Please note: This experimental research project has concluded.
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The NDLTD Union Catalog


The NDLTD Union Catalog project focused on theses metadata via the Protocol for Metadata Harvesting (OAI-PMH). It was a lightweight protocol for moving or sharing metadata that allowed synchronization of loosely coupled databases and mandates XML Dublin Core as the default metadata format.


The goals of this project were to:

  • Investigate OAI-PMH by participating in production and beta-tests sites
  • Promote the use of theses and dissertations.
  • Investigate services that can be built with OAI-PMH
  • Understand OAI-PMH from both serving and harvesting viewpoints.
  • Maintain a OAI harvestable public repository of ETDs for all institution that register their ETD OAI site with the Networked Digital Library of Theses and Dissertations (NDLTD)


The project team:

  • Wrote an OAI-PMH v2.0-compliant server in Java.
  • Brought up this server containing approximately 800,000 records in XML Dublin core format harvested from institutions all over the world. Dublin Core is the default format for the records some of the records are also in XML Electronic Theses and Dissertation Metadata Standard (ETDMS) and XML MARC formats.
  • Periodically harvested metadata from institutions.
  • Added and harvested records from new OAI servers.
  • Implemented SRW/SRU for searching records

OAI-PMH is expected to be the major method of moving large amounts of metadata between systems. It can be useful for interoperability beyond simple metadata and useful for repositories even without harvesting.

Related publication

  • McMillan, Gail. 2002. ETDs and Libraries. (PDF:510K/34pp.) [White paper commissioned by OCLC Research.]
  • Gail McMillan is Director, Digital Library and Archives, Virginia Tech. OCLC Research commissioned this report to help OCLC members understand what is involved in beginning and sustaining an ETD initiative.



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Thomas Hickey

Team Members

Jeff Young