Beyond Linked Data - Reasoning and the Semantic Web

1. Publishing and Using
Linked Open Data
Richard J. Urban, Ph.D.
School of Library and Information Studies
Florida State University
rurban@fsu.edu
@musebrarian
#lod4h

2. January 11, 2013
Friday’s Schedule
• 9:00-10:45 am Class Session Beyond Linked Data: Reasoning and the
Semantic Web
• 10:45 am- 11:00 break
• 11:00-11:45 Class Session: Open Project Studio
• Noon- 1:45 pm Lunch (on your own)
• 1:45-2:30 pm Class Wrap-Up: Linked Open Data for the Humanities:
Next Steps?
• 2:30-2:45 pm Break
• 2:45-3:45 pm Show and Tell
• 3:45-4:00 pm Closing Ceremony and Announcements
#lod4h

3. “An ontology is an explicit specification of a
conceptualization.” (Gruber)
DERI Using Ontologies http://www.deri.org/fileadmin/documents/DERI-TR-2003-10-29.pdf
#lod4h

4. OWL Versions
• OWL Full
– Allows most kinds of assertions, but not
computationally complete.
• OWL Description Logics (OWL DL)
– As expressive as possible why maintaining
computational completion/decidability.
– Based in Description Logics
• OWL Lite
– owl:disjointWith, unionOf, and others not allowed.
– Cardinality limited
– Equivalence limited to class identifiers
– Not much easier than OWL DL
#lod4h

5. Class axioms
A B A B
unionOf intersection
B
A
complement
#lod4h

6. Class axioms
A A
B
B
subclassOf equivalence
A B
disjoint
#lod4h

7. Property Types
• Functional
– A person can have only one spouse.
• Inverse
– hasChild is inverse of hasParent
• Inverse-Functional
– Links domains and ranges.
The object of a biologicalMotherOf is a women.
• Transitivity
– Chianti, Tuscany and Italy are regions, and Chianti is a
subregion of Tuscany, and Tuscany is a subregion of
Italy, then Chianti is also a subregion of Italy.
• Symmetric
– If Jack is married to Jill, then Jill is married to Jack
#lod4h

8. Identity
• owl:sameAs
Two resources are equivalent resources
• owl:differentThan
two resources are different resources
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9. OWL Reasoners
• Racer
• FaCT
• HermiT
• Some reasoning examples
#lod4h

10. Beyond OWL
• Semantic Web Rule Language (SWRL)
http://www.w3.org/Submission/SWRL/
• Based on Horn logic instead of Description
Logic
#lod4h

11. So what?
• Collection/Item Metadata Relationships
research.
http://goo.gl/FQldG
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