The trade network of the Belt and Road Initiative and its topological relationship to the global trade network   总被引：2，自引：0，他引：2  

Zhouying Song  Shuyun Che  Yu Yang 《地理学报(英文版)》2018,28(9):1249-1262

Unimpeded trade is one of the cooperation priorities in the Belt and Road Initiative proposed by China. On 15 May 2017, the Joint Communique of the Leaders Roundtable of the Belt and Road Forum for International Cooperation reaffirmed the participants’ shared commitment to build an open economy and ensure free and inclusive trade. The Belt and Road Initiative (BRI) is not only China's new action to drive its open and global development, but also a platform for an increasing number of countries to explore free and inclusive trade and promote a universal, rule-based, open, non-discriminatory, and equitable multilateral trade system. It is therefore important to examine the topological relationship between the BRI and global trade networks. More specifically, this article first analyzes the community structure of trade networks using a community detection algorithm, and then estimates the topological relationship between different trade communities. The findings of this article are as follows. First, this research identified three trade communities and two sub-communities in the BRI trade network, in which China is the core, Russia is the sub-core of the biggest trade community, and India, United Arab Emirates, and Saudi Arabia are cores of the second trade community (South Asia-West Asia). Second, it identified five trade communities in the global trade network, centred on China, USA, Russia, India-United Arab Emirates, and Germany- Netherlands-France-Britain and other European developed countries. Third, the topological analysis indicated that in the global trade network, most BRI countries are attracted by the core nodes of the BRI regions, such as the China, Russia and India-United Arab Emirates core nodes, and have strong trade contacts with BRI countries. Most Central-East European countries are mainly attracted by Germany-Netherlands-France-Britain and other developed European countries with a low penetration of BRI trade. Although some Southeast Asian countries are incorporated into the Asia-Australia-South Africa community with China as the core, they still need to strengthen trade linkages with BRI countries.  相似文献   

Classifying natural-language spatial relation terms with random forest algorithm     

Shihong Du  Xiaonan Wang  Chen-Chieh Feng  Xiuyuan Zhang 《International journal of geographical information science》2017,31(3):542-568

The exponential growth of natural language text data in social media has contributed a rich data source for geographic information. However, incorporating such data source for GIS analysis faces tremendous challenges as existing GIS data tend to be geometry based while natural language text data tend to rely on natural language spatial relation (NLSR) terms. To alleviate this problem, one critical step is to translate geometric configurations into NLSR terms, but existing methods to date (e.g. mean value or decision tree algorithm) are insufficient to obtain a precise translation. This study addresses this issue by adopting the random forest (RF) algorithm to automatically learn a robust mapping model from a large number of samples and to evaluate the importance of each variable for each NLSR term. Because the semantic similarity of the collected terms reduces the classification accuracy, different grouping schemes of NLSR terms are used, with their influences on classification results being evaluated. The experiment results demonstrate that the learned model can accurately transform geometric configurations into NLSR terms, and that recognizing different groups of terms require different sets of variables. More importantly, the results of variable importance evaluation indicate that the importance of topology types determined by the 9-intersection model is weaker than metric variables in defining NLSR terms, which contrasts to the assertion of ‘topology matters, metric refines’ in existing studies.  相似文献   

在图形简化中面状目标间拓扑关系渐进式转换的研究   总被引：1，自引：0，他引：1  

郭庆胜  蔡永香 《测绘科学》2007,32(1):30-31,39

拓扑关系是空间关系中最为重要的关系,在空间抽象中,拓扑关系会发生变化,如何控制这种变化?如何在更抽象的层次上维护空间拓扑关系的一致性,就是一个非常重要的问题。本文以拓扑关系成分抽象的转换方法为基础,研究了面之间拓扑关系的抽象规则,并详细探讨了这些拓扑关系的渐进式转换方法,绘制了相应的面之间基本拓扑关系渐进式转换图。  相似文献   

面向自然连续面群边线的协同化简方法     

张付兵  孙群  朱新铭  马京振 《地球信息科学学报》2022,24(4):631-642

自然连续面群边线化简是地形图中自然面状要素和地理国情普查数据中自然图斑自动制图综合的重要实施步骤。现有面要素边线化简算法大多以线化简算法为基础,未有效化简弯曲特征、保持面积平衡和满足图面视觉清晰性要求,且化简结果存在共享边界不一致、边线自相交和边线之间相交的拓扑问题。为此,结合自然连续面群表达特点和化简要求,本文提出一种面向自然连续面群边线的协同化简方法。首先将自然连续面群转换为拓扑数据结构组织,以待化简弧段及其相邻弧段为基础构建约束Delaunay三角网,标识化简区域;其次利用弧段双侧层次多叉树模型渐进式退化条带状弯曲、化简细小弯曲;最后自适应夸大狭窄“瓶颈”,实现边线的协同化简。以河南省某区域1:5万地形图中的植被与土质面要素进行化简实验,相较于对比方法,该方法能够有效保持自然连续面群边线化简前后的拓扑一致性、要素之间的面积平衡,充分化简目标尺度下的局部不清晰细节,化简结果精度高。  相似文献   

