update on work of joint dcmi/ieee ltsc task force
DESCRIPTION
Update on work of Joint DCMI/IEEE LTSC Task Force. CETIS Metadata & Digital Repositories SIG, UKOLN, Bath. Background. Metadata standards typically developed to support requirements of some community or domain Resources used across community/domain boundaries Implementers want - PowerPoint PPT PresentationTRANSCRIPT
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
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”)
28 June 2006CETIS MDR SIG, Bath 3
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
28 June 2006CETIS MDR SIG, Bath 4
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
28 June 2006CETIS MDR SIG, Bath 5
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
28 June 2006CETIS MDR SIG, Bath 8
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
28 June 2006CETIS MDR SIG, Bath 9
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
28 June 2006CETIS MDR SIG, Bath 11
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?
28 June 2006CETIS MDR SIG, Bath 12
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”
28 June 2006CETIS MDR SIG, Bath 13
Joint DCMI/IEEE LTSC Task Force
• 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
28 June 2006CETIS MDR SIG, Bath 15
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
28 June 2006CETIS MDR SIG, Bath 16
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
28 June 2006CETIS MDR SIG, Bath 17
Joint DCMI/IEEE LTSC Task Force
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