基于 SVG 技术构建 WebGIS 研究

可伸缩向量图形(Scable Vector Graphics,SVG) 是基于XML技术的开放的矢量图形标准.本文从可伸缩向量图形(SVG)本身的技术特点出发,以构建网络地理信息系统(Web GIS)为目的,重点探讨了其丰富的图形对象、特定标志以及功能强大的消息触发和事件处理机制;并且就利用SVG技术实现网络地理信息系统(Web GIS)的功能进行了深入的研究和实现.     

基于XML技术的Web GIS架构分析与实现

在Internet环境下,XML技术更适合矢量空间数据的显示和发布及Web交互式操作。随着XML技术的发展,利用GML、SVG和XSLT等XML技术构建新一代的Web GIS平台成为可能。通过分析基于XML技术的Web GIS平台的特点,选择了以XSLT作为表示层的StrutsCX框架,并在此基础上建立了基于XML技术的Web GIS平台的体系结构,给出了其关键技术的实现。     

基于SVG技术研究电网调度自动化系统中的应用

图形在电网能实现自动性控制的过程中扮演着重要的角色,并且是电网在不同的系统中进行交互操作的基本前提。该文在介绍IEC 61970标准对图形交互要求的基础上,探讨了电网调度自动化系统中基于可缩放矢量图形（SVG）/公共信息模型（CIM）的图形互操作性,即将SVG与CIM相结合,实现能量管理系统EMS图形文件与SVG文件的动态转换,既提高基于Web的图形发布水平,又便于不同EMS间图形的导出/导入,展示了SVG技术在电力系统图形交互方面的优势,并在实践中获得应用。     

改进规则的可放缩矢量图形地图的查询模型

分析了基于SVG(可放缩矢量图形)格式时态GIS(地理信息系统)领域,尤其是地理元素查询方面的研究现状,针对现有的XML(可扩展标记语言)查询方法进行了分析和对比.在基于SVG语法规则改进研究的基础上,并结合LISAⅡ(layered intersection scan algorithmⅡ,分层交叉扫描算法Ⅱ)查询技术,提出了一种适合改进规则的SVG格式的GIS数据地理元素查询模型及其算法,通过定义关键字查询语法规则表达式,定义关键字查询的""和"or"操作规则,实现了组合查询;通过定义实体元素节点,减少了节点数,提高了查询效率.该模型实现了SVG格式地图的地理元素查询,包括对整幅地图的各种组合查询和分图层的各种组合查询,解决了基于SVG格式地图元素查询的技术瓶颈.大量的数据验证表明,该查询模型是有效的.     

基于SVG的WebGIS体系结构的研究

针对目前WebGIS面临着Web语言不支持矢量图形、传输种类繁多的海量空间数据受网络带宽以及其他路由限制等一些技术难题，分析了SVG技术特点及其优势，将SVG技术引入到WebGIS，提出了一个建立基于SVG的WebGIS系统的体系结构，并阐述了其实现的相关技术等。     

基于SVG技术的电力监控管理系统的研究与实现

SVG是Internet中基于XML面向网络应用、采用文本描述的二维矢量图形图像标准格式.本文总结SVG的特点,设计了SVG应用软件体系结构,在此基础上提出一种基于SVG技术的电力监控管理系统的解决方案,实现WEB用户对电力系统设备的图形化远程访问和控制,该系统可以推广到许多应用领域.     

JavaScript在基于SVG的网络地图中的应用

SVG是近几年发展起来的一种基于XML的二维矢量图形格式，已经在网络地图领域得到了广泛的应用．该文在地图数据的SVG编码的基础上，简要介绍了SVG的DOM接口以及JavaScript语言在基于SVG的网络地图中的应用。     

基于SVG的矢量图在测井行业的应用

SVG是基于XML语言、面向网络应用、采用文本描述的二维矢量图形图像标准格式。本文介绍了SVG的特点并在此基础上提出一种基于SVG技术的测井成果图像实现方案。测试证实,该技术优于传统技术,扩展了SVG的应用领域,同时也为测井数据提供了一个先进的图形化解决方案。     

应用SVG实现基于Web的UML图形编辑

在XML技术的基础上,应用SVG技术实现了一种基于Web的UML图形编辑方法．该方法是以XML数据文件表示UML图,然后通过XSLT变换程序把XML数据文件在服务器端变换为SVG代码,SVG代码在浏览器中显示．对图形的编辑操作包括放大、缩小和移动等,该方法的最大优势在于允许用户随时随地通过Web进行编辑．     

利用SVG开发高质量Web图像应用

SVG是W3C的一种图形矢量标准,利用SVG和JavaScript技术通过对DOM树状文档结点对象的访问和操纵,能够实现在网上快速加载强大复杂的矢量图,从而在Web中实现高质量的图像应用。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to