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61.
在城镇化进程中,城市与近郊之间通过职住、货运、游憩等活动产生越来越紧密的交互联系,对于这些交互联系的准确识别和定量刻画,是理解城乡空间关系的重要手段,也能为城市的资源有效配置与合理规划提供重要的现状信息。本文通过对全北京在一日之内的手机信令数据所反映的人群移动轨迹的深入分析,融合城市的POI信息形成顾及人类活动时空信息的空间交互类型推断。以北京市为例,对城市中心与近郊之间远距离的强交互进行定性、定量和定位的探索。本文发现了北京市多尺度下空间交互模式和距离衰减规律,判断了城乡异常交互类型,对比了城乡之间和城市内部的交互模式的异同,以及基于交互类型视角提取了城乡异常交互的空间特征。研究认为,基于手机信令数据,利用停留点提取和高斯核密度估计的空间交互类型推断有效地发现了北京市周末的远距离出行类型特点,提取了其空间交互强度和空间特征,揭示了基于人类活动的北京市周末城乡交互模式。 相似文献
62.
It is well known that high-leverage observations significantly affect the estimation of parameters. In geodetic literature,
mainly redundancy numbers are used for the detection of single high-leverage observations or of single redundant observations. In this paper a further objective method for the detection of groups of important and less important (and thus redundant) observations is developed. In addition, the parameters which are predominantly
affected by these groups of observations are identified. This method thus complements other diagnostics tools, such as, e.g.,
multiple row diagnostics methods as described in statistical literature (see, e.g., Belsley et al. in Regression diagnostics:
identifying influential data and sources of collinearity. Wiley, New York, 1980). The method proposed in this paper is based
on geometric aspects of adjustment theory and uses the singular value decomposition of the design matrix of an adjustment
problem together with cluster analysis methods for regression diagnostics. It can be applied to any geodetic adjustment problem
and can be used for the detection of (groups of) observations that significantly affect the estimated parameters or that are
of negligible impact. One of the advantages of the proposed method is the improvement of the reliability of observation plans
and thus the reduction of the impact of individual observations (and outliers) on the estimated parameters. This is of particular importance for the very long baseline interferometry
technique which serves as an application example of the regression diagnostics tool. 相似文献
63.
Conventions on thermal expansion modelling of radio telescopes for geodetic and astrometric VLBI 总被引:7,自引:6,他引:1
Axel Nothnagel 《Journal of Geodesy》2009,83(8):787-792
Thermal expansion of radio telescopes has long been recognized as an effect which cannot be neglected in geodetic and astrometric
VLBI data analysis if millimeter accuracy is desired. In this article, the author documents the conventions which are being
set by the International VLBI Service for Geodesy and Astrometry (IVS) for a consistent modelling of this effect in its routine
product generation. For the largest telescopes, the annual cycle of thermal expansion may change the height of the VLBI reference
point by as much as 20 mm. However, for telescopes which are used in present-day IVS operations, the variations rather range
from 4 to 6 mm. 相似文献
64.
近年来,开源GIS软件取得迅猛发展,越来越多的科研机构、企业和组织开展了开源GIS软件开发和应用研究。本文首先综述了当前主流的开源G1S软件及其典型应用,讨论了开源GIS软件版权许可形式;其次,分别从模块功能、体系架构和开发使用环境等方面分析了主流开源桌面GIS软件和WebGIS的特点,并提出研发和教学方面开源GIS软件选择的建议;最后,讨论了基于GeoServer、Nasa World Wind、MapServer和SharpMap四种开源GIS软件在地图制图、3维可视化表达、网络地理信息服务和移动GIS软件等方面的典型应用实例,对开源GIS的应用和发展前景进行了展望。 相似文献
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67.
The Arunta Inlier is a 200 000 km2 region of mainly Precambrian metamorphosed sedimentary and igneous rock in central Australia. To the N it merges with similar rocks of lower metamorphic grade in the Tennant Creek Inlier, and to the NW it merges with schist and gneiss of The Granites‐Tanami Province. It is characterized by mafic and felsic meta‐igneous rocks, abundant silicic and aluminous metasediments and carbonate, and low‐ to medium‐pressure metamorphism. Hence, the Arunta Inlier is interpreted as a Proterozoic ensialic mobile belt floored by continental crust. The belt evolved over about 1500 Ma, and began with mafic and felsic volcanism and mafic intrusion in a latitudinal rift, followed by shale and limestone deposition, deformation, metamorphism and emergence. Flysch sedimentation and volcanism then continued in geosynclinal troughs flanking the ridge of meta‐igneous rocks, and were followed by platform deposition of thin shallow‐marine sediments, further deformation, and episodes of metamorphism and granite intrusion. 相似文献
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69.
Petroleum hydrocarbons are formed by breakdown of kerogen preserved in source rocks throughout the process of catagenesis. This process is accompanied by free radical generation in kerogen. The availability of measuring free radicals in kerogen using ESR to deduce a maturation estimation of potential source rocks has been hindered due to the presence of the solvent-extractable organic molecules (SEOM) trapped within the kerogen matrix. Spin concentration (Ns) of the kerogen treated with pyridine (KPy) represents the paramagnetic centers of the kerogen matrix itself and provides a potential parameter to evaluate kerogen maturation. 相似文献
70.
LD2000 System with 3S and Multi—sensor 总被引:2,自引:0,他引:2
This paper introduces a car-borne road information collecting and updating system (LD2000) developed by Wuhan Technical University of Surveying and Mapping.This system is capable of collecting road network information and creating digital road network effectively by means of GPS,GIS and multi-sensor integration.The design and development of LD 2000 system are also presented in this paper. 相似文献