三层程序设计结构的应用

一、三层程序设计结构的引入 应用程序设计已从“主机／终端”结构转变到现在的“客户／服务器”结构。在“主机／终端”结构中,主机运行了所有的系统和应用进程,通过在主机上运行分时操作系统,实现多用户共享主机,终端仅仅是用户和计算机交互的工具。这种结构当用户的数量增加时,所有的负载都在主机上,使系统性能降低,最后不可运行。“客户／服务器”结构改善了这种情况,应用负载分配在客户机（ＰＣ）和服务器上,使系统能负载更多客户,增加计算机在其它行业的应用。 随着Ｉｎｔｅｒｎｅｔ的迅速发展,各种应用都有Ｉｎｔｅｒ－ｎ…     

机场综合运维管理系统设计与实现

为保障导航台内导航设备的稳定运行和安全,设计了一套用于监控导航设备运行情况、环境参数的综合运维管理系统。该系统包括门磁、水侵、烟雾、火警、温度、湿度、空调控制、UPS、低压配电、视频和云台等。对该系统结构进行了详细设计,它由硬件监控传感器、视频采集、动环采集服务器、分布式数据库服务器和客户监控终端组成。该系统的数据库采用分布式系统设计,有效减轻了终端的存储压力。该系统的通信部分包括串口数据通信和视频数据通信。为了与监控单元兼容,设计了串口通信调度模块,并制定了通用串口通信协议。用户人机界面设计了用户管理、设备维护、监控监视、报警、系统设置、地图等功能。     

应“云”而生 IBM 10亿美元打造最新大型主机

近日,IBM发布了适用于云计算和企业数据的高安全系统zEnterprise EC12,并为之配备了目前世界运行速度最快的5.5GHz六核处理器,被IBM视为48年来最强大、技术最先进的版本。IT产业一直在不停地快速向前演进,行业趋势也随着技术的更迭不断在发生变化。对于计算模式,在早期五六十年代主要以大型主机集中处理模式为主,中途小型机、PC服务器分布式计算模式也曾风靡一时,而如今随着云计算、大数据趋势的到来,IT产业计算模式正演化出集中处理、分布处理两条路径。特别是大型企业对于大规模运算能力和混合运算功能、高安全性、大规模云计算能力的服务器需求日益强烈,大型主机在如今云时代背景下并没有黯然失色,反而受到越来越多大型企业客户的青睐。     

基于Android平台的物流仓储叉车调度系统的设计

传统仓储作业中,叉车完全由人工调派,管理人员无法获得叉车位置信息,调度效率低。为此,本文设计了一款基于Android平台的物流仓储叉车调度系统,由Android手机移动终端、服务器调度端、无线路由器三部分组成。该系统采用了基于Wi-Fi信号指纹的室内定位方法实现对叉车的实时定位。测试结果表明,该系统可以对实时显示叉车终端位置,并实现双向语音对讲,极大提高了调度效率。     

调度自动化机房UPS供电系统的设计与维护

就调度自动化机房UPS供电系统设计,提出了系统各组成部分具体设计方法与原则,包括供电方式的选择、UPS配置、电池容量计算方案等;对UPS主机和电池的正确日常维护可以及时发现设备异常,提高UPS运行效率、减少故障率。     

GPS监控调度系统在电力抢修中的应用

随着电力用户的逐年增加，保障用户的正常服务是提供优质服务的基础。由此，电力故障抢修工作成了能否提供优质服务的关键因素。对于客户的报修申告，抢修车辆及人员能否在承诺的时限内以最快的速度到达现场直接关系到客户对电业部门的满意度。为了加强电力抢修车辆管理，提高车辆运行效率，加强运行作业调度，在市级电业局建立一套电力抢修车辆GPS监控调度系统势在必行。     

集群系统中央控制器信令／调度单元的设计

这篇文章以自行研制的“多信道共用通信与报警系统”为例，对系统中央控制器的信令／度调单元做了比较全面的介绍，阐述了利用单片机实现系统信令／调度单元的控制过程，给出了系统信令／调度单元软件控制流程。     

业务监控平台技术浅析

本文介绍了业务监控平台技术。业务监控平台是节目生产监控系统,通过建立调度计划单元,用于根据电视节目生产流程配置探针单元的调度计划,调度计划执行单元,用于根据所述调度计划向探针单元发送数据抓取使得节目生产系统中各个节点的运行压力减小,进一步保障节目播出的安全性。     

