基于ARM的分布式网络测量探针的设计与实现

网络测量是评估网络性能和监视网络状况的重要手段。本文研究了分布式网络测量基础架构,并在此基础上设计了一种基于ARM和嵌入式实时操作系统的分布式网络测量探针,应用于DNMAI测量系统中,进行网络性能指标的测量。最后,文中以端到端时延测量为例给出了对探针测量数据的分析方法。     

基于排队网络的晶圆制造自动化物料运输系统性能模型

为快速有效地分析晶圆制造自动化物料运输系统的性能,以获得优化的系统设计方案,提出一种基于排队网络的性能分析模型。该模型考虑多运输小车的堵塞特性,将运输小车运行过程等效为排队网络过程,并采用虚拟元对自动化物料运输系统的捷径导轨特性进行描述,提高了性能分析模型的准确性。采用某晶圆制造企业的实际生产数据进行实验,并与仿真模型进行比较。结果表明:基于排队网络的性能分析模型与仿真模型在运输小车利用率、AMHS搬运能力和空载小车到达平均时间间隔等指标方面的相对误差值97%处于[-7%,9%]的区间范围,且比仿真模型具有更高的计算效率。     

网络制造环境下基于资源的分布式物流规划与集成

分析了网络环境下制造系统的发展趋势以及制造系统在分布式动态物流规划方面应解决的一些问题。探讨了离散制造系统在网络协作的制造环境下基于制造资源能力与状态的分布式系统的物流规划策略。最后,基于规划的物流信息提出了分布式物流系统集成的机制。     

基于多智能体的现代制造系统建模技术

多智能体技术在制造领域的应用是一个新兴的研究热点.文章对智能体的特性进行了全面阐述,提出了一种新的、动态的基于多智能体的制造系统建模方法.基于多智能体的制造系统模型是一个动态的、分布式智能体网络模型,可以对环境变化做出快速响应,动态生成最优的产品制造方案,实现系统模型重构和资源重新配置.     

基于CORBA技术的动态企业联盟系统平台的研究

在基于CORBA的分布式网络计算技术的基础上,本文提出了"基于CORBA技术的动态企业联盟系统平台的研究",并给出了系统总体框架及实现方法.通过该系统平台可以实现联盟企业问的信息资源共享与网络协作,从而实现敏捷化制造.     

双深度多层穿梭车仓储系统并行作业及建模分析

为了解决传统顺序作业方式下,双深度多层穿梭车仓储系统存在的系统响应时间长和作业效率低等问题,在分析提升机和穿梭车并行作业的基础上,提出该类仓储系统的分离—聚合排队网络模型,并设计基于Cox-ian分布的近似分解算法进行求解.构建基于分离—聚合点的闭环排队网络模型,将各服务点的一般分布用Cox-ian分布替代,进而求解分离—聚合点的吞吐率;用单个服务点替代分离—聚合点,得到基于分离—聚合点的开环排队网络模型,并采用最大熵值法求解,得到系统性能指标.以实际案例的4种配置进行分析验证,结果表明所提模型可以较大幅度提升双深度多层穿梭车仓储系统的性能和作业效率.     

基于混合遗传算法求解分布式流水车间逆调度问题

分布式调度是智能制造的新模式,急需新的调度方法来应对动态多变的市场需求。针对分布式置换流水车间问题,采用逆调度方法优化,通过最小调整加工参数,使得尽可能保证原排序的情况下调度最优。以最小化调整加工时间为目标,建立流水车间逆调度数学模型,针对逆调度问题特征,在遗传算法的框架下提出一种混合遗传优化算法。首先,基于逆调度参数可调的特征,提出基于工序的小数机制双层编码方案,能够实现参数的调整,保证可能解;提出改进启发式方法和基于规则的方法相结合的混合初始化方法;其次,采用适合问题特征的交叉、变异操作执行搜索;为协调全局搜索与局部搜索能力,设计局部搜索策略和学习机制的双种群协同搜索策略。为验证算法性能,基于问题实例采用三种算法进行比较,并且进行统计分析,其结果表明所提算法能更有效求解分布式流水线逆调度问题。     

分布式网络化测量系统——面向先进制造的新一代测量系统

随着"敏捷制造"、"网络制造"和"全球制造"等制造理念的提出,现代先进制造系统需要新型进测量系统。现代先进制造模式以分布式、柔性化、敏捷性为特征,决定了新型测量系统的特点。总结了先进制造系统和分布式测量系统的研究成果,然后从系统集成体系、系统数据交换格式、面向网络的测量设备以及系统分析与控制四方面对分布式测量系统的关键技术等进行了研究和探索。     

