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931.
杨光 《北华航天工业学院学报》2013,23(1):22-23,27
本文运用灰色理论研究数据变化趋势。挖掘蕴藏于数据中的火灾发生规律,预测其发展趋势,为消防部门进行火灾预防,达到"预防为主"的防控目的提供依据。 相似文献
932.
提出把空间数据系统的发展历程分为三个阶段:第一阶段是面向信道传输,主要解决数据如何在空间链路上有效可靠传输;第二阶段是面向数据源,主要解决如何自适应不同数据源的传输要求。这两个阶段的技术已经成熟并应用。文章预测,空间数据系统将走上第三阶段,即面向数据用户的体制,到那时用户可以根据自己的需求,主动从空间分布式数据库中获取数据。文章重点阐述了第三阶段的新概念设想,它的第一步是云遥测,然后进一步建成支持交互的空间云数据系统。 相似文献
933.
宫峰勋 《中国民航学院学报》1998,16(5):15-21
】阐述了时分多址信道数据接收处理的基本原理,提出了相应的自动相关监视数据的接收、处理方法,并运用该方法接收到了各国飞机的飞行数据,经过对这些数据的处理,导出了对应的处理结论,给出了自动相关监视数据的应用实例 相似文献
934.
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
935.
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
936.
937.
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
938.
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
939.
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
940.
Rafik Hamdi Nabil Ben Nessib Sylvie Sahal-Bréchot Milan S. Dimitrijević 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Using semiclassical perturbation approach in impact approximation, we have calculated Stark widths for 32 spectral lines of doubly charged argon (Ar III). Oscillator strengths are calculated using Hartree–Fock method with relativistic correction (HFR) and an atomic model including 17 configurations. Energy levels are taken from NIST database. For perturbing levels for which the corresponding energy does not exist in NIST database, the calculated energies are used. Our widths are compared with the experimental results. The results presented here are of interest for modelling and investigation of stellar atmospheres since argon in different ionization stages is observed in many astrophysical objects. Finally, the importance of Stark broadening mechanism is studied in the atmospheric conditions of sdB stars. Electron impact Stark widths are compared to thermal Doppler widths as a function of temperature and optical depth of atmospheric layers. 相似文献