电台业务支撑网络的设计和梯队式改造实践

本文首先从介绍宁波电台业务支撑网络现状入手，指出之前网络不足和改造的必要性，并在此基础上提出了改造原则，接着从实战角度阐述了从基础层、网络层、应用层以梯队式从低向高推进的解决方案，最后总结了改造成果。     

让图书馆搬“家”——联通沃阅读 开启快乐心境

在人类历史长河中，依靠工具革新促进时代转变的案例举不胜举。从最原始的甲骨文到手抄本，经历了约4300年；从手抄本到毕异发明的活字印刷术，经历了约1150年；从活字印刷术到英特网的出现，相差了524年；从英特网兴起到搜索引擎是17年；从搜索引擎到相关性排名算法，却只有7年——这一串骤然递减的数字，让我们情不自禁的感慨，从今天开始，我们的阅读已经在发生翻天覆地的变化。让我们想像一下……     

大炮林立 2005年末最火热长焦数码相机

2005年是数码相机产业飞速发展的一年，无论是从数码相机的细分市场来看，还是从各大厂商的扩充产品线来说，在整个2005年都保持了蓬勃向上的良好势头，入门级DC的像素级别从300万提高到了500万，各种类型各种档次的产品都完成了更新换代，     

电力系统智能自动化发展及新技术的应用

随着社会的发展，供电系统自动化的各项指标要求越来越高，自动化技术经历了从低到高，从地区到整体的发展模式，本文针对电力系统变电运行的自动化技术加以分析，从新技术的应用和发展趋势几方面展开讨论，分析了电力系统自动化的发展。     

第三代网络

从电话发明到现在已经一百多年了，电信网技术经历了无数次重要演进，从人工交换到自动交换，从模拟通信到数字通信，从电路交换到分组交换，从固定通信到移动通信，从窄带通信到宽带通信等，使电信网的业务能力大大提高，成本不断下降，其中一些重要技术的发明和应用，使电信网发生革命性变化，起到了更新换代的作用。然而，要准确划分换代的时间是困难的，因为网络的演进总是渐进的，在一代网络的应用还处在兴盛时期，下一代网络的技术就已开始出现，它适应了业务发展和新业务的需求，显示出更强的生命力，但要成为主导技术还需要不短的时…     

坚持“三个不能”和“两个要”

中国移动从1987年到现在已经走过了20年，中国移动从上市以后也已经10年了，20年以来，我国从蜂窝移动技术开始，到20世纪90年代数字技术发展到了今天，移动通信发展迅速，到目前我国移动电话用户总数达5亿户。[第一段]     

求解3G终端难题

《通信世界》周刊承办的盛况空前的“2004第三代移动通信应用峰会”胜利闭幕了，峰会从政策到产业格局．从WCDMA、CDMA2000到TD-SCDMA，从手机编码标准到芯片，从系统设备到终端．从网络规划到应用经验．从全球到中国，丰富的内容着实给与会者吃了一顿3G大餐。     

发烧友的新欲望─—浅谈“从组合音响到音响组合”

发烧友的新欲望─—浅谈“从组合音响到音响组合”解放曾几何时，不同档次的组合音响热曾两度从我国南方刮向北方，一时席卷大半个中同大地。发烧友从购买、占有与享受中获得了满足，音响企业从“热”中转危为安，获得了再生的机遇。然而，时代在前进，人们的观念在变化，...     

CATV在升级改造中如何选购光缆

本对县级有线电视在升级改造时如何选择与本地区相适应的光缆而从光缆的用途、材料、制作工艺做了较为详细的叙述，提出了从原材料认定质量，从生产过程认定质量，从技术指标等多方面认定质量的重要性。     

编者的话

近年来，以太网技术的发展令人瞩目。从十兆到百兆，从千兆到万兆，其发展速度远远超出了人们的想像；从同轴电缆到双绞线再到光纤以及无线传输，以太网充分结合了不同时期的传输介质，并能避行有效的互连：从局域网到城域网再到广域网，其优越的的跨越式组网能力大大拓宽了运营商提供服务的方式；     

Continuous variable structure controller for BLDDSM positioncontrol with prescribed tracking performance

The continuous, accurate, and robust sliding mode tracking controller based on a disturbance observer for a brushless direct drive servo motor (BLDDSM) is presented. Although the conventional sliding mode control (SMC) or variable structure control (VSC) can give the desired tracking performance, there exists an inevitable chattering problem in control which is undesirable for a direct drive system. With the proposed algorithm, not only are the chattering problems removed, but also the prescribed tracking performance can be obtained by using the efficient compensation of the disturbance observer. The design of the sliding mode tracking controller for the prescribed, accurate, and robust tracking performance without the chattering problem is given based on the results of the detailed stability analysis. The usefulness of the proposed algorithm is demonstrated through the computer simulations for a BLDDSM under load variations     

Dynamic feed-forward control of a parallel kinematic machine

This paper deals with the dynamic feed-forward control of a 6-UPS parallel kinematic machine (PKM). The control system consists of the closed-loop control subsystem and the dynamic control subsystem. The closed-loop control subsystem is constructed by using the PD control and low-pass filter. Moreover, zero phase error tracking control (ZPETC) is introduced to the closed-loop control subsystem to improve its response capability. Based on the rigid-body dynamic model of the PKM, the dynamic control subsystem is designed by using the computed torque control and feed-forward control. Since the phase lag of the closed-loop control subsystem is almost eliminated by ZPETC and PD control, the motion precision of the closed-loop control subsystem is improved largely. The influence of the dynamic characteristic of the PKM on the motion precision is decreased due to the introduction of rigid-body dynamic model into the control system. As a result, the motion precision of the moving platform is greatly improved.     

