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					           OAI-PMH
The Open Archives Initiative Protocol
     for Metadata Harvesting



        Presenter: Knud Möller
          Friday, 30.07.2004
                                    Content
             • Basic idea behind OAI-PMH
             • Architectural Overview
                 – Repositories and Harvesters
                 – Resources, Items and Records
             •   Internal Record Format
             •   Sets
             •   Selective Harvesting
             •   Response Format
             •   Command Overview
                          OAI-PMH - Knud Möller, DERI Galway   1
30.07.2004
               Basic idea behind OAI-PMH
             • provide a standard protocol for the harvesting/
               querying of metadata about any kind of
               resource - “What kind of resources can you
               provide and what are their properties?“
             • OAI-PMH is only the protocol, needs to be
               implemented
             • some implementations exist:
               – Emblem Project Utrecht
                 http://emblems.let.uu.nl/emblems/html/techoai.html
               – Virginia Tech (VTOAI)
                 http://www.dlib.vt.edu/projects/OAI/software/vtoai/vtoai.html


                             OAI-PMH - Knud Möller, DERI Galway                  2
30.07.2004
                           Architectural Overview
              Repositories and Harvesters
                                                                Harvester
               Harvester




                                        Repository

             Harvester
                                                                  Harvester




                           OAI-PMH - Knud Möller, DERI Galway                 3
30.07.2004
                             Architectural Overview
                Repositories and Harvesters
                                                                  Harvester
                 Harvester




                                          Repository

               Harvester
                                                                    Harvester


             Harvesters issue OAI-PMH requests for metadata via HTTP.


                             OAI-PMH - Knud Möller, DERI Galway                 4
30.07.2004
                             Architectural Overview
                Repositories and Harvesters
                                                                  Harvester
                 Harvester




                                          Repository

               Harvester
                                                                    Harvester


             Harvesters issue OAI-PMH requests for metadata via HTTP.
             A Repository processes the OAI-PMH requests and has to
             implement the protocol.
                             OAI-PMH - Knud Möller, DERI Galway                 5
30.07.2004
                  Architectural Overview
             Resources, Items and Records




                                                       Anything - physical artifact, a
                  Resource                             digital resource, a concept, etc.
                                                       Whatever the metadata is about.

                  OAI-PMH - Knud Möller, DERI Galway                               6
30.07.2004
                               Architectural Overview
                Resources, Items and Records




                                                                    Representation of resource in
                                                                    repository. Can disseminate
                                  Item                              metadata in various formats.
                                                                    Must always provide Dublin
                                                                    Core. Has unique identifier.
             oai:arXiv.org:cs/0112017



                                                                    Anything - physical artifact, a
                              Resource                              digital resource, a concept, etc.
                                                                    Whatever the metadata is about.

                               OAI-PMH - Knud Möller, DERI Galway                               7
30.07.2004
                               Architectural Overview
                Resources, Items and Records
                                                                    XML-encoded byte stream of
                                  Record                            actual metadata.
                                   (lom)


              Record                                Record
              (oai_dc)                               (id3)


                                                                    Representation of resource in
                                                                    repository. Can disseminate
                                  Item                              metadata in various formats.
                                                                    Must always provide Dublin
                                                                    Core. Has unique identifier.
             oai:arXiv.org:cs/0112017



                                                                    Anything - physical artifact, a
                              Resource                              digital resource, a concept, etc.
                                                                    Whatever the metadata is about.

                               OAI-PMH - Knud Möller, DERI Galway                               8
30.07.2004
                   Internal Record Format I
             <record>
                 <header>
                     <!-- blabla -->
                 </header>
                 <metadata>
                     <!-- blabla -->
                 </metadata>
                 <about>
                     <!-- blabla -->
                 </about>
             </record>




                            OAI-PMH - Knud Möller, DERI Galway   9
30.07.2004
                   Internal Record Format I
             <record>
                 <header>
                     <!-- blabla -->
                 </header>
                 <metadata>
                     <!-- blabla -->
                 </metadata>
                 <about>
                     <!-- blabla -->
                 </about>
             </record>




             <header>
                 <identifier>oai:arXiv.org:cs/0112017</identifier>
                 <datestamp>2002-02-28</datestamp>
                 <setSpec>cs</setSpec>
                 <setSpec>math</setSpec>
             </header>




