Metrics for characterizing network structure and node importance in Spatial Social Networks     

Dipto Sarkar  Clio Andris  Colin A. Chapman  Raja Sengupta 《International journal of geographical information science》2019,33(5):1017-1039

Social Network Analysis offers powerful tools to analyze the structure of relationships between a set of people. However, the addition of spatial information poses new challenges, as nodes are embedded simultaneously in network space and Euclidean space. While nearby nodes may not form social ties, ties may exist at a distance, a configuration ill-suited for traditional spatial metrics that assume adjacent objects are related. As such, there are relatively few metrics to describe these nuanced situations. We advance the burgeoning field of spatial social network analysis by introducing a set of new metrics. Specifically, we introduce the spatial social network schema, tuning parameter and the flattening ratio, each of which leverages the notion of ‘distance’ to augment insights obtained by relying on topology alone. These methods are used to answer the questions: What is the social and spatial structure of the network? Who are the key individuals at different spatial scales? We use two synthetic networks with properties mimicking the ones reported in the literature as validation datasets and a case study of employer–employee network. The methods characterize the employer–employee as spatially loose with predominantly local connections and identify key individuals responsible for keeping the network connected at different spatial scales.  相似文献   

西河水文站水准点稳定性分析     

陈荣  郑永伟  李庆华 《水文》2019,39(3):63-67

西河水文站设置有4个水准点,均埋设在冲击层地区。在该地区设置的水准点,即便严格执行《国家一、二等水准测量规范》(GB/T12898-2006)规定的埋石深度和尺寸标准,也很难认为它们是稳定不变的。利用西河水文站1999~2016年8次水准点高程校测成果,采用结点法,对4个水准点的稳定性指标进行分析计算,以期解决西河水文站水准测量工作中引据点选择的随意性,保证用稳定的水准点作为水准测量的引据点,达到既节约测量时间,又提高测量精度的目的。  相似文献   

Explanation of locking of four‐node plane element by considering it as elastic Dirichlet‐type boundary value problem     

F. Molenkamp  J. B. Sellmeijer  C. B. Sharma  E. B. Lewis 《国际地质力学数值与分析法杂志》2000,24(13):1013-1048

The aim of this study is to arrive at a better understanding of the phenomenon of locking of low‐order compatible displacement type of finite elements in particular for the hour‐glass mode of the plane four‐node element and dilative materials. To this end the properties of finite elements are investigated in an analytical way, where a finite element is considered as a plane boundary value problem with prescribed boundary displacement (Dirichlet problem). In this paper for the sake of simplicity the simplest possible linear comparison solid, namely isotropic linear elasticity, is applied, although recognizing fully that for a dilative material elasto‐plasticity would be more realistic. From the study described in this paper it is concluded that locking of the four‐node element is not due to any particular numerical formulation of this compatible finite element since, even the analytical solution suffers from this problem. The locking of this element is not related to incompressibility of the material either as the analytical solution shows locking to occur at a parameter set which differs significantly from the one in case of incompressibility. It is shown that locking is a consequence of the combination of the dilative material behaviour and the compatible displacement type of boundary conditions, which leads to infinite isotropic stresses in the element. These infinite isotropic stresses occur at the limit of uniqueness of the solution, which for this element is shown to occur outside the parameter range of the sufficiency of uniqueness. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

网络专题地图服务平台的设计与实现     

李林涛  徐笳 《四川测绘》2010,33(4):154-158

空间信息共享和互操作是GIS发展永恒的主题,本文主要研究了网络专题地图服务平台的设计与实践,从数据目录管理、多源数据节点的远程访问与调度、专题地图的按需动态生成与发布等关键技术着手,研究实现了面向用户的空间信息与行业统计信息的集成共享与可视化。利用ASP．NET创建了网络专题地图服务门户,验证了所提出的框架体系和关键技术的合理性和可行性。  相似文献   

Huxley方程的定性分析     

陈冲  吕海炜  刘启宽 《成都信息工程学院学报》2009,24(5):509-512

运用微分方程定性理论,对Huxley方程进行定性分析,得到了方程在有限奇点的稳定性及极限环不存在性的结论,并借助Maple软件做出相图．  相似文献   

基于K—means聚类的多面函数及其在DEM内插中的应用     

冯杨民  张菊清 《测绘工程》2009,18(2):16-18

中心节点的位置是影响多面函数拟合精度的关键因素之一。基于聚类算法的思想,提出采用基于K—means聚类的方法选取中心点,使得构造的中心节点对数据范同内的数据得到更好的响应,从而提高拟合的精度。最后通过实例验证本方法的有效性。  相似文献   

井间地震层析成像初始速度模型          下载免费PDF全文

段心标  金维浚 《地球物理学进展》2007,22(6):1831-1835

地震直达波走时层析成像可归结为求解一个大型的、稀疏的、常常是病态的线性方程组.求解方程组常用的迭代法,需要一个比较合理的初始猜测解,也即是初始速度模型.初始模型关系到反演的效率甚至成像的正确性.本文在前人研究基础上提出一种生成模型网格节点初始速度方法,假定震源到检波点路径为直线,记录每条射线穿过的单元和统计每个网格单元穿过的射线数目、自动拾取网格节点所在单元的数目等.实例中,由原始数学模型的正演旅行时资料生成节点初始速度模型,效果可以.最后,分别采用均匀模型和本文方法生成的初始模型进行迭代反演,通过比较,证实该自动生成节点初始模型的可行性和可靠性,并对存在的问题进行讨论和解释.  相似文献   

复杂网络牵制控制概述     

曹进德  宋强  刘芳  程尊水 《南京气象学院学报》2020,12(1):22-30

本文回顾了十多年来复杂网络牵制控制的研究进展,对复杂网络现有的牵制控制算法进行了归纳分类,然后基于网络拓扑及节点动力学特性讨论了网络牵制控制的一些必要或充分条件.针对牵制控制下的复杂网络,重点论述了牵制节点的选取策略,综合分析了牵制节点个数、耦合强度、牵制控制增益及节点动力学等因素对复杂网络牵制控制的影响,讨论了具有合作竞争关系符号网络牵制控制的进展,并简要介绍了复杂网络牵制控制的一些应用前景.最后,就复杂网络牵制控制将来的研究方向提了一些建议及展望.  相似文献   

长江中下游转换构造结与区域成矿背景分析   总被引：10，自引：0，他引：10  

宋传中  张华  任升莲  李加好  Lin Shouf  涂文传  张妍  王中 《地质学报》2011,85(5):778-788

中国东部中生代以来的地壳运动频繁,构造演化复杂,岩浆活动剧烈,成矿作用多样,是不同体制构造转换的重要地区.长江中下游地区是中生代特提斯构造体制与太平洋构造体制转换的经典地区,是两大构造体制交汇和转换的焦点部位,具有岩石圈物质重组、结构重建的时-空演化关系.长江中下游转换构造结由是中国东部中生代特提斯构造体制与太平洋构造...  相似文献   

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