应急装备制造网络的动态资源配置

针对应急装备制造过程的高波动性、高时效性特点,建立了多层制造服务网络模型,并提出基于排队理论的制造网络节点动态资源配置策略,以保证制造资源的合理使用与客户放弃概率的稳定可控。基于不同的制造网络服务目标水平,分别提出了制造网络节点资源动态调节的近似算法和数值解法。通过数值算例的仿真分析,验证了该方法可有效控制并稳定制造系统的目标性能,其针对各制造节点的资源的动态协同优化方案与仿真结果高度契合。所提出方法可应用于应急装备制造服务网络设计中,并为具有更为复杂结构的制造服务网络节点资源配置提供依据。     

电动工具性能试验方法的研究和实践

针对目前电动工具质量保证体系建立的现状,探讨了性能试验的方法,设计了基于网络的分布式电动工具性能测试系统,重点研究解决了计算机模拟加载这一关键技术.本文讨论了一种新的模拟加载机构的设计和计算机测控系统的建立方法,并进行了一系列动态性能试验,在此基础上重点研究了相应的控制算法,最后利用所研制的加载系统对各类直流电动工具进行了综合性能测试,测试结果证明系统的加载精度、响应速度和稳定性均达到了设计指标.目前,系统已在实践中获得了良好的应用.     

两种多层穿梭车系统的性能比较分析

物流配送中心订单响应速度的加快,对订单拣选系统提出了更高的要求。多层穿梭车系统因其柔性强、效率高等特点,近年来得到了广泛应用。多层穿梭车系统具有两种形式——基于转载车和基于环形输送线,二者均可实现货物的快速拣选,但在系统吞吐量和订单完成周期方面存在差异,致使企业决策者难以进行系统选择。基于上述原因,本文比较两种多层穿梭车系统的性能差异。建立两个系统的开环排队网络模型,然后求解系统吞吐量、订单完成周期,通过仿真验证了排队论模型的准确性,通过试验对两种系统的性能进行对比分析。结果表明,系统吞吐量与层数、巷道数相关,层数越多,巷道数越少,转载车系统相对于环线系统优势越显著;订单完成周期与层数、订单到达率相关,层数越多,订单到达率越低,转载车系统相对于环线系统越具优势。     

Robust clustering approach for the shortest path problem on finite capacity fuzzy queuing network

This paper introduces a new model in the field of fuzzy queuing networks based on the clustering and finite capacity concepts. The proposed model includes fuzzy queuing systems which are located at the nodes of the network. Arc lengths, interarrival times, and service times are all fuzzy triangular fuzzy numbers. In order to find the shortest path on this network, queuing systems should be transformed to waiting times. The waiting times of each system are calculated by a conditional transformation. On the other hand, a robust fuzzy method is proposed for clustering of the arriving customers to the network. Robustness of this method prevents noisy data to affect results. Outputs of the clustering reduce shortest path calculations drastically. Based on a simulation process, the fuzzy queuing network is reduced to a deterministic network. A robust simulated annealing is designed for this network to find the shortest path. Numerical results showed that the clustering process is successful in eliminating outliers, and could be addressed as an efficient method. The convergence and solution time of the algorithm is reasonably better in comparison with published methods. Several experiments are conducted to compare the proposed method with corresponding researches.     

A dynamic measurement system for evaluating dry bio-potential surface electrodes

In this paper, a dynamic measurement system (DMS) is presented for assessing performance of wearable and dry bio-potential surface electrodes (DBSEs) in air, especially motion artifacts. A pair of perforated membranes is assembled on the two ends of the barrel which contains electrolyte to simulate surface of the skin. The pressure of electrode/membrane can be controlled and measured, one of electrodes can move on membrane by the motion controller. Experimental results show maximum coefficient of variation (CV) of electrical impedance spectra (EIS) and dynamic open circuit potential variation (DOCP, so-called motion artifacts) of gold electrode pair are, respectively, 4.3% and 7.2% in continuous measurements, 12.6% and 22% in discontinuous measurements, the pressure and the length of motion track between electrode and membrane are strongly linear correlation with DOCP variations. EIS and DOCP of five types of electrodes were measured on DMS and their parameters of equivalent circuit (EC) of EIS and DOCP variation show larger is equivalent capacitance in electrode/electrolyte interface, less is DOCP variation. DOCP variations of two batches of electrode performed respectively on DMS and on skin have approximate 0.64 of Pearson correlation coefficient. In general, the DMS provides a powerful tool to investigate the mechanism of DOCP variation and evaluates the static or dynamic performance of electrodes. However, parameters of EC model by fitting EIS can predict the motion artifact and help the design of electrode and its integrated wearable garments.     

基于网络光盘库的优先排队模型分析

本文深入研究了网络光盘库的排队网络模型,根据用户访问请求的不同建立了优先排队模型,并对其进行了仿真模拟,为光盘库在海量存储系统中的应用、设计和性能优化提供理论方法和实验依据.     

Variants of Secondary Control with Power Recovery for Loading Hydraulic Driving Device

Current high power load simulators are generally incapable of obtalning both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-stat...     

