Ontology Design Pattern Property Specialisation

StrategiesKarl Hammar

Jönköping University / Linköping University

ODP Specialisation

• Typically a Content ODP contains/is packaged as a small reusable OWL ontology.

• Using that general/abstract ODP in a specific use case requires specialisation.

• Often done via import and mapping of original OWL ontology.

Research Question

• How are Content Ontology Design Patterns (ODPs) used or specialised in Ontology Engineering projects for the Semantic web, and what are the effects of such usage?

• Motivation: to develop better understanding of ODP usage, supporting development of improved (guided?) tooling for such use.

Method Overview

1. Gather OWL ontologies that reference known ODP namespaces.

2. Extract mapping axioms (e.g. subsumption or equivalency mappings b/w ontology and ODP).

3. Find recurring patterns in mapping axiom structure.

Understanding ODP Specialisation

• 347 non-trivial ontologies gathered through Google Search, LODStats, LOV, OntologyDesignPatterns.org, IKS project

• 41 ODP-using ontologies found, with 107 mapping axioms.

• 85 % of mapping axioms are one-way subsumption of classes or properties. ODP classes/properties are nearly always superclasses/superproperties.

• 20 ODP specialisation modules that specialise object properties.

• Three distinct ways of specialising properties were noted.

Property-Oriented Strategy• Most common way of modeling

property specialisation.

• New subproperties are created.

• Domains and ranges of sub properties narrower than domains and ranges of superproperties.

• Can be partially instantiated (e.g., domain or range are linked to more general term)

ce:Collection owl:Thingce:hasMember

rdfs:domain rdfs:range

cc:Content Collection

cc:Content Item

rdfs:rangerdfs:domain

cc:hasContentMember

rdfs:subClassOf rdfs:subClassOfrdfs:subPropertyOf

ir:InformationRealization

ir:InformationObjectir:realizes

rdfs:domain rdfs:range

wf:Weather Forecast

wf:Weather Information

rdfs:subClassOfrdfs:subClassOf

ir:realizes some wf:Weather Information

owl:equivalentClass

ir:realizes only wf:Weather Information

rdfs:subClassOf

Class-Oriented Strategy• Reuses original property;

constrains the use of that property by class restriction axioms.

• Restricts which (specialised) classes that may be related via a given property, i.e. locally emulates domain/range.

• Not logically equivalent to property-oriented strategy - but can be used to solve similar modeling problem.

Hybrid Strategy

• Does both: new subproperties are defined with domains and ranges and property restrictions on participating classes are also put in place (possibly redundantly).

Specialisation Strategies

Specialisation strategy Occurrences

Property-oriented 9

Class-oriented 6

Hybrid 5

RQs Evolved

• To what degree are the class-oriented, property-oriented, or hybrid property specialisation strategies used in published ontologies?

• What are the reasoning performance effects of specialising in accordance with the class-oriented or property-oriented strategies?

Strategy Use

Specialisation strategy Occurrences Distribution ODP specialisation

distribution

Property-oriented 193 78 % 45 %

Class-oriented 33 13 % 30 %

Hybrid 23 9 % 25 %

Strategy Effects

• Property-Oriented strategy treats properties as first-order citizens that can be annotated and typed.

• Property-Oriented strategy possibly more intuitive for non-expert users?

• Class-Oriented strategy makes resulting ontologies and datasets interoperable to greater degree.

• Class-Oriented strategy causes computationally unfavorable conditions and places ontology outside OWL2 EL.

Strategy Effects

Reasoning task Benchmark Reasoner PO time CO time

Consistency checking BSBM Pellet 1.274 s 1.897 s

Consistency checking BSBM HermIT 1.984 s 27.193 s

Consistency checking LUBM Pellet 8.230 s 42.887 s

Consistency checking LUBM HermIT 10.097 s 46 min

Realising individuals BSBM Pellet 2.389 s 9.482 s

Realising individuals LUBM Pellet 1.801 s 4+ hours

Conclusion• Three strategies for property specialisation are

found both amongst ODPs and ontologies in general.

• Pure Property-Oriented strategy less common among ODP-using ontologies than among ontologies in general.

• There may be tradeoffs between performance and interoperability that ODP users and tooling need be aware of.

INTERESTED IN ONTOLOGY ENGINEERING?

Participate in our survey, contribute to science, and win Amazon gift cards!

http://goo.gl/P1w9gG

$$

Marketing