ONTOLOGIESPresentation for e-business

systems development BN3374Tom Raby

What is an Ontology?

Definition:

“ Ontologies are ways of organising and describing related items, and are used to represent semantics.”

“ Ontology involves discovering categories and fitting objects into them in ways that makes sense.”

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The basic

objects Attributes – aspects, properties, features Values / Properties – Individual related specific

data. Value of the properties / attributes Relations – ways in which individuals/classes

relate to one another Events – the changing of attributes or relations

Components

Classes – Collections, concepts

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The

basic objects

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The basic

objects Attributes – aspects, properties, features

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The basic

objects Attributes – aspects, properties, features Values / Properties – Individual related

specific data. Value of the properties / attributes

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The basic

objects Attributes – aspects, properties, features Values / Properties – Individual related specific

data. Value of the properties / attributes Relations – ways in which individuals/classes

relate to one another

Example

Components

Classes – Collections, concepts Individuals – Instances or objects. The basic

objects Attributes – aspects, properties, features Values / Properties – Individual related specific

data. Value of the properties / attributes Relations – ways in which individuals/classes

relate to one another Events – the changing of attributes or relations

Example

What makes a good Ontology?

Syntax Identified with form, format and structure of the data. Programs such as RDF (research development framework) OWL

(ontology web framework) SQL and Java all improve the form and format of the ontology

Structure Databases, semantic web and ontologies require good structure to

organise and contain elements of the model. Semantics

Semantic interpretation is the mapping between some structured subset of data and the set of objects with respect to the intended meaning of those objects and the relationships.

Pragmatics Intent of the semantics and actual semantic usage. There is very

little pragmatics expressed or even expressible in programming or database languages, but will become important.

The need for Ontologies

With increasing levels of data, the need to categorise it and develop a framework and understanding of it increases.

Allows greater level of integration. Able to express the semantics of your data,

document collections, and systems using the same semantic resource that is machine interpretable.

Re-use previously developed versions, bring in different or related ontologies, and extend the ontology. This helps to establish community wide common semantics.

Closing Comments

Ontologies are used to improve the structure and data used in a web page

Categorise s and develops data into a structure that makes sense.

Complicated but becoming essential to generate full use of data

Needs to be machine interpretable. Machines cannot make assumptions like humans

QUESTIONS?

References

Deitel, P.J. Deitel, H.M. (2008). Internet &World Wide Web How to Program. 4th ed. New Jersey: Pearson Education Inc. 96.

Daconta, M. Obrst, L. Smith, K (2003). The Semantic Web. A Guide to the eFuture of XML, Web services, and Knowledge Management. Indianapolis: Wiley Publishing Inc. 181-238