共查询到20条相似文献，搜索用时 46 毫秒
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针对海量数据的大规模三维城市模型可视化,通过分析线性八叉树的特征,提出了基于线性八叉树的LOD层次细节技术,为实现快速可视化,提出了视相关层次细节方法,运用此方法对某三维城市模型进行实验。结果表明,该方法在八叉树基础上,以细节层次及视相关技术提高了三维可视化的速度,又能实现细节观察的需求。 相似文献
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随着计算机处理三维建模能力的不断提高,国内、外研究人员提出了很多种管理三维地形模型的数据结构和方法,其中八叉树是最具有代表性和相对简单的一种数据结构.为了提高数据的可扩展性,本文结合C++的标准模板库STL和八叉树结构来组织地形数据,并采用了Delaunay不规则三角剖分法对构建的三角形进行了处理,最终保证了DTM模型的成功构建. 相似文献
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碰撞检测是虚拟现实的重要组成部分,快速精确的碰撞检测算法直接决定三维仿真效果的好坏。提出了二维平面碰撞检测与动态八叉树相结合的新算法,使得碰撞检测效率有了很大提高。 相似文献
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城市三维模型海量数据动态组织调度方法 总被引：1，自引：0，他引：1
城市三维模型的海量特性和当前计算机硬件瓶颈给模型的实时渲染提出了较大的挑战.改进三维地理信息系统(GIS)中数据的组织与管理方式是提高三维场景可视化效率的有效途径,本文提出基于四叉树空间索引对数据进行组织,基于视点的层次模型技术(LOD)对数据进行动态调度,同时提出一种将纹理作为渲染单元重构网格数据的方法,对粗糙模型的渲染进行批处理,有效降低了耗时的渲染次数.实验证明,该方法是高效可行的,渲染帧率稳定在30帧左右,能够满足海量城市三维模型的可视化和实时交互需求. 相似文献
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八叉树结构是由四叉树结构推广到三维空间而形成的一种3D栅格数据结构,其树型结构在空间分解上具有很强的优势,为了有效地进行大量点云数据的存储和管理,重点讨论了线性八叉树编码技术。 相似文献
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基于随机参数化L系统的形式化语言对树木进行三维构模.依据树木与视点的空间关系,动态划分了基于林分的层次细节(LOD).对不同的细节层次采用不同的模型进行处理以达到真实感绘制.通过调整L系统的迭代、分层存储树木模型、十字交叉画树等策略分别对各个层次进行渲染,并对层级细节的渲染效率进行了比较.实验证明,本方法能够很好地模拟三维森林虚拟系统,可以满足森林三维场景的真实感和实时可视化效果的要求. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献
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《中国科学院院刊(英文版)》2014,(3):212-213
<正>In February 2014,the 30th Chinese Antarctic inland expedition team reported that they have successfully conducted the seeing measurement at the Antarctic Taishan Station using a Differential Image Motion Monitor(DIMM)developed by the Nanjing Institute of Astronomical Optic and Technology(NIAOT),Chinese Academy of Sciences.In astronomy,seeing is a physical parameter that describes the irregular movement and blur of the star 相似文献
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XIN Ling 《中国科学院院刊(英文版)》2014,(4):270-271
Amassive overhaul is coming to the Chinese Academy of Sciences （CAS）. To straighten its ＂fragmented, inefficient research＂, the academy has decided to restructure its 104 institutes for better teamwork. 相似文献
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SONG Jianlan 《中国科学院院刊(英文版)》2014,(4)
<正>DNA demethylation in mammalian zygotes,a biochemical process through which the parental genomes let go the epigenetic marks from their"past lives"to obtain totipotency,has long fascinated biologists:how does it happen?A joint team at the CAS Shanghai Institutes for Biological Sciences tells a surprising story. 相似文献
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China is one of the fastest growing economies worldwide. Are science and research also in the fast lane? We talked with LUO Yuan, scientist at the Institute of Coal Chemistry in Shanxi, and Axel Mosig, Professor at Ruhr University in Bochum, who has first-hand experience working and living in China. 相似文献
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INS 《中国科学院院刊(英文版)》2014,(4):311-311
Neonatal heart:Largely,postnatal coronary vessels might not have expanded from preexisting embryonic vasculature as formerly believed–see what CAS biologists revealed in page 311. 相似文献
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《中国科学院院刊(英文版)》2014,(4):312-312
<正>Recently a group of researchers at the unit of molecular virology,Institut Pasteur of Shanghai,Chinese Academy of Sciences revealed a new mechanism to regulate the survival of influenza A virus and reported their discoveries in the Journal of Virology on July 相似文献
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《中国科学院院刊(英文版)》2014,(4):319-320
<正>Amber-bearing deposits are among the most important Konservat-Lagersttten providing unique windows into past ecosystems.Fushun amber has been known for over a century and was traditionally regarded as an important source of medicine as well as organic gemstones.The inclusions,however,were not the subject of any comprehensive investigation 相似文献