关于如何有效清除传输系统无效告警的思考

传输系统作为铁路各类业务系统的承载系统,传输系统的稳定直接决定其它铁路系统能否安全运行,如数调系统、信号TDCS系统、客票系统、客票实名制系统、路局信息系统等重要铁路系统。     

浅析通信系统的安全运行

通信系统的安全运行,首先是通信电源系统的运行安全,其次是系统网络的安全设计和运行管理.通信电源系统,主要由备用发电系统、高压供电系统、变压器系统、不间断电源系统、后备电源系统、直流系统、接地防雷系统以及动力环境监控系统等多个子系统组成.通信离不开电源,通信电源是通信的保障,所以保证通信电源系统的安全运行,对保证通信系统的畅通乃至通信的安全有着积极的意义.     

电力高清视频会议系统组网方案与架构设计

随着电力企业高清生产视频会议数量增加,视频会议系统运维和管理需求提升,统筹并整合全网视频会议系统资源,建立统一的会议管理平台,是电力企业高清视频会议系统建设重要的工作内容.福建电力视频会议系统综合考虑国网资源池系统、应急视频会议系统、行政视频会议系统、软视频会议系统等视频会议系统资源,建成省内行政电视会议系统与国网资源池会议系统互为主备,实现双系统保障的能力;行政电视会议系统与国网资源池系统可与应急电视会议系统互为补充,实现跨系统会议;软视频会议系统作为硬视频会议系统覆盖范围的进一步延伸,提升了桌面视频会议能力.     

OFDM系统的扩频性能分析

提出传统OFDM系统中隐藏着类似扩频系统的性质。通过减少系统使用的子载波数,揭示了OFDM系统的扩频特性。使用扩频系统的理论分析方法,分析了OFDM系统的扩频性能。OFDM系统具有与传统扩频系统类似的扩频性能,因此可以采用OFDM系统构建扩频系统。     

海军用的光纤系统

海军研制了许多光纤系统,从演习应用系统,快速安装的改型系统,直到完全运行的系统等。这些光纤系统已用在海军的各种场合,如岸上固定系统,岸上战术系统,机载系统,舰上系统,水底系统,索道海底运输器,以及长距离固定的海底数据和通信系统等。图1列出了这些系统及活动领域的部份项目,其中许多已在商务书刊及技术会议上发表过。     

载人航天通信网

<正> 载人航天通信网可以为载人航天系统的指标、控制、跟踪、遥信、遥测、遥控提供优质,可靠不间断的服务,是以保障天地通信为特点立体化通信网。它由超短波通信系统,短波通信系统,卫星通信系统,微波通信系统,移动通信系统,光纤通信系统、话音交换系统、数据交换传输系统,图像采集编辑交换传输系统,时间统一系统及通信网监测管理系统组成。     

贵州电网应急卫星通信系统天线智能融冰技术研究与应用

卫星天线融冰系统是专门为卫星天线除雪、除冰而设计,文章阐述了系统的工作原理,并详细介绍贵州电网卫星通信系统天线智能融冰系统的融冰系统、传感系统、控制系统、数据传输系统、主站控制系统等功能。2011年年初,冰灾再次袭击贵州,该系统正常启动,保证了贵州电网卫星通信系统的畅通,说明了该系统的实用效果。     

SAP系统中的财务模块运维

越来越多的企业因为管理的需要实施了SAP系统,SAP系统的实施仅仅是SAP系统应用的第一步,如何使SAP系统长久稳定的运行,发挥SAP系统实际的价值,还需要SAP运维来保驾护航,解决系统运行中出现的各类问题,不断完善系统,提高系统的应用效率。     

电力信息化系统架构评价方法研究

系统架构是一个系统的基础,对于大型复杂的系统具有重要意义。采用适当的系统架构是好的系统的第一步,所以好的系统架构和评价是判断系统的关键。文章对电力行业信息化系统特点进行了探讨,并提出了针对电力信息化系统架构的评价方法。     

基于韵律特征的说话人确认系统融合研究

提出一种基于超音段韵律特征和GMM—UBM—MAP的文本无关的说话人确认系统,并与基于MFCC特征参数的说话人确认系统融合,研究提出新的两系统融合策略。在超音段中提取基于基频的韵律特征参数,建立辅助系统。融合时,以基准系统基于MFCC特征参数的说话人确认系统为主系统,基于韵律特征参数的系统为辅助系统,当主系统的得分与阈值接近时,将两系统得分融合再判断。通过NIST2006数据库的实验表明,融合系统相对原系统有16．39％的提升。     

Propagation of EM pulses excited by an electric dipole in aconducting medium

Exact solutions are given for the transient electromagnetic (EM) fields excited by an electric dipole antenna with an impulsive current in a conducting medium. There exists an optimum waveform for the antenna current which can generate an EM pulse with a maximum intensity at a particular distance from the antenna. It is found that the EM fields of an EM pulse excited by an antenna in a conducting medium can be divided into two parts. The first part is an impulse wave which propagates with the speed of light (1/√(μϵ)) and decays exponentially. The second part builds up gradually and propagates slowly, and more importantly this part attenuates as an inverse power of distance which is a much slower rate than an exponential decay     

Improvement of the efficiency droop of GaN-LEDs using an AlGaN/GaN superlattice insertion layer

