基于“北斗一号”虚拟管理型用户机系统的设计与实现     

武丽丽  华一新  陈艳丽  寇静行  罗安平 《测绘科学》2011,36(6):227-229

针对“北斗一号”卫星导航定位系统存在的监控能力有限、价格昂贵等问题,本文提出并设计了虚拟管理型用户机系统,介绍了虚拟管理型用户机系统的功能设计、结构设计,分析了“北斗”共享数据库,数据统一处理模块等关键部件的设计与实现,并以通信信息的发送和接收机制为例,阐述了系统的工作流程;并在实验与应用中证明了该系统的可行性与合理性...  相似文献   

利用遥感数据对单株木和森林场景进行建模     

郭俊  牛铮 《武汉大学学报(信息科学版)》2011,(2):181-184,198

针对遥感在三维可视化方面的不足,提出了用SRTM(航天飞机雷达地形测图任务)和TM(陆地资源卫星专题绘图仪)数据建立森林场景的方法。利用L系统语言和L-studio软件,通过提取的分枝规则建立了针叶树和不同叶面积指数(LAI)落叶树的几何模型,并将其作为森林场景内树木的纹理贴图。实验区的三维地形用四叉树结构建立,综合应用数据分块、动态载入、双缓存数组等措施提高大范围场景的漫游速度。从TM影像获取目视判读的遥感分类图和LAI反演图,结合控制树木的栽种位置和纹理选择,建立了单幅TM影像大小的森林场景。实验为其他遥感数据的三维显示提供了通用的建模方法。  相似文献   

利用虚拟节点的动态结构化P2P网络性能研究     

李伟  徐正全  杨铸 《武汉大学学报(信息科学版)》2011,36(12):1504-1507

利用P2P节点会话时间呈重尾Pareto分布、少数节点具有较长的会话时间的特征,在稳定的物理节点中,实现若干个虚拟节点,以改善P2P网络会话时间的分布状态。仿真结果显示,在少量的稳定节点中生成少数虚拟节点能够有效地提高网络的查询性能。  相似文献   

虚拟城市建设方法与技术探讨     

魏翔  吴易璿  陈俊侃  李维 《地理空间信息》2011,(4):8-10

随着虚拟现实技术的发展,虚拟城市作为数字城市的重要组成部分也得到了快速发展。以虚拟城市建设特点为依据,论述了城市三维建模的基本理论和技术,包括建模方式、模型要求、数据组织等方面的内容,并提出了相应的实施建议和解决方案。  相似文献   

基于力/触觉反馈的虚拟血管介入手术系统     

陈拓汉  宋爱国 《南京气象学院学报》2011,(5):414-418

设计了一种新颖的基于力/触觉反馈的虚拟血管介入手术系统.该系统以通用型力/触觉交互设备——NovintFal-con力/触觉再现装置为核心,能够完成虚拟血管手术环境中的力/触觉反馈.详细介绍了系统的硬件环境参数,并设计了基于3DSMAX的建模与CHAI3D的仿真软件系统.仿真实验结果表明:基于力/触觉反馈的虚拟血管介入手术系统可以有效地模拟血管介入手术时的力反馈状态,帮助医师进行血管介入手术术前训练,提高手术成功率.  相似文献   

FMTT方法研究华北及邻区上地幔P波速度结构   总被引：7，自引：4，他引：3       下载免费PDF全文

张风雪  李永华  吴庆举  丁志峰 《地球物理学报》2011,54(5):1233-1242

本文利用华北地震科学台阵190套宽频带地震仪在2006年10月至2009年3月记录的远震事件,采用波形互相关技术提取了52414条P波初动到时数据,进一步使用FMTT(Fast Marching Teleseismic Tomography)方法,获取了华北克拉通中、东部陆块下方上地幔分辨高达0.5°×0.5°的P波速...  相似文献   

Cytochrome P450 1A1 expression in cetacean skin biopsies from the Indian Ocean     

Jauniaux T  Farnir F  Fontaine M  Kiszka J  Sarlet M  Coignoul F 《Marine pollution bulletin》2011,62(6):1317-1319

The study describes cytochrome P450 1A1 (CYPA1) expression in the skin of different cetacean species (Megaptera novaeangliae, n = 15; Stenella attenuata, n = 7 and Stenella longirostris, n = 24) from the Mozambique Channel island of Mayotte. Immunohistochemical examination was performed with a monoclonal antibody against scup cytochrome CYPA1. The sex was determined using a molecular approach consisting in the genotyping sex-specific genes. CYPA1 was detected at the junction between epidermis and blubber on dolphins only, mostly in the endothelial cells. Similar observation was obtained in the dermis of one M. novaeangliae. Immunohistochemical slides were scored to evaluate the expression of the CYPA1 and a higher expression was observed in S. longirostris, suggesting a higher exposure to pollutants for this species. The difference of expression between sexes was not significant.  相似文献   

Regionalization of low flows based on Canonical Correlation Analysis   总被引：2，自引：0，他引：2  

George TsakirisIoannis Nalbantis  George Cavadias 《Advances in water resources》2011,34(7):865-872

Regional analysis of low-flow statistics is a critical step in solving water resources management problems related to the requirements of the Water Framework Directive. Important element in this analysis is the determination of homogeneous sub-regions based on physiographic characteristics of the corresponding basin. The purpose of this paper is to investigate the use of the canonical correlation method for partitioning the set of drainage basins of a region into a number of homogeneous sub-regions and determining the relations between the physiographic and low-flow statistics of the basins of each sub-region. The method is also proposed to be used for classifying an ungauged basin in a sub-region of gauged basins.  相似文献   

双相各向同性介质弹性波高精度波场分离数值模拟方法     

陈可洋 《内陆地震》2011,25(3):215-228

为了便于研究双相介质固流相混合弹性波场中纵横波波场的传播规律,提出了基于交错网格的Biot双相各向同性介质弹性波动方程高精度波场分离正演数值模拟方法.采用高阶交错网格有限差分法来构建一阶双曲型双相各向同性介质弹性波动方程正演算子实现波场正演,并在每一步递推过程中,分别计算出同相和流相分量相应的散度场(纯纵波场)和旋度场...  相似文献   

Bioavailability and Interaction of Si and P in a Coastal Saline Soil Amended with Pig Slurry     

Zhaoliang Song  Shengdao Shan  Zheyue Song 《洁净——土壤、空气、水》2011,39(3):212-218

The effects of widely applied organic waste amendment on soil Si and P bioavailability and their interaction have rarely been investigated. The study examined bioavailability and interaction of Si and P in response to pig slurry (PS) amendment in a coastal saline (CS) soil. The final purposes of the study are to assess fertilizer Si and P needs and to ensure environmental quality. The results show that PS amendment can cause accumulation of bioavailable Si in surface soil (0–20 cm), and significantly improve both soil bioavailable P content and soil P lability through PS‐Si and P input, and by the input of PS‐organic matter (OM) and enhancing the complexation of OM with soil Si and P. As a result of the Si‐P competitive sorption, Si shows a more rapid increase in bioavailability than P at the preliminary stage of PS amendment. However, under the weakly alkaline conditions as a result of relatively long term PS amendment, the fixation capacity of Si by soil solid components increases causing a rapider decline of Si bioavailability than that of P.  相似文献