的供应链总成本优劣依赖于其成本分担的比例,并详细计算出该比例值.为企业选择供应链协调机制提供决策依据.     

考虑分组策略的供应链一体化生产-配送模型

研究了供应链中单一生产商对多零售商的协调生产-配送策略问题。生产商配送单一产品给多个异质零售商,为了降低相关成本,根据零售商的订货周期将其分为两组,其中一组零售商的共同订货周期为T,另外一组零售商的订货周期为T/λ,而供应商的生产周期是KT(λ,K均为正整数)。供应链的目标是综合考虑供应商生产成本、配送成本、库存成本以及给所有零售商的补偿成本,并决策K和T以使得总成本最小。通过参数分析构建了两种情况下的一体化生产-配送决策模型,分析给出了其数学性质,得到了理论结果以确定最优决策,并说明了相关管理启示。通过数值对比分析,得出了分组配送策略可以改善供应链绩效的结论,并由此说明了模型的有效性。     

考虑价格折扣和运输柔性的库存运输优化研究

在考虑运输能力柔性和销售价格折扣的基础上,建立了零售商主导的分散优化模型、供应商主导的分散优化模型和库存运输联合优化模型,分析得出模型的性质。通过比较研究得出不同决策模式下最优策略和系统绩效的关系。研究表明,零售商主导的分散优化模型的库存成本小于运输库存联合优化模型的库存成本;零售商主导的分散优化模型的运输成本大于运输库存联合优化模型的运输成本;运输库存联合优化供应链的总成本小于零售商主导的供应链总成本。     

多级库存控制的连锁经营企业配送网络设计

研究了随机需求条件下连锁经营企业配送网络设计及其库存决策的联合优化问题.详细分析了基于POT(power of two)多级库存控制策略的连锁企业多级工作库存及订货成本,给出了门店及配送中心在满足给定服务水平条件下的安全库存成本.在综合考虑运输成本和配送中心选址成本的基础上,建立了以系统总成本最小为目标的配送系统总成本优化模型,并采用遗传算法求解该优化模型,在得到最优配送网络设计方案的同时,确定了配送中心订货周期及门店配送周期.通过算例验证了模型及算法的有效性,并分析了需求、运输距离和选址成本等因素的变化对系统总成本的影响,为连锁经营企业的物流配送网络设计及库存控制提供决策支持.     

考虑缺货的两阶段腐败一体化库存—路径模型

在一个生产商给多个零售商配送单一易腐品的供应链中,考虑了一体化库存路径决策问题,并且零售商为了减少库存和运输相关成本而采用缺货损失策略。产品使用同质车辆配送,而在运输及销售过程中产品具有不同的腐败速率(两阶段腐败)。通过构建数学模型以最小化包括生产、配送、腐败、库存、缺货成本在内的供应链总成本。针对供应链库存决策,用数学证明得到函数性质以确定零售商缺货时间、订货周期及生产商的生产周期。针对离散的路径决策,采用固定分区策略对零售商进行分组,在每个分组内采用遗传算法求解对应的运输策略。设计求解算法并编制matlab程序求解问题,结合数值算例和灵敏度分析说明了模型的有效性及相关管理启示。     

供应链视角下工程材料库存优化研究

目的为了达到节约工程建设行业企业材料管理成本的目的,以常用的2种工程材料钢材和水泥存储于同一仓库且由同一供应商供货的库存管理为研究对象进行研究。方法分析承包商采购材料情形下,供应商和承包商基于合作伙伴关系实现库存信息共享,建立2种材料两级库存联合库存成本优化的数学模型,并通过工程实例,运用粒子群算法求解,验证研究方法的有效性。结果不同的材料订购策略对工程供应链上的材料库存成本影响很大,数学模型可以给出恰当的订购策略,满足系统成本的最低要求,从而节约成本,提升工程供应链的整体竞争力。结论研究成果丰富了工程供应链管理理论、工程材料的库存管理理论,并对工程建设实践中的材料采购有一定的指导意义。     

考虑分割配送的易腐品一体化库存路径问题

一个供应商用多个同质车辆给多个零售商配送一种易腐品,满足多个周期中零售商的需求,决策计划期内零售商的到货计划、供应商的生产计划以及车辆路径问题以最小化系统总成本。考虑质量时间窗、载重成本、车辆返回时间间隔等因素,建立混合整数规划模型,将模型分为一个主问题、两个子问题,采用两阶段启发式算法和配送量调整机制来进行求解,通过数值算例和灵敏度分析验证了模型和算法的有效性。     

