MPEG-21 Digital Item Declaration (ISO/IEC 21000-2): an overview

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Access Interfaces for Open Archival Information
Systems based on the OAI-PMH and the OpenURL
Framework for Context-Sensitive Services
Jeroen Bekaert, and Herbert Van de
Sompel Research Library, Prototyping Team Los
Alamos National Laboratory
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introduction

• OAIS functional model specifies conceptual
  Producer-OAIS OAIS-Consumer access functions
• Kahn/Wilensky framework specifies the conceptual
  Repository Access Protocol
• Networked European Deposit Library (NEDLIB)
  standardized techniques for the content transfer
  from publishers to libraries, following the OAIS
  Reference Model
• JISC Digital Repository Programme need of
  standards/specifications that provide a
  technical implementation of the OAIS DIP/SIP
  interfaces
• American Physical Society mirror project
  introduced a standards-based (OAI-PMH) interface
  to the APS repository to allow recurrent and
  accurate transfer of digital assets
• we focused on the definition of
• common and standardized access interfaces
• that could be deployed across diverse OAIS
  digital respositories

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accessing digital assets in real-life IR

• DSpace. MIT/HP repository system
• DSpace Web user interface
• DSpace Lightweight Network Interface
• WebDAV based protocol, tailored to the DSpace
  Data Model
• does not provide methods to request versions of
  digital assets
• Fedora. Cornell University/University of Virginia
  open source repository
• two Application Programming Interfaces
• Fedora-API-A SOAP-enabled web service for
  accessing digital assets stored in the Fedora
  repository
• Fedora-API-A-LITE a streamlined version of the
  Fedora-API-A
• aDORe repository architecture designed at the
  Los Alamos National Laboratory
• defines two access interfaces
• OAI-PMH Federator provides an OAI-PMH enabled
  interface through which MPEG-21 DIDL documents
  stored in the aDORe environment can be requested
• OpenURL Resolver provides an interface through
  which disseminations of constituents of MPEG-21
  Digital Items can be requested

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an OAIS perspective on digital assets
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an OAIS perspective on the identification of
digital assets
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an OAIS perspective on the versioning of digital
assets
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the representation, identification and versioning
of digital assets in real-life repositories
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the representation, identification and versioning
of digital assets in real-life repositories
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the representation, identification and versioning
of digital assets in real-life repositories
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an OAIS perspective on the access of digital
assets

• Requests aimed at returning Dissemination
  Information Packages
• XML based, application-neutral representations of
  a digital asset
• multiple techniques exist ISO MPEG-21 DID, CCSDS
  XFDU, RDF,
• derived from an OAIS AIP
• referred to as a DIP Order
• Requests aimed at returning disseminations of one
  or more (parts of an) OAIS Content Data Object(s)
• returns a MIME typed bitstream
• derived from one or more OAIS Content Data Object
  files
• dependent on the version of the OAIS Content
  Information
• referred to as a Dissemination Request

2 approaches using AIP Identifiers or using
Content Information Identifiers
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ordering Dissemination Information Packages
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ordering Dissemination Information Packages
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Open Archives Protocol for Metadata Harvesting
(OAI-PMH)

• a low-barrier interoperability specification for
  the recurrent harvest of XML-based information
  between systems
• widely adopted in the digital library community
• machine consumption
• defines a data model (next slide)
• defines 6 types of protocol requests
• supporting protocol requests
• Identify, ListMetadataFormats, ListSets
• harvesting protocol requests
• ListRecords, ListIdentifiers, GetRecord

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Open Archives Protocol for Metadata Harvesting
(OAI-PMH)data model
resource
OAIS Content Info.
item (OAI-PMH identifier)
OAIS Content Identifier OAIS AIP Identifier
datestamp y
datestamp z
datestamp x
harvest compound digital assets, represented in
XML
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ordering OAIS DIPs using Content Information
Identifiers and OAI-PMH (Interface 1)
STEP 1 Request list of available OAIS DIP
formats STEP 2 Harvest most recent OAIS DIPs
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ordering OAIS DIPs using Content Information
Identifiers and OAI-PMH (Interface 1)

• for each OAIS DIP format, a different
  metadataPrefix/Schema is used
• svc_id infopathways/svc/dip.didl (MPEG-21
  DIDL)
• svc_id infopathways/svc/dip.xfdu (XFDU)
• svc_id infopathways/svc/dip.rdf (Pathways -
  RDF)
• harvest OAIS DIPs that package the most recent
  sets of OAIS Content Information available in an
  information system
• keep the retrieved content up to date using a
  datestamp based harvesting strategy
• only the most recent version. does not facilitate
  the harvesting of all versions of OAIS Content
  Information.
• harvest all versions (mirroring)? an interface
  similar to interface 1, but based on OAIS AIP
  Identifier

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NISO OpenURL Framework for Context Sensitive
Services (Z39.88-2004)

• Concept 1 ContextObject an information
  package that described a referenced resource
• Concept 2 the ContextObject is transported to an
  OpenURL Application to request services
  pertaining to the references resource

OpenURL
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NISO OpenURL Framework for Context Sensitive
Services

• a ContextObject consists of several pre-defined
  abstract entities. E.g.
• Referent the entity that is referenced
• ServiceType the service that is requested
• Etc.
• conceptual entities of a ContextObject are
  persistent over time can be represented in
  various ways as technologies evolve. E.g.
• KEV HTTP
• XML SOAP
• Etc.

baseURL? url_verZ39.88-2004
rft_idIdentifier svc_idinfopathways/svc/dip

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requesting OAIS DIPs using Content Information
Identifiers and NISO OpenURL
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readings

• A Standards-based Solution for the Accurate
  Transfer of Digital Assets. http//dx.doi.org/10.1
  045/june2005-bekaert
• Access Interfaces for Open Archival Information
  Systems based on the OAI-PMH and the OpenURL
  Framework for Context-Sensitive Services.
  http//arxiv.org/abs/cs.DL/0509090
• Representing Digital Assets for Long-Term
  Preservation using MPEG-21 DID.
  http//arxiv.org/abs/cs.DL/0509084
• Resource Harvesting within the OAI-PMH Framework.
  http//dx.doi.org/10.1045/december2004-vandesompel
  

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requesting Disseminations
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requesting Disseminations using Content
Information Identifiers and NISO OpenURL