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论文编号：	1783
作者编号：	1120050780
上传时间：	2010/6/9 8:26:45
中文题目：	基于网格的数字图书馆模式构建研究
英文题目：	Study on the Model Construction of Digital Library Based on Grid Technology
指导老师：	王知津
中文关键字：	数字图书馆 网格技术 体系结构 资源发现 服务模式
英文关键字：	Digital Library Grid Computing Architecture Resource Discovery Service Model
中文摘要：	近年来，网格技术与数字图书馆技术都得到了长足的发展，由于二者在研究目标和研究方向上具有诸多的一致性，因此在数字图书馆的构建与研究中常常引入网格技术。可以说，网格技术为数字图书馆的建设提供了有力的条件和支持。网格环境下的数字图书馆是一种建立在统一的标准和规范基础之上的采用先进的网格技术构建的信息资源共享系统，其目的是为用户提供一个统一、透明、高效的信息服务平台，实现数字图书馆资源和服务的互通互联。网格环境下数字图书馆的资源具有分布性、异构性、动态性、自治性等特点，这些资源可能属于某个组织或个人，并且存在于多种异构平台下，数字图书馆网格必须要将这些分散的信息资源有效地组织并连接起来，通过各种手段和方法整合成一个信息资源系统，使用户可以通过一个统一的界面，就可以访问到网格内所有的数字图书馆资源。 本文的研究正是基于数字图书馆与网格技术的蓬勃发展，通过探讨网格技术在数字图书馆建设领域的相关运用，旨在研究具体的基于网格的数字图书馆的构建模式。该项研究对于把握未来数字图书馆的发展方向具有重要的指导作用，并为网格技术在数字图书馆建设中的应用起到启发和推动的作用。 全文共分8章，其中第3至第7章是论文的主体部分，主要内容如下： 第一章主要介绍了论文的研究背景以及研究的目的与意义，着重指出开展基于网格的数字图书馆模式构建研究是数字图书馆发展到一定阶段的必然结果，是数字图书馆为适应用户信息使用行为变化的必然选择，是数字图书馆解决“信息孤岛”现象的必然要求；同时还介绍了本文的研究内容、研究方法以及研究的创新点。 第二章对网格理论和数字图书馆理论进行了回顾和综述，并对基于网格的数字图书馆国外与国内的研究现状进行了重点的剖析，并指出了现有研究的贡献与不足。 第三章首先对经典网格体系结构进行了分析，然后对基于网格的数字图书馆体系结构的类型进行了全面梳理与比较，并以此为基础结合网格环境下数字图书馆的功能特点，设计了一种面向个性化服务的层次式数字图书馆网格体系结构。该结构共分四层：资源层、调度层、应用层和门户层。 第四章从网格环境下数字图书馆资源的构成及特点出发，分析了传统数字图书馆资源组织的一般模型，设计了一种新型的网格环境下数字图书馆资源组织的模型——全局/本地双层资源池模型，并对资源组织的过程及工具进行了分析。 第五章阐述了基于网格的数字图书馆资源发现的目标，对四种资源发现模式（集中式、分布式、混合式和层次式）进行了详细地分析与评价，最后提出了一种层次式资源发现模式的改进方法，并描述了其原理和算法以及改进后的效果评价。 第六章分析了基于网格的数字图书馆信息服务的特点与目标，提出了网格环境下的数字图书馆服务模式是面向个性化的集成式服务模式，个性化强调的是服务要以用户为中心，而集成服务则体现为用户对资源和服务的存取是无缝的、透明的、一站式的，用户能够实现随时随地获取所需的任何资源和服务。并对该模式主要包括的六项内容——个性化信息定制与推送服务、合作式数字参考咨询服务、自适应学习服务、智能导师服务、科研协作服务、知识增值服务进行了深入探讨。 第七章围绕基于网格的数字图书馆的安全性，阐述了网格环境下数字图书馆访问控制中面临的主要问题和关键技术，并对包括自主访问控制模式、强制访问控制模式、基于角色的访问控制模式和基于任务的访问控制模式在内的四种模式进行了分析，指出采用基于任务和角色相结合的访问控制模式是一种较为理想的选择。 第八章总结了本文的研究结论，指出了研究的主要不足并对后续研究进行了展望。 本文的创新点是： （1）设计了一种基于网格的数字图书馆体系结构 根据网格环境下数字图书馆的功能特点，结合分层式网格资源管理体系结构，设计了一种面向个性化服务的四层体系结构。该结构既体现了网格异构环境的整合，又突出了数字图书馆个性化服务的功能。其中，最底层为资源层，它为数字图书馆提供各种数字资源和计算能力的支持，是整体结构的基础支撑；第二层为调度层，它主要起到屏蔽异构环境、调度程序运行、监控维护网格安全等作用；第三层为应用层，它主要解决信息资源组织、用户管理、数据挖掘等问题。顶层为门户层，它直接为数字图书馆用户提供各种个性化的服务功能。 （2）设计了一种基于网格的数字图书馆资源组织模式 资源组织为网格环境下数字图书馆服务提供了工作准备，是用户获取信息的基础。网格环境下资源的数量庞大且具有分布性、异构性、动态性、自治性等特点，通过对数字图书馆资源组织一般模式的分析并结合网格资源的特点，设计了一种基于网格的数字图书馆资源组织模型——全局/本地双层资源池模型。该模型通过划分资源的本地域和全局域，实现了资源的分层次管理，提高了系统的安全性和资源查找的效率，同时降低了通讯瓶颈。 （3）提出了一种层次式资源发现模式的改进方法 随着网格规模的扩大，网格中节点的结构也愈加复杂，资源发现作为一项关键技术对整个网格资源共享起到了至关重要的影响，其性能的优劣直接决定了网格的性能。在对资源发现模式进行深入研究的基础上，本文提出了一种层次式资源发现模式的改进方法。改进后的模式增加了高宽带节点与低宽带节点的概念，在继承原模式优点的基础上，增强了灵活性与可扩展性，提高了资源查找效率。 （4）提出了一种基于网格的数字图书馆的服务模式 在对基于网格的数字图书馆服务模式的特点和目标进行分析的基础上，提出了基于网格的数字图书馆服务模式，即面向个性化的集成式服务模式，并论述了该服务模式的六项内容：个性化信息定制与推送服务、合作式数字参考咨询服务、自适应学习服务、智能导师服务、科研协作服务与知识增值服务。 （5）提出了一种基于任务和基于角色相结合的访问控制模式 基于网格的数字图书馆面临着各种安全威胁，因此需要一种能实现通用服务、辅助智能、全局一体及自主控制的访问控制模式。根据网格环境下数字图书馆系统的具体要求和自身特性，提出了一种将基于任务和基于角色相结合的访问控制模式，该模式具有双重特性，既可以通过对角色的职责分离和继承关系等约束条件进行多种安全策略的配置，又可以增加对任务管理模块与系统状态的参考。
英文摘要：	In resent years，the technology of grid computing and Digital Library has experienced great development. Because of the consistency of their research object and research direction, we often introduced the technology of grid computing when we constructed a Digital Library System. We can say that the technology of grid computing has provided powerful conditions and strongly supports. In the Grid environment, the Digital Library is a type of information resources sharing system based on uniform standards and criterions, and the construction of the DL is adopted advanced grid technology. The aim is to provide a unified, transparent and efficient information service platform to the users, and to realize the interconnection and intercommunication of the Digital Library resources and services. The characteristic of the resources in the Digital Library Grid is distributed, heterogeneous, dynamic and autonomous. These resources maybe belong to an organization or individual, and exist in variety of heterogeneous platforms. Digital Library Grid must organize and connect thesse distributed information resources effectively. Through various means and methods, these resources have been integrated into an identity information resource system. Users can