电信IT支撑系统——因时而变

IT支撑系统是电信运营商转型中的重要组成部分,成为运营商差异化竞争的关键因素.lT支撑系统必须因时而变,更新自身角色,从支撑者转变为驱动者;增强自身功能,强化对产业链掌控、深度运营和全业务支撑等功能;优化系统技术架构,采用整体规划、集中化、虚拟化的模式进行系统建设.     

音视频与信息技术电子设备安全评估趋势

正电子设备在正常使用、异常工作、故障条件、合理可预见误用和滥用条件下,可能产生电击、着火、过热等危险,这些危险直接影响着人们的人身和财产安全。随着科技的进步,音视频和信息技术设备(含通信设备)自身的安全特点发生了很大变化,国内外的安全标准进行了相应     

Reliable prediction of EM radiation from a PCB at the design stageof electronic equipment

This paper presents a composite computer-aided design (CCAD) package for prediction of electromagnetic (EM) radiation from a printed circuit board (PCB) at the design stage of equipment. Such a CCAD package has been developed by combining an EM computation tool such as numerical electromagnetic code (NEC)-2, with other circuit design packages (CDPs). The method of prediction of EM radiation using the CCAD is well described in this paper. The predicted EM radiation has been validated experimentally and results showing good agreement are presented. Finally, the reliability of the CCAD package is investigated and presented     

Trends in the U.S. communications equipment market: a Wall Street perspective

After years of decline, we exit 2005 predicting that U.S. telco capital expenditures (capex) spending could approach double-digit year-over-year growth in 2005 with spending into 2006 focused on broadband access, wireless, and (later) carrier-grade Ethernet initiatives. This article provides a Wall Street analyst's perspective on select trends in the communications equipment market, with a view toward what the future might hold for the telecommunications industry.     

智能型框架式断路器单片机系统的电磁兼容性分析

一、简述 随着单片机技术的不断发展与完善,单片机已被广泛地应用于各行各业中,其应用程度和应用水平已逐渐成为衡量一个行业或一个部门技术水平的重要标志。框架式断路器做为低压配电系统的主开关也已突破传统的结构模式,在其保护和信息处理单元采用了单片机技术,典型产品有施耐德公司的M系列、美国GE公司的S系列、日本三菱公司的AE-     

EM and substrate coupling in silicon RFICs

An investigation of coupling between inductors and resonators fabricated in silicon substrates is presented and the effects on RF systems and components are discussed. A novel experimental technique to measure inductor and resonator coupling is presented. The experiment is extremely sensitive, fast, accurate, and unique in that no matching, probe de-embedding, or calibration is necessary as the ratio of two on-chip signals is measured to yield the results.     

Time-dependent EM field characterization in pulsed lasers

The development of the EM field in pulsed solid-state lasers is analyzed with a two-dimensional fast-Fourier transform computational model. The model is designed to enable on-line characterization of the EM field starting from a randomly generated initial spontaneous field. The temporal variation of the laser beam quality together with the power spiking behavior is studied, showing sharp brightness peaks at the beginning of the free generated laser pulse. The instantaneous beam pattern is followed throughout the laser pulse duration. Some important characteristics of the formation of resonator modes are given and the influence of the mode competition on the formation of typical patterns in the integrated beam is analyzed. Intensity pattern oscillations which can be attributed to the previously observed vortex formation were clearly detected, showing well-defined oscillation frequencies of the local EM field, unrelated to transverse intermode beat frequencies. Experiments were carried out on an Er:YAG laser confirming the beam pattern formation and showing good agreement with the computational model     

IT的奶酪

诱人的奶酪什么是安全?安全就是信誉,任何社会活动如果缺乏安全保障,就无法求得参与者的认同;在信息时代,安全意味着信息网络运营的价值,没有安全保障,信息资产就无法实现自身的价值。由于网络自身的缺陷,信息化的企业,政府或个人,都无法摆脱安全问题的困扰,从商业的角度看,问题也带来机遇,但机遇的把     

Propagation of EM waves in inhomogeneous anisotropic media

Maxwell's equations for the transverse (x,y) components of the electromagnetic field are solved numerically for horizontally stratified inhomogeneous anisotropic media using a Fortran IV program     

透地通信的电磁场并行仿真方法

为提高分析电磁波在地层媒质中传播特性的准确度和时效性,开发了地层媒质建模和FDTD的并行算法,并将两个过程有机集成形成适用于透地通信电磁场仿真的并行计算系统,在搭建的并行计算平台上进行了系统测试,测试统计数据表明该系统具有良好的扩展性和并行计算效率.     