Design,Implementation, and Validation of KOMPSAT‐2 Software Simulator

In this paper, we present design features, implementation, and validation of a satellite simulator subsystem for the Korea Multi‐Purpose Satellite‐2 (KOMPSAT‐2). The satellite simulator subsystem is implemented on a personal computer to minimize costs and trouble on embedding onboard flight software into the simulator. An object‐oriented design methodology is employed to maximize software reusability. Also, instead of a high‐cost commercial database, XML is used for the manipulation of spacecraft characteristics data, telecommand, telemetry, and simulation data. The KOMPSAT‐2 satellite simulator subsystem is validated by various simulations for autonomous onboard launch and early orbit phase operations, anomaly operation, and science fine mode operation. It is also officially verified by successfully passing various tests such as the satellite simulator subsystem test, mission control element system integration test, interface test, site installation test, and acceptance test.     

AN H∞ FUZZY TRACKING CONTROL SCHEME FOR AFFINE COUPLED SPATIO-TEMPORAL CHAOS

Due to the interactions among coupled spatio-temporal subsystems and the constant bias term of affine chaos, it is difficult to achieve tracking control for the affine coupled spatiotemporal chaos. However, every subsystem of the affine coupled spatio-temporal chaos can be approximated by a set of fuzzy models; every fuzzy model represents a linearized model of the subsystem corresponding to the operating point of the controlled system. Because the consequent parts of the fuzzy models have a constant bias term, it is very difficult to achieve tracking control for the affine system. Based on these fuzzy models, considering the affine constant bias term, an H∞ fuzzy tracking control scheme is proposed. A linear matrix inequality is employed to represent the feedback controller, and parameters of the controller are achieved by convex optimization techniques. The tracking control for the affine coupled spatio-temporal chaos is achieved, and the stability of the system is also guaranteed. The tracking performances are testified by simulation examples.     

基于VB和DLL技术的供水系统变频控制的实现

介绍了一种以VB6．0为开发工具，采用DLL技术实现的变频调速供水系统，通过计算机控制变频器进而控制三相异步电机驱动机械装置实现供水系统的自动控制与仿真。本文详细阐述了该系统的构成、工作原理、控制算法、手自动切换方式及数字滤波技术等。系统经运行测试，各项功能、指标均满足实验要求。     

Experiment study of ATP system for free-space optical communications

To meet the requirement of high tracking angular accuracy for the acquisition, tracking, and pointing (ATP) subsystem of the free-space optical communication, and provide the basis for the further optical communication between maritime mobile platforms, the experimental system, which executing part for the fine tracking is voice coil motor with high frequency and good performance for error compensation, is established, and the whole system can be controlled by personal computer. A series of experiments has been done for the simulation target of different uniform speed, and the data of tracking error for fine tracking and coarse tracking are collected, analyzed and evaluateds separately, and the real-time optical power of communication laser is also collected. The result shows that standard deviation for ATP system tracking error increases with the increase of target speed, while the range of tracking error appears to be no order. Furthermore, communication link can be hold for a long time.     

滑模变结构在AUV航向控制中的应用

针对自主式水下机器人的控制特点,建立了机器人的动力学数学模型。利用运动解耦的方法完成了水下机器人完备控制量的构建。在滑模变结构控制理论的基础上,设计了水下机器人的分布式滑模控制系统,并在Simulink下完成滑模控制器的建模。预先设定了仿真过程中机器人的运动轨迹跟踪,结果表明,滑模控制能有效地控制AUV的航向,对外部扰动具有较强的鲁棒性。     

基于直接反馈线性的永磁同化步电机直接转矩控制

文中应用一种基于直接反馈线性化（DFL）理论的非线性控制方法．通过对系统输出变量进行李微分,得到反馈线性化所需的坐标变换和非线性系统状态反馈．实现了永磁同步电机系统的输入输出线性化．并将原系统分解为两个线性子系统：转速线性子系统和励磁电流线性子系统,实现了系统的解耦。仿真结果表明：基于直接反馈线性化解耦的永磁同步电机直接转矩控制系统具有较好的速度跟踪性能并提高了系统对电流扰动的鲁棒性。     

一种基于AT89C52的远程直流电机控制系统

提出了一种远程直流电机的控制系统.控制系统由上位机、下位机子系统组成.上位机子系统为计算机主控单元,下位机子系统以单片机为核心,上、下位机子系统通过串行口进行通信.直流电机的驱动电路采用桥式回路,直流电机远距离的通讯采用RS422通讯规范.该系统具有操作界面直观、控制灵活等特点.     

Tracking and Vibration Control of Flexible Robots Using Shape Memory Alloys

This paper considers the tracking control problem for flexible robots with active vibration suppression by shape memory alloys (SMAs). With a singular perturbation technique, the flexible modes and joint angles are modeled as fast and slow variables, respectively. The fast subsystem comprising the nonlinear SMA dynamics is obtained in a strict feedback form feasible for the backstepping design. The SMA actuators are configured in redundant pairs for an active suppression of vibrations. For the slow subsystem, asymptotically stable tracking is ensured, while for the fast subsystem, uniform exponential stability is guaranteed. By invoking Tikhonov's theorem, it is shown that the error arising from the nonideal time-scale separation in the singular perturbation model is small. Simulation demonstrates the effectiveness of the proposed control