Methods of vendor managed inventory control in supply chain management

By inducing the typical inventory control problem - the bullwhip effect, this paper presents vendor managed inventory (VMI) control methods on the basis of traditional methods of inventory management methods, constructs a VMI mathematics model, and analyzes the influence of VMI on inventory cost and channel profit. Finally, a special case is studied to verify that VMI is an effective supply chain strategy that can not only increase channel profit of supplier and customer but also improve full channel coordination, thereby reducing the bullwhip effect.

IoT-Enabled RFID in Supply Chain Management: A Comprehensive Survey and Future Directions

Radio frequency identification (RFID) has emerged as a pivotal technology in supply chain management (SCM), significantly enhancing its efficiency and effectiveness. When integrated with the internet of things (IoT) to form RFID-IoT, this technology brings transformative advancements to SCM, enabling automated sensing, pervasive computing, and ubiquitous data access across the entire supply chain, from manufacturers and distributors to retailers and consumers. This integration facilitates real-time identification and monitoring of products, enhances various processes, improves logistic tracking, and ensures better product quality management. Despite its promising benefits, the adoption of RFID-IoT in SCM faces several challenges, including technical complexities, data security concerns, and high implementation costs. However, the future potential of RFID-IoT technology remains substantial. It is anticipated that further integration with other emerging technologies, such as block chain and artificial intelligence, will lead to more comprehensive and robust SCM solutions, offering unprecedented levels of transparency, efficiency, and automation in supply chain operations.

A supply chain management in a single-vendor and a singlebuyer integrated inventory model with backorders under imperfect production system

Lead time is an essential factor in any supply chain and inventory management system.In stochastic inventory models,lead time is often viewed as a prescribed constant or a random variable that is not subject to control.In many practical situations,lead times can be controlled by paying additional investment.Using this viewpoint,notion of the crashing cost into stochastic inventory model,in which lead time can be controlled by additional investment.Many researchers have developed various analytical inventory models we have considered the piecewise linear function.So in this proposed model,we derive the mathematical model which is developed by incorporating three types of lead time crashing cost functions(i)exponential function,(ii)polynomial function and(iii)negative exponential function.An integrated inventory model is recognized to find the optimal solutions of order quantity,lead time,total cost for buyer,total cost for vendor and the total number of deliveries from the single-vendor to the single-buyer in one production run.A solution process is suggested for solving the proposed model and numerical examples to illustrate the feature of the proposed model,and examined the effect of the key parameters on the optimal solution and managerial implications are discussed.Numerical examples show that this model offers significant improvements over existing models.A computer code using the software Matlab is developed to derive the optimal solution.The main contribution of this paper is developing a mathematical model and an effective solution procedure to find the optimal solution.Finally,a graphical representation of the computational algorithm is represented by a flowchart in each model.

Inventory Management of a Plant Spare Parts Supply Chain

In spare parts industries, firms are dealing with a situation which is more and more uncertain due to the supply chain structure and variable demands. This paper presents a Bayesian approach to forecast demand and subsequently determine the appropriate parameter S of an （ S - 1 ; S） inventory system for controlling plant spare parts. We apply the Bayesian approach in an innovative way to specify the initial prior distributions of the failure rates, using the initial estimates and the failure history of similar items. According to the proposed method, a lower base stock than the one currently used is sufficient to achieve the desired service level.

A Model on Inventory and Supply Management under VMI Tactics

This paper puts emphasis on how to arrange the stock and supply to the customer rationally under the VMI tactics. Having considered the supplier＇s delivery expenses, memory expenses and loss in short supply in model, the minimum total cost goal model of supply chain has been put forward using method of storing theory to charge example test the method of solving and analyzing the conclusion to propose.

A Petri Net Pareto ISO 31000 Workflow Process Decision Making Approach for Supply Chain Risk Trigger Inventory Decisions in Government Organizations

The Petri Net Pareto method proposed in this study has the advantages of acting directly on computing results by assessment of workflow process information. Our study contributes to the literature because it has investigated an ISO 31000 workflow process approach to group decision making for reducing backorders in the supply chain, from an integrated perspective utilizing Pareto charts and Petri nets. The contribution to the literature is also enhanced by the L-Project illustrative example that presents an evaluation hierarchy of supply chain risk. The proposed method is appropriate for use in situations in which assessment information may be qualitative or precise quantitative information is either unavailable or too costly to compute.

