Ontology development in Protégé

Lecture 2 Introduction to Protégé 2 Pablo Romero, Department of Informatics

Overview

• Components of an ontology

• The ontology development process Six basic steps

• Protégé Classes Properties

Lecture 2 Introduction to Protégé 3 Pablo Romero, Department of Informatics

A development method

• Determine domain and scope

• Consider re-using

• Enumerate important terms

• Define classes and class hierarchy

• Define properties of classes

• Define characteristics of properties

• Create individualshttp://www-ksl.stanford.edu/people/dlm/papers/ontology-tutorial-noy-mcguinness.pdf

Lecture 2 Introduction to Protégé 4 Pablo Romero, Department of Informatics

Determine domain and scope

• Basic questions What is the domain the ontology will cover? What are we going to use the ontology for? For what types of questions should it provide answer? Who will use and maintain it?

• Competency questions Which wine characteristics should I consider when choosing

a wine? Is Bordeaux a red or white wine? What is the best choice of wine for grilled meat? What were good vintages for Napa Zinfandel?

Lecture 2 Introduction to Protégé 5 Pablo Romero, Department of Informatics

Enumerate and hierarchy

• Enumerate Important terms (wine, grape, winery, location, colour, body, flavour,

fish, red meat, etc.) Don’t worry about

• Overlap between terms• Relationships• Properties

• Define class hierarchy Look for “independent terms” Top-down (wine; red, white, rosé) Bottom-up (Muscadet Sèvre et Maine, Muscadet Coteaux de la Loire,

Muscadet Côtes de Grandlieu; Muscadet) Combined

Lecture 2 Introduction to Protégé 6 Pablo Romero, Department of Informatics

Properties & their characteristics

• Several types of properties Relationships to other classes (maker of the wine, grape it comes from) Parts (Courses of a meal) Simple properties (name, colour, flavour)

• Properties are inherited by subclasses• Characteristics

Type (for simple properties) Domains and ranges (winery produces a wine) Restrictions

• Universal and existential• Cardinality (how many of them)

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Protégé

• Free, open source ontology editor• Allows generation, visualization, and manipulation of

ontologies• We’ll be working with Protégé-OWL• Created ontologies can be accessed from Java

programs through the Protégé-OWL API• Represents

Classes Properties Individuals

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Classes in Protégé

• All classes are subclasses of Thing

• Classes overlap by default!

• Can use tools menu to create class hierarchies

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Properties in Protégé

• Object or data type

• Properties can have Subproperties Inverse properties

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Properties in Protégé

• Properties can be Functional Transitive Symmetric Asymmetric Reflexive Irreflexive

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Domains and ranges

• Axioms not constraints Can lead to inconsistencies

• Inverse properties are updated automatically

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A family tree ontology

• Basic questions What is the domain the ontology will cover? Family relations What are we going to use the ontology for? Store family trees For what types of questions should it provide answer? Queries about

family members Who will use and maintain it? NA

• Competency questions Is your uncle your ancestor? Are Queen Elizabeth II and Phillip related? Who is their common ancestor? How many children did George V have?

Lecture 2 Introduction to Protégé 13 Pablo Romero, Department of Informatics

The family ontology

• Develop Enumerate important terms Define classes and class hierarchy Define properties of classes

• Implement in Protégé Create class hierarchy (disjoint classes?) Create property hierarchy (characteristics, disjoint) Establish domains and ranges

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Key points

• Ontology elements Classes Properties Individuals

• Development steps Determine domain and scope Consider re-using Enumerate important terms Define classes and class hierarchy Define properties of classes and their characteristics Create individuals

• Protégé allows the implementation of ontologies in an interactive way

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Resources

• Protégé website: http://protege.stanford.edu/

• Protégé tutorial http://www.co-ode.org/resources/tutorials/ProtegeOWLTutorial-p4.0.pdf

• Ontology development methodology http://www-ksl.stanford.edu/people/dlm/papers/ontology-tutorial-noy-

mcguinness.pdf

• Sample ontologies http://www.co-ode.org/ontologies/