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1.
A multi-echelon inventory system implies the existence of a hierarchy of stocking locations, and the dependence and interaction between them. We consider a multi-echelon, spare-part inventory management problem with outsourcing and backordering. The problem is characterized by deterministic repair time/cost, and supply and demand that lie within prescribed intervals and that vary over time. The objective is to minimize the total inventory and transportation costs. We develop a network model for problem analysis and present a network flow algorithm for solving the problem. We prove that the Wagner-Whitin property, known for the lot-sizing problem, can be extended to the spare-part inventory management problem under study.  相似文献   

2.
In the inventory model, people usually assume that the inter-demand time is independently identical distributed which may not be true in reality. Here we study an (s,S) continuous review model for items with an exponential random lifetime and a general Markovian renewal demand process. By constructing Markovian renewal equations, we derive the mean and the variance of the reorder cycle time and lead to a simple expression for the total expected long run cost rate. The numerical results illustrate the system behavior and lead to managerial insights into controlling such inventory systems.  相似文献   

3.
We argue that the influence of the home country wanes as the firm increases its geographic reach. We introduce the concept of the “home base” to capture the effect of the set of countries in which the firm operates. We expect the dynamic liability of foreignness defined relative to the home base to be a better predictor than the static liability of foreignness defined relative to the home country. We also expect the diversity of foreign experience to increase foreign market entry. We find support for these hypotheses with data on Chinese listed firms investing abroad between 1991 and 2007. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

4.
The commonly recommended network approach to project monitoring and scheduling can make very useful, detailed contributions to individual projects. However, it has not yet been adequately developed to deal with a large number of projects, particularly where considerable uncertainties are involved. To try to overcome this weakness an attempt has been made to use a project model that is so simple that it can easily be handled in large numbers. Although details of individual projects are lost, considerable benefit can be obtained from analyses of the resulting, collective data. This approach has been used successfully for some time to present project programmes and progress with the work in an engineering development laboratory and is currently being extended to assist with multi-project scheduling.  相似文献   

5.
In this paper, we propose an iterative approach to jointly solve the problems of tactical safety stock placement and tactical production planning. These problems have traditionally been solved in isolation, even though both problems operate in the same decision making space and the outputs of one naturally serve as the inputs to the other. For simple supply chain network structures, two stages and one or many products, we provide sufficient conditions to guarantee the iteration algorithm’s termination. Through examples, we show how the algorithm works and prove its applicability on a realistic industrial-scale problem.  相似文献   

6.
This paper presents a particle swarm optimization approach for inventory classification problems where inventory items are classified based on a specific objective or multiple objectives, such as minimizing costs, maximizing inventory turnover ratios, and maximizing inventory correlation. In addition, this approach determines the best number of inventory classes and how items should be categorized for the desired objectives at the same time. Experiments are employed to determine the best combination of algorithm parameter values. Extensive numerical studies are conducted and results are compared to other known classification methods. The performance of the algorithm on a practical case is also presented.  相似文献   

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This paper examines the robustness of a standard model of multi-echelon inventory systems, specifically the models discussed in Axsäter (Oper. Res. 48(5) (2000) 686). A simulation model was developed to explore the model's ability to predict system performance for a two-echelon one-warehouse, multiple retailer system using (R,Q) inventory policies under conditions that violate the model's fundamental modeling assumptions. In particular, the impact of non-stationary demand on this stationary demand inventory model was examined. The model performs well at the low demand and large retailer order batch size situations, but our testing of the model indicated that care must be taken when applying this model to situations that violate its fundamental assumption. These results should help practitioners to better understand the assumptions of these models and to determine when or when not to apply these models in practice.  相似文献   

9.
We formulate a general mixed produce-to-order and produce-in-advance inventory model having multiple stocking echelons and multiple retailers. We show that the problem to find an optimal inventory policy for such a model with a uniform or a normal demand distribution can be reduced to a general constrained optimization problem.  相似文献   

10.
It is common sense that the premises usually considered in inventory models have little applicability to new product inventory management. This paper develops a first practical approach to deal with this issue: the solution to the (Q, r) inventory model for uniform demand forecasts and lead-times. Based on the fact that the uniform distribution is defined by two parameters that are easy to estimate—maximum and minimum—this paper shows that such a premise may comprise a helpful and accurate decision support tool for managers until they begin to learn about the distribution characteristics of the demand during the lead-time.  相似文献   

11.
Recently, the amount of literature on analyzing the effects of investment strategies to control lead times has been increasing. Issues on investment to reduce lead times are important because variability in lead time between successive stages often has a great effect on the coordination of supply chain.This paper considers dual-sourcing models with stochastic lead times and constant unit demand in which lead times are reduced at a cost that can be viewed as an investment. In order to obtain an analytically tractable model, the distributions of lead times for two suppliers are assumed to be exponential. In our two-supplier model, we will concentrate on lead times as random variables, which are made endogenous in the stochastic lead-time model through “expediting factors”, the constants of proportionality between the expedited lead times and ordinary lead times, as was done by Bookbinder and Çakanyildirim (Eur. J. Oper. Res. 115 (1999) 300).Firstly, we determine the order quantity (Q), reorder point level (r), and order splitting proportion (k1) in the case of no lead-time reduction. Using the (Q,r) found, we decide the expediting factors and new k1 in the case of lead-time reduction. We compare the expected total cost per unit time for the two models and investigate savings. Additionally, sensitivity analyses are conducted with respect to the various cost parameter ranges, and remarks are made for further research.  相似文献   

