数字资源共享平台框架的设计和实现*

从数字资源共享平台的需求入手,分析了目前建设数字资源共享平台面临的一些问题,提出了一种数字资源共享平台的框架设计,并基于CNRI Handle System和OAI-PMH给出了该框架的技术实现方案.最后介绍了一个实现实例--中国大学数字博物馆共享平台.     

The aDORe federation architecture: digital repositories at scale

The need to federate repositories emerges in two distinctive scenarios. In one scenario, scalability-related problems in the operation of a repository reach a point beyond which continued service requires parallelization and hence federation of the repository infrastructure. In the other scenario, multiple distributed repositories manage collections of interest to certain communities or applications, and federation is an approach to present a unified perspective across these repositories. The high-level, 3-Tier aDORe federation architecture can be used as a guideline to federate repositories in both cases. This paper describes the architecture, consisting of core interfaces for federated repositories in Tier-1, two shared infrastructure components in Tier-2, and a single-point of access to the federation in Tier-3. The paper also illustrates two large-scale deployments of the aDORe federation architecture: the aDORe Archive repository (over 100,000,000 digital objects) at the Los Alamos National Laboratory and the Ghent University Image Repository federation (multiple terabytes of image files).     

网格环境下基于OAI的数字图书馆互操作机制

现有数字图书馆（DLs）互操作方案，在实现大规模数字图书馆集成方面都存在一定的局限性。该文将网格技术与OAI-PMH框架相结合，提出了一个数字图书馆网格（DL Grid）互操作框架，并对网格环境下元数据资源的发现、采集、重组等关键问题进行了分析和设计，初步实现了在集成的元数据基础上数字图书馆信息的共享。     

支持OAI-PMH的元数据互操作体系结构设计与实现

随着全球数字图书馆的迅猛发展,互操作成为亟待解决的重要问题。OAI-PMH协议的制定为在元数据级别上设计实现一个统一、高效的互操作框架创造了条件。文章基于北京大学数字图书馆项目,详尽阐述了一个典型的支持OAI-PMH互操作体系结构的完整的设计与实现;不仅包括在理论上逻辑清晰的设计方案,在实现上也采用了比较成熟又兼具理论和应用前景的技术,如Java、DOM、XML、Oracle9i等。该文的工作为将来联合式数字图书馆这一发展方向做出了很好的尝试。     

基于OAI-PMH架构的元数据分类研究

提出了一种基于规则和学习相结合的元数据分类存储的方法，该方法通过统计分析，提取对元数据分类影响较大的通用特征规则，对无法用规则分类的元数据，采用文本学习方法，将元数据记录看成由多个属性字段组成的文本，通过构造分类器实现分类。实验结果表明，采用元数据分类存储方法具有良好的检索性能。     

OAI-PMH中元数据重复问题解决方法

针对OAI-PMH框架中存在的元数据重复问题,根据重复元数据出现的两种情况给出了相应的解决方法.对于SP中来自同一个数据提供方中的元数据,根据元数据记录的标识符和时间戳去重;对于SP中来自不同数据提供方中的元数据,采用向量空间模型计算元数据间的相似度,进而达到去重目的.通过对OAI-PMH框架中元数据的去重,不仅减少了...     

基于P2P的数字图书馆分布式搜索关键技术*

在对现流行的互操作协议的发展和特征进行比较分析的基础上,介绍了基于P2P搜索方法的特点及分类.最后在原有OAI-PMH框架的基础上,提出一种基于P2P技术的数字图书馆分布式搜索模型 (P2P-DL) ,并对系统实现的关键技术进行了分析与设计.     

Representing digital assets usingMPEG-21 Digital Item Declaration

Various XML-based approaches aimed at representing compound digital assets have emerged over the last several years. Approaches that are of specific relevance to the digital library community include the Metadata Encoding and Transmission Standard (METS), the IMS Content Packaging XML Binding, and the XML Formatted Data Units (XFDU) developed by CCSDS Panel 2. The MPEG-21 Digital Item Declaration (MPEG-21 DID) is another standard specifying the representation of digital assets in XML that, so far, has received little attention in the digital library community. This article gives a brief insight into the MPEG-21 standardization effort, highlights the major characteristics of the MPEG-21 DID Abstract Model, and describes the MPEG-21 Digital Item Declaration Language (MPEG-21 DIDL), an XML syntax for the representation of digital assets based on the MPEG-21 DID Abstract Model. Also, it briefly demonstrates the potential relevance of MPEG-21 DID to the digital library community by describing its use in the aDORe repository environment at the Research Library of the Los Alamos National Laboratory (LANL) for the representation of digital assets.     

Using the web infrastructure to preserve web pages

To date, most of the focus regarding digital preservation has been on replicating copies of the resources to be preserved from the “living web” and placing them in an archive for controlled curation. Once inside an archive, the resources are subject to careful processes of refreshing (making additional copies to new media) and migrating (conversion to new formats and applications). For small numbers of resources of known value, this is a practical and worthwhile approach to digital preservation. However, due to the infrastructure costs (storage, networks, machines) and more importantly the human management costs, this approach is unsuitable for web scale preservation. The result is that difficult decisions need to be made as to what is saved and what is not saved. We provide an overview of our ongoing research projects that focus on using the “web infrastructure” to provide preservation capabilities for web pages and examine the overlap these approaches have with the field of information retrieval. The common characteristic of the projects is they creatively employ the web infrastructure to provide shallow but broad preservation capability for all web pages. These approaches are not intended to replace conventional archiving approaches, but rather they focus on providing at least some form of archival capability for the mass of web pages that may prove to have value in the future. We characterize the preservation approaches by the level of effort required by the web administrator: web sites are reconstructed from the caches of search engines (“lazy preservation”); lexical signatures are used to find the same or similar pages elsewhere on the web (“just-in-time preservation”); resources are pushed to other sites using NNTP newsgroups and SMTP email attachments (“shared infrastructure preservation”); and an Apache module is used to provide OAI-PMH access to MPEG-21 DIDL representations of web pages (“web server enhanced preservation”).     

基于OAI—PMH机构知识库互操作机制研究

主要介绍了基于OAI—PMH的机构知识库跨库互操作原理,给出了互操作模型,并以河北科技大学学位论文库的构建为例,对学位论文库的建设及实现与CALIS中心进行元数据收割进行了详细设计。