Update on work of Joint DCMI/IEEE LTSC Task Force

Pete Johnston & Andy Powell, Eduserv [email protected]

[email protected]/foundation

28

Jun

e 2

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6

Update on work of Joint DCMI/IEEE LTSC Task Force

CETIS Metadata & Digital Repositories SIG, UKOLN, Bath

28 June 2006CETIS MDR SIG, Bath 2

Background

• Metadata standards typically developed to support requirements of some community or domain

• Resources used across community/domain boundaries

• Implementers want– to use component parts of different standards in

combination

– to (re)use components of other implementers’ work

• Concept of “metadata application profile” (e.g. Heery/Patel, Duval et al)

– tailor standard to context

– combine components from different standards (“mix & match”)


Abstract Models for Metadata

• Abstract Model of metadata standard specifies– Nature of components and constructs used in standard– Set of rules for building abstract information structure

• IEEE LOM Abstract Model– AIS = LOM instance– Data elements containing other data elements– “Leaf” data element values associated with datatypes (how

value spaces interpreted)• DCMI Abstract Model

– AIS = DC description set– Description = set of statements about resource– Statement

• references to property, value, vocabulary encoding scheme, syntax encoding scheme

• value strings, value representations


Abstract Models & Application Profiles

• Both DC and LOM have notions of “metadata application profile”…

• … but based on respective Abstract Model

• DC Application Profile– how to use a set of identified properties, vocabulary

encoding schemes, syntax encoding schemes to construct a DC metadata description set

• LOM Application Profile– how to use a set of identified LOM data elements,

datatypes, vocabularies to construct a LOM instance

– LOM conceptual data schema includes AM and a “base” application profile


Abstract Models & Bindings for Metadata

• Abstract Models are syntax-independent

• Bindings describe – how abstract information structure is

serialised/encoded in a metadata format

– how instances of a metadata format are interpreted in terms of abstract information structure

• Both DC & LOM have bindings to XML formats

• However, formats interpreted in terms of different Abstract Models

– e.g. XML element parent-child relationships have different interpretations in LOM-XML and DC-XML

System A

DC DescriptionSet

DC-XMLInstance

Encode usingBinding

Construct usingDCAM & DCAP

Decode usingBinding

DC DescriptionSet

Interpret usingDCAM

System B

DC-XMLInstance

<?xml version="1.0"?><dcx:descriptionSet>

System A

Encode usingBinding

Construct usingLOM AM & LOM AP

Decode usingBinding

Interpret usingLOM AM

System B

<?xml version="1.0"?><lom:LOM>

LOMInstance

LOMInstance

LOM-XMLInstance

LOM-XMLInstance


The problem

• IEEE LOM standard and Dublin Core based on different Abstract Models

• LOM data elements and DC properties/classes can not be used in combination in same information structure

• Earlier work on DC-LOM interoperability focused on RDF

– mapping LOM to RDF – mapping DC to RDF

• Not generalisable to other DC formats


The proposed solution

• Develop a LOM-DCAM mapping– “LOM data elements” => “instances of DCAM

components/constructs” – Interpretation of LOM semantics in terms of DCAM

• Not a binding for LOM, but a translation – lossy in part– one-way translation

• Approach– conceptualise LOM as Entity-Relationship model

• build on earlier work for LOM RDF binding

– represent E-R model in terms of DCAM constructs– specify required terms, assign URIs

LOM Conceptual Data Schema

Dublin Core Abstract Model

DC-RDF Instance

DC-XML Instance

conforms to conforms to

bound to

translate(lossy)

bound to

LOMInstance

DC DescriptionSet

LOM-XMLInstance

DC DescriptionSet

CombinedDC DescriptionSet


Outcomes

• View of LOM as a basic DC Application Profile

• Availability of set of “LOM terms” which are usable in other DCAPs

• Availability of RDF binding of LOM “for free” via DC RDF binding (mapping)

• Separation of LOM-DCAM translation from RDF binding

• First step towards better alignment of DC and LOM abstract models?


Joint DCMI/IEEE LTSC Task Force

• Initiated at DC2005 in Madrid, Sep 2005

• Reports to DC Education WG & IEEE LTSC

• Chairs: Mikael Nilsson & Jon Mason

• Participation open to all: – mailing list (~20 subscribers), Wiki

• Joint: – Collaborative work on drafts

– Joint consensus

– Co-publishing of results

• Aim: an IEEE “Recommended Practice” and a DCMI “Recommendation”



• Charter approved by DCMI Advisory Board and IEEE LTSC SEC

• Draft PAR Scope & Purpose presented to LOM WG (March 2006)

• Three initial outputs available for discussion:1. Draft of LOM-DCAM mapping

– includes description of DCAP

2. Example instance based on mapping– LOM XML – DC Text

3. Draft of required property/class/value definitions– folllowing DC “Schema Model”/Usage Board conventions

LOM-XMLDescriptionSet ( Description ( ResourceURI (

<http://purl.org/poi/rdn.ac.uk/12345-67890> )

Statement ( PropertyURI ( dc:title ) ValueString ( “Wilfred Owen and Realis

m ” Language ( en-GB ) ) ) Statement ( PropertyURI ( dc:language ) ValueString ( “en-GB” SyntaxEncodingSchemeURI

( dcterms:RFC3066 ) ) ) Statement ( PropertyURI ( lom:keyword ) VocabularyEncodingSchemeURI ( a:NLS ) ValueString ( "Owen, Wilfred" Language ( en-GB ) ) ) ))

<lom>

<general>

<identifier>

<catalog>URI</catalog>

<entry>http://purl.org/poi/rdn.ac.uk/12345-67890</entry>

</identifier>

<title>

<string language="en-GB">Wilfred Owen and Realism</string>

</title>

<language>en-GB</language>

<keyword>

<string language="en-GB">Owen, Wilfred</string>

</keyword>

</general>

</lom>

DC-Text


Other related DCMI work

• Expressing DC metadata using XML– Working Draft for public comment (June 2006)– Revised XML binding for DC

• Expressing DC metadata using RDF– Working Draft for public comment (June 2006)– Mapping from DCAM to RDF

• DC-Text: A Text Syntax for DC metadata– Under discussion by DC Architecture WG

• Updating of DCMI term definitions– Under discussion by DC Usage Board


Next steps

• Verify mapping through more examples– Identify points of loss-iness

• Finalise mapping• Finalise terms, definitions, URIs• Finalise DCAP• Special Session at DC2006 (October, 2006, Colima,

Mexico)

• Prepare docs for formal review/publication

• Feed into DC Education WG work on DC Ed AP• Feed into IEEE LTSC work on “next generation” LOM



http://dublincore.org/educationwiki/DCMIIEEELTSCTaskforce

Pete Johnston & Andy Powell, Eduserv [email protected]

[email protected]/foundation

28

Jun

e 2

00

6

Update on work of Joint DCMI/IEEE LTSC Task Force

CETIS Metadata & Digital Repositories SIG, UKOLN, Bath

Update on work of Joint DCMI/IEEE LTSC Task Force

Documents

Transcript of Update on work of Joint DCMI/IEEE LTSC Task Force