分布式库存系统策略探讨与仿真

如何解决供需不平衡,实现供应链中成本与服务水平的协调控制是研究的一个重要问题,分布式库存系统的实施关键在于决策持有多少库存以及需求到达时库存缺乏如何处理。以具有自主决策权的几个零售商为对象,研究其库存转移状况,以及成本与服务水平,通过建立库存调拨模型,提出了三种调拨策略,包括自私型调拨策略,合作型调拨策略,混合型调拨策略,并根据这三种策略运用Anylogic软件进行仿真,分析比较三种策略的有效性,以得到最优结果。

Abstract：

The key point of the study is how to solve the imbalance of supply and demand, and how to coordinate the cost and service level in the supply chain. To solve the key problems in implementing the multi-location inventory system which lie in deciding how many items to hold at each retailer and how to deal with if there is a demand for an item at a retailer that has none of them in stock. A few independent decision-making retailers are the main research objects. It was targeted to study the transfer of their inventory status, as well as the costs and service levels, and through the establishment of inventory transshipment model, three transshipment strategies, including self-based strategy, cooperation-based strategy, hybrid strategy, were suggested. Then the software of Anylogic was adopted to simulate, analyze and compare the effectiveness of the three strategies in order to obtain optimal results.     

A perishable inventory system with service facilities, <Emphasis Type="Italic">MAP</Emphasis> arrivals and <Emphasis Type="Italic">PH</Emphasis> — Service times

We consider a continuous review perishable （s,S） inventory system with a service facility consisting of a waiting hall of finite capacity and a single server. We assume two types of customers, ordinary and negative, arrive according to a Markovian Arrival Process （MAP）. An ordinary customer joins the queue and a negative customer instead of joining the queue removes one ordinary customer from the queue. The removal rule adopted in this paper is RCE （removal of a customer from the end）. The individual customer＇s unit demand is satisfied after a random time of service which is assumed to have a phase-type distribution. The life time of each item and the lead time of the reorders have been assumed to be independent exponential distributions. The joint probability distribution of the number of customers in the system and the inventory level is obtained for the steady state case. Various stationary system performance measures are computed and the total expected cost rate is calculated. The results are illustrated numerically.     

A comparative study of the inventory system with service facility and postponed demands

In this article, we present a continuous review （s,S） inventory system with a service facility consisting of finite buffer （capacity N ） and a single server. The customers arrive according to a Poisson process. The individual customer＇s unit demand is satisfied after a random time of service, which is assumed to be exponential. When the inventory level drops to s＇an order for Q（= S-s） items is placed. The lead time of reorder is assumed to be exponential distribution. An arriving customer, who finds the buffer is full, enters into the pool of infinite size or leaves the system according to a Bernolli trial. At the time of service completion, if the buffer size drops to a preassigned level L （1 〈 L 〈 N） or below and the inventory level is above s, we select the customers from the pool according to two different policy ： in first policy, with probability p （0 〈 p 〈 1） we select the customer from the head of the pool and we place the customer at the end of the buffer; in the second policy, with p （0 〈 p 〈 1） the customer from the pool is transferred to the buffer for immediate service and after completion of his service we provide service to the customer who is in the buffer with probability one. If at a service completion epoch the buffer turns out to be empty, there is at least one customer in the pool and the inventory level is positive, then the one ahead of all waiting in the pool gets transferred to the buffer, and his service starts immediately. The joint probability distribution of the number of customers in the pool, number of customers in the buffer and the inventory level is obtained in the steady-state case. Various stationary system performance measures are computed and total expected cost rate is calculated. A comparative result of two models is illustrate numerically.     

