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 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

Digital library interface 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 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/NP5678 10.5678/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 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

CRADDL services

Components of a Digital Library User Interface Gateway Collection Services Persistent NAMES Name Service Index Services Repository Services 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 Digital Library

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 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

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+.

Users interact with resources and create tags Tag 1 Tag2 Tag 3 Tag 1

Social Tagging Environment Photo sharing Slide sharing Videoblogging and sharing Social networks Academic bookmarking Bookmarking

Citation linking

Get it! Citation linker

Examples Greenstone: http://www.greenstone.org/examples Fedora: DSpace 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/