基于排队的库存服务系统最优控制策略

研究一个连续盘点的(s,Q)补货的库存服务系统。基于排队理论建立库存水平状态平衡方程,并推导出库存水平稳态概率分布以及作为库存控制的系统稳态性能指标。以库存成本最小化为目标,构建服务水平约束的库存控制模型。针对模型的非线性约束与整数型变量的特征,采用一种改进的遗传算法(IGA)用于决策变量的寻优。数值实验表明,当目标服务水平大于库存系统内生的服务水平时,实施服务水平约束能够降低库存控制成本。     

一类弹性振动系统的控制问题

本文讨论具结构阻尼系数的细长体飞行器的弹性振动方程支配系统的最优控制问题 .本文将结构阻尼系数作为控制变量 ,以“范数最小”来衡量其最优性 .证明了弹性振动系统存在唯一的最优控制元     

Optimal Solutions in the Multi-location Inventory System with Transshipments

We consider a single-period multi-location inventory system where inventory choices at each location are centrally coordinated. Transshipments are allowed as recourse actions in order to reduce the cost of shortage or surplus inventory after demands are realized. This problem has not been solved to optimality before for more than two locations with general cost parameters. In this paper we present a simple and intuitive model that enables us to characterize optimal inventory and transshipment policies for three and four locations as well. The insight gained from these analytical results leads us to examine the optimality conditions of a greedy transshipment policy. We show that this policy will be optimal for two and three locations. For the n location model we characterize the necessary and sufficient conditions on the cost structure for which the greedy transshipment policy will be optimal.      

模糊需求下的库存风险及最优库存决策

分析了在模糊需求下,按经典库存模型中的经济订货批量和订货周期所导致的库存风险损失。推导了模糊需求下的经济风险函数。给出了风险函数在模糊需求分布下的重心决策方法,在此基础上得到了模糊需求下经济批量的修正公式,为模糊库存风险分析的研究提供了一种方法。     

Optimal Inventory Rule for a Linear Trend in Demand with a Constant Replenishment Period

The classical deterministic inventory model is considered for the case of constant time between each replenishment and linear trend in demand. The optimum policy is derived and shown to apply to both positive and negative trends. This policy is used in two examples considered in earlier papers on linear trend. It is shown to give only slightly higher costs than the optimal policy with varying replenishment periods, and is compared with a recent heuristic for that case.     

具有年龄结构的竞争系统的最优输入率控制的存在性

本文研究了一类具有年龄结构的竞争种群系统的最优输入率控制的存在性问题.利用不动点定理,下半连续和Ekeland变分原理,得到了最优控制的存在唯一性.     

Monitoring an Exponential Smoothing Forecasting System

The first part of this paper is concerned with the variance of the smoothed error when the forecasting system being used is exponential smoothing. The expression derived for this variance involves the variance of the noise, the smoothing constant and a sum of squared binomial coefficients. It is also shown that the variance of the sum of errors equals the variance of the smoothed error for one less degree of freedom divided by the square of the smoothing constant.The second part of the paper considers the practical application of the above result and also gives values for the tracking signal limits, obtained by simulation, which could be used in the automatic monitoring of a forecasting system.     

三级备件保障系统下的备件库存优化模型

目前我军装备备件保障通常采用三级保障模式,以各级备件期望短缺数量之和最小为目标,研究在不同库存水平条件下,三级备件保障系统的备件库存优化模型.经示例分析,验证了该模型的可行性和有效性,该结果可为多级备件保障提供理论依据.     

Analysis of the Optimal Relaxed Control to an Optimal Control Problem

Relaxed controls are widely used to analyze the existence of optimal controls in the literature. Though there are many optimal control problems admitting no optimal control, rare examples were shown. This paper will solve a particular optimal control problem by analyzing the optimal relaxed controls, showing the ideas we used to study such kind of problems. This work was supported by NSFC (No. 10671040), FANEDD (No. 200522) and NCET (No. 06-0359).     

Optimal Control of Failure-Prone Manufacturing Systems with Constant Repair Times

This paper considers a failure-prone manufacturing system with exponentially distributed operational times and constant repair times. Under the hedging-point policy, the steady-state probability density function of the buffer level is determined. The optimality of the hedging-point policy for this problem is proven, and analytical expressions for the computation of the optimal hedging point are determined. It is also shown that the optimal hedging point for the system with constant repair times provides a lower bound for the optimal hedging point for any other independent, identically distributed (iid) repair time sequence having the same mean. Using a queueing equivalence, an expression is derived for determining the optimal hedging point for any iid repair time sequence.     

一类机器人系统的最优控制

本文通过把结构阻尼系数当作控制变量来讨论一类弹性机器人系统的最优控制问题 ,并利用Banach空间几何性质证明了最优控制元的存在唯一性     

Optimal Control of an Elastic Tyre-Damper System with Road Contact

We study an elastic tyre with a wheel rim that is suspended at the chassis of a car by means of a spring-damper element. This quarter car model may be controlled by varying the damping constant of the electrorheological damper. Our mathematical model yields a coupled ODE-PDE problem with a free boundary at the tyre-road contact. In this study we approximate the tyre by the Hertz contact stress formula. The resulting optimal control problem with control constraints is solved numerically. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

一个备用部件的可修复人机系统的最优控制

讨论了两个运行部件并联和一个储备部件组成的可修复系统的非负解以及系统在某一时刻T的最优控制问题.     

损失制库存系统中最优订货量的若干分析

有损失制库存系统中的最优订货问题,一直是供应链管理中的一个重点和难点;本文主要研究两阶段损失制库存系统在总费用最小化的目标下;各阶估贩最优订货量大小,最终给出了第一阶段最优订货量的取值范围和第二阶段中最优订货量的精确表达式,以及当系统参数变动时,订货量的变化情况。     

允许租用货栈的库存系统的最优进货策略

本文从实际背景出发，提出了允许租用货栈的库存系统的库存模型，在一般时变需求并允许短缺的假定下，得到了寻求该系统最优进货策略的一种交替逼近方法。并给出了数字例子。     

供应链多级系列系统库存控制策略

供应链管理的目标是通过成员间的密切合作和信息共享,以最小的成本提供最大的客户价值(包括产品的服务),这就要求供应链上各节点企业的活动同步进行,对库存管理职能进行必要的整合,集中管理整个供应链系统的库存,从而降低整个供应链的库存成本.基于供应链多级系列系统为研究对象,给出了在需求率为恒定情况下的级库存的表达方式,提出了递归搜索的概念,并采用该办法求出了多级系列系统的最佳订货周期及批量,计算出了多级系统最小总费用.