semudate-samt how to align media metadata schemas, design and implementation of the media ontology
DESCRIPTION
This is the presentation of a joined research paper written by the W3C Media Annotations Working Group. The paper presents and compares different approaches to map metadata formats using semantic web technologies.TRANSCRIPT
ELIS – Multimedia Lab
How to Align Media Metadata Schemas?
Design and Implementation of the Media Ontology
Florian Stegmaier, Werner Bailer, Tobias Bürger, Mario Döller, Martin Höffernig, Wonsuk Lee,
Véronique Malaisé, Chris Poppe,Raphaël Troncy, Harald Kosch and Rik Van de
Walle
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Context
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
Interoperability issues
EXIF
MPEG-7
DC
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W3C Media Annotations Working Group
• http://www.w3.org/2008/WebVideo/Annotations/ • Mission
– Ontology• common set of properties (currently 28) describing
basic metadata for media resources– identifier, title, language, creator, creation date,
description, genre, rating, collection, copyright, target audience, frame size, sampling rate, bit rate,…
• mappings of existing formats to core ontology
– API• access to the metadata
– e.g., getValues(“creator”)
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ELIS – Multimedia Lab
W3C Media Annotations Working Group
• Mappings currently represented by mapping table http://www.w3.org/2008/WebVideo/Annotations/drafts/ontology10/WD/mapping_table.htm
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
MAWG property
Relation EBUCore How to do the mapping
Datatype
XPath
ma:identifier
exact dc:identifier string EBUCoreMain/ coreMetadata/ identifier/ dc:identifier
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MA Ontology
Mapping of Metadata Standards
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
MA properties
API (Web Interface Definition Language)
MPEG-7 Dublin Core
EBUCORE
EXIF…MEDIARDF
MA mapping (expressed as mapping table)
This paper compares different ways of implementing the MA mapping using semantic web technologies
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Implementation approaches
• Two types– expressing mappings using semantic web
language• SKOS• OWL and SWRL
– expressing mappings through pivot upper ontology
• format independent ontology• format dependent ontology
• Compared on simple and complex mapping– ma:title– ma:frameSize
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ELIS – Multimedia Lab
• Use SKOS constructs to relate properties
• Simple• Vocabularies need to be available in RDF• Some mappings/conversions can not be expressed
SKOS:Collection
Mappings in SKOS
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ma:titledc:title
ma:frameSizeEbucore:formatHei
ght
Ebucore:formatWidth
SKOS:exactMatch
SKOS:closeMatch
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Mappings in OWL and SWRL
• Use OWL constructs to relate OWL concepts in each ontology
• Assume OWL ontologies are available for each metadata format
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
OWL:equivalentProperty
ma:MediaResource
dc:title ma:title
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Mappings in OWL and SWRL
• Use rules (Semantic Web Rule Language) to define complex mappings
• Semantic and syntactic conversions
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ma:frameSize_1
ebu:formatWidth_1
ebu:ResourceManifestation_1
Unit“pixels
”
Value352
RULE
ma:width
352
ma:height
288
ma:MediaResource_1
ebu:formatHeight_1
Unit“pixels
”
Value352
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Mappings in OWL and SWRL
• Benefits– rules allow to do conversions of values e.g.,
summing integers, concatenating strings• Drawbacks
– might be complex to express all mappings
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ELIS – Multimedia Lab
Format Independent Ontology
• Use a generic upper ontology describing metadata• Map format-specific ontologies to the upper ontology
– mappings between the format-specific ontologies can be automatically inferred
• Consider the MA ontology as format-specific ontology• Generic metadata ontology (MEON):
– allows to describe metadata• Concept, AtomicConcept, CompoundConcept
– allows to describe relations between metadata elements• defines, contains
– includes a set of generic concepts for media resources• mainTitle, resolution, lines, columns, …
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ELIS – Multimedia Lab
MeonOntology
Format Independent Ontology
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
containscc1
resolutionlines columns
AtomicConcept
CompoundConcept
Concept
instanceOfinstanceOf
defines
definesdefines defines
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Format Independent Ontology
• MEON is central point to map metadata formats on each other
• Format-specific ontologies– metadata formats described using MEON
• Concept, AtomicConcept, CompoundConcept, defines, contains
– mapped to generic media concepts of MEON through relation (modeled as a Class)
• qualifies the relation (e.g., exact, more specific)• describes the mapping (e.g., hold functions for datatype
conversion)
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
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EBUCORE Ontology
MeonOntology
Format Independent Ontology
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
cc1
MA Ontology
ma:frameSize
ebu:formatHeight1
ebu:formatWidth1
resolution lines columns
relation relationrelation
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Format Dependent Metadata Ontology
• Ontology describes and relates elements of the metadata formats and the MA ontology– MA properties
• described by MAWGMetadataProperty Class
– metadata formats properties• described by StandardMetadataProperty Class
– mappings• described by MetadataPropertyRelation Class
– holds transformation rule– describes type of mapping– identifies compound relations
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
ELIS – Multimedia Lab
Format Dependent Metadata Ontology
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
MAWGMetadataProperty_01
MAWGMetadataProperty
StandardMetadataProperty
MetadataPropertyRelation
propertyName
“ma:title”
StandardMetadataProperty_01
propertyName
“dc:title”
metadataName“http: // purl . org /dc/ elements
/1.1/”
MetadataPropertyRelation_01
relationSemantic
“exact”
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Conclusions
• No clear winner– suggestions are welcome!
• Media ontology (including mappings) and API are work in progress– feedback is welcome!
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria
SKOS OWL + SWRL
MEON Ontology
Format dependent Ontology
Complexity + + - +
Scalability - - + -
Reasoning - + + -
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Questions?
How to Align Media Metadata Schemas? Chris Poppe
December 2nd 2009, SeMuDate09, Graz, Austria