PRODUCTION INVENTORY SYSTEM WITH RANDOM SUPPLY INTERRUPTIONS STATUE AND RANDOM LEAD TIMES

This article analyzes a continuous-review inventory system with random supply interruptions and random lead time which may be interrupted by a random number of supplier’s OFF periods. The inventory with constant demand rate is managed by a （r; q1, q2, · · · , qm） policy and supplies from an unreliable sole supplier. By renewal theory and matrix Geometric method, the long-run average cost function is obtained and some important properties of the function are proved. Furthermore, performance of the inventory is derived.

Vendor managed inventory and bullwhip effect

This paper studies that the bullwhip effect of order releases and the amplifications of safety stock arise within the supply chain even when the demand model is ARIMA(0, 1, 1) and the forecast method used is a simple exponentially weighted moving average. It also examines a vendor managed inventory (VMI) program to determine how it can help alleviate such negative effects, and gives the theoretical proofs and numerical illustrations. The results show that the effects with VMI are better than the effect without VMI in demand forecasting and safety stock levels, etc.

Comparative research on three-echelon and two-echelon medicine inventory model with positive lead-time

According to the principle of minimizing total cost, the three-echelon optimized medical inventory model with stochastic lead-time and two-echelon optimized medicine inventory model with fixed lead-time are established. The relationship between lead-time and inventory cost is studied by Matlab software. It shows that the variety of lead-time has an important effect on medicine inventory systems. Numerical simulation and sensitivity analysis of two models are presented by Lingo software. Based on analysis, it is concluded that the two-echelon model with lead-time results in inventory cost savings, and keeps the quality of care as reflected in service levels when compared with the three-echelon network structure.

Optimization purchase price and the profit policy undervendor managed inventory

The optimization policy of the purchase price and the profit under vendor managed inventory(VMI) is studied. For a salable product, supply chain mode of VMI is established, which is based on deterministic demand, having initial stock and having stock-out cost. With the further analysis of the mode, VMI is found to increase profits of the buyer in the short-term motivation. But VMI will reduce profits of the supplier under the matching condition. And in the short-term motivation, VMI will increase the purchase price to compensate the transfer cost of the supplier. As a result, the foundation of theory is provided to implement VMI in the supply chain, and have some definituded project significance.

Distribution Inventory Cost Optimization Under Grey and Fuzzy Uncertainty

The grey fuzzy variable was defined for the two fold uncertain parameters combining grey and fuzziness factors. On the basis of the credibility and chance measure of grey fuzzy variables, the distribution center inventory uncertain programming model was presented. The grey fuzzy simulation technology can generate input-output data for the uncertain functions. The neural network trained from the inputoutput data can approximate the uncertain functions. The designed hybrid intelligent algorithm by embedding the trained neural network into genetic algorithm can optimize the general grey fuzzy programming problems. Finally, one numerical example is provided to illustrate the effectiveness of the model and the hybrid intelligent algorithm.

Causes of Restocking Delays in Absence of Real Time Inventory Tracking of Airtel Airtime

The purpose of this research was to ascertain causes of Restocking Delays in a Distributor Company of Airtel Airtime (AA) that give justification for benefits of using Real Time Inventory Tracking (R.T.I.T) in an attempt to mitigate Restocking Delays. From a study out at the Private Marketing and Trading Services (PMTS) an Authorized Distributor of Airtel Products undertaken in 2017 evidenced by Airtime scratch card and Electronic, E-Recharge Airtime among other forms to encourage R.T.I.T among other products in Telecom Companies and other Business Enterprises. The research comprises of the following areas among which included a detailed focus on a Qualitative and Quantitative approach in obtaining different categories of Restocking Delays in form of Themes and Sub Themes encountered in the Distribution Supply Chain (SC) of AA that is contained in this paper. This research continues to capture an in-depth explanation of the Managerial and Operational causes of restocking delays in respect to AA. Similarly, fast consumer products and services other than AA require a solution to Restocking Delays through implementation of Real Time Inventory Tracking Model (R.T.I.T.M) of AA among Distributor Companies (DCs). This paper also elaborated on Literature, Methodology and Findings obtained from the study. The results were obtained from regression analysis by using the Statistical Package for Social Sciences (SPSS) that showed a higher significance of Stock Turnover Period and Airtime Denomination as a contributor to Restocking Delays whereas Messages from Airtel Head office to the Distributor had a non-significant contribution to restocking Delays as in Figure 9. The research recommends a Model for R.T.I.T in Telecom Distribution SC of AA and Omnichannel Inventory Management (OIM) as a significant contributor to timely reliable inventory restocking and promotes higher sales among DCs and retailers through minimized Restocking Delays. It shows that the forces of Demand and Supply change over time with different tastes and preferences of customers. The imbalance in AA stock levels changes at given times due to unforeseen forces of consumer demand experienced by DCs, explained by the “Bullwhip Effect” due to information distortion in the Supply Chain (SC).

