基于时变需求的树型多级库存优化研究

考虑到战术仓库的需求率具有时变性的特点,应用供应链管理的思想研究了一个战役仓库、多个战术仓库组成的树型多级库存优化问题,建立了战役仓库采用延迟化订货策略、战术仓库分别采用等间隔或等量订货策略时的模型,并采用自适应遗传算法实现了模型的求解,实例验证了模型及算法的有效性.实验结果表明,战术仓库采用延迟订货策略,战术仓库采用等量订货策略时总费用最低.     

供应链环境下的装备多级库存优化研究

研究了一个战役级、多个战术级仓库组成的树型多级库存系统,建立了战役级仓库分别采用等量等间隔、不等量等间隔订货策略的模型。采用自适应遗传算法实现了模型的求解,并用实例验证了算法的有效性。     

基于遗传模拟退火算法的军用仓库选址研究

战区物资供应强度大,运力有限,军用仓库选址的合理与否会直接影响到战役、战术物资供应的效率,该文运用遗传模拟退火算法研究了军用仓库选址问题,实例验证充分说明了遗传模拟退火算法在收敛速度及跳出局部极值的能力诸方面明显优于标准的遗传算法和模拟退火算法。     

两阶段需求相关的动态易逝品最优订货策略

以动态市场环境下的易逝品为研究对象,针对两阶段需求相关、每次订货时带有固定的订购费用以及未满足需求部分延期供给等实际现象,建立了动态易逝品销售商两阶段订货决策模型.对模型的最优解进行了理论分析,并提出了寻求两阶段订货策略的简单方法.以朗科优盘经销商的采购实例来说明该模型的应用价值.最后,通过探讨订货决策与需求波动、两阶段需求相关系数以及延期供给率等因素的关系,得出了一些重要的管理启示.     

基于混合需求的二级库存系统协同订货模型

在一般的二级库存优化模型均做如下假定：供应链的每一级节点面临的需求都是独立需求。但在实际中,只有最下游的节点面临的需求是独立需求,而其上游节点面临的需求都是与之相关的相关需求。因此,建立了基于混合需求的协同订货模型。将面临独立需求的最下游节点的订货合并为一个虚拟节点的订货策略,再对二级节点采用相关需求策略进行协同订货,从而构建使整体最优的模型。并给出了模型求解的遗传算法,最后对模型进行了实例演算。     

战役战术作战数据基与计算模型研究

本文从高技术局部战争的作战特点和实战需要出发,提出了战役战术作战数据基的概念,阐述了"未战而决胜负,先胜而后战"的作战思想和战役战术作战数据基与可计算性的重要意义,并对战役战术作战指挥控制软件设计的基本计算模型进行了探讨性研究。     

基于混合果蝇优化算法的选址-库存联合优化策略

针对装备维修保障仓库系统运营费用高、仓库点位布局不合理、备件库存结构不合理等问题,建立以多品种联合补货问题为基础的装备维修备件仓库选址-库存控制决策联合优化模型,模型可用于求解仓库的开设位置、维修活动需求点的指派情况、仓库补货时间以及库存水平等.根据模型的结构特点,利用多种群协同进化的方法改进传统果蝇优化算法的位置更新方式,设计一种内外两层搜索策略的混合果蝇优化算法,外层搜索策略作为算法的主程序用于搜索仓库选址决策变量,内层搜索策略采用改进的RAND算法用于搜索库存控制决策变量.仿真结果表明,混合果蝇优化算法具有良好的求解效率,能够确保库存系统在一定服务水平的基础上有效降低库存运营总成本.     

基于多级库存策略的网络营销模型设计

基于多级库存策略的网络营销模型设计这一课题,设计多级库存策略下的网络营销模型首先构建多级库存网络营销的成本函数为订货费用加上运输费用,划分库存管理营销层次,对模型数据进行统一化处理,基于销售层次最终建立网络营销模型.通过实例运用,与其他两种网络营销模型相比较,证明了多级库存策略的网络营销模型能有效地降低库存成本,提高营业额,具有推广性.     

