Digital Library Architecture and Technology. 2 Outline DL architecture Building blocks of DLs DL models Components of DLs DL open source software Modern.

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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E-journalsOnline

databasesRemote digital

libraries WWW

Search interfaces

Search interfaces

Search interfaces

Search engines&directories

OPACs Search interface

Digital library interface

Users

Local digital library

Libraryresources

Conceptual design of a digital library

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

6Arms 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

15 CRADDL services

16Repository Services

Components of a Digital Library

Collection Services

Index Services

PersistentNAMES

NameService

UserInterfaceGateway

DigitalObjects

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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:ServersMiddlewareClients

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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

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Client

QueryMapping

RetrievalMapping

DatabaseAccess

AccessControl

( AO Lserver)

client

servers

( libm i) / SQL

SQL

KNF

MapGenerator

HTTP/ m apbrow ser

m iddlew are

SessionLog

UserDatabase

log record

log record

user I D

session I D

QueryFanout

ResultMerge

... ...

HTTP/session , search, holdings,

collections, m etadata

Gazetteer DBMS

QueryView

RetrievalView s

( I nformix)

Catalog DBMS

QueryView

RetrievalView s

( I nform ix)

Gatew ay

QueryView

RetrievalView s

(e.g. Z39.50)

?

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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

Social networking sites

Social networking, bookmarking and tagging

Reviews Recommendation features Citation and reference linking Bibliometric tools

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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+.

Bookmark

Tag

share

Write reviews

Users interact with resources and create tags

Tag 1Tag2Tag 3

Tag 1Tag 2Tag 3

Tag 1Tag 2Tag 3

Tag 1Tag 2Tag 3

Tag 1Tag 2Tag 3

Tag 1Tag 2Tag 3

Tag 1Tag 2Tag 3

Social Tagging Environment

Photo sharing

Slide sharing

Videoblogging and sharing

Social networks

Academic bookmarking

Bookmarking

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Citationlinking

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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/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/