供应商具备多级生产率的供应链控制策略仿真

研究供应商具有多级生产率的供应链库存成本控制策略问题。在满足客户与销售商随机性订单需求的基础上,以供应链的整体运营成本最低为目标,运用Arena仿真平台对由供应商、销售商、客户构成的多级供应链库存系统进行了建模和仿真优化,制定合理的销售商的库存策略以及供应商的生产库存策略。为具备多级生产率的供应链系统控制策略提供了一种更科学合理的决策方法,对以后的类似研究具有一定的借鉴意义。     

An integrated multi-stage supply chain inventory model under an infinite planning horizon and continuous price decrease

This paper studies an integrated inventory model in a supply chain that involves procurement, production and delivery activities. The model is studied in an environment where products experience continuous price decrease and planning is performed in an infinite time horizon. In this model, a manufacturing facility purchases a fixed-quantity of raw materials from an outside supplier, processes the materials, and delivers a fixed-quantity of finished products to a customer periodically. In order to take advantage of the decreasing price trend, customers demand frequent deliveries of small lots of finished products, and this inventory management strategy has been used by many successful companies in technology-related industries. Therefore, the ultimate intention of this research is to study and model the inventory system for high-tech companies whose products are experiencing continuous price decrease. This model is used to determine an optimal economic lot size model for raw material procurement, production setup and finished goods delivering under an infinite planning horizon. Two efficient algorithms are developed in this paper to solve this nonlinear model and the test results consistently indicate that ordering of raw materials and delivery of finished goods should be frequent in small lots for low ordering and shipment costs. Finally an operational schedule is provided to show the implementation procedure of the model.     

Random network models and sensitivity algorithms for the analysis of ordering time and inventory state in multi-stage supply chains

Supply chains in reality face a highly dynamic and uncertain environment, especially the uncertain end-customer demands and orders. Since the condition of product market changes frequently, the tasks of order management, product planning, and inventory management are complex and difficult. It is imperative for companies to develop new ways to manage the randomness and uncertainty in market demands. Based on the graphical evaluation and review technique, this paper provides a simple but integrated stochastic network mathematical model for supply chain ordering time distribution analysis. Then the ordering time analysis model is extended so that the analysis of inventory level distribution characteristics of supply chain members is allowed. Further, to investigate the effects of different end-customer demands on upstream orders and relative inventory levels, model-based sensitivity analysis algorithms for ordering fluctuations and inventory fluctuations are developed. A detailed numerical example is presented to illustrate the application of the proposed models to a multi-stage supply chain system, and the results of which shows the effectiveness and flexibility of the proposed stochastic network models and algorithms in order and inventory management.     

考虑保质期的两级供应链MTS-MTO提前期优化研究

在具有保质期特性的快消品行业中,供应商在面向订单(MTO)生产策略下较长的订货提前期会给零售商带来高库存以及高运作成本,削弱供应链的快速响应能力.对比原来的MTO生产策略,提出一种面向库存-面向订单(MTS-MTO)混合生产策略.首先,基于产品保质期的特点建立MTO生产策略下的供应链成本模型,并给出供应链成本最优的经济订货批量;其次,根据MTO求出的最优经济订货批量,建立MTS-MTO生产策略下的供应链成本模型,并确定供应商的应持有库存M,求出供应商在MTS-MTO生产时的充要条件,为供应链决策提供依据;再次,给出一种基于满意度的Nash协商模型以确定零售商应给予供应商的补偿H;最后,通过数值分析验证并讨论符合MTS-MTO生产的产品特征.     

