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1.
以电信业为背景,在不确定需求下研究了两周期电信供应链的投资决策和订货策略.考虑供应商第1周期投资可以减小第2周期成本,建立了两周期二级供应链订货模型,分析了3种订货策略:集中式供应链订货策略、供应商占主导地位的订货策略和制造商占主导地位的订货策略.分别给出了不同订货策略下的最优订货量和收益分享比例,并比较了不同订货策略下的订货量.结果表明集中式决策下的订货量总是介于2种分散式决策下订货量之间,制造商对订货策略的选择不依赖于供应商的投资行为,而供应商对订货策略的选择依赖于投资所能减小的单位成本的大小.  相似文献   

2.
根据连锁经营企业的特点,提出了各分店和配送中心集中订货和相互之间在商品上的支援调拨策略。在理论上证明了集中订货和支援调拨策略可以降低总体订货量,通过模拟实验验证了该策略能够降低总体订货量的波动。建立了集中订货和支援调拨策略的数学模型。使用实际案例验证了该策略和模型能够带来显著的订货和库存量的下降和服务水平的提高。  相似文献   

3.
考虑了在订货时间不确定且EOQ不是整数情况下的最优订货量问题.通过平衡不确定性订货时间下库存成本和订货成本的策略,将不确定性订货时间下的最优订货问题转化为求解一般确定性订货时间下的订货问题.并进一步探讨了当EQQ不是整数时,如何通过建立数学规划来得到非平稳最优订货量.在数学规划模型的基础上,提出了一种新的启发式算法,同时给出了和一般求解方法GA算法的数值比较结果,验证了该启发式算法的有效性.  相似文献   

4.
建立了需求率依赖于库存量的单一供应商与单一零售商供应链库存及协调决策模型,首先分别对渠道内双方目标函数的性质进行分析,得出分散决策时零售商的最优订货量,并证明了集中决策供应链存在唯一最优的订货批量.进一步,采用零售商非线性信用期成本的核算方式,给出了能够取得供应链协调的供应商全信用期补贴策略.通过分析协调后供应链内双方...  相似文献   

5.
基于库存管理的基本目标,针对销售商库存管理行为对整个供应链产生的影响进行了研究,利用系统动力学的方法构造一个销售商的进货方式模型,综合考虑了销售的不同情况,利用系统动力学专业软件Vensim构建模型仿真,对销售商的订货行为进行仿真实验.并分析了根据销售量来决定订货量和综合考虑销售和库存因素决定订货量两种策略下各种指标的变化趋势,给出适合销售商经营特点的策略方案.  相似文献   

6.
基于传统的EOQ模型,研究以制造商碳排放量最小化和制造商利润最大化为目标的多目标优化决策模型。模型中制造商的碳排放量并不是单纯的与订货量呈线性关系,而是考虑每次订货时,运输产生的碳排放量与订货次数呈线性关系,库存产生的碳排放量与库存量呈线性关系。采用加权求和的多目标规划解法对模型进行求解,分析了碳税对多目标决策的影响,发现不同隶属度权重下,多目标决策的订货量、需求和碳排放量均呈现出不一样的变化趋势,说明碳税政策对于企业具有明显的减排效果。对于环保意识强的企业,政府应该采取降低碳税的政策;对于重视经济利益的企业,政府应该增加碳税来减少碳排放量。  相似文献   

7.
应用实验室和心理测量等方法,在高利润环境下研究了理性与经验决策者对于报童问题的订货决策差异及其原因。研究发现:相对于弱理性风格决策者,强理性风格决策者的订货量更接近最优订货量,所获得的期望利润更高,且表现出更低的需求追逐、中心化锚定和过度自信偏好;而相对于弱经验风格决策者,强经验风格决策者的订货量更偏离最优订货量,所获得的期望利润更低,且表现出更高的需求追逐、中心化锚定以及过度自信偏好。这些研究发现可为相关管理人员的选择及其订货决策的改善,提供理论支持和实践指导。  相似文献   

8.
姚胜  钱静 《包装工程》2008,29(2):88-90
探讨了在需求正态分布下不同包装策略下的库存量计算方法,并对相同的需求不确定性、需求相关系数、包装分布下包装延迟策略对库存的影响进行了分析比较.通过比较发现包装延迟策略在客制化需求日益增加的情况下,包装延迟策略能在一定程度下降低库存,为企业带来一定的收益.  相似文献   