12.
叶纶  何娟 《河北工业科技》2014,31(2):100-105
随着保理融资各交易阶段的进行,保理商所承受的风险相对由高至低,保理商利润非负的临界质押率水平及利率水平都发生了相应的动态变化。从价格波动规律出发,以进出口保理融资业务为代表,在满足下侧风险限制条件下,提出保理商针对各交易阶段提供融资业务利率的决策模型,并在此基础上分析保理融资中质押率、价格、违约可能性与利率的相互关系。研究得出利率水平随着各交易阶段的进行呈逐渐降低的趋势,灵活把握融资各阶段质押物价值、违约等风险因子变化,有利于降低融资风险性。  相似文献   

13.
Production-runs are an important cost minimizing scheduling and production planning activity. Commonly used classic lot-sizing models (i.e., economic manufacturing quantity or EMQ models) do not reflect current just-in-time (JIT) lot-sizing cost realities. The purpose of this paper is to present a cost comparison of the classic EMQ model and a revised EMQ/JIT model to show efficacy of a more cost inclusive model.  相似文献   

14.
Given a product design and a repair network for capital goods, a level of repair analysis determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which location in the repair network to do this. In this paper, we show how the problem can be modelled as a minimum cost flow problem with side constraints. Advantages are that (1) solving our model requires less computational effort than solving existing models and (2) we achieve a high model flexibility, i.e., many practical extensions can be added. Furthermore, we analyse the added value of modelling the exact structure of the repair network, instead of aggregating all data per echelon as is common in the literature. We show that in some cases, cost savings of over 7% can be achieved. We also show when it is sufficient to model the repair network by echelons only, which requires less input data.  相似文献   

15.
We report on two studies (a single and a multi‐industry) that empirically investigate a nomological network of relationships between strategic business unit product‐market strategy (differentiation, cost‐focus, and product‐market scope), marketing capabilities (architectural and specialized capabilities, as well as their integration), and business unit performance (market effectiveness and subsequent one‐year objective cash flow), along with a series of controls. Addressing important lacunae in the resource‐based view our main research objective is to augment understanding of how critical firm‐level marketing capabilities enable the realization of strategy, thus, further advancing both the resource‐based view and more recent capabilities theorizing. Specifically, we test seven hypotheses and find strong evidence that both architectural and specialized marketing capabilities, and their integration, positively mediate the product‐market strategy and derived business unit performance relationship. In contrast to many extant studies, both survey and objectively measured data are combined, and because the secondary data collected contains both resource‐level (input) data and subsequent one‐year financial data, a higher level of confidence may be attributable to our findings. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

16.
While comprehensive, ongoing competitive intelligence systems generate valuable input for broad strategic decisions, they often fail to provide the specific actionable information needed by managers operating in a project-oriented environment. This paper proposes a project-based framework for competitive analysis. The framework was developed from field reseach involving 16 projects. A comparison of project-based and comprehensive competitive analysis systems is made to illustrate their differences. A case example from field research is utilized to illustrate concepts central to this approach and its practical utility. A set of guidelines regarding pitfalls to avoid in project-based competitive analysis is presented.  相似文献   

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Past attempts to rationalize the many methods of technological forecasting have not been sufficiently practical; they have largely been based on an abstract sort of classification while their use has been of an ad hoc nature. This paper reviews the position and puts forward a rationale leading to a more logical classification of methods and a systematic approach to their use in practice. The proposed classification and systematic use of the many methods is based on the concept that a technological forecast has four prime elements or dimensions, qualitative, quantitative, time and probability. Only when all these elements are provided can a technological forecast be responsibly used in decision making in R & D and corporate planning.  相似文献   

20.
In this work we propose an efficient dynamic programming approach for computing replenishment cycle policy parameters under non-stationary stochastic demand and service level constraints. The replenishment cycle policy is a popular inventory control policy typically employed for dampening planning instability. The approach proposed in this work achieves a significant computational efficiency and it can solve any relevant size instance in trivial time. Our method exploits the well known concept of state space relaxation. A filtering procedure and an augmenting procedure for the state space graph are proposed. Starting from a relaxed state space graph our method tries to remove provably suboptimal arcs and states (filtering) and then it tries to efficiently build up (augmenting) a reduced state space graph representing the original problem. Our experimental results show that the filtering procedure and the augmenting procedure often generate a small filtered state space graph, which can be easily processed using dynamic programming in order to produce a solution for the original problem.  相似文献   

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