                             OAI-PMH - Knud Möller, DERI Galway      10
30.07.2004
                  Internal Record Format II
             <metadata>
                 <oai_dc:dc
                     xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/"
                     xmlns:dc="http://purl.org/dc/elements/1.1/"
                     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance“
                     xsi:schemaLocation=
                        "http://www.openarchives.org/OAI/2.0/oai_dc/
                         http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
                     <dc:title>Using Structural Metadata to Localize Experience
                         of Digital Content</dc:title>
                     <dc:creator>Dushay, Naomi</dc:creator>
                     <dc:subject>Digital Libraries</dc:subject>
                     <dc:description>With the increasing [..bla..] to particular
                         communities of users. </dc:description>
                     <dc:date>2001-12-14</dc:date>
                     <dc:type>e-print</dc:type>
                     <dc:identifier>
                         http://arXiv.org/abs/cs/0112017
                     </dc:identifier>
                 </oai_dc:dc>
             </metadata>



                             OAI-PMH - Knud Möller, DERI Galway                    11
30.07.2004
                 Internal Record Format III
             <about>
                 <provenance
                     xmlns="http://www.openarchives.org/OAI/2.0/provenance"
                     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                     xsi:schemaLocation=
                         "http://www.openarchives.org/OAI/2.0/provenance
                          http://www.openarchives.org/OAI/2.0/provenance.xsd">
                     <originDescription harvestDate="2002-02-02T14:10:02Z"
                         altered="true">
                         <baseURL>http://the.oa.org</baseURL>
                         <identifier>oai:r2.org:klik001</identifier>
                         <datestamp>2002-01-01</datestamp>
                         <metadataNamespace>
                             http://www.openarchives.org/OAI/2.0/oai_dc/
                         </metadataNamespace>
                     </originDescription>
                 </provenance>
             </about>




                             OAI-PMH - Knud Möller, DERI Galway                  12
30.07.2004
                                                   Sets
             • Items can be organized into sets.
             • Sets can either be organized flat or hierarchically.

               setName                                  setSpec

               Institutions                             institution

               Oceanside University of Nebraska         institution:nebraska

               Valley View University of Florida        institution:florida

               Subject                                  subject

               Existential Kenesiology                  subject:kenesiology

               Quantum Psychology                       subject:quantum


                                  OAI-PMH - Knud Möller, DERI Galway           13
30.07.2004
                     Selective Harvesting
             • Harvesters can specify some constraints on
               which items they are interested in
             • Regarding datestamps:
               – only items that where created, modified or deleted
                 (optional) in a certain time period
             • Regarding sets:
               – only items that belong to a specific set (or any of
                 its subsets)



                          OAI-PMH - Knud Möller, DERI Galway           14
30.07.2004
                          Response Format
             <?xml version="1.0" encoding="UTF-8" ?>
                 <OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/“
                     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance“
                     xsi:schemaLocation=
                         "http://www.openarchives.org/OAI/2.0/
                          http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd">
                     <responseDate>2002-05-01T19:20:30Z</responseDate>
                     <request verb="GetRecord"
                         identifier="oai:arXiv.org:hep-th/9901001“
                         metadataPrefix="oai_dc">
                         http://an.oa.org/OAI-script
                     </request>
                 <GetRecord>
                     <record>...</record>
                 </GetRecord>
             </OAI-PMH>




                             OAI-PMH - Knud Möller, DERI Galway               15
30.07.2004
                    Command Overview I
             • GetRecord: get a specific record, must
               specify item‘s URI and metadata prefix
             • Identify: retrieve information about a
               repository (name, protocol version, supports
               deletion, ...)
             • ListRecords: get either all records or a
               subset, must specify metadata prefix
             • ListIdentifiers: like ListRecords, but
               retrieves only headers

                        OAI-PMH - Knud Möller, DERI Galway    16
30.07.2004
                   Command Overview II
             • ListMetadataFormats: lists the available
               metadata formats of a repository
             • ListSets: returns the set structure of a
               repository




                        OAI-PMH - Knud Möller, DERI Galway   17
30.07.2004
                             References
             • OAI-PMH specification:
               http://www.openarchives.org/OAI/2.0/openar
               chivesprotocol.htm




                        OAI-PMH - Knud Möller, DERI Galway   18
30.07.2004
             Thanks and
             goodbye!
             OAI-PMH - Knud Möller, DERI Galway   19
30.07.2004

				
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