9.
熊超  罗敬龙  杨明学  安定 《硅谷》2012,(14):12-12,48
将库存平均费用降至最低,是库存问题一直关注的问题之一,库存问题由于需求量、需求时间等相关变量的随机性,很难达到供求相等的情况,是广义的排队论模型,用常规方法很难得出准确结论,但是可以通过C++编程对库存问题进行仿真,主要研究定量订购法,即在库存量小于某个量时重新订货。建立在定量订购法的基础上,寻找最佳订货点,从而使库存管理策略达到最优,使花费资金最少。运用排队论相关原理,以订货量,临界库存量为自变量,平均总费用为因变量,运用相关数学模型,用隐枚举法搜索出平均总费用最小的库存方案,通过计算机系统仿真,得出变化规律,对现实中得库存问题有一定指导意义。  相似文献   

10.
根据短生命周期产品的特征调整BASS扩散模型,并将其应用于短生命周期产品的需求预测,同时考虑产品需求对无形变质和短缺拖后量的影响,进而建立短生命周期产品多周期订货模型。通过算例分析获得短生命周期产品的成熟期开始时间和持续时间,进而求订货次数和订货量,给出多周期最优订货策略。数据实验结果显示基于BASS需求函数的库存控制模型可以提高需求预测精确度,有效降低库存成本,对企业库存控制具有指导意义。  相似文献   

11.
A combined manufacturing/remanufacturing system is modelled and its dynamic behaviour is investigated using a control engineering approach. The model is an extension of the automated pipeline, inventory and order based production control system (APIOBPCS), which is well understood from a dynamic perspective. It is assumed that the remanufacturing process is based on a PUSH policy. Utilising different levels of information transparency from the remanufacturing process, three system types are developed and compared. Mathematical and simulation analyses of the system types were undertaken and their robustness to remanufacturing process uncertainties were tested. Our analysis indicates that the greater the degree of information transparency, the greater the robustness of the hybrid system.  相似文献   

12.
We study the material requirements planning (MRP) system nervousness problem from a dynamic, stochastic and economic perspective in a two-echelon supply chain under first-order auto-regressive demand. MRP nervousness is an effect where the future order forecasts, given to suppliers so that they may plan production and organise their affairs, exhibits extreme period-to-period variability. We develop a measure of nervousness that weights future forecast errors geometrically over time. Near-term forecast errors are weighted higher than distant forecast errors. Focusing on replenishment policies for high volume items, we investigate two methods of generating order call-offs and two methods of creating order forecasts. For order call-offs, we consider the traditional order-up-to (OUT) policy and the proportional OUT policy (POUT). For order forecasts, we study both minimum mean square error (MMSE) forecasts of the demand process and MMSE forecasts coupled with a procedure that accounts for the known future influence of the POUT policy. We show that when retailers use the POUT policy and account for its predictable future behaviour, they can reduce the bullwhip effect, supply chain inventory costs and the manufacturer’s MRP nervousness.  相似文献   

13.
The inventory model in this paper is targeted to production systems with constant production rates but underlying possibilities for undesirable circumstances to threaten the production schedule. The inventory policy proposed explicitly considers energy cost when determining optimal size for order quantity, safety stock and inventory cycle length such that the total expected cost per unit time is minimised. The results are compared to a traditional inventory policy that does not consider the direct impact of energy cost. An analysis of the model reveals three production environment characteristics in which inventory policies are most significantly affected by changes in energy cost: heavy product weight, high regular product demand or high emergency product demand. If any one of the three key factors increases, then changes of the inventory decisions or related logistics costs become more significant. The cost effectiveness of implementing the proposed inventory policy also becomes more significant as any one of the three key factors increase with respect to energy cost.  相似文献   

14.
Bullwhip and inventory variance in a closed loop supply chain   总被引:1,自引:0,他引:1  
A simple dynamic model of a hybrid manufacturing/remanufacturing system is investigated. In particular we study an infinite horizon, continuous time, APIOBPCS (Automatic Pipeline Inventory and Order Based Production Control System) model. We use Åström’s method to quantify variance ratios in the closed loop supply chain. Specifically we highlight the effect of a combined “in-use” and remanufacturing lead-time and the return rate on the inventory variance and bullwhip produced by the ordering policy. Our results clearly show that a larger return rate leads to less bullwhip and less inventory variance in the plant producing new components. Thus returns can be used to absorb demand fluctuations to some extent. Longer remanufacturing and “in-use” lead-times have less impact at reducing inventory variance and bullwhip than shorter lead-times. We find that, within our specified system, that inventory variance and bullwhip is always less in supply chains with returns than supply chains without returns. We conclude by separating out the remanufacturing lead-time from the “in-use” lead-time and investigating its impact on our findings. We find that short remanufacturing lead-times do not qualitatively change our results.  相似文献   

