海军通信元数据可视化查询系统设计与实现

针对海军通信数据管理与应用需求,将数据可视化技术引入到元数据查询服务中,研究了海军通信元数据的可视化技术,研究了海军通信元数据可视化查询的实现流程,设计了海军通信元数据可视化查询系统的体系结构和功能模块,实现了海军通信元数据可视化查询系统并给出了查询实例.论文的研究成果,对改进海军通信元数据服务模式,实现海军通信数据资源与可视化技术的有效结合,提升海军数据可视化技术和装备水平具有重要意义.     

利用数据仓库技术解决异构数据库的集成问题

企业信息系统存在大量的异构数据库,如何集成异构数据库、解决信息孤岛现象是我们面临的问题。利用数据仓库技术来集成异构数据库是一个理想的解决方案。本文给出了异构数据库的集成方案,提出了从异构数据库抽取和转换数据的新方法,提出了ODBC用于数据抽取过程的思路,提出了数据转换规则集的概念并用于数据抽取过程中。数据仓库的建立不仅实现了企业信息系统中信息的集成,更重要的是为企业决策提供了信息源。     

Creating and using the urgent metadata catalogue and thesaurus

The Urban Regeneration and the Environment Research Programme (URGENT) required a system for cataloguing its datasets and enabling its scientific community to discover what data were available to it. This community was multidisciplinary in nature and therefore needed a range of facilities for searching. Of particular importance were facilities to help those unfamiliar with specialist terminology. To meet these needs, four applications were designed and developed: a Metadata Capture Tool for describing datasets in compliance with the National Geospatial Data Framework (NGDF) standard, a Term Entry Tool for creating an ISO compliant thesaurus, a Thesaurus Builder for merging thesauri and a Search Tool. To encourage users to help in cataloguing data, the capture tools were written as stand alone applications, which users could keep and use to build their own metadatabases. The tools contained export and import facilities that allowed the URGENT Data Centre to build a central database and publish it upon the web. During the development work, it was found necessary to extend the NGDF standard as it could not adequately describe time variant or 3-D atmospheric datasets. The four applications met their design objectives. However, a number of ergonomic issues will need to be addressed if the system is to meet the needs of the much larger up coming programmes. The main challenges will be moving from the NGDF standard to the ISO standard, hence bringing the work into line with the recommendations of the INSPIRE Project, and merging the metadatabase with the scientific database, which enable metadata maintenance to be semi-automated.     

利用元数据建模构建可扩展的灵活系统

软件需求的复杂化对现代软件的构建技术提出了很高的要求。构件技术在一定程度上解决了这个问题,但它很难处理不断扩充的功能与原有系统的适配与连接。本文提出了元数据建模的方法,通过使用基于XML描述的元数据并且利用莱些面向对象语言本身的自省机制(如Java的反射机制)来连接构件和基本框架的技术,以达到构建灵活系统的目的。本文同时给出了北航软件工程研究所使用元数据成功构建可扩展的QESAT(软件分析与测试工具)的示例。     

开放式地理信息系统的初步研究

由于不同的硬件平台、网络环境、操作系统、ＧＩＳ开发平台及数据库的存在,导致各部门建立起来的ＧＩＳ系统成为“信息孤岛”,未能实现各ＧＩＳ系统之间的互操作和互运算,未能达到资源共享的目的。因此,实现Ｏｐｅｎ ＧＩＳ方案成为ＧＩＳ界的共识。本文在此基础上提出用中间件、元数据和开放式的空间数据引擎来克服Ｏｐｅｎ ＧＩＳ在功能开放、数据开放等方面的障碍。     

信息系统中数据库操作自动化型元数据研究

本文提出了数据库操作自动化元数据的概念,并概括了它的特点,基于信息系统开发实践的角度,论述了信息系统中的五种数据库操作自动化型元数据,并给出这几种元数据的表示和管理方式。     

Exploiting user metadata for energy-aware node allocation in a cloud storage system

Cloud computing has gained popularity in recent years delivering various services as cost-effective platforms. However, the increasing energy consumption needs to be addressed in order to preserve the cost-effectiveness of these systems. In this work, we target the storage infrastructure in a cloud system and introduce several energy efficient storage node allocation methods by exploiting the metadata heterogeneity of cloud users. Our proposed methods preserve load balance on demand and switch inactive nodes into low-energy modes to save energy. We provide a mathematical model to estimate the outcome of proposed methods and conduct theoretical and simulative analyses using real-world workloads.     

物联网环境中数据存储与查询机制研究

物联网中存在射频识别设备、传感器、智能嵌入设备等数目众多的异质设备,运行着用于标识、感知、处理和传送信息的各类服务,因而存在大量、非连续且时间敏感的数据。这类数据对保证物联网产业链的正常运转非常重要,但现有的数据管理方法不能有效解决其存储与查询问题。基于此,针对物联网数据多维、多态的特征,在面向服务的物联网数据管理框架上,以都柏林元数据标准为基础,制定了支持学习的物联网数据多级元数据标准。设计了从XML元数据描述到关系数据库存储的数据处理流程,提出了优化的数据存储与查询方案。最后对提出的存储与查询方案进行了验证。     

论元数据及其作用

随着信息技术的发展,元数据已经广泛应用于多个领域。本文从元数据的概念入手,阐述了元数据的特点、作用及应用方向。而元数据还需要更快更强的发展,以服务于更多的用户,发挥更大的作用。