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Using Ontologies UsingUML or OWL
Rinke Hoekstra
28-04-2004 OWL and UML2
UML (1)
Integration of competing OO standards Language for communicating and
documenting software designs– Notation is graphical, not formal– OCL needed for formal constraints– UML aims at maximal expressivity (union vs.
intersection)– Different ‘model types’, for different aspects of a
system (12)
28-04-2004 OWL and UML3
UML (2)
Difficult to define a uniform semantics– Meta-model approach– Stereotypes
Class-diagrams used for Ontology specification
28-04-2004 OWL and UML4
OWL (1)
Standard language for the representation of Ontologies on the SW
Language to be handled by systems– Well-founded logical semantics– Set of logical constraints ‘embedded’– Principle of minimality (to the benefit of logical
reasoning)
Semantics founded on DL (SHIQ)
28-04-2004 OWL and UML5
Syntax
UML– XML serialization of UML diagrams in XMI– XMI non-standard– No other XML standards embedded (tools)
OWL– OWL syntax is RDF(S) is XML– Abstract syntax– Uses other XML standards (ID’s, xml:lang, XSD)– Allows: tight integration with other XML standards
28-04-2004 OWL and UML6
Generalizations/Subclasses
UML– ‘substitution’-relation– not (necessarily) transitive– stereotypes
OWL– subclass relation is ‘subset’-relation– Transitive– Meta-classes (Full)
Consequence: no taxonomies in UML (?!)
28-04-2004 OWL and UML7
Associations/Properties
UML– Not ‘first class’, i.e. dependent on class– n-ary associations possible– Every association different (names)
OWL– ‘first class’, i.e. independent of class– DL: Only binary associations (Full: reification)– Subproperties
28-04-2004 OWL and UML8
Packages/Namespaces
UML Packages– No standard– Internal to Case tool / Repository– Distributed identity– Package references– Semi-modular
OWL Namespaces– URI/URN standard– Global identity– Central identity– OWL imports or direct reference (via URI) – Modular
28-04-2004 OWL and UML9
Reasoning (1)
UML– Basic syntax checking– OCL
Competing formalizations Reasoning non-standard
– Compilation/translation necessary for reasoning OWL
– Consistency checking– Deriving new knowledge (Classification)
28-04-2004 OWL and UML10
Reasoning (1)
A primary task of OWL is classification Classification brings definitional bias UML has a functional bias Is that bad? Yes...
28-04-2004 OWL and UML11
Rules (1)
UML has OCL – OCL expresses rules (invariants) and constraints
OWL has itself, plus...– Restrictions on properties (local vs. at class)– Restrictions on classes– In the making: SWRL (RuleML) etc.
Sidenote: things expressed as rules are not always rules! Sidenote: new W3C charters in the making: Rules and Queries
28-04-2004 OWL and UML12
Rules (2)
UML– Rule is a production rule, or material implication
OWL– “Rule” is a conjunction
Norms are conjunctions + deontic operator Conflicts
– Norms: logical conflict– Rules: multiple rules ‘fit’, but only one may fire
28-04-2004 OWL and UML13
Tools (1)
UML– Many, closed-source tools (RR, Mega, Poseidon)– Hardly any open source tools– Non standard– Visual, no taxonomic view
OWL– Some open source tools (Protégé, OILEd)– Some closed source tools (OntoEdit)– Standard– Taxonomic view, optional visualization.
28-04-2004 OWL and UML14
Tools (2)
OWL– Standard DL classifiers– Future: DIG interface for Jena
http://www.sts.tu-harburg.de/~r.f.moeller/racer/interface1.1.pdf
28-04-2004 OWL and UML15
Tools (3)
OCL Constraints– In annotation-field (No check)
OWL Restrictions– In text-editor (No check) or,– In specifically tailored editor (check)
28-04-2004 OWL and UML16
Protégé
Open Source (Java) Extensible (plug-ins) Well-documented Large user community International OWL Plugin with constraint-editor Classifier, consistency checker
28-04-2004 OWL and UML17
Protégé Interface
If (Student OR Employee)ANDNOT (Student AND Employee)ANDPersonal-Role
Then PhDStudent
28-04-2004 OWL and UML18
Protégé OWLViz
28-04-2004 OWL and UML19
Protégé for UML Addicts
ezOWL– UML Class-diagram like editing environment– Full expressivity of OWL
XMI export/import– Not up-to-date with latest version & OWL
28-04-2004 OWL and UML20
(Un)Lucky for us
Translation possibilities of UML Class diagrams (Falkovych et al., Schreiber, DUET)
UML profile for OWL possible OCL has no formal semantics translation
always biased. UML2 supposed to bring some relief OWL has a problem with value ranges
28-04-2004 OWL and UML21
Sources
http://www.w3.org/TR/NOTE-rdf-uml/ http://www.swi.psy.uva.nl/usr/Schreiber/docs/owl-uml/owl-uml.html http://www.cs.vu.nl/~heiner/public/KTSW.pdf http://codip.grci.com/wwwlibrary/wwwlibrary/DUET_Docs/DAML-UML_
CoreMapping_V5.htm