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941.
942.
Hierarchical object oriented classification using very high resolution imagery and LIDAR data over urban areas 总被引:1,自引:0,他引:1
Yunhao Chen Wei Su Jing Li Zhongping Sun 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
Urban land cover information extraction is a hot topic within urban studies. Heterogeneous spectra of high resolution imagery—caused by the inner complexity of urban areas—make it difficult. In this paper a hierarchical object oriented classification method over an urban area is presented. Combining QuickBird imagery and light detection and ranging (LIDAR) data, nine kinds of land cover objects were extracted. The Spectral Shape Index (SSI) method is used to distinguish water and shadow from black body mask, with 100% classification accuracy for water and 95.56% for shadow. Vegetation was extracted by using a Normalized Difference Vegetation Index (NDVI) image at first, and then a more accurate classification result of shrub and grassland is obtained by integrating the height information from LIDAR data. The classification accuracy of shrub was improved from 85.25% to 92.09% and from 82.86% to 97.06% for grassland. More granularity of this classification can be obtained by using this method. High buildings and low buildings can, for example, be distinguished from the original building class. Road class can also be further classified into roads and crossroads. The comparison of the classification accuracy between this method and the traditional pixel-based method indicates that the total accuracy is improved from 69.12% to 89.40%. 相似文献
943.
杨琳 《西安航空技术高等专科学校学报》2009,27(4)
自从十八世纪中页鲍姆嘉通为美学奠定基础以来,众多哲学家、美学家写了无数论著来探讨美的含义.那么,美的本质究竟是什么呢?为什么美的问题会如此难以明晰?直到马克思主义美学产生后,这一美学命题才得到突破性地进展.马克思主义美学以实践为基础,认为实践是人类存在和发展的本质特征,从而提出"美是人的本质力量的对象化."将审美主体和审美客体有机地统一起来. 相似文献
944.
王璐璐 《北华航天工业学院学报》2011,21(2):31-33
网络营销(Electronic Marketing)是企业整体营销战略的一个组成部分,是建立在互联网基础之上,借助于互联网特性来完成企业一定营销目标的一种营销活动.网络的迅速普及和网络营销的迅速崛起以及全球经济一体化的形成,对当代项目管理提出了更高的要求.如何尽快采用信息化手段实施项目管理和决策,在项目的有限生命周期内... 相似文献
945.
概率风险评价(PRA)方法是一项成熟的量化风险评估技术,而可靠性相关数据不足,制约着该方法在国内载人航天领域的应用。针对这一问题,结合NASA的PRA工作经验,提出了一种适合国内载人航天PRA数据选用与分析的方法,综合运用产品的通用数据与特定数据,采用贝叶斯等数据融合方法,对产品进行量化评价。通过航天典型产品案例,与经典评估方法进行对比分析,结果表明,此方法更能反映产品的失效特性。文章提出的方法,可用于载人航天等具有小子样特征的产品PRA数据的选用与分析,为我国载人航天开展PRA工作提供参考。 相似文献
946.
王璐璐 《华北航天工业学院学报》2011,(2):31-33
网络营销(Electronic Marketing)是企业整体营销战略的一个组成部分,是建立在互联网基础之上,借助于互联网特性来完成企业一定营销目标的一种营销活动。网络的迅速普及和网络营销的迅速崛起以及全球经济一体化的形成,对当代项目管理提出了更高的要求。如何尽快采用信息化手段实施项目管理和决策,在项目的有限生命周期内尽其所能地发挥管理的功效使企业立于不败之地,开发和研究基于网络营销的项目管理是出路所在。 相似文献
947.
948.
Human beings are now facing global and regional sustainable development challenges.In China, Earth observation data play a fundamental role in Earth system science research. The support given by Earth observation data is required by many studies, including those on Earth's limited natural resources, the rapid development of economic and social needs, global change, extreme events, food security, water resources, sustainable economic and urban development, and emergency response. Application operation systems in many ministries and departments in China have entered a stage of sustainable development, and the State Key Project of High-Resolution Earth Observation Systems has been progressing since 2006. Earth observation technology in China has entered a period of rapid development. 相似文献
949.
Luciana Bianchi Alberto Conti Bernie Shiao 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The Galaxy Evolution Explorer (GALEX) has performed the first surveys of the sky in the ultraviolet (UV). Its legacy is an unprecedented database with more than 200 million source measurements in far-UV (FUV) and near-UV (NUV), as well as wide-field imaging of extended objects, filling an important gap in our view of the sky across the electromagnetic spectrum. The UV surveys offer unique sensitivity for identifying and studying selected classes of astrophysical objects, both stellar and extra-galactic. We examine the overall content and distribution of UV sources over the sky, and with magnitude and color. For this purpose, we have constructed final catalogs of UV sources with homogeneous quality, eliminating duplicate measurements of the same source. Such catalogs can facilitate a variety of investigations on UV-selected samples, as well as planning of observations with future missions. We describe the criteria used to build the catalogs, their coverage and completeness. We included observations in which both the far-UV and near-UV detectors were exposed; 28,707 fields from the All-Sky Imaging survey (AIS) cover a unique area of 22,080 square degrees (after we restrict the catalogues to the central 1° diameter of the field), with a typical depth of ∼20/21mag (FUV/NUV, in the AB mag system), and 3008 fields from the Medium-depth Imaging Survey (MIS) cover a total of 2251 square degrees at a depth of ∼22.7mag. The catalogs contain ∼71 and ∼16.6 million sources, respectively. The density of hot stars reflects the Galactic structure, and the number counts of both Galactic and extra-galactic sources are modulated by the Milky Way dust extinction, to which the UV data are very sensitive. 相似文献
950.
Milan S. Dimitrijević Magdalena Christova Zoran Simić Andjelka Kovačević Sylvie Sahal-Bréchot 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Stark broadening parameters for 36 multiplets of B IV have been calculated using the semi-classical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series and temperature dependence. 相似文献