What we can do with OWL• Logical consistency is not the main problem – e.g. owl:sameAs can be wrongly used and still we can have consistency• Why knowing OWL is not enough?
Ontology Language vs. ontology design• Having knowledge of language constructs does not mean being able to use it in a way that best fit your purposes i.e., requirements• OWL gives you logical language constructs, but does not give you explicit guidelines on how to use them in order to solve your tasks• Lessons from other engineering disciplines – Software design patterns – Data model patterns – Architectural patterns
Solutions?• Reusable solutions, called Ontology Design Patterns, help reducing arbitrariness of design• Experiments shows that using ODPs – Reduces mistakes in ontologies – Improves learning design practices – Help detecting uncovered requirements – Improves quality of produced ontologies
Ontology Design PatternsAn ontology designpattern is a reusablesuccessful solutionto a recurrentmodeling problem
Ontology design patterns• Small ontologies or • Components supported by ontology templates with specific functionalities explicit documentation of – selection, matching, design rationales composition, etc. • Implemented in repositories, registries, catalogues, open discussion and evaluation forums, and in new- generation ontology design tools – ontologydesignpattern.org – ODP and Watson APIs – NeOn XD Tools Plugin – etc. 8
N-ary relation• Chad Smith was the drum player of Red Hot Chili Peppers when they recorded their album Stadium Arcadium from September 2004 to December 2005.• A person plays a certain role in a band during an album recording, taking place during a certain time interval• PlaySituation(Person, MusicianRole, Band, Album, TimeInterval)
Transitive Reduction• I want to represent that a computer is composed of several parts – part of – transitive property• I also want to represent that each part can have “direct” components – e.g. the CPU is a direct component of a motherboard• A CPU is a direct component of a motherboard, hence it is part of a computer, but it is not its “direct” component
Parthood examples• The CPU is part of the motherboard• The motherboard is part of the computer partOf partOf
Parthood examples• The CPU is direct part of the motherboard• The motherboard is part of the computer partOf directPartOf
Parthood examples• The CPU is part of the motherboard• The motherboard is part of the computer partOf directPartOf partOf partOf
Parthood examples• The CPU is direct part of the motherboard• The motherboard is part of the computer partOf directPartOf partOf directPartOf partOf
PartOf and directPartOf• directPartOf does not inherit transitivity• directPartOf implies part of
Transitive reductionaProperty rdf:type owl:TransitivePropertyanotherProperty rdfs:subPropertyOf aPropertyanotherProperty does not inherit transitivity, but:entity1 anotherProperty entity2impliesentity1 aProperty entity2
Additional material and references• ODP portal training area – http://ontologydesignpatterns.org/wiki/Training:Main• Aldo Gangemi: Ontology Design Patterns for Semantic Web Content. International Semantic Web Conference 2005: 262-276• Valentina Presutti, Aldo Gangemi: Content Ontology Design Patterns as Practical Building Blocks for Web Ontologies. ER 2008: 128-141• Natasha Noy and Alan Rector. Defining N-ary Relations on the Semantic Web. W3C Working Group Note 12 April 2006. http://www.w3.org/TR/swbp-n-aryRelations/• Eva Blomqvist, Valentina Presutti, Enrico Daga, Aldo Gangemi: Experimenting with eXtreme Design. EKAW 2010: 120-134
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