Optimum profit model considering production,quality and sale problem

Chen and Liu [‘Procurement Strategies in the Presence of the Spot Market-an Analytical Framework’, Production Planning and Control, 18, 297–309] presented the optimum profit model between the producers and the purchasers for the supply chain system with a pure procurement policy. However, their model with a simple manufacturing cost did not consider the used cost of the customer. In this study, the modified Chen and Liu's model will be addressed for determining the optimum product and process parameters. The authors propose a modified Chen and Liu's model under the two-stage screening procedure. The surrogate variable having a high correlation with the measurable quality characteristic will be directly measured in the first stage. The measurable quality characteristic will be directly measured in the second stage when the product decision cannot be determined in the first stage. The used cost of the customer will be measured by adopting Taguchi's quadratic quality loss function. The optimum purchaser's order quantity, the producer's product price and the process quality level will be jointly determined by maximising the expected profit between them.     

基于Multi-Agent的供应链系统模型及其仿真

针对具有复杂自适应特征的供应链系统,设计了一个基于multi-agent的制造业供应链系统仿真模型.该模型分别从企业主体层和业务流程层构建供应链系统的agent模型,通过各独立ageIlt之间的来实现系统从接到客户订单到交付产品的整个过程.通过将任务分解并引入合同网模型来建立制造商与供应商之间的高效协商机制.通过在swarm平台上的系统仿真实验表明,该模型可较好的反映供应链内部的运行状况,并有良好的测试效果和稳定性.     

供应链存储系统无线射频识别使能的定量在制品法控制策略仿真

无线射频识别(radio frequency identification,RFID)技术的出现为库存控制策略的创新提供了一条有效的途径.本文利用RFID技术,将原有单个制造系统的流通卡系统推广到供应链的多级库存网络中,设计了RFID使能的电子流通卡系统.基于电子流通卡,实现了RFID使能的定量在制品法(constant work-in-process,CONWIP)控制策略;并建立了CONWIP控制策略的分销网络模型.为比较和验证CONWIP控制策略性能,开发了三级分销网络仿真系统,使用该系统,将其与RFID使能的(r,Q)策略进行比较,验证了CONWIP策略在一定条件下,能够有效降低存储成本、提高服务水平.     

A Web-based system for proactive management of supply exceptions

To avoid or mitigate the ripple effect of a supply exception (defined here as a partial and/or late delivery) in the supply chain, it is imperative to identify the exceptional event early and handle it effectively and efficiently between the affected parties. This paper proposes a Web-based system which enables the early identification of supply exceptions and provides structured business processes for handling them. Particularly, through the dynamic mapping of a specific customer order with finished goods inventory and the progress of internal work orders against a pre-defined milestone model for each product, the status of the customer’s order is determined. In case of an exception (i.e. a customer order cannot be fulfilled as promised in the order schedule), a standard process is triggered to handle it collaboratively by business partners through fast, effective negotiations.To achieve these objectives, a top-down system design approach was employed, which covers conceptualization of the key co-ordination processes, methodology development, design of system architecture and the integrative processes and subsequent system implementation. To demonstrate the effectiveness of the Web-based system, an example is used to compare the current process with the one proposed. The system was evaluated in the context of the IST project Co-OPERATE. Finally, the presented work is concluded and future research directions are indicated.     

Genetic algorithm for supply planning in two-level assembly systems with random lead times

This paper examines supply planning for two-level assembly systems under lead time uncertainties. It is supposed that the demand for the finished product and its due date are known. The assembly process at each level begins when all necessary components are in inventory. If the demand for the finished product is not delivered at the due date, a tardiness cost is incurred. In the same manner, a holding cost at each level appears if some components needed to assemble the same semi-finished product arrive before beginning the assembly at this level. It is assumed also that the lead time at each level is a random discrete variable. The expected cost is composed of the tardiness cost for finished product and the holding costs of components at levels 1 and 2. The objective is to find the release dates for the components at level 2 in order to minimize the total expected cost. For this new problem, a genetic algorithm is suggested. The proposed algorithm is evaluated with a variety of supply chain settings in order to verify its robustness across different supply chain scenarios. Moreover, the effect of a local search on the performance of the Genetic Algorithm in terms of solution quality, convergence and computation time is also investigated.     