Measuring IP Performance Metrics on Mobile Network with Heterogeneous Wireless Technologies

The new measurement scheme of IP performance metrics is proposed for the mobile network in heterogeneous wireless network environment. In the proposed scheme, when Mobile Nodes (MNs) inside the mobile network needs to understand the condition of multiple communication paths outside the mobile network, they can get IP performance metrics, such as delay, jitter, bandwidth, packet loss, etc., irrespective of the presence or absence of measurement functionality. At the same time, the proposed scheme does not require the MN to be involved in measuring IP performance metrics. The Multihomed Mobile Router (MMR) with heterogeneous wireless interfaces measures IP performance metrics on behalf of the MNs inside the mobile network. Then, MNs can get measured IP performance metrics from the MMR using L3 messages. The proposed scheme can reduce burden and power consumption of MNs with limited resource and battery power since MNs don't measure IP performance metrics directly. In addition, it can reduce considerably traffic overhead over wireless links on multiple measurement paths since signaling messages and injected testing traffic are reduced.     

工作流时间性能分析方法

工作流性能分析是对工作流进行评价和优化的基础,时间则是反映工作流性能的一个重要方面。工作流管理系统中通常有属于不同工作流的多个实例同时运行,从而在不同工作流的多个实例之间造成资源竞争。对此,从资源的角度出发,利用排队论提出了一种通用的工作流时间性能分析方法,其中采用工作流实例平均响应时间作为工作流时间性能的分析与评价的指标。最后,通过实例说明了该方法的可行性和有效性,并提出了未来的研究方向。     

Multivariable robust adaptive sliding mode control of an industrial boiler–turbine in the presence of modeling imprecisions and external disturbances: A comparison with type-I servo controller

To guarantee the safety and efficient performance of the power plant, a robust controller for the boiler–turbine unit is needed. In this paper, a robust adaptive sliding mode controller (RASMC) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler–turbine unit, in the presence of unknown bounded uncertainties and external disturbances. To overcome the coupled nonlinearities and investigate the zero dynamics, input–output linearization is performed, and then the new decoupled inputs are derived. To tackle the uncertainties and external disturbances, appropriate adaption laws are introduced. For constructing the RASMC, suitable sliding surface is considered. To guarantee the sliding motion occurrence, appropriate control laws are constructed. Then the robustness and stability of the proposed RASMC is proved via Lyapunov stability theory. To compare the performance of the purposed RASMC with traditional control schemes, a type-I servo controller is designed. To evaluate the performance of the proposed control schemes, simulation studies on nonlinear MIMO dynamic system in the presence of high frequency bounded uncertainties and external disturbances are conducted and compared. Comparison of the results reveals the superiority of proposed RASMC over the traditional control schemes. RAMSC acts efficiently in disturbance rejection and keeping the system behavior in desirable tracking objectives, without the existence of unstable quasi-periodic solutions.     

多层前向网络的动态结构设计方法及其在回弹预测中的应用

从构造的角度,开展神经网络的动态结构设计研究,提出一种基于泛化的多层前向网络动态结构设计方法,编制了相应的计算程序。在该方法中,基于Ockhams RAZOR原则,从一个较小的基本网络开始,通过动态增加隐结点或隐层,综合运用网络泛化能力的多种改进方法,改进的BP算法以及快速搜索机制和全局搜索机制相结合确定学习速率、动量系数、跳跃因子和正则化系数的方法,采用网络权值的局部和全局调节方案,对多层前向网络进行动态结构设计。上述方法在凸凹弧翻边回弹预测中的应用实例表明,运用该方法设计的网络具有较好的计算精度。     

Storage assignment optimization in a multi-tier shuttle warehousing system

The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem(TSP), which has been widely applied in the conventional automated storage and retrieval system(AS/RS). However, the previous mathematical models in conventional AS/RS do not match multi-tier shuttle warehousing systems(MSWS) because the characteristics of parallel retrieval in multiple tiers and progressive vertical movement destroy the foundation of TSP. In this study, a two-stage open queuing network model in which shuttles and a lift are regarded as servers at different stages is proposed to analyze system performance in the terms of shuttle waiting period (SWP) and lift idle period (LIP) during transaction cycle time. A mean arrival time difference matrix for pairwise stock keeping units(SKUs) is presented to determine the mean waiting time and queue length to optimize the storage assignment problem on the basis of SKU correlation. The decomposition method is applied to analyze the interactions among outbound task time, SWP, and LIP. The ant colony clustering algorithm is designed to determine storage partitions using clustering items. In addition, goods are assigned for storage according to the rearranging permutation and the combination of storage partitions in a 2D plane. This combination is derived based on the analysis results of the queuing network model and on three basic principles. The storage assignment method and its entire optimization algorithm method as applied in a MSWS are verified through a practical engineering project conducted in the tobacco industry. The applying results show that the total SWP and LIP can be reduced effectively to improve the utilization rates of all devices and to increase the throughput of the distribution center.