The Open Archives Initiative

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The Open Archives Initiative

• Marshall Breeding
• Director for Innovative Technologies and Research
• Vanderbilt University
• http//staffweb.library.vanderbilt.edu/breeding

Redefining Libraries Web 2.0 and other
Challenges May 2007 Xiamen, China
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From www.openarchives.org

• Standards for Repository Interoperability
• The Open Archives Initiative develops and
  promotes interoperability standards that aim to
  facilitate the efficient dissemination of
  content. OAI has its roots in the open access and
  institutional repository movements. Continued
  support of this work remains a cornerstone of the
  Open Archives program. Over time, however, the
  work of OAI has expanded to promote broad access
  to digital resources for eScholarship, eLearning,
  and eScience.

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Model for federated search

• Harvest metadata from multiple repositories
• Index metadata on a central service
• Offer a search interface on the central service
• Deliver access to digital objects on the original
  repositories

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Organization / Structure

• Data Providers
• Contribute metadata and content
• Run a module that responds to requests for
  metadata
• Service Providers
• Harvest metadata from one or more repositories
• Operate services that request metadata from data
  providers

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Not MetaSearch

• Avoids pitfalls of distributed-query approach
  to federated search
• Centralized, consolidated indexes allow for fast
  searching, sorting, ranking
• Not dependent on persistent connections with
  multiple repositories

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Open Archives Initiative

• Initiated in the pre-print servers for scholarly
  articles and research papers
• Need to provide federated search model rather
  than having each researcher search each
  repository separately
• Value-added services
• Santa Fe convention Oct 1999
• Need to develop a protocol to create
  interoperability among many different types of
  repositories, each with different types of
  documents and metadata

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OAI-PMH

• Open Archives Initiative Protocol for Metadata
  Harvesting
• XML protocol for harvesting metadata
• Uses unqualified Dublin Core as default
• Each community can specify its own metadata
  formats and profiles
• A simple protocol designed to have a low
  threshold of difficulty for implementation

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OAI-PMH Requests / Response

• Identify
• ListIdentifiers
• ListMetadataFormats
• ListRecords
• ListSets
• GetRecord

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A standard protocol

• Initial 1.1 version in July 2001
• Version 2.0 completed in June 2002

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Operational considerations

• Initial contact of an OAI harvester to a
  repository may involve a massive transfer of
  records
• Resumption token provides a mechanism for the
  repository to interrupt the transfer
• Harvestor may come back at a later time to resume
  the transfer
• Subsequent requests involve only added and
  changed records

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OAI in action

• Widely implemented
• Part of the standard infrastructure for pre-print
  servers, institutional repositories, etc.
• D-Space
• Fedora
• Pragmatic approach for any application needing to
  transfer records between systems
• Some service providers use additional protocols

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Examples

• Networked Digital Library of Theses and
  Dissertations
• The American South
• AmericanSouth.org

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Implementations

• Tools available in many different programming
  languages and environments
• Built-in to many digital library applications

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For detailed information

• http//www.openarchives.org/
• Understanding the Protocol for Metadata
  Harvesting of the Open Archives Initiative
  (Marshall Breeding, Computers in Libraries, Sept
  2002)
• http//www.librarytechnology.org/ltg-displaytext.p
  l?RC9944