河网水流数值模拟方法研究

讨论了河网概化的一般原则,并在分析单一河段水流数学模型的基础上,建立了可以适用于一般河网体系水流数值计算的数学模型,并采用荆江—洞庭湖的相关资料进行了验证.结果表明,模型的计算值与实测值吻合较好,说明该模型具有较好的适用性.     

西陇海兰新经济带节点城市的发展方向与产业分工

西陇海兰新经济带是我国西部大开发战略重点区域“两带一区”的重要组成部分。本文分析了西陇海兰新经济带节点城市发展与布局的总体特征,采用多层次多目标综合测度模型定量评价经济带上全部城市的综合竞争力,并把西安、兰州、乌鲁木齐确定为经济带上的一级节点城市,把咸阳、嘉峪关、宝鸡、酒泉、克拉玛依、哈密、石河子、库尔勒、天水、奎屯共10个城市确定为经济带上的二级节点城市。进而以此为依据,对西陇海兰新经济带各级节点城市进行发展方向定位和产业分工。     

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

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.     

社会性网络服务社区中人际节点空间分布特征及地缘因素分析

以开心网15个大学群为案例,应用信息熵和度分布两种方法,研究了社会性网络服务社区中人际节点空间分布特征及其地缘因素的影响。人际节点是以＂好友＂关系建立的链接来表达的,研究数据包括通过＂成员＂体现的好友和通过＂话题＂体现的好友2个层次,以便可以将虚拟的可能关系变为虚拟现实的确定关系。研究结果如下：①各大学群中好友空间分布...     

R~n上非膨胀映射的周期点

本文证明了:R到自身的非膨胀映射f的周期点集S是一凸集;f限制在S上是一等距映射;f至多有2~{n/2}个不同周期的周期点,其中{n/2}是不小于n/2的最小整数。     

一种基于小波变换的遥感影像道路自动提取方法

遥感影像上道路的自动提取是摄影测量与遥感、计算机视觉等领域的重要课题。本文通过对图像小波系数的分析,完成道路节点的提取。随后利用基于小波变换的边缘提取算子,对道路进行边缘提取。边缘提取出来之后,以道路节点为种子点,对道路进行Snake跟踪。为保证提取效果,对图像进行了预处理。实验表明,利用本文提出的理论与方法能为道路网的自动提取与识别提供一个可靠的依据,同时也对其他地物(如建筑物)的自动提取提供一个有价值的参考。     

基于小波包变换的地震信号频带序号到结点序号的快速转换算法

针对小波包处理地震非平稳信号过程中存在的“跳频”现象,以及现有方法不能快速准确地得到地震信号高层次小波包分解时频带序号和结点序号的排列规律的弊端,基于小波包变换算法和异或运算,提出一种频带序号到结点序号的快速转换算法。基于MATLAB平台,以唐山南北向地震波为例,编制相应程序进行分析,得到的地震频带序号与其小波包树结点序号的排列规律与现有方法得到的结果完全一致,验证了该转换算法的正确性。     

On a question of A. Wintner about Jacobi coordinates in the three-body problem

In his work on the elimination of the nodes in the Three-Body Problem, Jacobi considered a certain straight line (defined below, in the Introduction) which lies always within the invariable plane. Here we settle the question of Wintner on the classification of all motions for which this line fails to exist.     

A Numerical Model for Mixing Areas of Pollutant Discharging into Tidal Flows

- A combined numerical model for computing mixing areas of pollution vertical jet discharging into tidal flows has been developed. This numerical model is composed of a 2-D depth-averaged dynamic far-field numerical model and a 2-D vertical dynamic near-field numerical model. The former uses finite node method to compute velocity, and improved finite node method to compute pollutant concentration distribution; the latter is a k-e turbulence model, and uses SIMPLE (Semi-Implicit Method for Pressure Linked Equations) method to compute velocity. At the same time, the former provides boundary conditions for the latter. This model can simulate both far- field pollutant concentration distribution and near-field vertical recirculation quickly and precisely. This model has been verified by measured data of pollutant F of the Dachang reach of the Changjing River and test data presented by Chen el al. (1992). On the basis of verification, the authors use a designed hydrograph to compute this mixing area for a cer     

山东地质调查信息网络节点建设与示范应用

山东省地质调查院节点网络采用以太网星型拓扑结构,主干提供百兆带宽,完成了1栋楼4个楼层共70个信息点、1个中心机房的综合布线。部署了服务器、主干交换机、支交换机、路由器、防火墙、UPS等网络设备,以及网络操作系统、网络防病毒系统和网络数据服务系统等软件。该节点网络已通过了中国地质调查局组织的专家验收,实现了与国家地质骨干网的连接,满足了新形势下地质调查工作的信息传输、存储和共享服务的需求。