Transcript Ontology - UNC School of Information and Library Science

What is an Ontology?
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No exact definition
A tool to help organize knowledge
Or a way to convey a theory on how to
represent a class of things
Examples of definitions
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Philosophy
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Dates back to 5th Century B.C. when
Empedocles divided the world into four
elements – earth, fire, water and air.
– Aristotle, classification
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Often confused with the word
epistomology, which is about knowledge
and knowing
Defined by philosophers as the nature
of being or existence.
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Webster’s Dictionary
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Webster’s Third New International
Dictionary defines Ontology:
1. A science or study of being specifically, a
branch of metaphysics relating to the
nature and relations of being.
2. A theory concerning the kinds of entities
and specifically the kinds of abstract
entities that are to be admitted to a
language system.
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Thomas Gruber
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“An ontology is a specification of a
conceptualization”
The conceptualization is an abstract
and simplified view of the world you
want to represent, which is specified in
a format based on the relationships
between them.
– Examples: hierarchy, cluster, relational
diagram
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The Role of Ontology
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Basic Role:
– To provide a language which allows a
group of people to share information
reliably in a chosen area of work
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The Role of Ontology
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Some areas of application
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Indexing
Knowledge Sharing & Reuse
Artificial Intelligence (AI)
Enterprise Modeling
Software Design
Molecular Biology
eCommerce
Semantic Web….
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Structure of Ontology
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Most ontologies are structured as
taxonomies or hierarchies
Basic ontology has two classes of
elements: the entities and the
relationships between them (what
does this remind you of  ?)
– Organized according to axioms or rules
that control how the world will be
defined.
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Important Facts
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What exists is only what is represented
in the ontology (again like database
modeling with entities/relationships)
Most ontologies focus on a specific area
to conceptualize (e.g. subject thesauri)
Must be updated to keep up with
dynamic world
No set discipline or methodology!
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Example Biomedical Ontologies
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GO--Gene Ontology
– http://www.geneontology.org/
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OBO--Open Biomedical Ontology
umbrella web address for well-structured
controlled vocabularies for shared use across
different biological and medical domains.
http://obo.sourceforge.net/
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FMA--Foundational Model of Ontologies
– http://sig.biostr.washington.edu/projects/fm/Ab
outFM.html
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Tools for working with Ontologies
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Protégé
– http://protege.stanford.edu/
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WC3 Web 2.0 tools like
– OWL Web Ontology Lanaguage.
http://www.w3.org/TR/owl-features/
– RDF Resource Decription Framework
http://www.w3.org/RDF/
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Further Introduction to
BioMedical Ontologies
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See Barry Smith’s 2 day course notes
http://ontology.buffalo.edu/smith/BioOnt
ology_Course.html
Link to introduction (slides 9-45)
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