The document discusses the Open Archives Initiative (OAI), which aims to promote interoperability standards to facilitate sharing of content. OAI originally defined a metadata harvesting protocol (OAI-PMH) to share academic papers. OAI has since expanded to promote broader access to digital resources. The document outlines how OAI-PMH works, challenges to its adoption, and experiments with sharing content beyond just metadata, such as through the OAI-ORE specification currently under development.

1. Sharing With the Open
Archives Initiative
Jenn Riley
Metadata Librarian
Indiana University

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Purpose of Open Archives Initiative
 “develops and promotes interoperability
standards that aim to facilitate the efficient
dissemination of content”
 “has its roots in the open access and
institutional repository movements”
 “Archive” defined broadly: “as a repository for
stored information”

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Early history of the Open Archives
Initiative
 Originally defined a “metadata harvesting
protocol” – OAI-PMH
 Grew out of efforts to share e-prints
 Original work supported by:
 Digital Library Federation (DLF)
 Coalition for Networked Information (CNI)
 National Science Foundation (NSF)

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OAI-PMH
 Protocol history
 Version 1.0 released January 2001
 Version 1.1 released July 2001
 Version 2.0 released June 2002
 No further major revisions planned
 Protocol for harvesting metadata, not content
 No inherent assumption that the metadata
describes digital content

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Diagram from OAI for Beginners - the Open Archives Forum online tutorial at
http://www.oaforum.org/tutorial/english/intro.htm
How OAI-PMH works

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Data providers
 Set up a server that responds to harvesting
requests
 Required to expose metadata in simple Dublin
Core (DC) format
 Can supplement DC with metadata in any other
format expressible with an XML schema (e.g.,
CDWA Lite)

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Service providers
 Harvest and store metadata
 Generally provide search/browse access to this
metadata
 Can be general or domain-specific
 Can choose to collect metadata in formats other
than DC
 Can provide value-added services
 Sometimes re-expose metadata to other
aggregations

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Typical service provider behavior
 Today
 Collect and normalize metadata
 Provide basic discovery
 Send user back to home institution for more
information and/or access to content
 Future
 Metadata enrichment
 Resource licensing
 …

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Why share metadata?
 Benefits to users
 One-stop searching
 Aggregation of subject-specific resources
 Benefits to institutions
 Increased exposure for collections
 Broader user base
 Bringing together of distributed collections
Don’t expect users will know about your
collection and remember to visit it.

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Why share metadata with OAI-PMH?
 “Low barrier” protocol
 Shares metadata only, not content,
simplifying rights issues
 Same effort on your part to share with one or
a hundred service providers (basically)
 Wide adoption in the cultural heritage sector
 Quickly eclipsed methods such as Z39.50

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Sharing can be hard
 Some initiatives have fizzled out
 CIMI
 AMICO
 Some are still going
 ARTstor
 RLG Cultural Materials
 CAMIO and other AMICO derivatives
 Art museums have been most active
 Customizing for each individual aggregator isn’t
sustainable

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Sharing is easier with OAI-PMH
 Framework for sharing with multiple
aggregators
 Museum-centric OAI initiatives are emerging
 CDWA Lite from the Getty
 RLG Museum Collections Sharing Working Group
 Museums are beginning to explore more
open sharing models

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Challenges to OAI-PMH adoption for
museums
 Protocol implicitly assumes you want
metadata to be harvestable by anyone
 DC a poor match for describing most
museum materials
 Museums often want to share content as well
as metadata (with select partners)
One solution? Start a specialized service
provider in the community.