基于AirSim平台的无人机蜂群侦察搜索仿真与分析

当前关于无人机蜂群侦察搜索运用的研究缺乏可供参考的具体战术运用的模式分析方法.针对上述问题,基于AirSim仿真平台,通过对具体战术背景下的无人机蜂群进行仿真与分析来选择最优策略,提出模式分析的方法.首先,以AirSim仿真平台为基础设计无人机蜂群仿真模型和模拟环境;其次,提出用于模式分析的指标和计算方法;然后,结合战术背景设计基于长条策略的横队队形、基于螺旋策略的横队队形、基于长条策略的三角队形和基于长条策略的分组队形等4种运用模式;最后,通过仿真收集数据进行模式分析.仿真实验结果表明:无人机蜂群对明确区域进行侦察搜索时,采用基于长条策略的横队队形模式和基于长条策略的分组队形模式较合理.     

变压器故障灰色Verhulst预测模型的研究

针对变压器试验在时间上具有非等间隔的特点,对传统等间隔Verhulst灰色模型进行了改进,提出了基于非等间隔Verhulst灰色模型的变压器故障预测方法.建立了非等间隔Verhulst灰色预测模型,该模型不仅考虑了预测数列的非等间隔性,还从初始条件选择、背景值改造等方面对原有模型进行了改进,实例验证表明本文提出的方法具有较高的精度.     

普通立体仓库的货位优化模型与算法研究

在物流仓储的总成本中,库存成本占很大比重。企业为了减少库存成本,不断设法去改进和优化仓库"存储"的过程。针对普通立体仓库的入库过程,在考虑叉车载重、货位容量和存储策略等限制条件下,建立了以入库作业过程中工作人员行走总路程最小为目标的货位优化模型。根据问题和模型特点,将货位优化问题分为两层优化:货位选择优化层和货位顺序优化层;然后将传统遗传算法同启发式算法相结合对模型进行求解;最后通过仿真实验验证了模型和算法的合理性和可行性。该成果可用于解决多数普通仓库的货位优化问题。     

Pareto遗传算法在货位配置中的应用研究

固定货架是自动化立体仓库应用最广泛的存储设备，货位配置是否优化直接影响货架的稳定性和存取操作效率。因此，建立了货位配置优化问题的数学模型，提出了采用Pareto遗传算法解决多目标组合优化问题，可得到Pareto最优解集。此算法包括5个基本算子：选择、变异、交叉、小生境技术、Pareto集合过滤器。通过仿真实验验证了将Pareto遗传算法应用在实际货位配置优化问题中，取得了较好的结果。     

智能化立体仓库入库货位分配的综合优化算法

智能化立体仓库对现代企业提高仓储利用率和生产效率具有重要作用。介绍了秦皇岛港务集团公司立体仓库管理系统中仓库货位计算机分配的智能化算法,该算法充分考虑了重量均匀分布、就近货位选择、备件品种均匀分布、备件使用率、货位空置时间等因素,根据整个仓库的当前状态计算入库货位,为入库货位的选择提供辅助决策。实际项目运行表明,所提的综合货位优化分配算法是有效的,对提高仓库的安全性、入库工作效率等具有非常重要的意义.     

Particle swarm optimization for bitmap join indexes selection problem in data warehouses

Data warehouses are very large databases usually designed using the star schema. Queries defined on data warehouses are generally complex due to join operations involved. The performance of star schema queries in data warehouses is highly critical and its optimization is hard in general. Several query performance optimization methods exist, such as indexes and table partitioning. In this paper, we propose a new approach based on binary particle swarm optimization for solving the bitmap join index selection problem in data warehouses. This approach selects the optimal set of bitmap join indexes based on a mathematical cost model. Several experiments are performed to demonstrate the effectiveness of the proposed method on the bitmap join index selection problem. Further testing of the method is performed using a database environment specific cost function. The binary particle swarm optimization is found to be more effective than both the genetic algorithm and data mining based approaches.     

A multi-warehouse inventory model for items with time-varying demand and shortages