基于BOM-Supply Hub的供应链设计模型

为探讨供应链上游环节结构变化对供应链设计的影响,根据物料清单特点,及它与供应商多层属性的相关关系,从物料清单各链节间嵌入供应中心的变化,建立起没有供应中心、单级供应中心和两级供应中心的供应链设计模型。为计算这三类混合整数规划模型,采用遗传算法进行求解。通过算例比较发现,在同一周期下,基于供应中心供应链设计,比没有供应中心供应链设计的总费用低而且库存量少。同时,基于供应中心供应链设计比没有供应中心供应链设计能抑制牛鞭效应,特别是基于两级供应中心供应链设计对抑制库存放大的效果更明显。

基于Supply-Hub的智能制造企业库存管理

以产业集群为背景,在传统供应链体系中加入Supply-hub作为核心制造商的主要供货点,以信息共享平台为辅助,搭建了供应链结构模型,并对此结构下的主要运作模式进行了分析,总结了供应链中的横向、纵向、双向协同的模式。以此供应链体系为对象,建立了包括供应商库存成本、集配中心库存成本、制造商库存成本、制造商缺货成本、制造商协同补货成本和制造商协同收益等六个方面的成本模型,以测算供应链体系的整体成本情况。

基于零库存目标的体外诊断试剂供应链质量评价与改进研究

目的:制定体外诊断试剂供应链的零库存管理目标,评价供应链质量,改进试剂供应中存在的问题。方法:从体外诊断试剂的库存量、供应效率和产品质量方面分析体外诊断试剂管理中存在的问题,制定医院运营、管理质量和患者利益最优化的管理体系,构建零库存管理路径和质量评价模型。选取2020年1月至2023年3月江苏省苏北人民医院采购的21种类型85个型号的体外诊断试剂,根据供应链质量管理方式不同,分别采用按需库存管理模式(模式1)和零库存管理模式(模式2),对比两种管理模式的需求采购、库存管理和临床使用效果。结果:采用模式2管理方式的体外诊断试剂的采购需求达标率、供应能力优质率和临床使用匹配度分别为(93.35±3.62)%、(94.87±2.63)%和(96.08±2.31)%,均高于模式1,其差异有统计学意义(Z=2.489、2.836、2.838,P<0.05),存产品长期积压、环境不达标和信息不及时的例数分别为(2.92±2.54)例、(2.83±1.59)例和(5.58±3.12)例,均低于模式1,其差异有统计学意义(Z=2.959、3.037、3.703,P<0.05);临床科室、医技科室及采购中心对模式2的体外诊断试剂的供应配送和信息沟通的满意度分别为97.8%和93.3%、97.0%和87.9%、100%和84.6%,均高于模式1,其差异有统计学意义(χ^(2)_(临床科室)=5.428、6.133,χ^(2)_(医技科室)=3.958、3.937,χ^(2)_(采购中心)=5.159、4.996,P<0.05)。结论:零库存管理模式能够提高体外诊断试剂需求采购的规范性,降低库存管理中积压失效问题的发生率,提升临床供应服务质量。

Cost Allocation for Inventory Problem with Transportation Discount under Carbon Tax Policy

In this paper,we deal with the problem of cost allocation among multiple retailers in an inventory system with transportation quantity discount under the widely-used carbon tax regulation.We first develop an inventory model with transportation discount under the carbon tax policy,and determine the optimal order quantity per order such that the total cost is minimized in the case of individual and joint ordering.We show that the total cost for the group of retailers can be reduced by placing joint orders while the total carbon emissions may increase.Then,we provide a sufficient condition which indicates that when the costs and carbon emissions associated with each order initiated are relatively high,enterprises can achieve dual objectives(both carbon emission reduction and cost reduction)through joint ordering.To allocate the total cost among the retailers,we introduce an inventory game and show that this game is concave.Based on this,we propose a cost allocation rule,which belongs to the core of the game.

