供应链存储系统无线射频识别使能的定量在制品法控制策略仿真

无线射频识别(radio frequency identification,RFID)技术的出现为库存控制策略的创新提供了一条有效的途径.本文利用RFID技术,将原有单个制造系统的流通卡系统推广到供应链的多级库存网络中,设计了RFID使能的电子流通卡系统.基于电子流通卡,实现了RFID使能的定量在制品法(constant work-in-process,CONWIP)控制策略;并建立了CONWIP控制策略的分销网络模型.为比较和验证CONWIP控制策略性能,开发了三级分销网络仿真系统,使用该系统,将其与RFID使能的(r,Q)策略进行比较,验证了CONWIP策略在一定条件下,能够有效降低存储成本、提高服务水平.     

多重入生产线的CONWIP投放方法研究

CONWIP（Constant Work in Process）是一种基于拉式（pull）控制物料投放的方法。最初应用于Flow Shop式生产系统,通过限制半成品数量以控制生产线运作提供可靠的制造周期。然而,原始的CONWIP方法不能适应半导体这类同一加工站多重人的生产系统。该文根据半导体生产线多重人的特性,提出与多重人瓶颈相结合的CONWIP投放方法,不仅控制生产线中的半成品数量,并且结合了TOC（Theory of Constraints）思想,从而提高生产线的性能。最后,通过一些仿真证明了方法的有效性。     

饱和路网中动态交通分配和控制一体化建模研究

对饱和路网中动态交通分配和交叉口信号控制的一体化建模进行了研究 .描述了一个双层规划问题 .上层以动态用户均衡为目标建立分配模型 ,下层以系统最优为目标进行信号设置 .考虑了饱和路段上的车辆排队行为和驾驶员路径选择行为 ,并在模型中加以描述 .最后将遗传算法与传统的非线性最优规划方法相结合求解了一体化模型     

基于排队网络的流水线模拟器任务缓存新分析模型

流水线软件模拟器是嵌入式微处理器软件仿真系统的关键技术,提出对嵌入式微处理器流水线仿真系统的排队网络建模与缓存大小分析方法.对SPARC-V8流水线模拟器建立M/M/1/N型排队网络模型,分析指令到达及服务阻塞机制.为了解决模型计算中的阻塞问题,在排队网络模型中增加"保持节点",得到扩展的等价排队网络模型.采用近似计算迭代算法,得到系统性能评价指标,并建立排队网络节点性能关系曲线,确定各功能模块的任务缓存大小.根据得出的任务缓存计算值设置流水线软件模拟器实际缓存大小,实验表明模型计算数据与实际运行数据基本一致.该评价方法对嵌入式微处理器流水线仿真系统的建模与性能分析具有重要的指导意义.     

基于排队论的交通堵塞问题的模型选择

针对道路堵塞问题,建立了依赖状态的排队论与交通波模型.通过对数据的采集和处理,并分别运用排队论和交通波模型求出交通堵塞时车辆的排队长度,通过比较可以知道,运用排队论模型得出的车辆排队长度更符合实际情况,可以作为实际交通堵塞问题参考.     

FMS的CONWIP控制

生产存储控制是FMS设计的重要方面之一。CONWIP控制系统可以保证有效地使用昂贵的FMS设备的同时,使FMS满足顾客的需求,为此,对CONWIP控制下的FMS进行仿真,以分析不同处理时间对CONWIP控制下的FMS性能的影响。     

城市交通路口车辆排队系统仿真及优化

针对城市路口车辆排队系统数据不稳定、时效性差的缺点,提出了利用Flexsim仿真技术模拟路口车辆排队系统的方法.论文首先通过分析现场数据,得出车辆排队系统排队规则、车辆排队系统服务时间;然后,利用ExpertFit拟合分布软件拟合排队系统车辆到达时间间隔函数,并利用排队系统函数进行模型仿真;最后,根据模型仿真结果分析,提出优化方案.结果证明,Flexsim仿真技术能有效地模拟路口交通的堵塞情况,对改善路口交通状况有较好效果.     