The impact of replenishment parameters and information sharing on the bullwhip effect: A computational study

Demand variability amplification across the supply chain, known as the bullwhip effect, results in serious inefficiencies across the chain. Managers are expected to minimize this phenomenon in their chain in order to reduce costs and increase customer satisfaction by making critical decisions on replenishment policy. We study how specific replenishment parameters affect order variability amplification, product fill rates and inventory levels across the chain. Furthermore, we study how demand information sharing can help towards reducing order oscillations and inventory levels in upper nodes of a supply chain. A two-stage supply chain consisting of a warehouse and stores that face customer demand is modeled. Real demand data are used as the underlying customer demand during the experiments.     

Coordination-based inventory management for deteriorating items in a two-echelon supply chain with profit sharing

This study develops a model for inventory management consisting of a two-echelon supply chain (SC) with profit sharing and deteriorating items. The retailer and the supplier act as the leader and follower, in which the supplier faces a huge setup cost and economic order quantity ordering strategy. The market demand is affected by the sale price of the product, and the inventory has a deterioration rate following a Weibull distribution. The retailer executes three profit-sharing mechanisms to motivate the supplier to participate in SC optimisation and to extend the life cycle of the product. A search algorithm is developed to determine the solutions as using the profit-sharing mechanisms. The outcomes from numerical experiments demonstrate the profitability of the proposed model.     

Determination and exchange of supply information for co-operation in complex production networks

Today's manufacturing industry is characterised by strong interdependencies between companies operating in globally distributed production networks. The operation of such value-added chains has been enabled by recent developments in information and communication technologies (ICT) and computer networking. To gain competitive advantages and efficiency improvements such as reduced inventory and higher delivery reliability, companies are introducing information exchange systems that communicate demand to suppliers and production progress information to customers in the network. This article proposes a system that supports co-operation in complex production networks by enabling companies to determine and exchange supply information with their customers. The requirements for such a system are analysed and it is embedded in a framework of supply chain management business processes. The system facilitates the determination and exchange of meaningful, reliable and up-to-date order status information from the supplier to the customer. Based on comparing the progress of an internal production order with a pre-defined milestone model for each product, the status of the customer order is determined and—in case of lateness—communicated to the customer together with an early warning. To demonstrate the developed supply information concepts and processes, the business process is implemented as a pilot system and evaluated by the user companies participating in the 5th Framework IST project Co-OPERATE.     

Manufacturing production plan optimization in three-stage supply chains under Bass model market effects

The Bass model is a very successful parametric approach to forecast the diffusion process of new products. In recent years, applications of the Bass model have been extended to other operational research fields such as managing customer demands, controlling inventory levels, optimizing advertisement strategies, and so forth. This study attempts to establish an application for optimizing manufacturers’ production plans in a three-stage supply chain under the Bass model’s effects on the market. The supply chain structure considered in this research is similar to other common supply chains comprised of three stages, namely retailer, distributor and manufacturer. The retailer stage has to handle customer demands following the Bass diffusion process. Market parameters and essential information are assumed to be available and ready for access. Each stage is expected to determine its inventory policy rationally. That is, each stage will attempt to maximize its own profits. These decisions will back-propagate their effects to upper stages. This study adopts a dynamic programming approach to determine the inventory policies of each stage so as to optimize manufacturers’ production plans.     

全球仓库配送系统创建高效的物流

The heart of any modern manufacturing business is an efficient warehouse management and distribution service. Customers' expectations about product delivery times and availability have changed such that they demand fast service-at low cost and with low errors. This paper introduces a computerized system solution called Warehouse Administration Service System or WASS, which enables the manufacturers, especially those manufacturers who are doing global business, to control their product flow from production to the customer. WASS supports the receiving, storing, shipping and inventory management of goods in which manufacturers create an effective logistics and supply chain management. The paper also shows the successful case that SKF* uses the WASS in its global warehouse distribution network to service customers in the most efficient way and concept of green supply chain.     