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Some service providers
 OAIster
 National Science Digital Library
 Sheet Music Consortium
 Open Language Archives Community

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“Shareable” metadata
 Promotes search interoperability - “the ability
to perform a search over diverse sets of
metadata records and obtain meaningful
results” (Priscilla Caplan)
 Is human understandable outside of its local
context
 Is useful outside of its local context
 Preferably is machine processable

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Models for sharing with OAI-PMH
OAIHarvester
Digital asset management system
Metadata
creation
module
OAI data
provider
module
Transformation
Metadata
creation
system
Stand-alone
OAI data
provider
Transformation
DC
QDC MODS
CDWA Lite
DC CDWA Lite
QDC MODS
Metadata
creation
module
Static
Repository
Gateway
Transformation
XMLFile

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Basic metadata sharing workflow
 Create metadata, thinking about shareability
 Determine format(s) you wish to share your
metadata in
 Transform records into versions appropriate for
sharing via OAI
 Validate transformed metadata
 Load transformed metadata into OAI data provider
 Test with OAI Repository Explorer
 Communicate with service providers
 See what your metadata looks like once a service
provider harvests it

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Expanding the scope
 “Over time, however, the work of OAI has
expanded to promote broad access to digital
resources for eScholarship, eLearning, and
eScience”
 Some experiments with sharing content
 CIC Metadata Portal
 Fedora Asset Actions
 MPEG-21 DIDL over OAI-PMH
 OAI-ORE

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CIC Metadata Portal
 Research project to build an OAI-based
aggregator for a consortium of academic
libraries in the Midwest
 Created a version of qualified DC to indicate
the location of a thumbnail image
 Integrated harvested thumbnails into search
interface
 Procedure documented in January 2006 D-
Lib Magazine article

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Asset Actions
 Grew out of need for “actionable URLs”
 XML schema designed for facilitating the sharing
and manipulation of digital objects
 Define core functions for digital objects of all types,
e.g., “get preview”
 Begun to define further functions for specific content
types
 Proof-of-concept implementation created for DLF
Aquifer project
 Can be shared via OAI-PMH as a supplemental
metadata format
 Documented in October 2006 D-Lib Magazine
article

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MPEG-21 DIDL over OAI-PMH
 Repository architecture at Los Alamos National
Laboratory uses MPEG-21 DIDL for complex digital
objects
 OAI-PMH repositories integral parts of the internal
repository architecture
 These internal OAI-PMH repositories do not support
DC metadata – “Because mapping a DID that
represents a complex digital object to simple DC is
quite an impossible task, support of DC by these
OAI-PMH repositories is rather meaningless.”
 Described in 2004 JCDL paper
 Lay the groundwork for OAI-ORE

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OAI-ORE
 Open Archives Initiative Object Re-Use and
Exchange
 Two-year Mellon-funded project beginning October
2006
 Will develop specifications that allow distributed
repositories to exchange information about their
constituent digital objects
 Goal is to facilitate “a new digitally-based scholarly
communication framework”
 Imagine how research could be transformed if users
had seamless access to information in any
repository, anywhere, and the tools to use them

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Goals for initial OAI-ORE project
 Formation of an international advisory committee,
consisting of leaders in e-Science, institutional
repositories, publishing, library, and educational
technology communities.
 Formation of an international working group that will
meet over the two year period and develop the set
of ORE specifications.
 Establishment and management of an experimental
deployment community that will exercise the
developed standards in a variety of contexts.
 Establishment of a sustainable community to
support the widespread deployment and
management of the standards fabric.

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OAI-ORE potential for cultural
materials
 Original focus is on scholarship, and sharing
text and datasets
 No inherent limitations to these uses
 Facilitates, but doesn’t require exchange of
actual content
 Focus on complex objects better suited to
cultural materials than OAI-PMH model
 It’s still early, but inherent flexibility of model
looks promising for cultural materials

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For more information
 jenlrile@indiana.edu
 These presentation slides
<http://www.dlib.indiana.edu/~jenlrile/presentations/getty2007/oai.ppt>
 OAI home page <http://www.openarchives.org>
 OAI-PMH <http://www.openarchives.org/pmh/>
 OAI-ORE <http://www.openarchives.org/ore/>