Towards an Open Information Infrastructure for Disaster Research and Management: Data Management and Information Systems Inside DFNK

The development of new and better methods for preventing and managing natural disasters requires a variety of different data sets, covering the range from referenced data, e.g. topographic data and digital elevation models, to various kinds of thematic data, e.g. data about soil, vegetation and land usage as well as monitoring data like precipitation and water levels. So a well-organised data and information management and the implementation of a modern processing environment to acquire, store, analyse and visualise data were decisive for the success of the German Research Network Natural Disasters (DFNK). An information infrastructure was established to support data management and information flows inside the network. A web-based portal offers general information to the public and internal documents, data and software tools to the project community. A catalog service allows the overview of existing but distributed data scombined with flexible data retrieval. Based on internet technology and global standards these concepts contribute to a superior information infrastructure and finally substantiate to the development of Spatial Data Infrastructures (SDI). SDIs aim is to improve availability and usability of spatial data for the manifold application areas. Disaster management is one field depending on a very high level on high-quality data equipment, and on a working SDI.     

ISEE: Internet‐based Simulation for Earthquake Engineering—Part II: The application protocol approach

This paper develops new techniques for integrating a number of different structural laboratories together through the Internet in order to jointly conduct a single structural experiment. A computer‐networking platform, called Platform for Networked Structural Experiments (PNSE), was developed to achieve this goal. PNSE runs directly on top of the Transmission Control Protocol/Internet Protocol (TCP/IP). It is a multi‐client system consisting of a number of client programs, which include one command generation program and a number of facility control programs, connected to a server program via TCP point‐to‐point connections across the Internet. An associated application protocol, called Networked Structural Experiment Protocol (NSEP), was developed to work with the PNSE. In addition to communication rules, the NSEP defines general experimental information, significant laboratory events, commands and signals, as well as obligated behaviours of all PNSE programs. Both domestic and transnational pseudo‐dynamic (PSD) tests were performed to verify the validity and efficiency of the PNSE. Test results showed that on the PNSE: signals were correctly transmitted; significant laboratory events were promptly reflected; and data transmission was remarkably efficient, with the round‐trip time (RTT) between Taiwan and the United States less than 0.1701 s. The characteristic of environment independency was also demonstrated through the successful collaboration of different facility control programs running on different operating systems. Copyright © 2007 John Wiley & Sons, Ltd.     

用VML技术构建WebGIS客户端矢量图形的方法研究

在WebGIS中显示矢量数据的关键问题是网络传输。借助VML图形技术,可以很好地解决该问题。本文首先介绍了WebGIS技术的发展现状以及VML的基本要素,然后根据矢量图形类型和VML要素的自身特点,提出基于VML图形技术的点、线和面矢量数据的浏览器端实现方法。结合背景图层,该方式可以在WebGIS中得到充分地应用。特别是对于构建专业的网络图形服务具有一定的借鉴作用。     

基于线性二次型的多级联输水渠道最优控制

灌溉输配水是水联网链路的重要环节,其自动控制水平直接影响着水联网效率和风险控制能力,对实现水资源高效管理与利用有重要意义。通过变化输水渠道线性积分时滞控制模型,建立了多级联渠道离散时间状态空间方程,基于线性二次型理论设计最优状态反馈控制器,利用MATLAB求解和SOBEK模拟进行了验证。在甘肃省昌马南灌区多级联渠道运行过程优化控制的模拟结果显示,线性二次型算法能够使控制点水位较快恢复并稳定在设定值,控制过程动作与水位波动次数少、幅度小,效果远优于常规分布式PI反馈控制。线性二次型算法能够应对多级联渠道时滞、耦合特性和一般未知取水扰动,实现可靠供水服务和有效运行控制。目前算法仅采用反馈控制,尚无法应对过大未知取水扰动,还有进一步改进空间。     

面向网页文本的地理要素变化发现

地理要素变化发现是地理信息数据库动态更新的重要组成部分。互联网在信息传播中扮演着越来越重要的角色,网页文本中蕴含着一些现势性很强的地理要素信息,可作为地理要素变化发现的数据源。本文结合网络爬虫和朴素贝叶斯分类模型,提出并实现了一种面向网页文本的地理要素变化发现方法。首先,本文在收集分析地理要素变化新闻锚文本的基础上,构建了网络地理要素变化新闻关键词库,并基于关键词库设计了适于地理要素变化发现的网络爬虫,实现了候选网页文本的主动获取;接着为了提取地理要素变化新闻,本文训练构造了适于地理要素变化发现的朴素贝叶斯分类器,对候选网页文本进行筛选。最后通过实验对比了本文方法与现有方法在准确性和全面性上的表现。     

分布式体系结构下的地理信息服务的分层协议架构

分布式体系结构的出现以及物联网的建设使地理信息服务的发展出现新一次飞跃,这为地理信息服务带来了新的机遇。本文回顾了地理信息服务的发展,论述了地理信息服务在分布式条件下可能发生的新变化,基于对计算机网络体系结构TCP/IP协议集的研究,提出了为未来的分布式地理信息服务体系建立的一种分层协议架构,从而促进地理信息服务的标准化、体系化,加速全民地理信息服务体系的建设。     

基于物联网与WebGIS的智能公交系统

通过对物联网技术与WebGIS技术特点的分析,阐述了物联网与WebGIS之间的关系。运用WebGIS对空间信息的强大处理能力与物联网物物相连的特性,采集交通环境中的城市公交车各类信息收集至WebGIS平台进行存储与分析,并利用Google map api实现城市公交信息的可视化表达与各传感器的查询定位,为WebGIS与物联网的综合应用研究提供了新的思路。     

基于ZigBee物联网智慧家居系统的设计与实现

"智慧家居"是融合了自动化控制、网络通信,以及物联网技术于一体的安全化、网络化、智能化的家居控制系统,基于ZigBee局域网搭建,实现了高效、舒适、安全、便利的居家环境。     

网络遥感影像资源的获取途径

对国内外提供遥感影像数据的主要网站进行了调查与分析,总结归纳出网站所提供影像的主要数据特点及数据使用方法。为广大遥感影像用户获取网络遥感影像资源提供便利。