嵌入式移动计算与通讯终端平台的发展趋势及中国IT企业的机遇与应对策略

首先从技术角度介绍了嵌入式计算与通讯平台的发展趋势；透过技术的发展，管窥了中国IT企业的一个重要产业机遇；分析了相关领域的竞争态势和竞争规律。最后，对中国企业如何应对这一机遇阐述了个人见解。     

Induced EM fields inside human bodies irradiated by EM waves of up to 500 MHz.

In this paper, the internal EM field and the specific absorption rate of EM energy induced inside human bodies by EM waves of up to 500 MHz are theoretically quantified based on a tensor integral equation method. Numerical results for a realistic model of a man of 177 cm high irradiated by EM waves of various frequencies and of vertical and horizontal polarizations are presented. The resonance phenomenon and the effect of body heterogeneity on the induced field are studied. Some theoretical results are compared with existing experimental results.     

Characterization of EM downhole-to-surface communication links

A downhole-to-surface communication channel consisting of a long vertical cylinder (the stem) and an isolated downhole in-line cylinder (the electrode) embedded in a homogeneous Earth is considered in this work. A signal voltage is applied between the electrode and stem, and the received voltage is picked up at the surface between the stem and a ground point or between two ground points. The analysis includes consideration of conductor longitudinal and surface impedance, joint resistance, voltage source resistance, and Earth propagation effects to provide a realistic model for assessing the performance of the communication channel for measurement-while-drilling, drill stem testing, and production testing in oil and gas industry applications. Simulation results indicate that consideration of all of these effects is imperative for satisfactory modeling.     

Synthesis of EM geophysical tomographic data

In order to test tomographic inversion schemes under controlled conditions, we have developed a forward electromagnetic model, using the volume current method (VCM). The algorithm can handle thin irregular-shaped bedding planes as well as inclusions or localized anomalies. It is thus ideal for modeling oil trap regions in the earth. Both transmission and reflection images, in magnitude and phase, are presented. Model results are given for a complex lithology as appropriate for an enhanced oil recovery zone. Particular emphasis is placed upon understanding the qualitative effects of bedding layer planes, both continuous and broken, on the electro-magnetic response of an elliptical shaped anomaly. The point is made that resolution of reservoir features in complex lithoiogies, as encountered in enhanced oil recovery applications, requires accurate processing of both amplitude and phase tomographic data.     

EMC单片机EM73P461A在工业中的应用

EMC单片机EM73P461A是一款台湾产的基于PIC内核的4位单片机，文中介绍了它的一些功能及在工业中的应用，通过实际应用介绍了它的优缺点及在应用设计当中应该注意的问题。     

复杂电磁环境无线电系统SUE评估

针对复杂电磁环境下无线电系统的频谱效率评估问题,提出了一种带环境参数的SUE评估方法,用以解决复杂电磁环境及动态频率指配策略带来的电磁空间占用表示问题。给出了移动通信系统的SUE的仿真计算示例,结果表明该方法计算结果与经验吻合,计算过程可操作性强。通过根据具体的系统用途和所处的电磁环境复杂性设定M、Tw、Tc等参数,该方法的应用具有较好的扩展性。     

Application of three-parameter lognormal distribution in EM data analysis

The three-parameter lognormal distribution has been demonstrated for applications in electromigration data analysis, especially for Cu interconnect structures with insufficient redundancy. Examples are given on estimating parameter values from experimental data using the maximum likelihood method. Detailed analyses are presented on confidence bound estimations of the parameters and their propagation to lifetime projections.     

信息技术在制造业中的应用

本文简要介绍了信息技术在制造业中应用的几个方面,最后对制造业如何建立自己的信息技术应用系统提出了几点看法。     

基于EM算法的非高斯噪声参数估计

EM算法是一种从＂不完全数据＂中求解模型参数的极大似然估计的方法,在非高斯噪声的参数估计问题中是一种比较优秀的算法。非高斯噪声的参数估计问题的主要困难是充分统计量是不存在的,这意味着从观测空间到估计空间的映射依赖于这里试图估计的参数。在未知噪声概率密度的情况下,EM算法可以更准确地对非高斯噪声参数进行估计,估计方差接近C-R下界。