供应链中控制多级存储的射频辨识Push/Pull混合策略设计与仿真

由于射频辨识(radio frequency identification,RFID)激励的电子看板系统能够从远端看见供应链节点企业库存的状况,使得广域分布的供应链多级存储能够实现RFID激励的Pull控制.本文根据供应链分销网络多级存储的结构特点,以及系统运作期间各阶段节点企业的功能,在不同阶段采用不同的控制策略.因此,设计了多种不同的RFID激励的Push/Pull混合控制策略.为了比较和验证各混合策略对多级存储的控制性能,建立了以总库存成本、总缺货损失、总运行成本和库存周转率作为评价策略性能的指标体系.由于供应链系统的动态性与随机性,难以进行数学建模和精确求解,因此基于离散事件系统仿真原理,设计并实现了仿真模型.通过对各策略下多种结构的供应链分销网络多级存储的仿真,验证并分析了制造商阶段采用Push控制,分销商和零售商阶段采用Pull控制的策略的有效性和最优性.     

信息共享受限条件下的供应链网络系统牛鞭效应控制策略

研究在信息共享受限条件下供应链网络库存系统的牛鞭效应控制问题,建立了包括市场需求、信息可获得性、信息及时性等不确定性因素的库存网络系统状态转移模型,从系统内部动力学机制的角度分析了牛鞭效应的成因,提出了动态库存控制策略,并给出了策略参数设计的线性矩阵不等式组算法.运用系统稳定性理论,深入分析了信息共享对牛鞭效应的影响,并通过仿真结果验证了库存控制策略的有效性和实用性.     

基于遗传算法和排队网的串联CONWIP系统流通卡数的确定方法

在CONWIP(constant work in process)系统中,流通卡数是系统有效运行的关键因 素.文中针对串联CONWIP系统,提出了非线性整数规划模型和排队网模型相结合的问题描述 模型,以及遗传算法与排队网络分析相结合的问题求解算法.实例仿真验证了该方法的有效性.     

基于模糊控制的拉式策略在装配生产控制中的应用

利用模糊控制鲁棒性强的特点, 将其引入单产品装配线的生产控制系统中, 构造新的拉式控制策略. 在建立控制系统周期审查模型和完成控制器设计的基础上, 通过缩小变异范围改进遗传算法求解以极小化在制品量和投放波动为目标, 顾客满意率为约束条件的多目标规划, 从而达到优化控制系统参数的目的. 为考察模糊控制系统性能, 通过实例与多阶段定量在制品法(Constant work-in-process, CONWIP)、Kanban和一般拉式策略 (Generic pull, GP) 系统进行比较, 结果表明模糊生产控制系统不仅能维持较低的在制品水平, 更重要的是能维持较低的订单投放波动水平.     

3级网状随机性库存控制策略的仿真优化

研究了多制造商,多分销商和多零售商的3级网状随机性库存系统的(r,Q)库存控制策略问题.由于该系统具有顾客到达时间服从泊松分布,随机顾客需求量,随机顾客购买行为,随机订货时间和制造商生产容量有限制等特点,使得解析方法很难描述系统中的多种复杂随机因素并无法求解有效的库存控制策略.为此建立了以总成本最小为目标的数学模型,运用了基于仿真的优化方法,通过将仿真方法与粒子群优化算法相结合对问题进行求解.最后通过仿真实例与比较,验证了模型和基于仿真的粒子群优化方法的可行性和有效性.也表明了基于仿真的优化方法在供应链管理中的适用性.     

基于遗传算法的纺织企业机配件库存控制

合理压缩库存量,降低库存成本对于纺织企业来说意义重大.建立了在非平稳需求下的库存控制模型,并采用遗传算法求解,给出了满足库存成本最小的(s,S)控制策略.通过求解某配件的(s,S)控制策略,验证了算法的有效.     

