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)

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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