Presentation to the Metadata Developer Network Workshop 2014 (MDN Workshop 2014), 4th of June 2014, Geneva, Switzerland. Also available on http://www.slideshare.net/dri_ireland Abstract: In this presentation, we report on our experience using the EBU Core OWL ontology for annotating audiovisual archival content stored in an EBU Core XML Schema compliant tool used by RTÉ, the national public service broadcaster of the Republic of Ireland. We first describe the goal of the project and elaborate on the role of Semantic Web ontologies and technologies. We continue with a report on some of the challenges while using the EBU Core OWL ontology. We finally formulate several recommendations on the conceptual model and the ontology development method.

1. RTÉ Content Discovery Project
Christophe Debruyne
c.debruyne@ria.ie
christophe.debruyne@insight-centre.orgchristophe.debruyne@insight-centre.org
MDN Workshop -- 4th of June 2014

2. Outline
• Context
• Goal and Challenges of the RTÉ Content Discovery Project
• Tasks and Data Annotation• Tasks and Data Annotation
• EBU Core – Identification of problems
• Addressing the issues
• Using the ontology
• Conclusions and Recommendations

3. Context
RTÉ, Ireland's National
Television and Radio
Broadcaster
National trusted digital
repository for Ireland's
social and cultural data.
Centre for Data Analytics
Documents
Television
Radio
Stills
Linking and preserving data
held by Irish Institutions with
central internet access point.
• Standards
• Cataloguing
• Archiving
• Preservation
• Insight @ NUIG = DERI
• Semantic Technologies
• Linked Data
• Data Analytics Platform

4. Goal of the RTÉ Content
Discovery Project
• Discover implicit knowledge
• across the different archives
• and the Web of Data
• To facilitate internal workflows (e.g., search)
• For wider reuse and repackaging RTÉ’s
Documents
Television
Radio
Stills
• For wider reuse and repackaging RTÉ’s
information
• Challenges
• Heterogeneous databases
• Different guidelines and practices
• Legacy data (from previous systems)
• … “Linking Open Data cloud diagram,
by R. Cyganiak and A. Jentzsch.
http://lod-cloud.net/”

5. Part of a wider ambition …

6. OUTCOMES FOR RTÉ

7. RTÉ Content Discovery
In this presentation we focus on Television and Radio archives
Documents Television Radio Stills
• In this presentation we focus on Television and Radio archives
• The Television and Radio archives
• Are maintained on two different instances of the same system
• A system that is EBU Core “compatible”
• Different content, different guidelines, …

8. Three main tasks
• Annotate the data.
• Using relevant standards, ontologies and vocabularies.
• Resource Description Framework (RDF).
• Obtain an integrated view of the different archives by
creating links between the RDF representations of RTÉ’s
archival assets across the different archives.
• Apply advanced methods for discovering related data for a
given subject in external sources such as the Linked Data
Cloud.

9. Data annotation
Relational
Database
D2RQ RDF Dump Triplestore
Television
Radio
Map symbols of
database to
predicates
(relations and
concepts) in
chosen ontologies
/ vocabularies
Use D2RQ to
generate RDF
dump
Store RDF dump in
adequate triple
store (Jena TDB)
Which ontologies?
• Dublin Core, DC Terms
• Foaf
• EBU Core OWL
• …

10. EBU Core OWL
• The RTÉ Content Discovery platform will rely on Semantic
Web technologies to reason. Ontologies will therefore need
to be correct.
• But … while adopting the EBU Core OWL ontology, several
problems where identified.
• We contacted EBU to resolve these issues.
• We provide an overview of some of these problems.

11. Problems
• (1) Forgotten concept unions
• The property ebucore:description has multiple domain axioms.
<rdfs:domain rdf:resource="&ebu;BusinessObject"/>
<rdfs:domain rdf:resource="&ebu;MediaResource"/>
• Unintentionally the wrong implicit information can be inferred.• Unintentionally the wrong implicit information can be inferred.
• (2a) Property unsatisfiability – via class axioms
<owl:Class rdf:about="&ebu;BusinessObject">
… <owl:disjointWith rdf:resource="&ebu;Resource"/> …
</owl:Class>
• Because of (1) and (2), the property description could not be
used

12. Problems
• (2b) Property unsatisfiability – role hierarchies and datatypes
• Duration has the range xsd:string
• The subproperties of duration have other ranges (e.g., double in
the case of duration in edit units)
• Because each subproperty also inherits the range of the• Because each subproperty also inherits the range of the
superproperty, all instances in the object of that property must
be at the same time a string, and a double. This type conflict
results in a contradiction.
• With (2a) and (2b) we identified 40 properties that lead to
problems.

13. Problems
• (3) Inconsistencies between formal and informal definitions
• BusinessObject is defined as: "An image, a document, an annotation
[…], a tag […], or an audiovisual media resource […]. Other types of
BusinessObjects may be defined as subclasses.“BusinessObjects may be defined as subclasses.“
• Resource is defined as: "A manifestation of a BusinessObject." and
disjoint with BusinessObjects. Meaning no individual can be an
element of BusinessObjects and Resources at the same time.
• The domain of a title is BusinessObject, yet, it’s definition is:
"Specifies the title or name given to the resource. […]"

14. Problems
• (4) User readable labels
• Many different properties have the same human readable label,
which could confuse the end user – e.g., when generating an
Interface.
• E.g., there were 11 properties with the label “Name”• E.g., there were 11 properties with the label “Name”
• Some properties had empty labels
• (5) Roles – Loss of context
• Agents were related to Business Objects (BO)
• Agents were related to a Role
• But … a role did not relate to agents in relationship with a BO
• This lead to a loss of context.

15. Addressing the issues
• Problems were addressed over email.
• The discussions are “lost”, traces are only known to us …
• The ontology-engineering activities of EBU Core should adopt
appropriate methods and tools for collaboration.
• Participation of others
• Traceability (!)
• The ontology is still being developed as we go along, and we
have been able to make (parts of it) work…

16. Using the ontology

18. Conclusions and Recommendations
• RTÉ Archives aims at a wider reuse and repackaging of their
archival content on digital platforms through the innovative
use of Semantic and Linked Data technologies.
• We adopted the EBU Core OWL ontology for annotating the
television and radio archives, yet identified some issues.
• We adopted the EBU Core OWL ontology for annotating the
television and radio archives, yet identified some issues.
• We collaborated on resolving those issues together with EBU
• However, we feel that appropriate collaborative methods and
tools should be adopted to facilitate the ontology-
engineering process and – more importantly – enable other
to participate AND have visible traceability of the decisions.

19. References
• D2RQ, http://d2rq.org/
• Digital Repository of Ireland, http://www.dri.ie/
• Insight, http://www.insight-centre.org/• Insight, http://www.insight-centre.org/
• Jena TDB, http://jena.apache.org/documentation/tdb/
• RTÉ Archives, http://www.rte.ie/archives