This paper develops a deterministic replenishment model with multiple warehouses (one is an owned warehouse and others are rented warehouses) possessing limited storage capacity. In this model, the replenishment rate is infinite. The demand rate is a function of time and increases at a decreasing rate. The stocks of rented warehouses are transported to owned warehouse in continuous release pattern. The model allows shortages in owned warehouse and permits part of the backlogged shortages to turn into lost sales—which is assumed to be a function of the currently backlogged amount. The solution procedure for finding the optimal replenishment policy is shown. As a special case of the model, the corresponding models with completely backlogged shortages and without shortages are also presented. The models are illustrated with the help of numerical examples. Sensitivity analysis of parameters is given in graphical form.Scope and purposeIn practical inventory management, there exist many factors like an attracted price discount for bulk purchase, etc. to make retailers buy goods more than the capacity of their owned warehouse. In this case, retailers will need to rent other warehouses or to rebuild a new warehouse. However, from economical point of views, they usually choose to rent other warehouses. If there are multiple warehouses available, an important problem faced by the retailers is which warehouses to be selected to hold items replenished, when to replenish as well as what size to replenish. For such a problem, the existing two-warehouse models, based on an unrealistic assumption that the rented warehouse has unlimited storage capacity, presented some procedures for determining the optimal replenishment policy. This paper extends the existing two-warehouse models in three directions. Firstly, the traditional two-warehouse models assumed the storage capacity of the rented warehouse unlimited. The present paper relaxes this impractical assumption and considers the situation with multiple rented warehouses having a limited capacity. Secondly, the traditional two-warehouse models considered a constant demand rate or a linearly increasing demand rate. In this model, the demand rate varies over time and increases at a decreasing rate, which implies an increasing market going to saturation. Thirdly, we extend the two-warehouse models to the case with partially backlogged shortages. The purpose of this paper is to build a multi-warehouse replenishment model to help decision-makers solve the problem of which warehouses to be chosen to store items replenished and how to replenish.     

基于效能评估的导弹战术决策支持技术初探

美国"战斧Ⅳ"巡航导弹可以用于打击地面战术目标和移动目标,扩展了战术打击能力.针对具备类似作战能力的导弹,为了能够给战术指挥员提供有效的辅助决策支持,以便对飞行中的导弹进行战术调整和目标重新瞄准,讨论了基于效能评估来辅助战术决策的思想和方法.首先从分析导弹武器系统作战效能评估应具备的功能入手,建立了导弹武器系统效能的评估指标体系,并详细描述了战术机动性能指标的计算方法,最后,通过战术想定和作战模拟验证,得到的结论是,采用这种辅助决策技术可以显著提高导弹的作战效能.     

Two-echelon, multi-commodity supply chain network design with mode selection, lead-times and inventory costs

Designing distribution networks - as one of the most important strategic issues in supply chain management - has become the focus of research attention in recent years. This paper deals with a two-echelon supply chain network design problem in deterministic, single-period, multi-commodity contexts. The problem involves both strategic and tactical levels of supply chain planning including locating and sizing manufacturing plants and distribution warehouses, assigning the retailers' demands to the warehouses, and the warehouses to the plants, as well as selecting transportation modes.We have formulated the problem as a mixed integer programming model, which integrates the above mentioned decisions and intends to minimize total costs of the network including transportation, lead-times, and inventory holding costs for products, as well as opening and operating costs for facilities. Moreover, we have developed an efficient Lagrangian based heuristic solution algorithm for solving the real-sized problems in reasonable computational time.     

A hybrid genetic algorithm based heuristic for an integrated supply chain problem

Supply chain management is becoming an essential component of efficient decision-making for companies, as they are increasingly implementing optimization strategies in order to improve their business performance. In this paper we develop a capacitated multi-echelon joint location-inventory model, according to which a single product is distributed from a manufacturer to retailers through a set of warehouses, the locations of which are to be determined by the model. Each retailer is assigned exactly one warehouse, while each warehouse can serve multiple retailers. The model decides where to locate warehouses, assigns retailers to the warehouses and decides the times between orders at the warehouses and the retailers, so as to minimize the cost of operating the supply chain. Notably, the model considers capacity constraints for each warehouse, ensuring that the reorder quantity is below the capacity limit. We develop a genetic algorithm (GA) based heuristic to solve the problem and the GA is validated on small size problems by comparing its solution to the optimal solution obtained by the General Algebraic Modeling System (GAMS). We focus our attention on specifically customizing the GA and thus an experimental analysis is carried out to find the optimal parameter setting for the GA as well as to obtain insights on the effect of the various GA parameters. Finally, a sensitivity analysis is conducted to show the effect of the capacity constraints.     

一种基于轨道均匀分布的混沌遗传优化算法*

提出一种轨道均匀分布的混沌遗传优化算法。根据logistic映射概率密度分布,得到轨道均匀分布的反三角函数logistic映射。结合遗传算法,构造混合混沌算法。该算法在混沌优化区间等概率搜索子空间,克服了logistic映射优化算法对优化区间边缘进行大概率搜索的缺点,从而有效地提高搜索速度。仿真算例表明了该方法的可行性和反三角函数logistic映射的应用前景。