T.Sharon-A.Frank1

Internet Resources Discovery (IRD)

Types of

Digital Libraries

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Contents

Types of DLsComparisonsAdditional Aspects

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Sample list of Digital Libraries

• LOC - Library of Congress American Memory (http://memory.loc.gov/ammem/)

• NSDL - National Science DL (http://nsdl.org)• IPL - Internet Public Library (http://www.ipl.org)

• CDL - California DL (http://www.cdlib.org)

• ADL – Alexandria DL (http://www.alexandria.ucsb.edu)• BL - British Library (http://www.bl.uk/)• NZDL – New Zealand DL (http://www.nzdl.org/)

• Einstein Archives Online (http://www.alberteinstein.info/)

Types of DLs

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Basic SE (BSE)

Meta SE (MSE)

Popularity SE (PSE)

Stand Alone DL (SDL)

Harvested DL (HDL)

Federated DL (FDL)

Digital Library

(DL)Search Engine

(SE)Directory

(Catalog, Guide, Subject Gateway)

Web Repositories Hierarchy

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Types of DLs

• Stand-alone Digital Library (SDL) – also self-contained, several collections

• Federated Digital Library (FDL)– also confederated, networked

• Harvested Digital Library (HDL)– also distributed

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Exemplary Digital Libraries• Stand Alone DL (SDL)

•Library of Congress (LC) and National Digital Library(NDL)

•Internet Public Library (IPL)

•Snunit

• Federated DL (FDL)•Networked Computer Science Technical Reference

Library (NCSTRL)

•Online Computer Library Center (OCLC)

• Harvested DL (HDL)•SourceBank (http://www.sourcebank.com/)

•ArticleCentral.com! (http://www.articlecentral.com/ ) •Harvest/Katsir, OAI

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Virtual (Symbolic) (VDL)

MetadataOriented

Several SDL

(General)

Collection

General VDL

Specialty

VDLLibrary Index

Weblog

List

Real (Physical) Self-contained (SDL)

Data-Objects Oriented

Single SDL

(Specialty)

Collection

Stand-Alone (SDL)Stand-Alone (SDL)

First Generation Digital Libraries

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Stand-alone Digital Library (SDL)

• A regular DL

• Usually localized on server/LAN

• Self-contained material:– edited/generated

– scanned/digitized

– purchased

• Single or Several digital collections

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Federated Digital Library (FDL)

• Contains many autonomous libraries

• Usually heterogeneous repositories

• Connected via a network

• Forms a virtual library

• Unified/Transparent user interface

The major problem is interoperability

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Harvested Digital Library (HDL)

• Harvests digital objects, not full DLs.

• Objects harvested into metadata (protocol was Harvest/SOIF, nowadays OAI).

• Does not have to contain objects, just metadata/summaries.

• But has regular DL characteristics.

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SDL vs. HDL

Single Digital Library Harvested Digital Library

Items Origin Purchased/Digitized Gathered

Items Location Local/Networked Scattered

Material Items+Catalog Catalog

Repository Size Large Small

Update Medium Fast/Dynamic

CompositionMethod

Interoperability Inherent

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References• Academic Info: Digital Library http://

www.academicinfo.net/digital.html• Moving to the Electronic Library

http://www.sims.berkeley.edu/courses/is101/s96/elib.html• Digital Library Definition (ARL at DL SunSITE) http://

sunsite.berkeley.edu/ARL/definition.html• Digital library scope http://www.dlib.org/metrics/public/papers/dig-lib-scope.html• What are Digital Libraries

http://www.clir.org/pubs/issues/issues04.html#dlf• UIUC DLI Glossary http://dli.grainger.uiuc.edu/glossary.htm• Digital Libraries: A selected Resource Guide

http://www.lita.org/ital/1603_klemperer.htm