The Semantic Web contains a number of dierent knowledge artifacts, including OWL ontologies, RIF rule sets and RDF datasets. Efective exchange and management of these artifacts demand the use of metadata and prompt availability of accurate reference documentation. In this paper, we analyze the current practices in metadata usage for OWL ontologies, and we propose a vocabulary for annotating RIF rules. We also introduce a software tool {Parrot{ that exploits these annotations and produces reference documentation for combinations of ontologies and rules. http://www.springerlink.com/content/t3777727338n4233/

1. Metadata for web
ontologies and rules:
current practices and
perspectives
Carlos Tejo-Alonso, Diego
Berrueta, Luis Polo and Sergio
Fernández

2. Context
<rdf:Description rdf:about="#Bicycle ">
<rdf:type rdf:resource="&owl;Class"/> logic
<rdfs:subClassOf rdf:resource="#Vehicle"/>
<rdfs:label xml:lang="en">bicycle</rdfs:label>
<dct:description xml:lang="en">
Vehicle consisting of two wheels held in a
frame one behind other, propelled by pedals
</dct:description> annotation
<dc:creator>Iván Mínguez</dc:creator>
</rdf:Description>

3. Motivation to annotate
• Facilitate search
• Improve exchange and reuse
• Link them to the natural language
• Generate reference documentation

4. Overview
• Current ontology & rule metadata usage
• Proposed vocabulary to annotate rules
• Parrot, a documentation tool for
ontologies and rules
• Conclusions/Future Work

5. Metadata vocabularies
• General purpose: DC, SKOS or RDFS
– dc:creator, skos:prefLabel, rdfs:comment
• For ontologies: OWL
– owl:versionInfo
• For rules: no specific vocabulary
(with significant adoption)

6. Ontology metadata study

7. Ontology metadata study
• Massive use of RDF Schema(label & comment)
• Property synonymy
dc:description rdfs:comment
dct:description skos:definition
• Absence of:
– multimedia
– legal rights and license information
– expressive multilingual metadata

8. Rule metadata: a proposal
Metadata Recommended properties
Labeling dc:title, dct:title, rdfs:label,
skos:prefLabel, skos:altLabel
Authoring foaf:maker, dc:creator, dc:contributor,
dc:publisher, dct:creator, dct:contributor,
dct:publisher
Description dc:description, dct:description, rdfs:comment,
skos:definition, skos:example, skos:note
Multimedia foaf:depiction, og:video
Versioning owl:versionInfo, dct:hasVersion,
skos:changeNote
Rights dc:rights, dct:license
Date dc:date, dct:issued, dct:modified
Documentation dct:source, rdfs:seeAlso, rdfs:isDefinedBy

9. Annotated rule (example)
(* ex:rule ex:rule [
rdfs:label -> “Example Rule”@en
dc:creator -> “Luis Polo” annotatio
dc:date -> “1981-01-20”
og:video ->
n
<http://youtu.be/5h10QHpA5EU>
dct:publisher -> http://ontorule-project.eu
] *)
Forall ?person ?age (
If And( ?person #foaf :Person logic
?person [foaf:age -> ?age]
External(pred:numeric-less-than(?age 18))
)
Then Do( Assert(?person#ex:Under18Person) )

10. Parrot overview
OWL
Report
RIF
• Multimedia-rich, customizable reports for humans
• Supports multiple metadata
• Combination of rules and ontologies
• Supports multilingual annotations

11. Parrot usage
Web service
Eclipse plugin
Command Line Interface

12. Parrot DEMO
http://ontorule-project.eu/parrot

13. Conclusions
• Ontology metadata exists in the wild, but
there is still room for improvement
• Metadata facilitate rule exchange between
Business Rules Management System
• We expect to impact on the quality and
quantity of the metadata annotations in rules
and ontologies

14. Future work
• To expand the analysis to large ontologies
• To account the use of metadata in RIF
documents as they become available
• To extend proposal of rule metadata
properties as new requirements arise

15. Thanks for your attention
contact: carlos.tejo@fundacionctic.org
http://www.flickr.com/photos/ockam/2591316903/

16. About this presentation
Fifth Metadata and
Semantics Research
Conference (MTSR 2011)
12-14 October 2011
Yaşar University, Izmir – TURKEY
http://mtsr2011.yasar.edu.tr

17. Acknowledgements
This work has been partially supported by the
European Commission under ONTORULE project