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Taxonomies and Ontologies

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The terms “Taxonomy” and “Ontology” are often used inter-changeably and are often confused. However, the terms to express different concepts.

  • Taxonomy is about classification, and so represents “Is-A” relationships. For example, in the zoological world, a domestic cat (“Felis catus”) is a member of the family “Felidae” which itself is a member of the order “Carnivora”. Such taxonomies are typically, but not always, hierarchical. An object can exist simultaneously in many different taxonomies. So, a cat also belongs to the group “predators”, which would also include the insect “praying mantis”.
  • Ontology is about the concepts and relationships that can exist for an object or a group of objects[1]. For example, the “Part-Of” (“Part Holonym” [2]) relationship is used to describe the parts of a car (a wheel is part of a car). Therefore, a taxonomy is a type of ontology by this definition.

SharePoint 2007 introduced the managed metadata service to allow the definition of taxonomies to be used for classifying items and documents through metadata columns. Companies are encouraged to define their own or use industry standard taxonomies for classifying documents across the organization to ensure standardization and improve searchability.

Less work has been done in integrating ontologies within SharePoint, although progress by a number of third-party software vendors is being made. “WordNet” [3] provides a rich source of generic ontological information using the English language, and codifies many types of relationships between nouns, verbs, adjectives and adverbs using “cognitive synonyms” (synsets). Vertical market ontologies are now being built, such as for financial governance by the “GRC3 – Governance, Risk and Compliance Competence Centre” at the University of Cork, Ireland (http://www.ucc.ie). Integration of such ontologies in SharePoint will be the next step in improving search, leading to the possibility of useful question-answering systems.

[1] What is an Ontology? http://www-ksl.stanford.edu/kst/what-is-an-ontology.html

[2] Speech and Language Processing, Jurafsky & Martin, 2nd Pearson International Edition p.653

[3] Princeton University “About WordNet.” WordNet. Princeton University. 2010.  http://wordnet.princeton.edu 

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Written by Nick Grattan

July 24, 2012 at 7:21 pm

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