Transcript Interaction Design Chapter 6

Ontology development in
Protégé
Overview
• Components of an ontology
• The ontology development process
 Six basic steps
• Protégé
 Classes
 Properties
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A development method
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Determine domain and scope
Consider re-using
Enumerate important terms
Define classes and class hierarchy
Define properties of classes
Define characteristics of properties
Create individuals
http://www-ksl.stanford.edu/people/dlm/papers/ontology-tutorial-noy-mcguinness.pdf
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Determine domain and scope
• Basic questions
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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?
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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
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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
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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
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Is your uncle your ancestor?
Are Queen Elizabeth II and Phillip related?
Who is their common ancestor?
How many children did George V have?
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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
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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-noymcguinness.pdf
• Sample ontologies
 http://www.co-ode.org/ontologies/
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