access to the digital library resources through a unified interface in the grid. Based on the development of the technology of the Digital Library and the grid computing, this dissertation discusses the grid technology related to the use of construction of Digtial Library. The purpose of the research is to find out the construction model of Digital Libaray based on Grid. This study has an important role in guiding the development direction of future Digtial Library, and has played a positive and promoted role for using the grid computing technology in the construction of Digital Library. This dissertation contains eight chapters, thereinto which the third, the fourth, the fifth, the sixth and the seventh are core contents. The main contents of the dissertation are as followings: The first chapter makes out the background, motive, contents, and framework of the research, and emphasizes that the research content is the inevitable result when the Digital Library develops to a certain stage, and that is the inevitable choice when the Digital Library attempted to fit the change of the user’s information behavior, and that is the inevitable requirement when the Digital Library solves the problem of Information islands. Furthermore, this chapter also describes the contents of this research, research methods and research innovations. The second chapter summarizes the related research and literature about grid computing and Digital Library, and reviewes the foreign and domestic research status of Digital Library based on grid, and points out the contributions and shortcomings of the current research. The third chapter firstly analyzes the classical architecture of grid, and then compares the types of the grid-based digital library architectures. As a basis for this, the dissertation designs a personalized service oriented hierarchical architecture of grid-based digital library. This architecture is divided into four layers: resource layer, scheduling layer, application layer and portal layer. The fourth chapter expounds the composition and characteristics of Digital Library resources on the grid, and analyzes the general model of the resource organization in traditional digital library, and designs a new grid-based digital library resources organization model: Global / Local double-layer resource pool model. Finally, the dissertation tries to explore the process and the tools of the resources organization. The fifth chapter puts forward targets of resource discovery in digital library grid. Currently, resource discovery have four models: centralized type, distributed type, mixed type and hierarchical type. Based on the detailed analysis and evaluation, the dissertation proposes an improved method aimed at hierarchical resource discovery model and describes its principle and algorithm, as well as the effect of improved method. The sixth chapter analyzes the characteristics and purposes of information service in the grid-based digital library, and puts forward in the grid environment the service model of digital library is facing personalized integration service model. Personalized service emphasizes that the services should be focus on the user’s demand, and integration service embodies that the user’s access to the resources is seamless, transparent, and one-stop style. Users can achieve any resources needed anytime and anywhere. There have six contents in the personalized integration service model: individualized information customization and pushing service, collaborative digital reference services, self-adaptive learning services, intelligent tutor services, scientific collaboration services, knowledge increment services. The seventh chapter firstly represents the security features of the digital libary in gird environment, and then describes the main problems and key technologies in grid-based digital library access control model. Furthermore, the disseratation analyzes four access control models that is respectively DAC (Discretionary Access Controls), MAC(Mandatory Access Controls), RBAC(Role-based Access Control) and TBAC(Task-based