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。     

随机需求随机补货间隔零售商补货控制策略研究

研究分销系统中零售商的补货控制策略．分销系统中各零售商可独立决定自己的补到水平．零售商需求率是随机变量．服从某一泊松分布;分销中心循环为各零售商送货．送货间隔是随机变量．认为所有未满足的需求销售机会都丢失,零售商既要支付库存持有费用．又要支付缺货损失费用．给出了收益数学期望值函数,求出了送货间隔是均匀分布随机变量时使收益数学期望值最大化的零售商补到水平控制策略．     

RFID应用系统与ERP系统间的业务集成

传统的RFID(Radio Frequency Identification)应用系统或RFID中间件不支持与ERP系统的业务集成,而数据集成需要对ERP进行大规模系统重构.针对RFID技术应用与ERP系统集成问题,设计了以XML业务单据作为数据传输载体的业务中间件框架.详细介绍了基于XML语言的业务流程规则定义方法,并深入分析了实现单据交换解析的数据映射机制,以库存管理中的入库操作为例,系统地阐述完整的业务控制流程,最后以双沟酒业RFID项目的成功实施案例验证了该集成方案的有效性.     

基于RFID技术的烟草零售企业库存数据准确性研究北大核心CSCD

针对烟草零售企业供应链中普遍存在的库存数据失真问题,建立了在(Q,R)补货策略条件下RFID技术对烟草库存数据影响的数学模型,并进行了计算机仿真研究,通过对比RFID技术实施前后烟草库存数据的变化情况,说明了RFID技术可有效地提高烟草零售企业库存数据的准确性、减少缺货问题的发生,进而提高烟草销售商的运营效率。     

Development and evaluation of a Basestock-CONWIP pull production control strategy in balanced assembly systems

In this study, a new pull production control strategy called Basestock-Constant Work-in-Process (B-CONWIP) is proposed. It is used to control the flow of materials and information in balanced assembly production systems. This proposed control strategy uses one type of authorization cards called CONWIP card that limits the work-in-process (WIP) in the whole system. It has been applied in a single-product and a mixed-product assembly system balanced by two efficient Genetic algorithms introduced in literature. The performance of this control strategy is compared with another pull production control strategy called Basestock Kanban CONWIP (BK-CONWIP), which is a very promising production control strategy found in literature. The proposed strategy has two control parameters, CONWIP authorization cards and basestock levels while BK-CONWIP has three control parameters Kanban authorization cards, CONWIP authorization cards and basestock levels. The comparison is based on three performance measures average system WIP, percentage of satisfied customer demand (service level) and WIP variation between workstations. The performance of the proposed strategy B-CONWIP and BK-CONWIP is mainly similar in both types of assembly systems when mean demand rates are low with respect to mean service rates with the proposed strategy being easier to control and optimize. On the other hand, when mean demand rates are high with respect to mean service rates; B-CONWIP is preferable if service level is more important, while BK-CONWIP is preferable if WIP level is more important. Regarding WIP variation, it mainly depends on the efficiency of the balancing approach. The more efficient the balancing approach, the less WIP variation. Treating demand as lost instead of backordered results in decreased average system WIP and does not affect service levels in both PCSs. It is also shown that S-KDP is more flexible in dealing with situations of variable product mixes than d-KDP because control parameters can be used by any product which minimizes the effect of the unbalanced systems.     

A hierarchical model of the impact of RFID practices on retail supply chain performance

The primary purpose of this study was to evaluate the impact of radio frequency identification (RFID) practices on supply chain performance. We examined eight variables of RFID applications grouped in two categories: location (supplier’s warehouse, retailer’s central warehouse, retailer’s local warehouse, retailer’s owned stores) and utilisation (standards, transportation, pallet level, specialised software). Given the inherent difficulty in assessing supply chain performance and the widespread use of different performance models, such as the SCOR and balanced scorecard, we developed a list of performance indicators. Factor analysis produced 7 supply chain performance factors: supplier, inventory, distribution, ordering, plan, sales, and forecasting.Empirical data were collected via an online survey administered to 300 retail companies. 130 usable questionnaires were returned, for a 43.3% response rate. To the best of our knowledge, this is the first study to provide an analytical model that places supply chain performance indicators as dependent variables in a hierarchical regression equation with RFID variables as independent variables. Results found that the implementation of RFID practices significantly affect the supply chain performance in the following areas: supplier, inventory, distribution, plan, sales, and forecasting. RFID can improve the performance of distribution systems, including products dispatched and inventory in transit by 33.8% and stock availability by 45.6%. This study contributes to both the RFID and the supply chain performance literatures. Limitations and suggestions for further research are also discussed.     