华讯视频协作管理平台

简介华讯视频协作管理平台是建立在Cisco视频会议系统基础上的,集成了会议调度控制,设备远程排障,数据收集分析,终端管理,会议预约,运行状态监测,报表等功能,给客户一个模块化的统一操作界面的协作管理平台,并提高视频会议使用及管理的效率。     

基于GIS的Dijkstra算法在运输系统的应用

在市场竞争中,如何利用有限的资源,通过合理的安排和调度,尽可能降低成本是一个十分重要的问题。文中通过分析地理信息系统GIS（Geographic Information System）,在此基础上应用最短距离算法——Dijkstra算法求解最优路径,用JVAV语言编程实现,并将这一部分作为新型车辆运输调度系统——智能运输系统的一个底层子模块。系统开发基于Oracle及GIS系统软件,全面支持物流企业多种运输模式的运行要求,客户可以方便地通过车载终端或者手机访问系统所运行的服务器。     

校园计算网格作业自适应调度的研究和实现

由于网格资源具有分布、异构、动态、自治等特性。使得网格作业调度成为网格计算中具有挑战性的任务之一。针对校园高性能计算资源负载不均衡、管理模式不统一的问题，提出了校园计算网格自适应调度系统的解决方案。详细研究了网格作业的白适应调度技术，设计了含有负载均衡能力的资源动态信息收集模型，并给出自适应调度算法。实现了校园范围内高性能计算资源的负载均衡和统一的资源管理。     

Quality of Service Aware Reliable Task Scheduling in Vehicular Cloud Computing

Vehicular Cloud Computing (VCC) facilitates real-time execution of many emerging user and intelligent transportation system (ITS) applications by exploiting under-utilized on-board computing resources available in nearby vehicles. These applications have heterogeneous time criticality, i.e., they demand different Quality-of-Service levels. In addition to that, mobility of the vehicles makes the problem of scheduling different application tasks on the vehicular computing resources a challenging one. In this article, we have formulated the task scheduling problem as a mixed integer linear program (MILP) optimization that increases the computation reliability even as reducing the job execution delay. Vehicular on-board units (OBUs), manufactured by different vendors, have different architecture and computing capabilities. We have exploited MapReduce computation model to address the problem of resource heterogeneity and to support computation parallelization. Performance of the proposed solution is evaluated in network simulator version 3 (ns-3) by running MapReduce applications in urban road environment and the results are compared with the state-of-the-art works. The results show that significant performance improvements in terms of reliability and job execution time can be achieved by the proposed task scheduling model.     

A non‐cooperative game model for reliability‐based task scheduling in cloud computing

Cloud computing is a newly emerging distributed system. Task scheduling is the core research of cloud computing which studies how to allocate the tasks among the physical nodes, so that the tasks can get a balanced allocation or each task's execution cost decreases to the minimum, or the overall system performance is optimal. Unlike task scheduling based on time or cost before, aiming at the special reliability requirements in cloud computing, we propose a non‐cooperative game model for reliability‐based task scheduling approach. This model takes the steady‐state availability that computing nodes provide as the target, takes the task slicing strategy of the schedulers as the game strategy, then finds the Nash equilibrium solution. We also design a task scheduling algorithm based on this model. It can be seen from the experiments that our task scheduling algorithm is better than the so‐called balanced scheduling algorithm.     

分布式集群环境下作业流智能监控系统的研究

实时监控分布在企业内部网络集群系统上的各类作业的提交、运行及完成归档情况,是现代企业信息化管理的重要内容。本文提出并设计了一个基于分布式集群环境下的作业流监控系统,采用客户端/服务器(Client/Server,C/S)结构,客户端进行作业流的设计、提交及图形化显示,对作业从提交到返回执行结果的全过程进行控制;服务器端采用集群网络环境下的负载平衡策略,将作业分配到某台主机上进行实时处理,并将处理结果返回到客户端。经过实际企业应用测试,表明该系统能够较好的完成各类作业在异构集群计算机上的整个生命周期的智能监控任务。     

可管理多媒体网络计算机(MMNC)

本文提出一种基于普适计算模式的可管理的多媒体网络计算机MMNC(Manageable Multimedia Network Computer).MMNC采用服务器进行信息存储和管理、客户端进行任务计算与用户交互的计算模式.它通过MRBP协议为用户提供系统定制,并通过虚拟交换与调度技术将服务器系统中的应用程序代码调用到客户机上执行,实现了客户端的无操作系统化和按需定制程序加载,具有很好的灵活性和扩展性,而且具有成本低、安全性高等优点.     