三维体目标间拓扑关系与方向关系的混合推理   总被引：1，自引：1，他引：0  

刘新  刘文宝  李成名 《武汉大学学报(信息科学版)》2010,(1)

重点研究了三维空间中拓扑关系和方向关系间的混合空间关系推理。用Allen区间关系对描述基于投影的空间划分方法得到的方向区域和用九交矩阵描述的拓扑关系,用定义法研究混合空间关系推理,推理结果用组合推理表表示。  相似文献   

SOM拓扑保序机理的模拟弹性力分析     

冯天瑾  马琳涛  丁香乾 《中国海洋大学学报(自然科学版)》2005,35(1):116-120

针对SOM内在原理和基本特性中一些未解决的重要问题,定义了输出阵列上神经元i承受的、正比于模式向量及权向量之间距离的2种模拟弹性力：输入模式向量对胜者i的拉力,以及阵列中胜者j对邻近i的牵动力;分析了弹性力的9个性质,对SOM学习过程中神经元权向量的演变过程及拓扑映射保序的机理给出了易于理解的、形象的解释。  相似文献   

模糊面元素空间拓扑关系抽象化方法研究   总被引：7，自引：3，他引：4  

郭庆胜  杜晓初 《测绘学报》2004,33(4):307-310

空间拓扑关系的判定是地理信息系统中进行空间查询、空间分析、空间推理等操作的基础.在分析模糊区域空间拓扑关系的基础上,用空间关系向量定量描述这些拓扑关系.依据空间抽象的要求,通过计算向量之间的相关程度,对模糊区域的空间拓扑关系进行抽象,并根据空间拓扑关系的区域分布特征对抽象后的结果进行调整.  相似文献   

基于拓扑谓词的空间拓扑关系相似性度量模型与应用   总被引：1，自引：0，他引：1  

安晓亚  杨云  刘平芝 《地球信息科学学报》2013,15(2):159-165

空间拓扑关系相似性度量是空间数据相似性度量的重要组成部分,它是空间数据检索和空间场景相似查询的基础和关键。本文旨在建立一种能够同时度量简单和复杂拓扑关系间的相似性度量模型。首先,以9个拓扑谓词提出一种简单拓扑关系间相似性度量方法,即定义简单拓扑关系之间距离为两个9交集矩阵之间的距离,从而得到简单拓扑关系之间的相似度。然后,综合考虑实体集合间的数量相似度和维数相似度,建立实体集合间的简单拓扑关系相似性度量模型,并在上述实体集合间简单拓扑关系相似性度量的基础上,采用分解-组合的策略先将复杂拓扑关系分解为若干个局部拓扑关系,通过组合局部拓扑关系之间的相似度,直至建立复杂拓扑关系间的相似性度量模型。实验表明,制图综合中的选取对空间实体集合之间拓扑关系相似度的影响最大,其他因素影响较小,因此,其能以拓扑关系相似度来度量制图综合对拓扑关系的改变程度。  相似文献   

土地定级估价的分析研究与实践——以新疆拜城县为例          下载免费PDF全文

李争光  丁建丽  欧阳广交 《山东国土资源》2012,28(2):50-54

近几年来,经济发展迅速,土地级别划分及地价水平已有较大的变化,原有的基准地价体系已不能适应现时经济发展的要求,地价体系也亟需修正更新。该文结合拜城县的具体情况,并遵循所选因子与土地的相关性,确定拜城县城区土地定级因素,在分析各定级因素权重的基础上,计算各因素的分值,划分土地等级。通过对拜城县城区的土地进行定级估价作出修正和更新,将对土地的监督管理工作起到良好的促进作用。  相似文献   

一种结合拓扑信息和SIFT特征的多源遥感影像自动匹配方法     

杜春鹏  李景山 《测绘通报》2017,(10):115-119

基于单一特征的匹配办法在多源遥感影像匹配中往往不适用的问题,提出了一种结合拓扑信息和SIFT特征的自动多源遥感影像匹配方法。该方法首先在两幅影像中使用SIFT算法在尺度空间上提取特征向量,其次对这些特征点使用最近邻提取1：N的多个可能的匹配点对,然后结合位置信息和拓扑信息对这些可能的匹配点对进行剔除,并使用RANSAC方法剔除粗差,最终得到同名匹配点。试验结果表明,相比于计算机视觉领域常用的SIFT算法,本文方法可有效地提高匹配正确率,并获得更多正确的同名点。  相似文献