混凝土生产浇筑过程的建模及资源配置分析

在详细描述混凝土生产浇筑系统工作过程和资源配置的基础上,建立了混凝土生产浇筑系统的排队论模型,针对所建立的排队论模型GI/M/4,对混凝土生产浇筑系统资源配置的合理性进行了理论分析,结果表明,实际系统的资源配置基本合理,同时验证了文中建立的排队论模型的正确性.     

考虑机器故障和有限缓冲器的级联生产线系统的建模和分析

本文在建立机器故障和系统阻塞的近似模型的基础上给出了系统的排队网络模型.利用 这一模型,可以对问题解析地求解,以分析系统的性能,而不需要复杂的计算.仿真结果表明, 其解的精度令人满意.     

排队模型的计算机模拟

排队系统是离散事件系统中最典型的问题。计算机模拟是求解排队系统和分析排队系统性能的非常有效的方法。通过对高速路收费站车辆排队问题的模拟,建立了不同的三类计算机模拟模型。并给出了其中一种单队列、多服务台（并联）的排队模型在高速路收费站车辆调度中的应用。     

CONWIP based control of a lamp assembly production line

Efficient and effective production control systems are very important for manufacturing plants. CONWIP, one of these production control systems, has a high potential of becoming the best one available because it suits a variety of production environments and is easy to implement. In the following paper, we compare the single-loop and multi-loop CONWIP production control systems for an actual lamp assembly production line producing different kinds of products with discrete distribution processing time and demand. A model is formulated with respect to total cost and service level. A novel rule-based genetic algorithm (GA) approach is proposed for the multi-loop CONWIP system to find the optimum parameter setting. The results have shown that the single-loop CONWIP production control system is more efficient than the multi-loop system. It can greatly decrease the total cost and the WIP (Work-In-Process) with zero shortage probability.     

多阶段CONWIP 系统流通卡分布的确定方法

在ＣＯＮＷＩＰ系统中,流通卡分布是系统有效运行的关键因素。针对多阶段ＣＯＮＷＩＰ系统,提出了基于遗传算法和仿真的流通卡分布的确定方法。研究实例表明,基于遗传算法获得的结果是合理的,并且节约了计算时间。     

A hybrid closed queuing network model for multi-threaded dataflow architecture

In this paper, a closed queuing network model with both single and multiple servers has been proposed to model dataflow in a multi-threaded architecture. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A closed queuing network model is suitable for large number of job arrivals. The normalization constant is derived using a recursive algorithm for the given model. State diagrams are drawn from the hybrid closed queuing network model, and the steady-state balance equations are derived from it. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the closed queuing network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived.     

铁路集装箱中心站装卸系统排队模型及分析

针对铁路集装箱中心站装卸系统的设备性能运用闭排队网络模型进行研究。根据铁路集装箱中心站装卸系统的作业特点建立其闭排队网络模型,在该模型中内部集装箱卡车作为顾客在轨道门吊和正面吊两个服务节点以及一个虚设的“运输”服务节点接受服务。由于服务节点的服务时间不能很好地用传统分布表示,导致针对乘积形式排队网络的求解方法并不适用。于是采用近似平均值分析算法求解闭排队网络模型并获得相关的设备性能参数,并分析了装卸系统的设施配置。最终通过与仿真模型所得结果的对比,验证了模型和求解算法的正确性。     