access control).At last the disseratation indicates that combination of Task-based and Role-based access control model is the ideal choice when we construct a large-scale digital library grid. The eighth chapter summarizes the main conclusion of this dissertation, and points out expectations of continuous research in this field. Innovations of the research include the following aspects: (1) Designed an Architecture of Grid-based Digital Library According to the features of grid-based digital library and the hierarchical structure of grid resource management system, the dissertation designed a personalized service oriented hierarchical architecture. This architecture embodies the integration of grid heterogeneous environment, and emphasizes the personalized service function of the digital library. The bottom layer is resource layer, as the basic support of the architecture, which provides plentiful digital resources and computing power; the second layer is scheduling layer, whose role is shielding the heterogeneous environment, arranging the program course and monitoring the grid security; the third layer is application layer, which is mainly to solve the problem of resource organization, users management and data mining and so on; the top layer is portal layer, which directly provides various personalized service functions to users. (2) Designed a Resources Organization Model of Grid-based Digital Library Resources organization provides work preparation to grid-based digital library service, and it is the foundation of user’s information acquisition. The features of the resources in grid-based digital library are tremendous, distributed, heterogeneous, dynamic and autonomous. The dissertation analyzes the general model of the resource organization in traditional digital library, and designs a new grid-based digital library resources organization model: Global / Local double-layer resource pool model. Dividing the resources into global domain and local domain, this model realizes the hierarchical management, improved the security and efficiency of the resource finding and reduced the communication bottleneck. (3) Improved the hierarchical resource discovery model The grid scale more large the grid net structure more complex. Resource discovery is one of the key techonology and plays a crucial impact in the grid resource sharing. The efficiency of the resource discovery function directly decides the capability of the grid. Based on the detailed analysis and evaluation, the dissertation improved the hierarchical resource discovery model. Improved model introduces the concept of high-bandwidth node and low-bandwidth node, and inherites advantages of the original model. It also enhanced flexibility and expandability, improved efficiency of resource discovery. (4) Designed a Service Model of Grid-based Digital Library Based on the analysis of characteristics and purposes of service model in the grid-based digital library, the dissertation puts forward a facing personalized integration service model, which consists of six contents: individualized information customization and pushing service, collaborative digital reference services, self-adaptive learning services, intelligent tutor services, scientific collaboration services and knowledge increment services. (5) Combined the Task-based and Role-based Access Control Model Because of security threats facing to grid-based digital library, the access control model needs to realize general service, intelligent auxiliary, global uniformity and autonomous control. According to specific requirements and their own features of the grid-based digital library, the disseratation indicates that combination of Task-based and Role-based access control model is the ideal choice when we construct a large-scale digital library grid. This model have double speciality, on the one hand it can config multiple security policies through duty separation and inheritance relationship of roles; on the other hand it can add some reference value of system task status.
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