15.
This paper focuses on the discrete-time automatic pipeline, inventory and order-based production control system (APIOBPCS), a well-established production and inventory control model. The feedback mechanism within the replenishment rule enables the model to mitigate the bullwhip effect, but introduces a stability problem. In this research, a comprehensive stability analysis is conducted for arbitrary lead times using difference equation theory. On the basis of stability, a state space approach is advocated to analyse the impact of replenishment parameters, demand processes, and lead times on the robustness of the bullwhip effect. The stability results demonstrate that the production control system can easily be destabilised without incorporating the work-in-progress (WIP) feedback loop. Furthermore, it reveals that the stability problem for long lead times can be simplified with the stability condition independent of the lead time. The results obtained in this study provide useful guidelines for the selection of replenishment parameters to guarantee stability and mitigate the bullwhip effect.  相似文献   

16.
Supply and production uncertainties can affect the scheduling and inventory performance of final production systems. Facing such uncertainties, production managers normally choose to maintain the original production schedule, or follow the first-in-first-out policy. This paper develops a new, dynamic algorithm policy that considers scheduling and inventory problems, by taking advantage of real-time shipping information enabled by today’s advanced technology. Simulation models based on the industrial example of a chemical company and the Taguchi’s method are used to test these three policies under 81 experiments with varying supply and production lead times and uncertainties. Simulation results show that the proposed dynamic algorithm outperforms the other two policies for supply chain cost. Results from Taguchi’s method show that companies should focus their long-term effort on the reduction of supply lead times, which positively affects the mitigation of supply uncertainty.  相似文献   

17.
Inventory based capacity control (INCAP) is a very simple method that allows inventory levels to be effectively controlled by using short-term capacity flexibility in make-to-stock settings. Moreover, INCAP can be used for finished goods inventories as well as for semi-finished goods inventories. The basic idea is to define upper and lower inventory limits and to adjust capacities if the inventory level reaches either limit. Should the inventory fall below the lower limit, capacity is increased to prevent stock-outs. Similarly, in order to avoid excess inventories the capacity is decreased should the inventory rise above the upper limit. INCAP is thus able to control inventory levels within a defined inventory range. In order to do so, it applies short term measures like over-time or extra shifts to increase capacities and cancels work hours or shifts to decrease capacities. Simulation experiments based on data from the automotive industry show that INCAP is able to improve the performance of a manufacturing system in that it significantly reduces the inventory levels necessary for guaranteeing a satisfactory service level. Overall, INCAP is found to be a straightforward but powerful method, able to cope both with uncertainties in production output as well as with varying demand. However, some restrictions do apply: INCAP depends not only on a minimum level of short-term capacity flexibility, but also in the standard set-up presented here it is limited to make-to-stock environments with similar products.  相似文献   

18.
A new forecast-based dynamic inventory control approach is discussed in this paper. In this approach, forecasts and forecast uncertainties are assumed to be exogenous data known in advance at each period over a fixed horizon. The control parameters are derived by using a sequential procedure. The merits of this approach as compared to the classical one are presented. We focus on a single-stage and single-item inventory system with non-stationary demand and lead-time uncertainty. A dynamic re-order point control policy is analysed based on the new approach and its parameters are determined for a given target cycle service level (CSL). The performance of this policy is assessed by means of empirical experimentation on a large demand data set from the pharmaceutical industry. The empirical results demonstrate the benefits arising from using such a policy and allow insights to be gained into other pertinent managerial issues.  相似文献   

19.
This paper develops a fuzzy inventory model to counteract the demand fluctuation in supply demand networks, which combines fuzzy logic controller with (s,?S) policy based on economic order quantity (EOQ) model. Following a literature review and a discussion of counteractions to the bullwhip effect and the obstruction of general counteraction in supply demand networks, a multi-echelon fuzzy inventory model in supply demand networks is proposed. A simulation model with one- and two-echelon supply demand network is built and tested for (s, S) policy based on the classical EOQ model and the proposed fuzzy inventory model. Based on the simulation, results of the relevance performance are presented and discussed, which show that the proposed multi-echelon fuzzy inventory model provides not only a cost-effective management of inventory (e.g. lower inventory levels and cost) in market uncertainty, but also another effective alternative for counteracting demand fluctuation. In particular, the proposed multi-echelon fuzzy inventory model shows benefit in counteracting demand fluctuation in multi-echelon supply demand networks. Finally, some conclusions and suggestions for further research works are presented.  相似文献   

20.
基于企业全面库存的管理思想,对库存成本、库存控制、库存系统优化等管理经验与前人研究成果进行分析,借鉴先进企业的库存管理理念和方法,以大型制造企业为核心研究对象,在集供应商、制造商、经销商为一体的供应链作为研究框架的基础上,运用供应链系统理论作为研究方法,分析了库存管理现状、影响因素及产生原因,从优化生产管理、整合企业内部供应链和跨企业供应链的角度提出了库存控制的相应对策,以实现全面的库存优化,提高经营效益。  相似文献   

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