Structural Analysis of Platforms with the Effect of Joint Flexibility

- A modified space beam element is presented in this paper to consider the local joint flexibility of T, Y tubular joints subjected to axial forces and in- plane bending moments for analysis of platforms. Two numerical examples are shown to verify the efficiency and validity of the method presented here.     

基于改进聚类分裂的动态R-树实现方法

在R*-树的构建过程中引入聚类技术能够有效地提高索引的性能,传统的k-means聚类算法对初始值非常敏感,聚类过程较为复杂。基于此,文中提出一种改进聚类分裂的动态R*-树实现方法,在节点分裂的过程中引进聚类技术,对R*-树的基本结构加以改进,从而获得动态的结构重组。实验表明,动态R*-树以略高的构建开销换取较高的查询效率,大幅度提高索引树的空间利用率,在批量数据动态加载和处理等方面具有较高的实用价值。     

“一带一路”倡议下中国与重要节点地区的贸易格局及影响因素--以外高加索国家为例

外高加索国家地处欧亚十字路口,是古丝绸之路上的重要国家,也是“一带一路”的核心节点,区位战略意义重大。该文分析了外高加索三国自1991年独立以来中国与其贸易发展历程,借助HM指数和贸易互补性指数,从贸易总体格局和贸易商品特征两个角度分析双向贸易关系,并探究了影响其贸易发展的因素。结果表明:1)中国与外高加索三国长期保持贸易往来,贸易总额呈波动攀升趋势,阶段性特征明显;贸易差额起伏变化,整体长期维持贸易顺差状态;外高加索三国对中国的贸易依赖性显著大于中国对其依赖性。2)中国对外高加索三国出口商品互补性显著高于进口互补性,说明与作为中国进口商品来源国相比,外高加索三国作为中国商品的消费市场更具优势;中国对外高加索三国出口商品类型较为相似,结构呈集中与多元并存态势,主要出口商品逐步由资源、劳动密集型的低附加值商品向技术密集型等高附加值商品转变,而中国自外高加索三国进口的商品类型虽有所扩展,但主要类型仍较为单一,高度集中于未加工或半加工类资源型商品。3)地理距离、政局稳定性、产业结构、地缘关系、贸易环境及便利性是影响中国与外高加索三国贸易发展的主要因素。     

京津冀城市群经济网络结构分析

分析京津冀城市群经济网络对京津冀协同发展具有重要的指导意义。从综合经济实力和交通联系2个方面分析了经济网络的节点与线路,采用社会网络分析法研究经济网络的结构,以剖析其经济网络空间结构的现状特征。研究结果表明,京津冀城市群的经济网络处于起步阶段,中部联系紧密区的经济网络最为紧密,南部联系稳定区的经济网络初具雏形,北部联系薄弱区的经济网络尚未形成。基于经济网络中存在的问题,提出优化经济网络的建议。     

三维前方交会在大型金属网架结构中的应用

探讨了三维前方交会法在大型无支撑金属网架结构屋面施工的质量监测方法,并对实测数据进行了分析,结果表明该方法保证施工质量,达到设计要求,为今后的安全运营提供了可靠的依据。同时为大型无支撑建筑屋顶的变形监测提供了一种测量监测依据。     

基于GIS的城郊物流规划

指明了城郊物流的特殊性和规划的基本要求,明确了可用于城郊物流规划中的G IS技术。采用G IS手段,制作了区位图,界定了城郊的性质,展现了本区的空间结构、交通体系和物流现状,结合模型分析预测出物流需求。重点探讨了3级物流结点的体系架构,阐述了各级结点的规划依据,设计了对应的算法,定位了物流园区、物流中心、配送中心的具体位置;以上位规划原则和可视化分析,提出对内、对外物流通道建设方案。     

一种面向应用的非平面路网数据模型及其实现

已有的路网数据模型有平面模型和非平面模型两类,但它们都没能完全表达空间路网的真实结构。将平面路网数据模型与节点高差以及方向车道结合,提出一种基于非平面的路网数据模型,用以表达实际的非平面路网。同时探讨了基于该模型的一种实现方式,并在广州市智能交通管理指挥系统中得到初步应用。     

Integrating algebraic multigrid method in spatial aggregation of massive trajectory data

The advanced technologies in location-based services and telecom have yield large volumes of trajectory data. Understanding these data effectively requires intuitive yet accurate visual analysis. The visual analysis of massive trajectory data is challenged by the numerous interactions among different locations, which cause massive clutter. This paper presents a new methodology for visual analysis by integrating algebraic multigrid (AMG) method in data aggregation. The non-parametric method helps to build a multi-layer node representation from a graph which is extracted from trajectory data. The comparison with AMG and other methods shows that AMG method is more advanced in both the spatial representation and the importance of nodes. The new method is tested with real-world dataset of cell-phone signalling records in Beijing. The results show that our method is suitable for processing and creating abstraction of massive trajectory dataset, revealing inherent patterns and creating intuitive and vivid flow maps.     

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E) Organisations non Gouvernementales / Non Governmental Organizations

SUMMARY

The evaporation tank consists of a square pan with a flat base, 2 metres long and 0, 7 metre deep, set into the ground with the rim 0, 1 metre above, and connected to a well on which is installed a limnigraph. This limnigraph records continuously fluctuations of the free water surface.

The recordings show that a large amount of water can be evaporated during rainfall. This phenomenon is specific at every evaporation tank with a free water surface. It is only during the dry intervals that a strong correlation can be established between the evaporation measured in the tank and the potential evapotranspiration of the surrounding natural surfaces. In order to locate the dry intervals and to measure the evaporation only during these intervals, it is necessary to use an apparatus provided with a continuous recording mechanism