利用SPOT5卫星影像更新地形图的方法——以加纳铁路为例

以加纳铁路预可研为例,对利用SPOT5卫星影像数据更新1:5万地形图的方法进行了探讨,证明该方法易于掌握,辅助更新效果显著,能够为铁路设计提供实效性的地形图.     

首都机场线直线电机系统的轨道设计与创新

依据首都机场线的工程特点及直线电机系统的轮轨关系特性,介绍轨道设计的主要技术参数,包括轨距、轨底坡、曲线超高、轨枕布置间距等,说明直线电机车辆在轨道荷载体系、技术参数、设备选型及结构设计等方面与传统地铁有所不同,并阐述全线轨道设备与结构统一以及全面提高轨道平顺性的理念、创新技术.     

浅谈川黔线监控与货运系统通道畅通问题

本文详细分析了川黔线自安装远程监控系统后,TMIS2M网被一分为二所造成货运上报请求车困难、收不到装车货运计划、远程更新货票死机等问题,并提出了解决这些问题的有效方法和途径。     

公路大断面风积砂隧道施工技术

经棚隧道断面较大，且地质条件特殊，本文介绍了经棚隧道在实际施工过程中的施工工艺要点和一些成功经验，仅供同行参考。     

A New Region-of-interest Coding Method to Control the Relative Quality of Progressive Decoded Images

Based on the ideas of controlling relative quality and rearranging bitplanes, a new ROI coding method for JPEG2000 was proposed, which shifts and rearranges bitplanes in units of bitplane groups. It can code arbitrary shaped ROI without shape coding, and reserve almost arbitrary percent of background information. It also can control the relative quality of progressive decoded images. In addition, it is easy to be implemented and has low computational cost.     

被动调质阻尼器对斜拉桥弯扭耦合抖振的控制分析

基于Ｒ．Ｈ．Ｓｃａｎｌａｎ教授的斜拉桥风致抖振分析理论，作者导出了调质阻尼器（ＴＭＤ）作用下斜拉桥弯扭耦合抖振响应的计算公式，经过大量的数据处理，给出了ＴＭＤ参数的优化公式，并以美国的Ｂａｙｔｏｗｎ Ｂｒｉｄｇｅ为例，对该桥有无ＴＭＤ情况下的抖振响应作了对比分析，结果表明，被动ＴＭＤ对该桥的抖振具有较好的抑制效果。     

Audio Video Compression Stream Synthesis and Implementation

Multiplex of digital streams is one of the key technologies in audio-video communication, and determines audio-video quality. A design scheme for an MPEG2 compliant digital television system including audio-video encoding and multiplexing was implemented. The principles and elements of system layer stream synthesis were analyzed. The key technologies of video and audio PES packetization were discussed, such as stream structure,scheduling matching, audio-video synchronization, data flow and buffering. DSP and FPGA are combined to construct header information and packet structure. The substitution of traditional RAM or PLD results in high operational efficiency and saves memory space. A scheduling algorithm was introduced for PES coding, using the monitor information of PES buffers. DTS is generated by multiplexer to guarantee synchronization. The system is not only simple but also stable, and maintains synchronization constraints of the standard. It supports both analogy and digital audio-video source input, and provides real-time MPEG2 compliant TS/PS output. It has perfect performance and meets the national broadcasting requirements.     

用MATLAB仿真异步电机直接转矩控制系统

采用ＭＡＴＬＡＢ语言对电压源逆变器供电下异步电机直接转矩控制系统进行动态仿真,分析其动态性能指标,建立了仿真模型。     

图的控制数的Hopfield网络模型和算法

对图G（V,E）,及二值函数f:V→｛0,1｝记f｛v｝=｛u│u∈N[v],且f(u)-1｝,其中N[v]＝｛u│vu∈E｝∪｛v｝若f满足任意v∈V,│f[v]│≥1,则称f为G的一控制函数,并称f(V)= ∑v∈V（f(v)为f的权;图的控制数γ（G）定义为图的控制函数的最小权,即γ（G）＝min｛│f(V)│f为G的一控制函数｝类似的可定义图的边控制数,本文建立了确定图的控制数的Hopfield网络型和算法。