考虑供应商交货数量风险的订货量分配模型

针对有装配线最小批量要求且供应商交货数量随机条件下的多物料订货量分配问题,以订货成本、采购成本、库存持有成本和拖期成本组成的总成本最小为优化目标,构建了混合整数随机规划模型;使用离散粒子群优化算法对模型进行求解,通过两组算例将粒子群优化算法与遗传算法和枚举算法进行了对比分析,算例结果验证了离散粒子群优化算法解决该问题的可行性和有效性。最后,通过一组实例分析了不同单位拖期成本和单位库存成本情形下的订货量分配方案以及单位拖期成本/单位库存成本这一比例对总成本的影响。实例结果表明,物料的订货量分配方案与单位拖期成本/单位库存成本有关,且总成本与该比例呈线性相关关系。     

具有缺陷品的双渠道供应链库存优化策略

为研究双渠道供应链库存优化问题，考虑由一个网络零售商和一个传统零售商构成的缺陷品双渠道供应链系统，允许不同渠道零售商之间采用横向转运策略协调库存水平，引入渠道间消费者购买转移，运用马尔科夫链来描述零售商的库存状态，建立以库存成本最小为目标的数学模型，并运用遗传算法进行求解。通过对允许转运和不允许转运2种方案的对比，得出在分销缺陷产品的双渠道供应链中，双渠道间采取转运策略可以降低最优库存量和总成本；随着购买转移概率的增加和产品缺陷率的增加，转运策略带来的系统绩效均不断降低。     

异质车辆配送可重复装货易腐品库存—路径模型

研究了易腐品的订货、配送和车辆选型一体化决策问题。在一个供应商供应单一产品给多个零售商的供应链中,产品在运输阶段存在腐败,采用运行温度、车辆相关成本和腐败率有差异的异质车辆进行配送,联合决策模型的目标是确定每个零售商的配送车辆类型、配送路径及配送周期使得总成本最小。通过建立数学模型,证明了给定车辆类型和行驶路径后,单一车辆存在最优配送周期,由此设计了改进的节约算法嵌套对车辆类型的遍历对问题进行求解,结合实际企业背景,通过数值算例说明了易腐品配送车辆的选型问题,并得出了对企业的管理启示。     

Vendor-managed inventory with consignment stock agreement for single vendor–single buyer under the emission-trading scheme

This paper presents a joint economic lot size (JELS) model for coordinated inventory replenishment decisions under the vendor-managed inventory (VMI) with consignment stock (CS) agreement and an emission-trading scheme. The paper assumes a single product that flows along a two-level supply chain system, with a single vendor and a single buyer. The total cost of the system is the performance measure, which is the sum of the vendor’s and the buyer’s total costs. The total cost includes the set-up and order costs, inventory holding costs, greenhouse gases (GHG) emissions tax and penalty costs. A mathematical model is proposed to determine: (1) the vendor’s production lot size quantity; (2) the number of shipments sent by the vendor to the buyer in a cycle; and (3) the production rate that minimises the total cost of the supply chain. Some numerical examples are carried out, as well as comparisons with the traditional JELS model for a classic two-level supply chain. Results show that the performance of the system is better when it is operated under a VMI with CS agreement, which is capable of reducing the traditional inventory holding costs and, for some values of given parameters, the GHG emissions tax and penalty costs.     

Manufacturing lot-sizing,procurement and delivery schedules over a finite planning horizon

In this study, an integrated manufacturing system for technology-related companies whose products are experiencing continuous price decrease during the life cycle is studied for optimal procurement, production and delivery schedules over a finite planning horizon. The model considers the inventory cost both at manufacturing and at delivery from supplier. Since the price is continuously decreasing, a manufacturing firm delivers the finished goods in small quantities frequently. Frequent deliveries in small lots are effective to reduce the total cost of the supply chain. The key for high-tech industries is to reduce the inventory holding time since the component prices are continuously decreasing, and this can only be achieved by implementing an efficient supply chain. Therefore, the main purpose of this paper is to develop an integrated inventory model for high-tech industries in JIT environment under continuous price decrease over finite planning horizon while effectively and successfully accomplishing supply chain integration so that the total cost of the system is minimal. An efficient algorithm is developed to determine the optimal or near-optimal lot sizes for raw material procurement, and manufacturing batch under a finite planning horizon. Finally, the solution technique developed for the model is illustrated with numerical examples.     

