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Digital Library Architecture and Technology. Outline. DL architecture Building blocks of DLs DL models Components of DLs DL open source software Modern features in digital library architectures. Introduction. DLs contain a variety of materials, technologies, services and standards
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Outline • DL architecture • Building blocks of DLs • DL models • Components of DLs • DL open source software • Modern features in digital library architectures
Introduction • DLs contain a variety of materials, technologies, services and standards • The Web itself, LIS centres as well as database providers and vendors are all examples of information services that can play a role in DLs • Digital library architectures provide a view of the underlying structures and frameworks on which DLs are built
Conceptual design of a digital library E-journals Online databases Remote digital libraries WWW Search interfaces Search interfaces Search interfaces Search engines& directories Library resources Local digital library OPACs Search interface Digital library interface Users Chowdhury (2002) Introduction to digital libraries…
Components of a DL system Arms (1997) names the following components for digital libraries: • User interfaces • Repository • Handle system • Search system
Arms et al. An Architecture for Information in Digital Libraries. D-Lib Magazine, February 1997.
User interfaces • User interface for end-users to get access to the library and its collections • User interface for librarians and system administrators who manage collections
Repository • Repositories store and manage digital objects and other information. A large digital library may have many repositories of various types, including modern repositories, legacy databases, and Web servers. • The repository access protocol (RAP). Is used to recognize the rights and permissions that need to be satisfied before a client can access a digital object.
Handle system • Handles are general purpose identifiers that can be used to identify digital objects, over long periods of time and to manage materials stored in any repository or database. • DOI: Digital Object Identifiers • Example: 10.1234/NP567810.5678/ISBN-0-7645-4889-4 • Persistent Uniform Resource Locator (PURL) developed by OCLC – names the location of an object
Search system • There will be many indexes and catalogs in a digital library that can be searched to discover information before retrieving it from a repository. • These indexes may be independently managed and support a wide range of protocols. • Databases, information retrieval systems, and content management systems are examples
CRADDL architecture • Cornell Reference Architecture for Distributed Digital Libraries (CRADDL - pronounced "cradle"), a set of components that form the core of a digital library infrastructure.
CRADDL architecture • Content in the architecture is stored in the form of digital objects • The repository service provides the mechanisms for the deposit, storage, and access to digital objects • Digital Objects are identified by unique URNs • The index serviceprovides the mechanism for discovery of digital objects via query • The collection serviceprovides the mechanisms for the aggregation of access to sets of digital objects • User interface services or gatewaysprovide human-centered entry points to the functionality of the digital library
Collection Services Name Service Persistent NAMES User Interface Gateway Index Services Repository Services Components of a Digital Library Digital Objects
Alexandria DL architecture • One of the six projects funded under the Digital Libraries Initiative (DLI), • A digital library of geospatial information, based at the University of California, Santa Barbara • Several databases, gazetteers and thesaurus • Sophisticated architecture
Alexandria DL architecture • A three-tier model consisting of: • Servers • Middleware • Clients
Alexandria DL architecture • Servers: maintain collections of metadata describing the library’s holdings and for implementing query and retrieval mechanisms • Middleware: performs standard service on these collections • Clients: search sessions, list the library collections, retrieve metadata, and holdings
DL open source software • Greenstone • Fedora • D-space • Eprint
Greenstone • An open-source multilingual application developed by the New Zealand Digital Library Project at the University of Waikato • Developed and distributed in cooperation with UNESCO and the Human Info NGO.
Greenstone features • Accessible through web browsers • Full text and fielded search • Browsing facilities • Facility to add DC metadata • Multimedia collections • Can support millions of documents • Collections can be published on CD-ROM
Fedora • Flexible tools for managing and delivering digital content. • Jointly developed by Cornell University and the University of Virginia Library • National Science Digital Library (NSDL) uses Fedora • It supports the DC metadata format • It can run on MySQL and Oracle
DSpace digital repositorysystem • Jointly developed by MIT Libraries and Hewlett-Packard Labs • Stores, indexes, preserves, and distributes digital research material. • Various applications: Institutional Repositories, Learning Object Repositories (LORs), eTheses , Electronic Records Management (ERM), Digital Preservation, Publishing
EPrints • Was developed at the University of Southampton, released in late 2000 • The objective was to facilitate open access to peer-reviewed research and scholarly literature • EPrints serves as an archive for other electronic documents such as images and audio. • Currently installed in more than 241 institution.
Modern Features in Digital Library Architectures
Social networking sites • Social networking, bookmarking and tagging • Reviews • Recommendation features • Citation and reference linking • Bibliometric tools
share Bookmark Tag Write reviews Hull, D., Pettifer, S. R., and Kell, D. B. (2008). Defrosting the digital library: Bibliographic tools for the next generation web. PLoS Comput Biol, 4(10):e1000204+.
Tag 1 Tag2 Tag 3 Tag 1 Tag 2 Tag 3 Tag 1 Tag 2 Tag 3 Tag 1 Tag 2 Tag 3 Users interact with resources and create tags Tag 1 Tag 2 Tag 3 Tag 1 Tag 2 Tag 3 Tag 1 Tag 2 Tag 3
Videoblogging and sharing Photo sharing Social networks Bookmarking Academic bookmarking Slide sharing Social Tagging Environment
Citation linking
Examples • Greenstone: http://www.greenstone.org/examples • Fedora: • Tufts University: http://dl.tufts.edu/ • University of Viginia: http://www.lib.virginia.edu/digital/collections/ • DSpace • U of A: http://repository.library.ualberta.ca/dspace/index.jsp • U of Wolverhampton(UK) : http://wlv.openrepository.com/wlv/ • Queen’s University: https://qspace.library.queensu.ca • EPrints • British Library: http://sherpa.bl.uk/ • E-LIS: http://eprints.rclis.org/ • History and Theory of Psychology: http://htpprints.yorku.ca/