Building extraction from DSM acquired by airborne 3D image     

YOU Hongjian LI Shukai 《地球空间信息科学学报》2003,6(3):25-31

1　IntroductionAutomaticbuildingextractionistheresearchfocustoobtainthree dimensional (3D)informationofcity .Therearetwomainapproachestoextractbuildingsbyremotesensing :oneisbasedonaerialphotosandtheotherisbasedonstereophotosordigitalsurfacemodels (DSM) .Man madebuildingsgenerallyhavesuchcharacteristicsaslimitedarea ,evidentandregularboundary ,heightdifferencebetweenbuildingandground ,etc .Somemethodsareproposedtoextractbuildingsbyusingremotesensingbasedonthesecharacteristics .Inthe 1 980s ,…  相似文献   

Environmental sustainability and scenarios of urbanization in arid area     

You Fei  Li Yu  Dong Suo-cheng 《中国地理科学(英文版)》2005,15(2):120-130

Based on data of questionnaire and field survey and two developing models of Business As Usual (BAU) and the Intensive Urbanization (IU), this article, taking Wuwei City, a medium size city and typical oasis arid area in Gansu Province with very vulnerable and sensitive natural environment but long history of oasis economy, as an example, evaluated the sustainability of its environment and analyzed the scenarios of Wuwei’s household energy consumption, waste discharge in transportation industry, primary industry, secondary industry, tertiary industry, by the integration of the systematical dynamics model Stella and Polestar language to simulate the future development of the research area. The results showed that, first, the developing model of IU was propitious to Wuwei City named for oasis economy and vulnerable natural environment. The strategy of "Intensive Urbanization" can change the structure of energy utilization, and improve the efficiency of energy utilization. Second, the proportion of domestic energy consumption will decrease with industrialization and economic development, while that of tertiary industry, secondary industry and transportation will gradually grow up according to strategy of "Intensive Urbanization". Third, the Wuwei City is facing a severe eco-environmental crisis under the conventional patterns of development and a better future under a sustainable urbanization scenario, in the next 10 to 20 years. The different developing trends were clarified and the relative countermeasures were put forward for the policy makers according to the driving forces. Foundation item: Under the auspices of Key Program of the National Natural Science Foundation of China (No. 90102013) and Key Innovation Sub-project of Chinese Academy of Sciences (No. KZCX1-10-07-04) Biography: YOU Fei (1972–), male, a native of Pianguan of Shanxi Province, Ph.D., assistant professor, specialized in regional sustainable development and ecological economy. E-mail: yofae@sina.com  相似文献   

青藏高原1993年GPS观测成果的精度分析     

游新兆  王启梁  王琪  蔺镜刚  吴星华 《大地测量与地球动力学》1994,(3)

应用线性回归、符号检验等数理统计方法研究了１９９３年完成的跨青藏高原首期ＧＰＳ网３９条基线的数据处理结果。通过对单基线观测中误差、重复观测基线互差及异步环闭合差的精度分析，认为由１６个观测点组成的跨青藏高原ＧＰＳ监测网的基线平均相对精度达０．１ｐｐｍ。  相似文献   

三峡二期工程蓄水后的垂直形变场   总被引：16，自引：12，他引：4  

杜瑞林  乔学军  邢灿飞  游新兆  王琪 《大地测量与地球动力学》2004,24(1):41-45

根据三峡地区的数字高程模型(DEM)，模拟三峡二期工程蓄水位达到135m后的水体负载，利用Farrell提出的质量负荷产生的地球形变理论，推算三峡水库水位达到135m后整个库区的垂直形变，与三峡库区GPS形变监测网获得的蓄水前后的垂直形变图像进行对比分析，结果显示：在三斗坪-巴东库段，两者中都出现了3个相同的、明显的垂直形变集中区。在三峡大坝附近，模拟结果比观测结果大8～15mm，说明坝址附近的花岗岩具有较强的刚性；而在香溪，模拟结果比观测结果要小23mm，且GPS观测到长江两岸的垂直变化差异达到22mm，说明该段地质构造的特殊性和复杂性。综合分析表明，三峡大坝坝址所在地的地质构造和地壳是稳定的。  相似文献   

中国大陆地壳现今运动的GPS测量结果与初步分析   总被引：9，自引：8，他引：1  

游新兆  杜瑞林  王琪  乔学军  华晓伟 《大地测量与地球动力学》2001,21(3):1-8

利用中国大陆及周边地区 1991～ 2 0 0 0年间一系列全球定位系统 (GPS)观测资料 ,计算了 340个GPS站点的位移速率 ,得到了统一的中国大陆现今地壳运动速率场。这些站主要集中于青藏高原及其周缘的喜马拉雅、川滇、河西走廊、阿尔金、天山 ,以及华北、福建东南沿海等主要构造活动区。固定测站速率精度优于 1mm/a ,流动测站速率精度优于 3mm/a。根据GPS结果对中国大陆现今地壳运动的状况进行了分析。  相似文献   

