Digital Library Architecture and Technology

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Digital Library Architecture and Technology
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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

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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

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Conceptual design of a digital library
E-journals
Online databases
Remote digital libraries
WWW
Search interfaces
Search interfaces
Search interfaces
Search engines directories
Local digital library
Library resources
OPACs
Search interface
Digital library interface
Users
Chowdhury (2002) Introduction to digital
libraries
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Components of a DL system

• Arms (1997) names the following components for
  digital libraries
• User interfaces
• Repository
• Handle system
• Search system

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Arms et al. An Architecture for Information in
Digital Libraries. D-Lib Magazine, February 1997.

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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

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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.

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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/NP5678
  10.5678/ISBN-0-7645-4889-4
• Persistent Uniform Resource Locator (PURL)
  developed by OCLC names the location of an
  object

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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

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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.

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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 service provides the mechanism for
  discovery of digital objects via query
• The collection service provides the mechanisms
  for the aggregation of access to sets of digital
  objects
• User interface services or gateways provide
  human-centered entry points to the functionality
  of the digital library

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CRADDL services
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Components of a Digital Library
Digital Objects
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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

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Alexandria Digital Library
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Alexandria DL architecture

• A three-tier model consisting of
• Servers
• Middleware
• Clients

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Alexandria DL architecture

• Servers maintain collections of metadata
  describing the librarys 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

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DL open source software

• Greenstone
• Fedora
• D-space
• Eprint

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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.

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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

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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

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DSpace digital repository system

• 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

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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.

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Modern Features in Digital Library Architectures
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Social networking sites

• Social networking, bookmarking and tagging
• Reviews
• Recommendation features
• Citation and reference linking
• Bibliometric tools

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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.
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Tag 1 Tag2 Tag 3
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Users interact with resources and create tags
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Citation linking
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Get it! Citation linker
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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/dspa
  ce/index.jsp
• U of Wolverhampton(UK) http//wlv.openrepository
  .com/wlv/
• Queens 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/