Distribution planning for multi-echelon networks considering multiple sourcing and lateral transshipments

Nowadays, due to the increasing complexity of business environment, especially demand uncertainty, supply chain managers need to establish more-effective sourcing and distribution strategies to ensure high customer service and low stock costs. To overcome this challenge multi-echelon network structures and alternative distribution strategies such as lateral transshipments and multiple sourcing should be considered in inventory optimisation models. In this article, we propose a scenario-based modelling approach to solve a two-stage multi-echelon inventory optimisation problem with a non-stationary demand. The model is based on a distribution requirements planning (DRP) approach and minimises the expected total cost that is composed of the fixed allocation, inventory holding, procurement, transportation, and back-ordering costs. Alternative inventory optimisation models, including the lateral transshipment strategy and multiple sourcing, are thus built, and the corresponding stochastic programmes are solved using the sample average approximation method. Through a numerical investigation conducted with several generated instances and an empirical investigation based on the case of a major French retailer’s distribution network, we show the substantial benefit of lateral transshipments and multiple sourcing in reducing the expected total costs of the distribution network.     

考虑残次品和碳排放的供应链多级库存的EOQ模型

针对供应链多级库存系统,探析残次品与碳排放对该系统的影响作用与供应链库存持有成本、订购成本、运输成本和检查成本的构成函数,建立多级库存的EOQ模型,提供考虑残次品和碳排放的供应链订货经济批量和库存控制策略,并用算例验证了模型的有效性。     

Flexible work-in-process production system in supply chain management under quality improvement

For a complex product production, any flexible manufacturing system with a work-in-process inventory is recommended for a supply chain management (SCM) system. Building a flexible manufacturing system increases the total cost of the supply chain; for this reason, a discrete investment is important. For flexible production systems, production rate within a finite specific interval of production rate as work-in-process inventory is calculated. The aim of the supply chain is to reduce the total cost when demand during the lead time is a random variable with a normal distribution. A crashing cost is utilised to reduce the duration of lead time within the supply chain system. A model is proposed to obtain the optimal flexible production rate with the reduced total cost of the supply chain. A classical optimisation technique is employed to obtain the closed-form and quasi-closed-form solutions of the decision variables. An improved algorithm is designed to obtain the global minimum cost of SCM under the framework of a flexible production system. An illustrative numerical example and sensitivity analysis are given to test the model. A numerical study proves that this model obtains the minimum cost with the optimal decision variables.     

Supply chain cell activities for a consumer goods company

The supply chain cell is a new cross-functional area in many industries in India. It involves the integration of production planning, dispatch order generation and logistics planning, apart from general logistics, which primarily includes distribution. This paper deals with the study conducted for a fast moving consumer goods company having 14 production locations and 22 branches/clearing and forwarding agents. There were 36 packing lines, with each line packing different varieties of stock-keeping units. In this company, supply chain cell activities were concentrated on the middle of the classical supply chain. An attempt has been made to integrate production logic with the logistics by considering the total cost concept. The total cost concept also includes non-quantifiable parameters, which have been incorporated by the use of the analytical hierarchy process. An optimization technique has been proposed simultaneously to support the planning logic developed. The supply chain cell helps to optimize the total supply chain cost as well as enabling it to supplement other benefits such as an improvement in inventory turnover and a reduction in the inventory carrying cost.     

Just-in-time purchasing: an integrated inventory model involving deterministic variable lead time and quality improvement investment

Nowadays supply chain management is a popular practice in manufacturing systems, and just-in-time (JIT) production plays a crucial role in supply chain environments. Companies are using JIT production to gain and maintain a competitive advantage. The characteristics of JIT systems are consistent high quality, small lot sizes, frequent delivery, short lead time, and close supplier ties. This paper presents an integrated inventory model to minimize the sum of the ordering/setup cost, holding cost, quality improvement investment and crashing cost by simultaneously optimizing the order quantity, lead time, process quality and number of deliveries while the probability distribution of the lead time demand is normal. This integrated inventory model is useful particularly for JIT inventory systems where the vendor and the purchaser form a strategic alliance for profit sharing.     

资金约束时零售商融资与订货决策及价值分析

针对供应链中存在资金约束的情形,建立了包含制造商（M）、零售商（R）双层结构、不考虑残次品率、库存成本和融资周期长短的简洁供应链决策模型。研究了当市场需求不确定和零售商资金不足情形下,零售商选择是否融资这两种情况下,其订货决策的变化,以及零售商和制造商的收益变化。通过有无融资条件下零售商不同数量自有资金时订货量和期望收益对比和零售商自有资本一定时订货量随周期变化的数值分析,证明了零售商的融资决策与订货量决策会随着其自有资金及市场需求的变化而变化;验证了融资可以提高零售商和供应链的收益,而且能够使得供应链的总产品尽快达到最佳产量,有效满足消费者需求。