Report on Work of Joint DCMI/IEEE LTSC Task Force

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
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 Description Set DC-XML Instance Encode using Binding Construct using DCAM & DCAP Decode using Binding DC Description Set Interpret using DCAM System B DC-XML Instance <?xml version="1.0"?> <dcx:descriptionSet>

System A Encode using Binding Construct using LOM AM & LOM AP Decode using Binding Interpret using LOM AM System B <?xml version="1.0"?> <lom:LOM> LOM Instance LOM Instance LOM-XML Instance LOM-XML Instance

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 LOM Instance DC Description Set LOM-XML Instance DC Description Set Combined DC Description Set

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:
Draft of LOM-DCAM mapping
includes description of DCAP
Example instance based on mapping
LOM XML
DC Text
Draft of required property/class/value definitions
folllowing DC “Schema Model”/Usage Board conventions

LOM-XML
DescriptionSet (
Description (
ResourceURI ( <http://purl.org/poi/rdn.ac.uk/12345-67890> )
Statement (
PropertyURI ( dc:title )
ValueString ( “Wilfred Owen and Realism”
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

Update on work of Joint DCMI/IEEE LTSC Task Force CETIS Metadata & Digital Repositories SIG, UKOLN, Bath

Report on Work of Joint DCMI/IEEE LTSC Task Force

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