Coordinated ordering decisions for products with short lifecycle and variable selling price

The supplier–buyer coordination is an important policy in the supply chain management. The buyer in the two-echelon inventory system with regular selling season has to face the uncertainty of customer demand, supplier’s delivery time and variable price change. At the same time, the supplier has to consider the inventory holding and delay cost. The objective of this study is to develop an integrated supply chain strategy for products with short lifecycle and variable selling price to entice cooperation. The strategy must provide a win–win situation for both the supplier and the buyer. A numerical case example, sensitivity analysis and compensation mechanism are given to illustrate the model.     

双源采购跳跃-扩散库存控制模型

供应中断和退货会引发库存短缺和剧烈波动,所以,如何缓解它们的影响,成为当前企业管理者亟待解决的难题.在采用双源采购策略防御库存短缺和跳跃-扩散过程描述库存水平变化条件下,利用连续时间Markov链、水平穿越和鞅理论,分别确定了库存水平分布及循环的期望费用和时间函数,在此基础上,构建了系统长程平均费用率模型.最后,仿真结果表明,供应商的可靠性和中断类型,对最优控制策略和系统费用产生较大影响.另外,双源采购策略能够有效缓解供应中断对库存的影响,尤其是,当供应商的可靠性较低或中断类型均为频率低持续时间长时.     

整合供应商选择的多层级选址-库存模型

针对多级供应链网络设计中选址和库存一体化决策问题,基于梯级库存策略,建立了整合供应商选择的多层级选址-库存模型。模型以网络中供应商的选择成本、工厂和配送中心的打开成本、层级之间的运输成本、库存成本、采购成本和生产成本之和最小为目标,同时对供应商的选择、工厂和配送中心的选址、配送中心对顾客的分配、层级之间的运输量、工厂和配送中心的订货批量进行决策。为了求解所建立的模型,设计了基于部分编码的粒子群优化算法。20个不同规模的算例测试表明：所建立的模型是有效的,能用于多层级供应链网络的设计;所设计的算法无论是在求解精度,还是在运算速度上都明显优于数学优化软件Lingo 9.0,尤其是当供应链网络中总节点数较大时。     

Multi-objective optimization for inventory control in two-level assembly systems under uncertainty of lead times

Supply planning for two-level assembly systems under lead time uncertainties is considered. It is supposed that the demand for the finished product and its due date are known. The assembly process at each level begins when all necessary components are in inventory. A holding cost at each level appears if some components needed to assemble the same semi-finished product arrive before beginning the assembly at this level. It is assumed also that the component lead time is a random discrete variable. The objective is to find the release dates for the components at level 2 in order to minimize the expected component holding costs and to maximize the customer service level for the finished product. For this new problem, we consider two multi-objective approaches, which are both based on genetic algorithms. They are evaluated with a variety of supply chain settings, and their respective performance is reported and commented. These two heuristics permitted to obtain interesting results within a reasonable computational time.     

A collaboration model for new product development through the integration of PLM and SCM in the electronics industry

As customer requirements for high-tech products vary and become complicated, the lifecycle of these products becomes much shorter. In response to this market environment, many manufacturing companies have established a global simultaneous launch strategy for new products to occupy markets before competitors. In this process, careful scheduling of the global simultaneous launch strategy is critical. In particular, to meet the launch schedule for each country in which a new product will be released, a collaboration process among relevant departments must be prepared, and correct product information should be maintained among major cooperative work support systems according to new product development business processes. This paper suggests a collaboration model integrating product lifecycle management and supply chain management as an approach to supporting complicated new product development procedures. We use a practical case study to evaluate this model.     

闭环供应链混合切换库存控制模型研究

针对一类具有回收、再制造、再分销的闭环供应链系统,以再制造产品的补货能力为切换信号设计了基于再制造优先的混合切换库存控制策略,使得市场需求优先由再制造产品满足,并应用切换控制理论研究混合切换库存控制策略的性能特征,分析系统参数对闭环供应链系统的关键性能指标的影响。仿真分析表明,合理的切换控制策略可以有效抑制闭环供应链运作过程的波动,保证系统具有良好的“牛鞭效应”特征、平稳的库存管理成本以及较高的顾客服务水平。