采用八叉树和OSG分页结点的海量点云三维可视化

针对现有海量点云可视化方法存在索引构建时间长、内存占用大等问题，研究一种八叉树索引结合OSG分页结点的快速可视化方法，可在占用较小内存的基础上快速建立点云索引并实时调度。采用八叉树索引结构对海量点云进行数据组织，建立各层级的八叉树结点并以文件映射的方式分块保存，对结点文件重组织转换为支持OSG渲染引擎的多分辨率点云数据。采用基于OSG分页结点的实时调度技术，对海量点云进行高质量可视化。与目前两款主流的点云数据处理商业软件进行实验对比分析，结果表明所提方法具有索引建立速度快、内存占用小等优点，同时可视化交互更加流畅，适用于各种配置计算机下海量点云数据的调度管理与实时可视化。     

Handover and Uplink Power Control Performance in the 3.84 Mcps TDD mode of UTRA Network

In this article we consider the performance of the 3.84 Mcpstime-division duplex (TDD) mode of UTRA (Universal TerrestrialRadio Access) network. We emphasize two of the radio resourcemanagement algorithms, handover and uplink power control, whoserole in the overall system performance is studied extensively.First, a handover algorithm used in WCDMA (Wideband Code DivisionMultiple Access) standard is considered in a TDD-mode operation.This gives rise to a careful setting of different handoverparameters, and the evaluation of the effects to the systemperformance. Secondly, the specified uplink power controlalgorithm is considered. Since it is based on several user-mademeasurements which may involve both random and systematic errors acareful study about the suitability of the power control scheme iscarried out.     

Breakdown characteristics of oil and paper insulation for a very fast transient voltage

This paper describes the dielectric breakdown characteristics of oil and oil‐impregnated paper for very fast transient (VFT) voltages. Blumlein circuits generate VFT voltages of 60 and 300 ns in a pulse width that simulates disconnecting switching surges in gas‐insulated switch gears. We measured the breakdown voltages of needle‐to‐plane, plane‐to‐plane oil gaps and several pieces of paper between plane electrodes for VFT and lightning impulse voltages. The measured data were formulated in V‐t characteristics and Weibull probability distributions. The inclination n of V‐t characteristics of insulating paper is 150, which is less than n = 13.7 of the plane‐to‐plane oil gap in the VFT time range. The shape parameters of Weibull distribution obtained in this study show that the scattering of breakdown voltages of paper is much less than that of oil. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 16–24, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10043     

小波包变换压缩与地震数据处理

探讨了地震数据经小波包变换压缩后对后续处理过程的影响,以及经过某些处理后的数据会对小波包变换压缩产生什么影响等问题。将小波包变换压缩地震数据的结果与快速傅里叶变换压缩地震数据的结果进行了对比,其结果表明:应用小波包变换压缩地震数据,有效信号的损失非常小,压缩比大于快速傅里叶变换的压缩比。在大批量地震数据处理中可以使用小波包变换压缩地震数据。     

钠冷快堆中喷雾钠火的计算分析

根据钠冷快堆中喷雾钠火的特点建立了理论模型，编制了SSPRAY程序。该程序模拟钠喷雾燃料过程中钠滴的运动、钠和氧气的燃烧反应、热量传递和质量传递等瞬态过程。用该程序计算了气体和墙壁温度、气体压力、氧气摩尔份额、喷雾流燃烧速率和热量热递速率等主要参数。利用AI实验数据和美国SPRAY－3A的计算结果对程序进行了验证，结果符合较好。     

气体绝缘封闭电器的高速瞬变过程和现场试验

随着ＧＩＳ的工作电压不断提高和发展，一系列新的现象和问题也同时出现。从国外一些科研，设计，制造部门所研究发表的内容看，大致有隔离开关操作和高速瞬变过程，粒子影响和对干扰定位的技术，元件的监督，现场试验等课题，本文对以上问题加以综合介绍。     

江苏省县级电力信息网的3种组网方案

对江苏省县级电力信息网工程采用的利用ATM设备、SDH设备和WDM设备的3种组网方案进行了阐述，并分析了各种方案的优缺点。     

Research on the Handover of a Novel Cellular Architecture in Wireless Personal Communication Systems

1　IntroductionHandoverbetweencellsisplayinganimportantroleincellularcommunicationsystems[1～ 1 2 ] .Thehandoverprocedureanditseffectivenessareseriouslylimitedbythecellulararchitectureasaresultofmar ketplanning .Basedonthehexagonalcellulararchi tecture,manyhandoverprocedureshavebeendis cussedandevaluated ,andmostoftheimprovementproposedonthemleadstotheintroductionofsector ingcellularorlayeredcellularmodel.Otherwise ,abetterhandoverprocedureisessentialinmaintainingacallinprogressbutitreflectshi…     

轴快流CO2激光器气体压力控制

激光切割对激光功率模式、功率密度和功率稳定性要求很高,采用轴快流CO2激光器时,控制工作气体压力工作在最佳状态并保持其恒定是激光器输出连续、稳定功率的必要条件和关键技术之一。在深入研究激光器工作原理和影响激光输出功率因素的基础上,采用带积分分离的智能PID控制算法对工作气体压力进行调节。该过程控制算法简单实用,可以有效地提高气体压力控制精度,改善功率控制精度和稳定性,并用实验加以验证。     

FAFFA加速的PO-MM研究复杂金属载体上线天线电磁特性

本文提出了一种快速远场近似(FAFFA)加速的混合物理光学矩量法(POMM),利用FAFFA加速计算矩阵方程中的矩阵矢量积,明显提高了计算效率.对物体表面上的远场组之间的耦合作用推导出了一组简洁的计算公式,并分析了计算复杂度.复杂金属组合体上线天线输入导纳、互导纳和方向性图的计算结果与文献结果一致.利用该方法分析计算了一个舰船模型上线天线的电磁特性.数值结果表明了这种方法的正确性和工程应用中的有效性.