分类号密级
UDC编号
华中师范大学
硕士学位论文
虚拟天文台数据访问服务(VO-DAS)之任务调度研究
及VO-DAS的应用
田海俊
指导教师郑小平教授、赵永恒研究员、崔辰州副研究员
华中师范大学物理科学与技术学院申请学位级别硕士学科专业名称理论物理
论文提交日期2007年6月论文答辩日期2007年6月
培养单位物理科学与技术学院
学位授予单位华中师范大学
答辩委员会主席
Job Scheduling Research in Virtual Observatory Data Access Service(VO-DAS)
and
VO-DAS Application
Hai-Jun Tian
Supervisor:
Prof.Xiao-Ping Zheng&Prof.Yong-Heng Zhao&Dr.Chen-Zhou Cui
HuaZhong Normal University
May,2007
Submitted in total fulfilment of the requirements for the degree of Master
in Theory of Physics
programme用法
摘要
天文观测数据资源具有时间跨度大、数据量大、存储管理分散、管理工具驳杂等特点。如何提供给天文学家一个统一访问这些分布存放的异构数据资源的方案，是虚拟天文台的一个重要研究课题。
计算机与互联网技术的飞速发展，网格技术、XML技术、语义网技术等全新IT技术的涌现，以及在此技术背景下，国际虚拟天文台联盟(IVOA)依据天文自身的特点不断提出并完善的各种规范标准，使得海量、分布式、多波段天文数据的无缝融合和处理成为可能。
对于异地异构数据的统一访问，我们基于开放网格服务架构（OGSA）提出了一种网格的解决方案：使用OGSA-DAI技术实现了对异地异构的天文星表数据、图像数据和光谱数据的统一封装（DataNode）；利用ADQL语言完成对任务的统一描述；基于WSRF框架完善了对数据资源、计算资源以及存储资源的任务调度。我们设计的虚拟天文台数据访问服务（VO-DAS）实现了对数据资源、计算资源、存储资源的自动发现以及异地异构数据的联合访问并对访问结果进行数据分析的一体化工作模式，这将使天文数
据源的多波段交叉证认、海量数据分析及对分析结果的可视化等成为可能。VO-DAS支持国际虚拟天文台联盟（IVOA）的各项相关标准，使得它具有良好的互操作性，它的对外接口简单实用、可以针对不同需求的天文数据用户发展出多种网格应用产品。
论文以VO-DAS的任务调度及其实现为重点，分别对VO-DAS的设计模式、Session 机制、生命周期、资源销毁、异常处理等模块进行了详细的阐述，并从多个角度分别给出了系统的设计图。为了验证以OGSA-DAI为基础的天文数据访问的可行性和性能，我们采用两个科学范例对VO-DAS原型进行了实验。
论文最后以VO-DAS对China-VO Ephemeris WS计算平台的扩展为例，介绍了VO-DAS外部接口的扩展方法，以及VO-DAS在星历计算方面的应用，并简要阐述了VO-DAS在其他方面的科学应用。
关键词：虚拟天文台，数据访问，网格技术，OGSA-DAI
Abstract
The resources of observed data in astronomy have such characters as large time span,great quantity of data,break-up storage and management,heterogeneous man-agement tool,and so on.An important research subject of the virtual observatory is about how to provide the astronomers with a programme on visiting these resources stored in different organisms.
The great development of the computer and the internet technology,the emerge of the totally up-to-date IT technology,such as grid technology,XML technology, semantic network technology,and so on,and on this technology background,ac-cording to the character of astronomy itself,the International Virtual Observatory Alliance(IVOA)continuously put forward and make them perfect various standard document,this make it possible the merge monolithic of the astronomy data which great capacity,break-up and multiple wave band.
As for consolidated visit to the resources stored in different organisms,basing on OGSA,we put forward a solution programme for the grid:making use of the OGSA-DAI technology,we can carry out the DataNode of the astronomy data about the surface of the stars,the picture data and the spectrum data in different organisms; taking advantage of ADQL language,we can go through with the description of the whole task;grouding on WSRF structure,we can make it perfect in dispatching tasks of the data resources,caculation resources and storage resources.The VO-DAS that we have designed bring into
effect the close-coupled work pattern:auto-discover the data resources,caculation resources and storage resources,visite the resources stored in different organisms and data-analyse the result,this will make it possible the multiple wave band cross-authentication,the data-analysis and the visualisation of the analysis result.VO-DAS support all the related standards of the IVOA,this makes it have excellent operability,its external interface is simple and practical,it can develop various grid application products aimed at different demands of different astronomy data clients.
Focusing on diapatching VO-DAS tasks and bringing it into effect,we elaborate on the modules of VO-DAS,such as its design mode,Session organisms,life cycle, resources destroying,exception handling,and so on,and put forward the blue prints of the system indifferent angles.To verify the feasibility and performance of the visit
to the astronomy data basing on OGSA-DAI,we adopt two scientific model to test the prototype of VO-DAS.
Take for example the expansion of the VO-DAS to the caculation platform of the China-VO Ephemeris
WS,we introduce the expansion method of VO-DAS’exterior interface,and VO-DAS’application in the caculation of the star calendar,and we also elaborate on VO-DAS’application in the scientific applications in the otherfields.
Keywords:Virtual Observatory,Data Access Service,Grid,OGSA-DAI

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