A PARTIAL ROBUST OPTIMIZATION APPROACH TO INVENTORY MANAGEMENT FOR THE OFFLINE-TO-ONLINE PROBLEM UNDER DIFFERENT SELLING PRICES

This study examines an optimal inventory strategy when a retailer markets a product at different selling prices through a dual-channel supply chain, comprising an online channel and an offiine channel. Using the operating pattern of the offiine-to-online （020） business model, we develop a partial robust optimization （PRO） model. Then, we provide a closed-form solution when only the mean and standard deviation of the online channel demand distribution is known and the offiine channel demand follows a uniform distribution （partial robust）. Specifically, owing to the good structural properties of the solution, we obtain a heuristic ordering formula for the general distribution case （i.e., the offiine channel demand follows a general distribution）. In addition, a series of numerical experiments prove the rationality of our conjecture. Moreover, after comparing our solution with other possible policies, we conclude that the PRO approach improves the performance of incorporating the internet into an existing supply chain and, thus, is able to adjust the level of conservativeness of the solution. Finally, in a degenerated situation, we compare our PRO approach with a combination of information approach. The results show that the PRO approach has more ＂robust＂ performance. As a result, a reasonable trade-off between robustness and performance is achieved.

行为运营管理研究综述

经理人的决策质量对于实现高效运营管理至关重要。然而,在商业实践中,经理人的决策过程常常伴随着非理性行为,并最终导致决策偏差。决策偏差是企业无法实现高效管理的根本问题,其成因广泛、机理深邃,治理困难,因此面临着重大的研究挑战。近年来,学术界针对运营管理中的各种场景,尤其是库存和供应链管理,进行了一系列研究。这些研究广泛识别了不同类型的决策偏差,并反复检验了这些偏差的稳健性,探索了决策偏差的形成机制和干预治理方法。然而,现有的研究视角广泛,方向零散,缺乏对决策偏差的系统性认知和梳理。因此,本文系统性地讨论库存与供应链管理中的决策者行为偏差问题,分析其科学内涵和形成机理,并对一些重要进展进行梳理和凝练。同时,对其研究与实践的未来方向进行了展望,为学术研究和业界应用提供关于决策偏差的深入洞察,以期实现“知偏识正”。

基于Vensim的汽车零部件供应链管理研究

利用系统动力学和Vensim软件搭建汽车零部件供应链模型,分析“牛鞭效应”在供应链中需求变异放大现象对供应链库存的影响。通过绘制因果关系图,建立三级零部件供应链模型,对时间延迟、期望库存持续时间、库存调整时间、移动平均时间节点进行分析,研究发现这4个辅助变量都会加剧“牛鞭效应”。根据汽车零部件供应链的特点,提出针对性策略来弱化“牛鞭效应”,优化企业库存管理,提高库存利用率、最小化库存支出,改善企业现金流。

随机情景下MTS/MTO串联生产系统库存控制策略

该研究探讨供应链库存控制策略及生产协同重要性。将备货型生产(make-to-stock, MTS)与按订单生产(make-to-order, MTO)两级串联模式应用于高效响应性供应链的生产与库存联合控制问题并刻画其最优策略。针对订单到达服从泊松过程和生产时间服从指数分布情形,通过马尔科夫过程转移速率一致化技术建立起马尔科夫决策过程模型并得到相应贝尔曼最优方程。基于最优费用函数结构性质,将最优生产与库存控制策略刻画为依赖系统状态的基本库存策略。随后,将模型拓展到批量生产情形。数值算例验证了最优策略单调结构性质,给出不同情境下的最优策略绩效。同时将最优策略与两种常见策略进行比较。基础情境下,容限策略偏离最优7.36%,短视策略偏离最优25.73%。其他情境下,最优策略都明显优于另两种策略。