A Complete Multiagent Framework for Robust and Adaptable Dynamic Job Shop Scheduling

This paper presents a complete multiagent framework for dynamic job shop scheduling, with an emphasis on robustness and adaptability. It provides both a theoretical basis and some experimental justifications for such a framework: a job dispatching procedure for a completely reactive scheduling approach, combining real-time and predictive decision making. It resolves various disruptions as flexibly as dispatching rules while providing more stability. It is ready to be implemented in a distributed environment where agents have minimum global information thereby improving system fault tolerance. Computational experiments on dynamic job arrivals provide the experimental justification of the framework. First, a comparison of computational results on unpredictable job arrivals among the presented framework and commonly used dispatching rules is presented to show the effectiveness and robustness of the developed framework. Then, a comparison of the computational results among four cases of dynamic job arrivals is presented to demonstrate the effects of making full use of available uncertain information about disruptions using this framework for the enhancement of scheduling robustness.     

DCOM组件在B／S系统开发中的应用

分布式计算技术在软件开发中得到了广泛的应用，它使复杂的大型网络应用程序在结构上更清晰，更易于开发。组件对象模型COM（Component Obiect Model）和分布式组件对象模型DCOM（Distributed COM）是微软软件体系结构中使用的分布式对象技术。通过分析基于COM／DCOM组件技术的分布式计算的基本原理，总结了开发使用COM/DCOM组件的基本方法和三层分布式应用程序的实现过程。最后给出了一个用DCOM组件构造的三层分布式应用系统实例。     

Media Synchronization and QoS Packet Scheduling Algorithms for Wireless Systems

Wireless multimedia synchronization is concerned with distributed multimedia packets such as video, audio, text and graphics being played-out onto the mobile clients via a base station (BS) that services the mobile client with the multimedia packets. Our focus is on improving the Quality of Service (QoS) of the mobile client's on-time-arrival of distributed multimedia packets through network multimedia synchronization. We describe a media synchronization scheme for wireless networks, and we investigate the multimedia packet scheduling algorithms at the base station to accomplish our goal. In this paper, we extend the media synchronization algorithm by investigating four packet scheduling algorithms: First-In-First-Out (FIFO), Highest-Priority-First (PQ), Weighted Fair-Queuing (WFQ) and Round-Robin (RR). We analyze the effect of the four packet scheduling algorithms in terms of multimedia packet delivery time and the delay between concurrent multimedia data streams. We show that the play-out of multimedia units on the mobile clients by the base station plays an important role in enhancing the mobile client's quality of service in terms of intra-stream synchronization and inter-stream synchronization. Our results show that the Round-Robin (RR) packet scheduling algorithm is, by far, the best of the four packet scheduling algorithms in terms of mobile client buffer usage. We analyze the four packet scheduling algorithms and make a correlation between play-out of multimedia packets, by the base station, onto the mobile clients and wireless network multimedia synchronization. We clarify the meaning of buffer usage, buffer overflow, buffer underflow, message complexity and multimedia packet delay in terms of synchronization between distributed multimedia servers, base stations and mobile clients.     

网格计算基本原理及其系统管理关键技术问题

网格计算可以充分利用网络资源,为海量计算用户提供集成方便的数据处理服务,文章从网格计算的基本概念和工作原理介绍入手,分析了资源管理、任务调度、服务质量和安全性等网格计算的关键技术问题,并对其技术应用与发展现状进行总结。     

SAMBA — Agent-Supported Visual Interactive Control for Distributed Team Building and Empowerment

Using computers to co-ordinate work is meant to improve the efficiency of distributed teams, but has the potential to decrease effectiveness by fragmenting work into seemingly unrelated tasks. It can also replace team-based communication activities such as workload negotiation, which will make workers feel isolated and not in control of their work. If the workforce is demotivated, customer service quality and employee job satisfaction will suffer.This paper shows how workload negotiation and informal team-building activities can be integrated with an operational support system for workload control and job scheduling. A proof-of-concept demonstrator, called SAMBA, has been built. The demonstrator uses agent-based negotiation strategies and allows workers and team managers to control the system in a visual interactive fashion. This type of system could be used to enable workers to set work preferences, trade jobs, share knowledge as well as build informal alliances to help each other with their work. Managers will be able to review and control local business rules and scheduling preferences.The approach presented in SAMBA can be generalised to support team-based collaboration in environments where team members have different perspectives on the collaboration process and artefact, e.g. call centre staff could control call routeing preferences, on-job training scheduling and so on.