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黄河流域动力系统泥沙时序混沌特征分析——地理系统综合研究的一种尝试 被引量:6
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作者 马建华 楚纯洁 《地理研究》 CSCD 北大核心 2006年第6期949-958,共10页
选取黄河头道拐、潼关、花园口和利津断面1952~2000年的泥沙含量为时序,在G—P重构相空间的基础上,分别计算了各断面泥沙时序的关联维(D2)、K2熵和Hurst指数。结果表明,各断面的最小饱和镶嵌维(m)、D2和K2熵分别为5、3.24和0... 选取黄河头道拐、潼关、花园口和利津断面1952~2000年的泥沙含量为时序,在G—P重构相空间的基础上,分别计算了各断面泥沙时序的关联维(D2)、K2熵和Hurst指数。结果表明,各断面的最小饱和镶嵌维(m)、D2和K2熵分别为5、3.24和0.13,说明黄河流域各级系统均具有混沌特征,并且从上游到下游混沌特性逐渐增强。随着混沌特性的增强其平均可预报时间下降,头道拐断面为8年,其余断面为3年。各断面Hurst指数均大于0.68,在可预报时间内,各断面泥沙时序具有持续性下降趋势,并用2001~2004年实际数据得到了验证。文章还给出了黄河流域动力系统的一般形式,该系统至少需要8个状态变量,2个控制变量。 展开更多
关键词 黄河流域动力系统 泥沙时序 混沌特征 地理系统综合研究
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Situation and Development Tendency of Indoor Positioning 被引量:82
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作者 邓中亮 余彦培 +2 位作者 袁协 万能 杨磊 《China Communications》 SCIE CSCD 2013年第3期42-55,共14页
This paper introduces the significance of indoor positioning and analyzes the related problems. The latest research on indoor positioning is introduced. Further, the positioning accuracy and the cost of typical local ... This paper introduces the significance of indoor positioning and analyzes the related problems. The latest research on indoor positioning is introduced. Further, the positioning accuracy and the cost of typical local and wide area indoor positioning systems are compared. The results of the comparison show that Time & Code Division-Orthogonal Frequency Division Multiplexing (TC-OFDM) is a system that can achieve real-time meter-accuracy of indoor positioning in a wide area. Finally, in this paper, we indicate that the seamless high-accuracy indoor positioning in a wide area is the development trend of indoor positioning. The seamless Location Based Services (LBS) architecture based on a heterogeneous network, key technologies in indoor positioning for decimeter-accuracy and seamless outdoor and indoor Geographic Information System (GIS) are elaborated as the most important research fields of future indoor positioning. 展开更多
关键词 indoor positioning LBS REVIEW wide area local area TC-OFDM
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Landfill Site Selection in AI-Najaf Governorate, Iraq 被引量:1
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作者 Mohammad A. Al-Anbari Muhannad Y. Thameer +1 位作者 Nadhir Al-Ansari Sven Knutsson 《Journal of Civil Engineering and Architecture》 2016年第6期651-660,共10页
Solid waste management aspect is one of the most important challenges facing the local administration in the Govemorate of Najaf. Therefore, this study aims to provide for solid waste management problem by choosing th... Solid waste management aspect is one of the most important challenges facing the local administration in the Govemorate of Najaf. Therefore, this study aims to provide for solid waste management problem by choosing the best locations for the establishment of sanitary landfills in the governorate. In this study, GIS (geographic information system) and MCDA (multi-criteria decision analysis) were used based on 17 environmental, economic and geological criteria converted to input digital map layers. These were urban centres, cemetery, airports, electrical power lines, oil pipes, railways, roads, slope, historical sites, main rivers, industrial areas, religion sites, wells, military area, electrical power plants, nature reserves and national borders to select most importance sites in the govemorate. AHP (analytic hierarchy process) method was used in weighting the criteria used. All layers' maps were graded from 0 (not suitable) to 5 (most suitable) using spatial information scale then SAW (simple additive weighting) method was integrated in GIS used to calculate the suitability index for the studied area. The results indicated that 4.4% of the study region is suitable for landfill siting with grading values greater than 4.0. This included five sites distributed in three qadhaas of governorate. 展开更多
关键词 Multi-criteria decision analysis GIS Iraq Najaf landfill.
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中国历史上的移民发源地之三──苏北的苏州移民 被引量:3
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作者 葛剑雄 《寻根》 1997年第3期16-17,共2页
中国历史上的移民发源地之三苏北的苏州移民□葛剑雄阊门是苏州城的西北门。但在成千上万苏北人的心目中,阊门却有其特殊的含义,因为几百年来,他们的祖祖辈辈都说,他们来自苏州阊门。苏北,一般是指江苏省长江以北、陇海铁路以南的... 中国历史上的移民发源地之三苏北的苏州移民□葛剑雄阊门是苏州城的西北门。但在成千上万苏北人的心目中,阊门却有其特殊的含义,因为几百年来,他们的祖祖辈辈都说,他们来自苏州阊门。苏北,一般是指江苏省长江以北、陇海铁路以南的大部分平原地区,大致就是明、清时的... 展开更多
关键词 中国历史 移民后裔 朱元璋 苏北人 发源地 元末明初 苏州人 阊门 地理系统研究 苏州府
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Bounding species distribution models 被引量:1
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作者 Thomas J. STOHLGREN Catherine S. JARNEVICH +1 位作者 Wayne E. ESAIAS Jeffrey T. MORISETTE 《Current Zoology》 SCIE CAS CSCD 北大核心 2011年第5期642-647,共6页
Species distribution models are increasing in popularity for mapping suitable habitat for species of management con- cern. Many investigators now recognize that extrapolations of these models with geographic informati... Species distribution models are increasing in popularity for mapping suitable habitat for species of management con- cern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding ex- trapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suit-able habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647,2011]. 展开更多
关键词 Niche models Geographic information systems EXTRAPOLATION CLAMPING
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