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Publishing and Using Linked Open Data

Richard J. Urban, Ph.D.

School of Library and Information StudiesFlorida State Universityrurban@fsu.edu@musebrarian

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January 11, 2013Friday’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

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“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

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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

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Class axioms

A B

unionOf intersection

A

complement

A B

B

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Class axioms

BA

BA

subclassOf equivalence

BA

disjoint

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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

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Identity

• owl:sameAsTwo resources are equivalent resources

• owl:differentThantwo resources are different resources

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OWL Reasoners

• Racer• FaCT • HermiT

• Some reasoning examples

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Beyond OWL

• Semantic Web Rule Language (SWRL)http://www.w3.org/Submission/SWRL/

• Based on Horn logic instead of Description Logic

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So what?

• Collection/Item Metadata Relationships research.http://goo.gl/FQldG