The following three terms: classifications, taxonomies and

sounderslipInternet και Εφαρμογές Web

22 Οκτ 2013 (πριν από 4 χρόνια και 17 μέρες)

92 εμφανίσεις

Classifications, Taxonomies, Ontologies, Thesauri

The following three terms: classifications, taxonomies and
ontologies are often confused.

This is caused by a trend to use the most fashionable of the three
terms “ontology”.


Classification: Definition

Merriam
-
Webster definition:
systematic arrangement in groups or
categories according to established criteria.

An example of a classification would be the division of all plants in
the classes decorative and non
-
decorative.


Taxonomy: Definition

Longman definition:
the process or a system of organizing things
into different groups that show their natural relationships,
especially plants or animals


Meriam
-
Webster definition:
orderly classification of plants and
animals according to their presumed natural relationships


A taxonomy can described as (hierarchical) classification of items
created according to data internal criteria.


Ontology: Yet Another Definition

"The term
ontology

has many meanings and shades of meaning. In
the contest of this work*, we refer to what is sometimes called a
"structural" ontology
--

a machine readable set of definitions that
create a taxonomy of classes and subclasses and relationships
between them.“


*
Web Ontology (WebONT) Working Group Charter at
http://www.w3.org/2001/sw/WebOnt/charter




Classifications and Taxonomies: Comparison

Taxonomies are classifications that:


have hierarchical structure


list items that are organised according to their natural
relationships


Taxonomies and Ontologies

Most ontologies could be described as taxonomies + definitions +
various properties and relations (rather than just taxonomic, i.e.,
is_a, relations)


Thesauri and Ontologies

Nowadays, thesaurus most commenly means a listing of words
with similar, related, or opposite meanings.

"A formal definition of a thesaurus designed for indexing is:


a list of every important term (single
-
word or multi
-
word) in a given
domain of knowledge; and


a set of related terms for each term in the list.“*

"In Information Technology, a thesaurus represents a database or
list of semantically orthogonal topical search keys.

In the field of Artificial Intelligence, a thesaurus may sometimes be
referred to as an ontology.“*

Additional reading:
http://www.metamodel.com/article.php?story=20030115211223271

* http://en.wikipedia.org/wiki/Thesaurus


Animal Kingdom Taxonomy


Kingdom, class, order, genus, species


Gray wolves are dogs. Dogs are carnivore. Carnivores are
mammals. Mammals are animals.


National Center for Biotechnology Information (US)
:


http://www.ncbi.nlm.nih.gov/Taxonomy/

Ontology Management and Maintenance Tools

Protégé is a free, open source ontology editor and knowledge
-
base
framework. Protégé ontologies can be exported into a variety of
formats including RDF(S), OWL, and XML Schema. For more
cf.:

http://protege.stanford.edu/


Protege Tutorial

Some tutorials:


http://protege.stanford.edu/publications/ontology_development/ontology101
-
noy
-
mcguinness.html


http://www
-
smi.stanford.edu/projects/protege/amia2003/AMIA2003Tutorial.ppt


http://protege.stanford.edu/doc/users.html#tutorials


Some Important Existing Ontologies


Cyc:

http://www.opencyc.org/

http://www.cycfoundation.org/


Suggested Upper Merged Ontology (SUMO):

http://www.ontologyportal.org/


WordNet Lexical reference system:

http://wordnet.princeton.edu/


Gene Ontology:

http://www.geneontology.org/


Foundational, Core and Linguistic Ontologies:

http://www.loa
-
cnr.it/Ontologies.html


Last but not Least

Ontoverse:


www.ontoverse.org


http://www.ontoverse.org/de/grundlagen/grundlagen_1.html