Some Inventory Models for Information Systems

A considerable amount of research has been done on the rapidly evolving technological alternatives for information systems and data base design. Enthusiasm for the feasibility of such systems may have overridden consideration of their value to management. In this paper information is treated as a commodity to be inventoried. Models similar to traditional inventory models are developed to include a novel aspect of information—-that depletion does not accompany demand. The concept of shortage cost is extended to provide a management tool reflecting the value of various levels of information content in the determination of optimal strategies for additions to and deletions from information systems.     

矩阵损失下线性混合模型中的局部线性Minimax估计

本文研究了一般线性混合模型中固定效应和随机效应的线性组合的Minimax估计问题.在矩阵损失函数下,考虑了这个组合的线性估计在线性估计类中的局部极小极大性.关于适当的假设,得到了线性可估函数的唯一局部线性Minimax估计.     

Finite-horizon equipment replacement analysis

The optimal solution to the infinite-horizon equipment replacement problem with stationary costs is to continually replace an asset at its economic life. The economic life is the age that minimizes the Equivalent Annual Cost (EAC), which includes purchase, operating and maintenance costs less salvage values. We explore the question of whether this is a good policy for the finite-horizon problem, which occurs when companies only require an asset for a specified length of time, usually to fulfill a specific contract. We identify cases, according to capital costs, operating costs, and the interest rate, when this policy is good and when it deviates significantly from optimal. Furthermore, we provide a bound on the minimum number of times that an asset is retained at its economic life over a finite horizon. This is facilitated through a new dynamic-programming formulation to the problem based on the integer-knapsack problem with nonlinear costs. The bound can be derived from any feasible solution, although we provide a closed-form solution for the case of convex EAC values.     

多品种生产库存模型的几个问题

首先讨论了在一台设备上同时加工几种产品的同周期生产库存模型，并且给出了一个补充条件。其次，对于产品之间存在一定比例关系的情形，提出了一个生产库存的最优化模型。进一步还讨论了多品种库存的一般性模型。     

Finite-horizon variance penalised Markov decision processes

We consider a finite horizon Markov decision process with only terminal rewards. We describe a finite algorithm for computing a Markov deterministic policy which maximises the variance penalised reward and we outline a vertex elimination algorithm which can reduce the computation involved.     

两类存贮订购模型

以经济采购批量为出发点通过对几种采购存贮模型的分析,建立了以获利效率为比例系数的采购模型和综合分类采购模型,使模型具有一定的通用性和指导作用,并给出其适用范围,再通过具体计算示例,说明该方法的有效性.     

Sensitivity of Cost Functions in Inventory Models

This article is concerned with the effects of alternative forms of surplus and shortage cost functions and also with the effects of alternative forms of probability density function of demand in an inventory control situation.     

Some Network Flow Models and Heuristics for Multiproduct Production and Inventory Planning

The focus of this paper is on modelling dynamic, deterministic, multiproduct, multistage production planning problems as single commodity network flow problems. The advantages of such formulations are discussed relative to computation of good integer solutions and continuous solutions with additional constraints. Special results for a single period problem are developed.     

Continuous Review Perishable Inventory Systems: Models and Heuristics

We consider continuous review perishable inventory models with renewal batch demands. Assuming zero lead time, we construct an embedded Markov chain. With a probabilistic approach, we derive a closed-form long run average cost function under the (s, S) replenishment policy. Numerical analysis is then used to identify the properties of the cost function and to demonstrate the impacts of changing batch sizes and other system parameters. Based on these results, a heuristic approach to handle problems with positive lead times is proposed. The performance of the heuristics against simulation results demonstrates its effectiveness and accuracy     

基于协同补货期库存协调模型的扩展研究

在协同预测的库存补充策略和基于协同补给期的一个供应商与一个订货商之间的库存协调策略的研究基础之上,主要研究一个供应商与多个订货商库存协调策略,并与协调之前的库存成本相比,用数值实验的方法证明了合作能够降低供应商与订货商的库存成本,增加效益,给供应链带来了整体效益.     

包装企业库存优化管理模型分析

就包装企业库存管理信息系统的特点、实行库存优化控制管理的必要性、库存控制数学模型、ＡＢＣ库存分类控制法及库存管理功能模块的作了一些探讨。     

Two-Parameter Approximations For Multi-Echelon Repairable Inventory Models With Batch Ordering Policy

In this paper we present a model for multi-echelon repairable systems with batch ordering policy at the bases. Such an ordering policy is desirable when demand rates and/or the set up cost for ordering are relatively high. Operating characteristics of such a system are analyzed. A two-parameter approximation scheme for the distribution of the number of orders outstanding and consequently backorders is developed, and its performance evaluated. It is found that, under a variety of scenarios including both finite and infinite servers at the repair facility, the approximation scheme is very effective in providing a relatively simple means to determine the stocking levels at both the depot and the bases to minimize the cost of inventory holding and backorders. For the special case when the batch size is one, we confirm the effectiveness of the use of the negative binomial distribution as an approximation for the distribution of orders outstanding, as suggested by recent studies, under a much more general setting.     

集群式供应链多级跨链间库存协作模型研究

针对集群式供应链多级跨链间库存管理协作,利用系统动力学仿真方法,分别探讨了相同链节之间库存互补模型和不同链节之间库存互补模型,并对比分析这两种库存互补模型.通过对仿真数据进行分析得出,采用不同链节之间库存互补能够在保持库存水平不发生较大变化的前提条件下较大地提高顾客需求满足率,并且能够较稳定地保持这种高水平满足率,因此采用不同链节之间库存互补模型,比采用相同链节之间库存互补模型更有优越性.     

Minimax centre estimation for inspection of spherical parts

A mathematical programming formulation is presented for the problem of finding the centre and radius of the sphere such that the largest distance from a sample of points to the boundary of the sphere is minimized. This problem has application in spherical parts inspection. The problem is non-convex, so necessary optimality conditions are developed and used in an exact algorithm. An heuristic technique is shown to produce very good solutions in a short time. Computational experience is included.     

一类极大极小优化问题的信赖域算法

借助于K-T条件和NCP函数,提出了处理一类极大极小优化问题的信赖域算法。数值实验结果表明该方法足行之有效的。     

一类极大极小优化问题的信赖域算法

借助于K-T条件和NCP函数,提出了处理一类极大极小优化问题的信赖域算法.数值实验结果表明该方法是行之有效的.     

基于极小极大算法的双臂机器人精度提升方法

针对双臂机器人绝对精度和协作精度的指标要求,基于激光跟踪仪测量的双臂末端三靶球点位数据,使用极小极大的搜索算法,提出了鲁棒的双臂机器人运动学几何参数校准方法.该方法分两步:首先,分别对左右两臂的几何参数进行校准,在左(右)臂末端安装三个靶球,以三个测量点中的最差绝对定位误差为指标函数建立非线性优化问题,确保校准结果的鲁...