基于库存切换的不确定动态供应链网络系统模糊鲁棒控制

研究基于库存切换的不确定动态供应链网络系统的鲁棒运作问题.首先,建立含有系统参数不确定和顾客需求不确定的动态供应链网络的离散T-S模糊模型;然后,提出一种新的模糊鲁棒控制策略,该控制策略不仅可以有效遏制子系统切换时产生的较大波动,而且可以抑制不确定因素对供应链网络的影响,进而保证供应链网络在不确定环境下鲁棒稳定;最后,通过仿真实例表明了所提出模糊鲁棒控制策略的有效性.     

Improving inventory effectiveness in RFID-enabled global supply chain with Grey forecasting model

A RFID-enabled global TFT–LCD supply chain associated with Grey forecasting model (GM) of Company A has been simulated and analyzed in this research. Three key performance indicates (KPI) including total inventory cost, inventory turnover and bullwhip effect are analyzed in the simulation experiments in order to compare the effectiveness of five different supply chain inventory models. The effectiveness of integrated system which is composed of supply chain operation, Grey short-term forecasting model and RFID system has been examined by aforementioned three KPIs. According to the result of Taguchi experiments, RFID-enabled R-SCI_GM supply chain model which integrates the GM(1,1) forecasting model based on (s, Q) pull-based replenishment policy reduces 43.36% of the total inventory cost compared with that of the non-RFID SCI_GM model. It apparently shows that a great improving effectiveness of supply chain inventory cost can be conducted while RFID system is incorporated with the GM(1,1) forecasting model.     

An assessment model for RFID impacts on prevention and visibility of inventory inaccuracy presence

Bullwhip effect has been considered as one of major research topics in supply chain management. Most of the studies disregarded the mismatch between the recorded inventory and the reality. However, it is shown that the inventory inaccuracy under uncertainty is a widespread phenomenon in both retail and distribution centers. Due to the propagation of information distortion along the supply chain, the financial impacts of inventory inaccuracy include not only the cost of direct inventory loss but also the increasing holding and shortage cost at each stage. The emergence of RFID technology offers a possible solution to alleviate the growing cost of inventory inaccuracy. By making full use of RFID technology, this paper attempts to compare the inventory inaccuracy impact on bullwhip effect in terms of order variance amplification and supply chain performance under two scenarios: (1) all members are aware of the inaccuracy and optimize their operations; (2) all members deploy RFID technology to reduce inventory inaccuracy. Informed order policy is used as benchmark to capture the true RFID value and differentiate two types of RFID impacts, prevention and visibility, to provide more manageable insight. In particular, the incentive of sharing information in supply chain is also provided by comparing the cost of two supply chain settings.     

基于零售商资金约束供应链采用RFID技术的决策及融资分析

为研究零售商存在资金约束和库存错放时,供应链成员采用无线射频识别(radio frequency identification,RFID)技术及融资决策的均衡问题,以单制造商和单资金约束零售商组成的两级供应链为研究对象,基于报童模型构建供应链成员采用RFID技术前后零售商是否融资4种情景下的收益模型,求解出相应的最优解并探讨供应链成员RFID采用决策与零售商的融资策略.研究发现:当零售商的自有资金适中时,供应链成员采用RFID技术一定程度上能够缓解零售商的资金约束;零售商选择融资时,供应链及其成员能够承担更高的RFID成本;零售商分摊RFID固定成本的比例对制造商、零售商和供应链能够承担的RFID标签成本阈值有决定性的影响.     

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。     

含时滞的不确定性供应链网络系统牛鞭效应控制策略及其经济性能分析

考虑需求、生产能力、供应链结构等内外不确定性因素和供应链系统运作延迟,构建了不确定环境下含时滞的供应链库存网络系统状态转移模型.针对牛鞭效应问题,提出了基于库存水平波动状态的控制策略和相应的经济性能指标;借助线性矩阵不等式方法,深入分析库存策略的参数优化设计对牛鞭效应以及经济性能的影响.仿真结果表明,在经济性能约束下,该库存策略具有较强的牛鞭效应遏制能力,从而表明了策略的有效性和实用性.