OWL and SDD

1
OWL and SDD

• Dave Thau
• University of Kansas
• thau_at_learningsite.com

2
OWL in Context

• W3C Standard Web Ontology Language
• OWL builds on RDF and RDFS
• Much like DAMLOIL (2001)
• Which grew out of Description Logic
• Description logics are variants of predicate
  logic

3
Example Ontology
Person
hasChild (1, NIL)
Female
Parent
Ontologies have Concepts Instances Properties

Woman
Mother

• Mother(VERA)
• hasChild(VERA, DAVE)
• Is Mother a subclass of Person?
• Is Dave an instance of Person?

4
Some SDD and OWL Similarities
5
Other Similarities

• Metadata, including versioning information
• Supports multiple languages
• You can import ontologies into each other
• Properties are not imbedded in concepts

6
OWL The Assembly Language of Knowledge
Representation

• Relationships between classes
• equivalentClass
• subClassOf
• Intersection, union, complement, disjunction
• Relationships between instances
• sameAs, differentFrom
• Properties of properties
• Domain, Range
• Cardinality
• Transitive, Symmetric
• allValuesFrom, someValuesFrom
• Functional, InverseFunctional
• Relationships between properties
• subPropertyOf
• inverseOf

7
Simple Example
lt?xml version"1.0"?gt lt!DOCTYPE rdfRDF
lt!ENTITY food "http//www.w3.org/TR/2003/CR-owl-gu
ide-20030818/winegt gt ltrdfRDF
xmlns"http//www.ku.edu/kansas_wines"
xmlnsrdf"http//www.w3.org/1999/02/22-rdf-syntax
-ns" xmlnsrdfs"http//www.w3.org/2000/01/rd
f-schema" xmlnsowlhttp//www.w3.org/2002/07
/owl xmlnswinewinegt ltowlOntology
rdfabout""gt ltowlversionInfo
xmllang"en"gtv 1.17 2003/02/26 125651 thau
lt/owlversionInfogt ltrdfscommentgtThis is
about wines available in kansaslt/rdfscommentgt
ltowlimports rdfresource http//www.w3.org/TR/
2003/CR-owl-guide-20030818/wine
/gt lt/owlOntologygt ltowlClass rdfIDKansasWine"
gt ltrdfssubClassOf rdfresource"wineWine"/
gt ltrdfslabel xmllang"en"gtkansas
winelt/rdfslabelgt ltrdfslabel
xmllang"fr"gtvin du kansaslt/rdfslabelgt
lt/rdfssubClassOfgt lt/owlClassgt lt/rdfRDFgt
8
SDD and OWL

• What does OWL get you?
• Access to inference engines
• Access to ontology tools
• Defined vocabulary
• What are the risks?
• Creating DL compliant ontologies non-trivial
• Inference engines may not scale
• How do you tie SDD XML entities to OWL classes?

9
OWL DL vs OWL Full

• OWL Full is very expressive but reasoning can
  be intractable
• Reasoning in OWL DL is tractable, but it has many
  restrictions
• Biggest restriction something cant be both an
  instance AND a class
• Implication 1 Relations between classes are
  restricted to the small set of OWL relations
• Implication 2 You REALLY need to know what your
  instances are and what your classes are.

10
partOf

• In the glossary of SDD there is one partOf
  element. What does it mean?
• X is a component of Y (a leaf of a plant)
• X is a member of Y (one zebra in a herd)
• X is a quantity of Y (a sample of sap)
• Does the wholes existence depend on the part?
• Does the parts existence depend on the whole?
• Does the part inherit properties of the whole?

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The traditional partOf types

• hasDComponent
• hasDMember
• hasDSegment
• hasDQuantity
• hasDStuff
• hasDIngredient

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A tree hasComponent trunk

• Define a property called hasDComponent the D
  means direct
• IsDComponentOf (inverse hasDComponent)
• hasComponent (hasDComponent)
• trunkOf isa isDComponentOf
• hasTrunk (inverse trunkOf)
• Tree isa Plant
• Trunk isa (the trunkOf Tree) and (the
  hasCondition Condition)
• BrokenTrunk isa Trunk and hasCondition hasValue
  BROKEN
• BrokenTree isa Tree and the hasTrunk BrokenTrunk
• Condition(BROKEN)
• Condition(WHOLE)
• Trunk(THIS_TRUNK).hasCondition(BROKEN)
• Tree(MY_TREE).hasTrunk(THIS_TRUNK)

13
Transforming SDD -gt OWL?

• DL is possible as long as
• Definitions are complete enough (what do you mean
  by partOf? Synonym?)
• Entities involved in hierarchical relationships
  dont have other relationships
• Full is possible more easily

14
Conclusions

• SDD could use ideas from OWL
• Separate class hierarchy and property hierarchy
• Multiple types of partOf
• It would be interesting to translate part of an
  SDD document into OWL for reasoning
• What class is this thing?
• What happens to my ability to classify something
  if two species are combined?