Prediction Model on Chinese Annual Live Hog Supply and Its Application

In this paper,a prediction model on Chinese annual live hog supply was established.With cointegration test,backward and forward stochastic selection and other methods,four main factors(hog price,prices of inputs in hog production,the level of hog inventory,as well as emergency and government policy) were chosen from 16 relevant factors to establish the model and make improvement.Applied the improved model,annual live hog supply in China from 2013 to 2016 was predicted in three scenarios.The predicted results showed that if there were no major emergencies from 2013 to 2016,there would be an upward trend in Chinese live hog supply year by year.The supply of live hogs in China in 2013 would be about 707.663 million head,in 2014 would be between 715.935 and 742.969 million head,in 2015 between 734.458 and 779.413 million head,and in 2016 between 750.923 and809.450 million head.     

AN AGENT—BASED SIMULATION ON MARKET CONSIDERING KNOWLEDGE TRANSITION AND SOCIAL IMPACT

In this paper, an agent-based simulation about knowledge transition associated with social impact in market is introduced. In the simulation, the genetic algorithm is used to generate the next generation products and a dynamic social impact model is used to simulate how customers are influenced by other customers. The simulation and its results not only show some features and patterns of knowledge transition, but also explore and display some phenomena of business cultures. On the basis of the innovation model of knowledge-based economy, the transition between technical knowledge and products knowledge is discussed, and a fuzzy linear quantification model which can be used to simulate the transition is introduced.     

基于Extend与HLA的装备保障仿真集成研究

分析了Extend应用于装备保障仿真的不足,在讨论基于HLA的装备保障仿真系统的基础上,提出了Extend与HLA/RTI的四种仿真集成方式,依据Extend模型是否需要与HLA/RTI进行时间同步分别给出了集成方法,设计了基于适配器的Extend与HLA集成框架,详细说明了适配器的组成功能及工作流程,最后利用一个装备保障仿真系统应用实例证明了仿真集成的思路是可行的和必要的。

Abstract：

Because of the shortages of Extend software applied to equipment support simulation,four integration types between Extend and HLA were proposed about the building of equipment support simulation system based on HLA.According to whether Extend simulation model was synchronous to HLA/RTI on the mechanism of advance simulation time,the methods were respectively put forward to support these types,and an integration architecture between Extend and HLA was designed based on a general adaptor.The components and functions of this adaptor,and its running mechanism were detailedly analyzed later.Finally,an application of a simulation system proves that the idea to integrate the two platforms is feasible.     

装甲装备月份维修计划优化制订方法研究

分析装甲装备月份维修计划的制订目前存在的问题,通过研究任务与装甲装备月份维修计划之间的相关关系,提出了根据任务的强度确定维修时机为优化目标的维修计划优化模型,统筹考虑维修资源、规章制度等因素。经LINGO软件仿真验证,结果显示该模型能够极大化装备的使用效益,实现科学化、精确化的送修,以及对装备的集约化管理。

Abstract：

The problems were analyzed that lay in the formulation of the armored equipment month maintenance plan. Based on researches about the relationship between the mission and the month maintenance plan, a maintenance plan optimization formulation model was brought forward. The model took factors such as maintenance resources, rules and regulations into overall consideration, and selected maintenance opportunity based on the strength of the mission as optimization goal. The model was validated by LINGO simulation. The result shows that the model can not only maximize the use efficiency, but also realize the scientific and precise delivery and the intensive management of the equipment which needs preventive maintenance.     

Product design on the basis of fuzzy quality function deployment

In the implementation of quality function deployment （QFD）, the determination of the target values of engineering characteristics is a complex decision process with multiple variables and multiple objectives that should trade off, and optimize all kinds of conflicts and constraints. A fuzzy linear programming model （FLP） is proposed. On the basis of the inherent fuzziness of QFD system, triangular fuzzy numbers are used to represent all the relationships and correlations, and then, the functional relationships between the customer needs and engineering characteristics and the functional correlations among the engineering characteristics are determined with the information in the house of quality （HoQ） fully used. The fuzzy linear programming （FLP） model aims to find the optimal target values of the engineering characteristics to maximize the customer satisfaction. Finally, the proposed method is illustrated by a numerical example.     