With an n-AlGaN(4 nm)/GaN(4 nm) superlattice(SL) inserted between an n-GaN and an InGaN/GaN multiquantum well active layer,the efficiency droop of GaN-based LEDs has been improved.When the injection current is lower than 100 mA,the lumen efficiency of the LED with an n-AlGaN/GaN SL is relatively small compared to that without an n-AlGaN/GaN SL.However,as the injection current increases more than 100 mA,the lumen efficiency of the LED with an n-AlGaN/GaN SL surpasses that of an LED without an n-AlGaN/GaN SL. The wall plug efficiency of an LED has the same trend as lumen efficiency.The improvement of the efficiency droop of LEDs with n-AlGaN/GaN SLs can be attributed to a decrease in electron leakage due to the enhanced current spreading ability and electron blocking effect at high current densities.The reverse current of LEDs at -5 V reverse voltage decreases from 0.2568029 to 0.0070543μA,and the electro-static discharge(ESD) pass yield of an LED at human body mode(HBM)-ESD impulses of 2000 V increases from 60%to 90%.     

Polarization characteristics of the radiation field from anaperture in an impedance surface

The radiation field from an aperture in an impedance surface is studied by using a newly proposed expression of an equivalent magnetic current. Simple relations between the polarization and the surface impedance are derived concerning two subjects: the currents on a reflector illuminated by an aperture in an impedance surface and the cross polarization of the aperture     

Enterprise traffic with a differentiated service mechanism

As an enterprise grows, its network bandwidth requirement also increases dramatically. Network performance of an enterprise will impact its operational performance. How do we efficiently manage an enterprise network's resources in an E‐business era? This research proposes a differentiated service mechanism to manage traffic flows in an enterprise. This mechanism would enhance the performance of an enterprise network and help an enterprise efficiently transmits important information. With a high‐performance enterprise network, the enterprise can then operate more efficiently and improves its competitive capability. Copyright © 2001 John Wiley & Sons, Ltd.     

光接入网：第三讲 光配线网

本讲首先绍光配线网的组成，然后重点讲述了ＯＤＮ的４种典型结构，接下来讲述ＯＤＮ模型，重点是光通道损耗模型和计算方法，最后简要介绍了ＯＤＮ的反射及其要求。     

Analysis of magnetic stimulation of a concentric axon in a nervebundle

The authors present an analysis of magnetic stimulation of an axon located at the center of a nerve bundle. A three-dimensional axisymmetric volume conductor model is used to determine the transmembrane potential response along an axon due to induced electric fields produced by a toroidal coil. The authors evaluate four such models of an axon located in: (1) an isotropic nerve bundle with no perineurium, (2) an anisotropic nerve bundle without a perineurium, (3) an isotropic nerve bundle surrounded by a perineurium, and (4) an anisotropic nerve bundle surrounded by a perineurium. The transmembrane polarization computed along an axon for the above four models is compared to that for an axon located in an infinite homogenous medium. These calculations indicate that a nerve bundle with no sheath has little effect on the transmembrane potential. However, the presence of a perineurium around the nerve bundle and anisotropy in the bundle significantly affects the shape of the transmembrane response. Therefore, during magnetic stimulation, nerve bundle anisotropy and the presence of perineurium must be taken into account for calculation of stimulus intensities for threshold excitation     

A Common Source Input Cross Coupled Quad CMOS Mixer*

A CMOS doubly balanced mixer circuit is implemented with a source follower input and a cross coupled mixing quad. The circuit employs an all N-channel configuration and is suitable for high frequency applications. As a down-converter with an RF input of 2.0 GHz and an IF output of 200 MHz, the mixer demonstrates 9 dB of conversion loss with a corresponding input referred third order intercept of 0 dBm. As an up-converter with an IF input frequency of 400 MHz and an RF output of 2.4 GHz, the mixer demonstrates 14 dB of conversion loss.     

Exterior Algebraic Processing for Remotely Sensed Multispectral and Multitemporal Images

This paper describes remotely sensed multispectral and multitemporal image processing from an algebraic point of view. Especially, image analysis by means of an inner product, an exterior product, and an inner product between two exterior products are presented.     

An algorithm to solve integer programming problems: An efficient tool for reliability design

In many reliability design problems, the decision variables can only have integer values. The redundancy allocation is an example of one such problem; others include spare parts allocation, or repairmen allocation, which necessitate an integer programming formulation. In other words, integer programming plays an important role in system reliability optimization. In this paper, an algorithm is presented which provides an exact, simple and economical solution to any general class of integer programming problems and thereby offers reliability designers an efficient tool for system design. The algorithm can be used effectively to solve a wide variety of reliability design problems. The scope of use of this algorithm is also indicated and the procedure is illustrated by an example.     

Staying Ahead of the Digital Tsunami: The Contributions of an Organizational Communication Approach to Journalism in the Information Age

This essay addresses the challenges facing journalism in the information age by advocating for the study of journalism from an organizational communication perspective. The communication field has maintained an illogical divide between journalism and organizational communication scholarship. First, I present an overview of subdisciplinary identities. Second, I argue for an organizational communication approach to the study of journalism and refer to an empirical study as an exemplar of this approach. Finally, I present ideas for future research regarding the study of journalism and these subdisciplines. This approach is applicable to settings like newspapers, television news, and other media organizations. Analyzing journalism from an organizational communication perspective can connect academic subdisciplines and aid practitioners in understanding a rapidly evolving media landscape.