Research on Relationship between Elastic and Plastic Deformation of Material     

Li You Chen  Zhida Zhu  Weishen 《岩土力学》1988,9(3):41-50

Based on a lot of experiment results, it is put forward that the elastic part and plastic part of deformation of general metal material, and isotropic homogeneous, and continuous rock material follow a law—the relative law of elastic and plastic deformation. The law results from testing study and is partly proved theoretically.  相似文献   

长江三峡工程诱发地震监测系统中的GPS监测网及其观测结果   总被引：1，自引：1，他引：0  

杜瑞林  游新兆  乔学军 《大地测量与地球动力学》2001,21(1):46-52

阐述长江三峡工程诱发地震监测系统中的 GPS监测网的设计思路 ,并介绍了该网的第一、二期观测情况及数据处理结果。认为该网无论是技术设计还是运行质量 ,均达到世界一流的先进水平 ,其站间基线长度及其分量的测定精度优于 5mm。  相似文献   

江蓠新品种培育     

曾淑芳  刘思俭  揭振英  吴丽荷  尤春暖  费修绠  张学成 《广东海洋大学学报》1990,(1)

目前我国人工栽培江蓠分为两种主要方式:一是在半咸淡水塘中地播栽培细基江蓠繁枝变种,种苗容易解决,栽培方法简单,产量较高,但琼胶含量低;另一种是在浅滩上用浮筏式夹苗栽培真江蓠、细基江蓠、龙须菜等,培养种苗较麻烦,且产量较低,成本也较高,但琼胶含量高,质量也较好。为取两者的优点,我们把细基江蓠繁枝变种和细基江篱进行杂交,得出了杂交种。实验室培养结果表明,杂交种的琼胶含量介于两者之间,能在半咸淡水中正常生长。初步认为是一个适合于半咸淡水塘中栽培的优良品种,很有发展前途。  相似文献   

Dynamic stiffness matrix of a poroelastic multi-layered site and its Green＇s functions   总被引：3，自引：1，他引：2  

梁建文  尤红兵 《地震工程与工程振动(英文版)》2004,3(2):273-282

Few studies of wave propagation in layered saturated soils have been reported in the literature. In this paper, a general solution of the equation of wave motion in saturated soils, based on one kind of practical Biot‘s equation,was deduced by introducing wave potentials. Then exact dynamic-stiffness matrices for a poroelastic soil layer and halfspace were derived, which extended Wolf‘s theory for an elastic layered site to the case of poroelasticity, thus resolving a fundamental problem in the field of wave propagation and soil-structure interaction in a poroelastic layered soil site. By using the integral transform method, Green‘s functions of horizontal and vertical uniformly distributed loads in a poroelastic layered soil site were given. Finally, the theory was verified by numerical examples and dynamic responses by comparing three different soil sites. This study has the following advantages: all parameters in the dynamic-stiffness matrices have explicitly physical meanings and the thickness of the sub-layers does not affect the precision of the calculation which is very convenient for engineering applications. The present theory can degenerate into Wolf‘s theory and yields numerical results approaching those for an ideal elastic layered site when porosity tends to zero.  相似文献   

Scattering of SV waves by a canyon in a fluid-saturated, poroelastic layered half-space, modeled using the indirect boundary element method     

Jianwen Liang  Hongbing You  Vincent W. Lee   《Soil Dynamics and Earthquake Engineering》2006,26(6-7):611-625

The scattering of SV waves by a canyon in a fluid-saturated, poroelastic layered half-space is modeled using the indirect boundary element method in the frequency domain. The free-field responses are calculated to determine the displacements and stresses at the surface of the canyon, and fictitious distributed loads are then applied at the surface of the canyon in the free field to calculate the Green's functions for displacements and stresses. The amplitudes of the fictitious distributed loads are determined from the boundary conditions, and the displacements arising from the waves in the free field and from the fictitious distributed loads are summed to obtain the solution. The effects of fluid saturation, boundary conditions, porosity, and soil layers on the surface displacement amplitudes and phase shifts are discussed, and some useful conclusions are obtained. It is shown that the surface displacement amplitudes due to saturation and boundary conditions, different porosities, or the presence of a soil layer can be very dissimilar, and large phase shifts can be observed. The resulting wavelengths for an undrained saturated poroelastic medium are slightly longer than those for a drained saturated poroelastic medium; and are longer for a drained saturated poroelastic medium than those for a dry poroelastic medium. As porosity increases, the wavelengths become longer; and a layered half-space produces longer wavelengths than a homogeneous half-space.  相似文献