新型压电式气动PWM数字比例阀建模及仿真研究

针对采用电磁铁为电-机械转换器的传统气动PWM比例阀存在着响应时间慢,稳态精度差等缺点,提出了一种以压电叠堆为电-机械转换器的新型压电式气动PWM数字比例阀,建立了其数学模型,并利用Matlab/Simulink建立其仿真模型;通过仿真及试验结果的对比,证明了所建数学模型是准确的。仿真研究了先导阀芯输出位移、PWM载波频率及PID控制等对阀性能的影响,为今后进一步优化结构参数及控制参数的选择提供了依据。

Abstract：

The traditional electro-pneumatic PWM proportional valve driven by electro-mechanical converter of electromagnet has the disadvantages of slow response and poor control precision etc.To solve this problem,a novel piezoelectric type pneumatic PWM digital proportional valve driven by the electro-mechanical converter of piezoelectric stack was proposed.The mathematics model of PWM proportional valve was set up and its simulation model was built by means of Matlab/Simulink.By the comparison of simulation and experiment results,the built mathematical model was proved to be accurate.Moreover,the effect of pilot valve core displacement,PWM carrier frequency and PID control to the PWM valve performance was researched by simulation,which will provide theoretical steering to further optimize the valve structure parameters and the choice of control parameters.     

Synchronization of chaos using radial basis functions neural networks

The Radial Basis Functions Neural Network （RBFNN） is used to establish the model of a response system through the input and output data of the system. The synchronization between a drive system and the response system can be implemented by employing the RBFNN model and state feedback control. In this case, the exact mathematical model, which is the precondition for the conventional method, is unnecessary for implementing synchronization. The effect of the model error is investigated and a corresponding theorem is developed. The effect of the parameter perturbations and the measurement noise is investigated through simulations. The simulation results under different conditions show the effectiveness of the method.     

一类随机需求下分销系统的主从对策模型及仿真

针对由一个制造商(主方)和一个经销商(从方)组成的分销系统,在一类兼具价格弹性和服务敏感性的随机需求模式下,给出了经销商和生产商利润函数,建立了分销系统主从对策模型,并用数值方法进行求解。最后,通过仿真比较了这类需求模式与仅具有价格弹性的随机需求模式对分销系统绩效的影响,同时也分析了需求波动的变化、经销商目标利润率的变化、价格折扣的变化给模型带来的影响。     

基于模型预测控制的供应链操作优化仿真方案

基于模型预测控制算法为供应链中的操作决策问题建立动态定量的供应链整体系统模型进行研究,结合供应链特点改进目标函数,使得利润最大化同时保证了客户服务最大可能地接近期望水平,提出了一整套供应链滚动操作优化决策方案,为供应链决策者提供一体化的动态决策支持;并进一步针对不确定性市场需求的现实,引入风险值库存管理策略,定量测量和控制需求预测误差带来的库存风险,设计出应用于需求不确定市场环境下供应链滚动操作优化决策方案.基于GAMS的仿真结果证明了算法的有效性.     

库存管理模拟Multi-Agent建模方法研究

针对物流库存管理决策问题,把客户满意度作为考核系统效率的关键指标之一,研究库存系统中的出入库量、服务水平、库存规则以及各种成本等要素之间的关系,提出一种基于多智能体的系统模拟建模方法。建立库存管理模拟Multi-Agent系统,模拟运行结果可以给出库存补进建议,帮助管理人员进行决策。研究了一个应用实例,利用具体历史数据对建模方法和模型进行了验证和分析。     

网络化制造环境下离散供应链系统预测控制策略

针对离散供应链系统中客户需求的高度不确定性，提出最小方差控制方法。该方法相对于传统的预测控制策略，更适合于追踪需求变化减少或消除“牛鞭效应”。首先，将具有z变换的各单元传递函数整合成一个闭环传递函数，以此为整个供应链网络建模，采用白回归移动平均模型描述客户需求趋势，并通过客户需求预测确定两种库存目标水平。其次，建立基于订单策略的目标函数，利用最小方差预测器处理客户需求，提出了供应链的性能指标函数和“牛鞭效应”的分析方程，并通过设定最小方差控制器参数调节超额库存和未交付订货。最后，仿真结果表明最小方差控制在预测市场变化、追踪客户动态需求和保持合理库存水平上是可行和有效的。     