Pareto-Optimal Sustainable Transportation Network Design under Spatial Queuing

This paper presents a multi-objective network design problem with environmental considerations for urban networks with queues. A spatial queuing link model is introduced to take account of the spatial effect of queuing. With this more realistic link performance function capturing spatial queuing, the network equilibrium flow patterns can be more accurately identified. Furthermore, to better estimate vehicle emissions, this paper proposes a refined emission estimation model, which distinguishes between travel speeds in free-running state and queue-forming state over a link. A multi-objective bi-level programming is then developed, in which the upper-level problem optimizes the investment decisions, whereas the lower-level problem characterizes the user equilibrium with spatial queuing delays. The metaheuristic of non-dominated sorting genetic algorithm II (NSGA-II) is adopted to solve the multi-objective network design problem. Numerical tests on the Sioux Falls network and the Barcelona network confirm the effectiveness of our proposed model and algorithm in identifying queuing equilibrium flows and Pareto optimal solutions. The refined models and valuable information about trade-offs among objectives are particularly helpful for environmentally sustainable transport network planning.

     

基于改进的排序式选举算法的语音情感融合识别

根据情感的连续空间模型,提出一种改进的排序式选举算法,实现多个情感分类器的融合,取得了很好的情感识别效果。首先以隐马尔可夫模型（HMM）和人工神经网络（ANN）为基础,设计了三种分类器;然后用改进的排序式选举算法,实现对三种分类器的融合。分别利用普通话情感语音库和德语情感语音库进行实验,结果表明,与几种传统融合算法相比,改进的排序式选举法能够取得更好的融合效果,其识别性能明显优于单分类器。该算法不仅简单,而且可移植性好,可用于其他任意多个情感分类器的融合。     

基于声望模型的联合呼叫接纳控制算法

为了弥补异构无线网络中呼叫接纳控制研究场景的局限性,降低终端选择接入网时的盲目性,将研究场景从两个接入网延伸为多个接入网,提出一种基于声望模型的联合呼叫接纳控制算法。将声望模型应用于网络选择过程,增加了网络反馈机制。在用户侧,终端根据网络声望值大小选择接入网;在网络侧,采用动态带宽分配和缓冲队列策略来提高接入成功率。仿真结果表明,该算法有效降低了新呼叫阻塞率和切换呼叫掉线率。     

A hybrid approach to minimize state space explosion problem for the solution of two stage tandem queues

Two stage open queuing networks are used for modeling the subsystem-behaviour in computers and communication networks, mass storage devices, memory servers, and queuing analysis of wireless mobile cellular networks. The queuing analysis of wireless systems is essential in order to quantify the impact of different factors on quality of service (QoS); performance measures so that wireless protocols can be designed and/or tuned in an optimal manner. In that sense two stage open queuing systems are particularly important to model handoff phenomena, especially for the integration of two different systems such as cellular and wireless local area networks (WLANs). Analytical solutions for two-dimensional Markov processes suffer from the state space explosion problem. The numerical difficulties caused by large state spaces, make it difficult to handle multiple servers at the second stage of a tandem queuing system together with server failures and repairs. This study presents a new approach to analytical modeling of open networks offering improvements in alleviating this problem. The proposed solution is a hybrid version, which combines well known spectral expansion, and hierarchical Markov reward rate approaches. Using this approach, two-stage open networks with multiple servers, break-downs, and repairs at the second stage and feedback can be modeled as three-dimensional Markov processes and solved for performability measures. Comparative results show that the new algorithm used for solution, provides a high degree of accuracy, and it is computationally more efficient than the existing approaches. The proposed model is capable of solving other three-dimensional Markov processes.     

分布式测量系统服务窗口动态调度方法研究

在网络制造环境下, 动态时间性能是测量系统的重要指标. 针对基于 CORBA (Common object request broker architecture) 和尺寸测量接口标准 (Dimensional measurement interface standard, DMIS) 的分布式测量系统 (Distributed measurement system, DMS), 根据多用户非抢占优先排队网络静态性能模型, 提出基于无穷小摄动分析的样本轨道划分方法, 建立测量系统服务窗口的动态调度算法, 实现测量系统的时间性能调优. 通过在一个制造工厂中进行的应用实验, 证明了此方法的有效性.