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今年才四十岁出点头儿的刘欣,出生在沈阳,在辽宁读的大学,工作以后,经历颇多。在沈阳的银行干过,去深圳下过海,在报社杂志社工作过,涉足过出版业,在国内多家社团担纲组织工作,眼下在北京创办了欣欣向荣文化传播中心。 相似文献
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面向数字中国建设中国的现代大地测量基准 总被引:2,自引:0,他引:2
在回顾我国大地测量基准建设历史的基础上,分析了在当前建设信息化社会,创建数字中国,对现代地理空间基础框架中测绘基准的需求。提出了在我国建设现代大地测量基准的建议。在平面基准方面,建议在国家GPS2000网(三网)的基础上,进一步加密国家GPS网点和永久性追踪站,构建有足够分布密度的三维高精度动态大地坐标框架,为我国今后建立新的大地坐标系统创造条件。在高程基准方面,建议在仪器设备和规范细则方面作好准备工作,依法定期对国家高程控制网进行复测。在重力基准方面,在国家2000重力基准网和国家2000(似)大地水准面的基础上,有步骤的按省或地区推算具有厘米级精度,10km级栅格分辨率的似大地水准面。在条件成熟时,我国应考虑采用三维地心坐标系统。 相似文献
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既然选择了走生态文明的发展道路,就必须在改造客观世界的进程中,不断推进科学发展、可持续发展,推进人与自然的和谐。在通向未来的发展探索中,林业是生态建设的主体,在建设生态文明中被赋予重大使命。林业在建设生态文明中肩负着重要使命一是林业具有强大的生态功能,在实现生态良好方面发挥着主体作用。 相似文献
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朱敦尧 《武汉大学学报(信息科学版)》1987,(2)
本文探讨了制约地图符号设计的内在的基本规律,提出了地图符号的约定性原则和等价性原理。把作为地图符号的物质时象同传输过程中的地图符号区别开来,分析了地图符号的价值及价格,并对内涵地图符号和外延地图符号及其相互关系进行了研究,最后提出了新的地图符号分类原理。 相似文献
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Valérie Ballu Jérome Ammann Olivier Pot Olivier de Viron Glenn S. Sasagawa Gilles Reverdin Marie-Noelle Bouin Mathilde Cannat Christine Deplus Sébastien Deroussi Marcia Maia Michel Diament 《Journal of Geodesy》2009,83(2):147-159
Decades of cruise-based exploration have provided excellent snapshots of the structure of mid-ocean ridges and have revealed
that accretion is a mixture of steady-state and quantum events. Observatory-type studies are now needed to quantify the temporal
evolution of these systems. A multi-disciplinary seafloor observatory site is currently being set up at the Lucky Strike volcano,
in the axial valley of the slow spreading Mid-Atlantic ridge as a part of the MoMAR (monitoring of the Mid-Atlantic Ridge)
initiative. The aim of this observatory is to better understand the dynamics of the volcano and the hydrothermal vents hosted
at its summit as well as their plumbing systems. In August 2006, the GRAVILUCK cruise initiated an experiment to monitor the
deformation of Lucky Strike volcano. A geodetic network was installed, and seafloor pressure, gravity and magnetic data were
collected. In this paper, we present the method used to monitor volcanic deformation, which involves measuring relative depth
difference between points within a seafloor geodesy network. We show that, taking into account oceanographic variability and
measurement noise, the network should be able to detect vertical deformations of the order of 1 cm. 相似文献
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Three-dimensional building models are important for various applications, such as disaster management and urban planning. The development of laser scanning sensor technologies has resulted in many different approaches for efficient building model generation using LiDAR data. Despite this effort, generation of these models lacks economical and reliable techniques that fully exploit the advantage of LiDAR data. Therefore, this research aims to develop a framework for fully-automated building model generation by integrating data-driven and model-driven methods using LiDAR datasets.The building model generation starts