集群式供应链跨链库存应急互补的仿真和优化

基于系统动力学,考察一供应链应急库存补充来自于另外其他相邻供应链,也即集群式供应链.对两供应链中两零售商跨链间的库存应急互补进行建模和仿真.在此基础上,通过改变库存满足销售周期,以及将单级跨链互补扩展到两级和三级跨链互补,来优化和改善库存管理.研究发现,当同时存在三级(供应商商、生产商和零售商)跨链库存互补时,集群式供应链的两单链库存平均值和波动幅度大为减少,并且两链的顾客需求满足率均得到较大提高.最后,设计出了一种混合式契约,来实现这种集群式供应链跨链间库存应急互补的协调和合作.     

顾客选择行为与库存

库存成本与顾客服务水平之间的权衡是供应链库存管理中的一个主要内容，从顾客服务水平的内涵出发，通过在两级树型库存系统引入顾客价值函数，构建出新的权衡顾客服务水平与库存成本的模型，并模拟分析了顾客选择行为对库存成本的影响。     

流程式多品种成批轮番生产的分批与调度集成

随着顾客需求多样化和个性化,现代流程工业已由过去单一品种大量生产转向广泛采用多品种成批生产方式.本文基于供应物料和库存约束得出逐阶段加工中各批之间的优先级关系,采用连续时间建模策略建立了流程式多品种成批轮番生产分批和调度集成决策的混合整数规划模型,该模型考虑了计划决策方面的分批与调度集成,以及生产工艺上的多阶段、共享生产装置(设备)、库存限制、品种切换调整时间和物料动态转化率,在此基础上给出了模型求解的改进粒子群算法.通过企业实际背景算例验证了所给出规划模型的有效性和求解算法的良好性能.这既是对流程式多品种成批轮番生产分批及调度理论的拓展,也为流程工业企业多品种成批轮番生产管理实践提供了理论依据和方法支持.     

An M/M/1 Queueing-Inventory System with Geometric Batch Demands and Lost Sales

This paper studies an M/M/1 queueing-inventory system with batch demands. Customers arrive in the system according to a compound Poisson process, where the size of the batch demands for each arrival is a random variable that follows a geometric distribution. The inventory is replenished according to the standard (s,S) policy. The replenishment time follows an exponential distribution. Two models are considered. In the first model, if the on-hand inventory is less than the size of the batch demands of an arrived customer, the customer takes away all the items in the inventory, and a part of the customer’s batch demands is lost. In the second model, if the on-hand inventory is less than the size of the batch demands of an arrived customer, the customer leaves without taking any item from the inventory, and all of the customer’s batch demands are lost. For these two models, the authors derive the stationary conditions of the system. Then, the authors derive the stationary distributions of the product-form of the joint queue length and the on-hand inventory process. Besides this, the authors obtain some important performance measures and the average cost functions by using these stationary distributions. The results are illustrated by numerical examples.     

需求季节性变动的血液库存系统仿真研究

以国内某大型医院的血液库存系统为对象,建立了一个离散事件系统仿真模型,根据该血液库存系统运行的历史数据统计得到模型中参数的分布规律,通过仿真模型的重复运行得出了系统的最优订货点.考虑到该系统需求季节性变动的特征,对模型进行了改进,提出了一个预期订货点模型,仿真实验表明预期订货点策略能更有效地降低库存成本.本文的研究有助于血液库存管理措施的制定与改进,对其它易变质物品库存管理也有一定的借鉴作用.     

考虑变质策略的库存系统的动态建模与仿真

首先通过选择使库存总费用的日平均值最低的最优库存策略，建立了收复杂的变质的库存系统的仿真模型，然后基于MATLAB／Simulink软件动态实时模拟了变质的（t，s，S）策略下的库存系统的入库、出库时机和数量。仿真结果清晰、直观，为现代经营者做出正确的库存决策提供了有价值的参考。