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PLEDGE Project Wiki

Welcome to the PLEDGE project, a collaboration between the MIT and UCSD Libraries and the San Diego Supercomputer Center. With funding from the National Archives and Records Administration we are conducting research and advanced development on prototypes for scalable, interoperable digital archives and preservation environments, working primarily with the DSpace digital repository platform and the SRB data grid middleware. The project proposal can be downloaded here media:PLEDGE proposal 2005.pdf

Articles and Presentations

  • An article submitted to the UK Digital Curation Centre conference in Glasgow, UK (November 2006)


  • An article about PLEDGE for the JCDL 2006 conference explains the major concepts of the project and how it relates to other activities in the policy arena for repositories and archives


Digital Preservation Policies

The current list of digital repository policies is here, in Word and PDF formats,



A comparison of this list with the new TRAC:Criteria and Checklist:


This comparison identifies those TRAC Criteria in the new list that are not currently in the PLEDGE list and those policies that the PLEDGE project has identified that are not included in the TRAC Criteria.

Former Versions

Older versions of these documents are available at: DraftPolicyDocuments

Sample DSpace Policy Definitions and Metadata

DSpace Policies are defined in order to explore the implementation of policy encoding, their enforcement in DSpace systems and their incorporation into sample DSpace AIPs.

DSpace Definitions

Nine policies have been identified as pertaining to the federation and storage relationship between DSpace and iRods. These policies have been defined below and encoded as REI metadata that is included in a DSpace AIP transfered from DSpace to iRods.


DSpace Policy Definition Process Documentation

The process that was developed to define policies for DSpace has been analyzed and documented as a result of this research.


Sample DSpace Policy Metadata

This a sample encoding of the DSpace replication policy in n3 and rdf formats.









DSpace AIPs with Policy Metadata

Former versions of the DSpace policy defintions, encodings and AIPs can be found at PolicyExpressions.

Translating Policy Metadata to iRods Rules Language

Policies encoded in the REI Policy Expression Language must be translated into iRods rules language to be enforced by the iRods rules engine. A sample translation has been attempted for the policy TI0011 Replication. The policy metadata and rules declarations are included here along with analysis of the translation process.

PLEDGE Policy Metadata


iRods Rule Declaration




Policy Expression Languages

The chosen Policy Expression Language is

Other candidate Policy Expression Languages we reviewed were

DSpace History System Analysis

  • A description of the new DSpace History system is at

  • A description of the new DSpace event mechanism and prototype implementation notes is at and

Metadata Crosswalks for VDC Integration

In the second year of this project we are working to incorporate the Virtual Data Center into PLEDGE activities. This integration involved transforming descriptive and administrative metadata out of DDI formats and into MODS and PREMIS for inclusion in METS SIPs. Information about metadata work for the VDC Integration is available here: VDCIntegration

Related Work

A list of background readings and related works is here: RelatedWork

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For more information contact MacKenzie Smith, Associate Director for Technology, MIT Libraries (kenzie at

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