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Digitometric Services forOpen Archives Environments

Tim BrodySimon Kampa, Stevan Harnad,

Les Carr, Steve Hitchcock{tdb01r,srk,harnad,lac,sh94r}@ecs.soton.ac.uk

University of Southampton, Intelligence, Agents, Multimedia Group

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Open Archives Initiative

The protocol is openlydocumented, and metadatais “exposed” to at least somepeer group (note: rights management can still apply!)

Archive defined as a“collection of stuff” --not the archivist’s definition of “archive”. “Repository” used in most OAI documents.

Promotinginteroperability

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OAI Data Model:Resources/Items/Records

All available (meta)data about

the resource

Dublin CoreMetadata

MARCMetadata

???XML

Item = OAI identifier

resource

item

records

record = metadata + identifier + datestamp

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Protocol Responses

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Protocol

Service Provider Data ProviderHTTP URL Requests

XML Responses

Identify

Collection-level Description

ListRecords?metadataPrefix=xyz

All repository xyz records

ListRecords?from=2003-04-02&…

All repository xyz records since 2003-04-02

1

2

3

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Other Commands

• ListIdentifiers– Return only the identifier/datestamp/set

membership• ListMetadataFormats

– Return the available data formats• ListSets

– Return the set structure (if there is one)• GetRecord

– Return a record given by OAI identifier

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Interest in OAI

• 111 registered OAI repositories– Many unregistered (e.g. all GNU EPrints.org

and DSpace archives)• 4,500,000 public records

– http://arc.cs.odu.edu/• NSDL project, UK’s JISC Information

Environment• OLAC (language community built on OAI)

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Why OAI?

1. Mandated Dublin Core allows the quick establishment of basic services and tools

2. Simple and metadata-neutral protocol allows more interesting possibilities (without breaking 1.) and extensions …

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Adding Caching to OAI-PMH

LargeRepositories Services

SmallRepositories

LegacyOAI Im plementations

N o n -a g g re g a te d O A I-P M H

LargeRepositories Services

SmallRepositories

A g g re g a te d O A I-P M H

OAI Caches

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Celestial (OAI Cache)

• Developed to maintain a local metadata copy– Avoid repeated, large harvests during development

• Provides an abstraction over multiple OAI versions– (hence acts as a gateway to older implementations)

• Useful for testing OAI implementations & improving performance

• Using XSLT provides a Web interface to OAI• Provides redundancy

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Citebase Search – Data Model

R epos ito ries

M etadata H arvest

C e les tia l

(O A I-P M H )

Full-text H arvest

M eta D atabas e

R efe ren cesD ataba se

C ita tionD ataba se

W ebIn te rface

O A I-P M HIn terface

Citebase

e-Services

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Content

• 250,000 full-text resources– 240,000 of which arXiv.org

• 6 million references– 29 mean refs/paper (therefore failed to extract

references for 18% of papers)– (n.b. modal refs is 19)

• 1 million references linked internally to the full-text (15%)

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Citebase Search

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Citebase Search:Navigation by Citation Links

Current Article Co-cited

Article withreference list

Referencelink

Future

Past

Related

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Citebase Search

citescites

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Citebase Search

citescites

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Citebase Search

“Co-cited”

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Read/Cite Cycle

A u th o r R e ad s a n d C ite s P a p e r

A u th o rs fo llo w c ita tio n s , r e a d a n d c ite

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Digitometric Services for OAI

• Tools for visualising research metadata• Builds an analysis service on Citebase• Knowledge mapping (co-authors, co-

citation, etc.)

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Co-Citation Network

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Full Co-Citation Map

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Digitometric Services forOpen Archives Environments

• http://www.openarchives.org/• http://opcit.eprints.org/• http://citebase.eprints.org/• http://www.eprints.org/• http://www.hyphen.info/

– AKT Project (knowledge)

Thank you for listening!Tim Brody