by employing LiDAR data for building detection and approximate boundary determination. The generated building boundaries are then integrated into a model-based processing strategy because LiDAR derived planes show irregular boundaries due to the nature of LiDAR point acquisition. The focus of the research is generating models for the buildings with right-angled-corners, which can be described with a collection of rectangles under the assumption that the majority of the buildings in urban areas belong to this category. Therefore, by applying the Minimum Bounding Rectangle (MBR) algorithm recursively, the LiDAR boundaries are decomposed into sets of rectangles for further processing. At the same time, the quality of the MBRs is examined to verify that the buildings, from which the boundaries are generated, are buildings with right-angled-corners. The parameters that define the model primitives are adjusted through a model-based boundary fitting procedure using LiDAR boundaries. The level of details in the final Digital Building Model is based on the number of recursions during the MBR processing, which in turn are determined by the LiDAR point density. The model-based boundary fitting improves the quality of the generated boundaries and as seen in experimental results, the quality depends on the average LiDAR point spacing. This research thus develops an approach which not only automates the building model generation, but also achieves the best accuracy of the model while utilizing only LiDAR data. 相似文献
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为解决GF-2影像在传输、存储及实际使用中面临的局部篡改问题,本文提出了一种用于GF-2影像完整性认证的感知哈希算法。首先采用固定分块的方式,将整幅影像分割成多个子块,运用SIFT算子提取子块的关键点特征信息;然后采用SVD方法提取SIFT关键点特征信息的特征值,选取其中较大的10%特征值构建子块的感知哈希序列;最后串联所有子块的感知哈希序列生成整幅影像的感知哈希值。在影像认证过程中,通过计算原始影像与待认证影像的感知哈希值的差异,从而实现对影像内容的认证。试验表明,该算法能够实现GF-2影像中地物篡改的检测与定位,同时对LSB水印嵌入、DAT格式转换及BMP格式转换等内容保持操作具有良好的稳健性,为GF-2影像的安全使用提供保障。 相似文献
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本文根据多参数的R-C不等式和优效计量定理,得到了函数模型和随机模型参数估计的方差下界公式。函数模型的参数估计是优效估计量,但随机模型的参数估计即方差分量估计不是优效估计量;作为特例,单位权方差的估计是优效估计量,同时证明了函数模型和随机模型参数估计的不相关性。 相似文献
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现阶段整星座低轨卫星观测数据的缺失制约了LEO卫星导航增强研究,针对该问题,本文设计了LEO导航增强星座地基观测仿真系统,构建生成了LEO星座伪距和载波相位观测值的仿真模型;介绍了仿真系统设计流程和架构、仿真地基LEO观测数据;使用RTKLIB进行了标准单点定位(SPP)和精密单点定位(PPP)解算,验证了仿真系统搭建的正确性,以及伪距和载波观测值仿真的正确性。结果表明,相较于只考虑几何距离的地基观测数据,该系统考虑各误差模型后观测数据置信度高,可用于支撑LEO导航增强星座定位研究。 相似文献
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新工科背景下遥感实验教学CDIO-OBE模式改革 总被引:5,自引:4,他引:1
新工科建设是新科技、新产业、新经济形势下我国规划人才战略的重要部署,开拓了我国工程教育改革的新路径。本文介绍了遥感实验教学与新工科教育理念相对接,按新工科建设要求探索工程教育人才培养的新模式改革。遥感实验教学借鉴国际工程教育最新模式CDIO及美国工程教育通用模式OBE,将二者结合实施CDIO-OBE模式教学实践,包括:借鉴《华盛顿协议》体系和欧盟EUR-ACE体系及我国工程教育专业认证标准,制定实验教学整体学习产出;基于课程与学习产出匹配矩阵,优化实验课程体系;根据课程学习产出,设计教学内容;按CDIO组织课程教学,实现教学产出。CDIO-OBE模式以学习产出驱动CDIO下项目和团队的整体训练,通过实现预期学习产出,促进新工科背景下遥感工程人才的培养。 相似文献
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2009年武汉市植被净初级生产力估算 总被引:1,自引:0,他引:1
利用CASA模型,结合实测的光合有效辐射(PAR)数据、MODIS归一化植被指数(NDVI)和Land Cover数据、气象数据等资料,估算了2009年武汉市的植被净初级生产力(NPP)。结果显示,武汉市的植被平均单位面积年NPP产量达到464.19gC·m^-2·a^-1。6、7、8三个月NPP积累值最高,占全年的56.8%;12、1、2三个月NPP值最低,仅占5.6%。黄陂区由于林地较广,NPP值较大,在1 000gC·m^-2·a^-1以上;而城市周边由于植被覆盖面积较小,NPP值较低,在400gC·m^-2·a^-1以下。 相似文献