The Protégé Short Note (Part 1)

Introduction

What is Protégé ?

Protégé is a free, open source ontology editor and a knowledge management system. Protégé provides a graphic user interface to define ontologies. It also includes deductive classifiers to validate that models are consistent and to infer new information based on the analysis of an ontology. Like Eclipse, Protégé is a framework for which various other projects suggest plugins.

-Wikipedia-

As mentioned in Wikipedia Protégé is an ontology editor. It provides user community with a suite of tools to construct domain models and knowledge-based applications with ontologies. It provides a rich set of tools for creation, visualization, and manipulation of ontologies in various representation formats.

This article is based on the book “A Practical Guide To Building OWL Ontologies Using Protégé 4 and CO-ODE Tools Edition 1.3 “ by Matthew Horridge. My aim is to illustrate the theory content in more graphical way so it will be more easy to understand quickly.

You must have the following prerequisites in order to follow the content

• Basic knowledge in what ontologies are and for what they are used.
• Protégé installed in the computer with necessary plugins.

(Protégé 4, which is available from the Protégé website , and the Protégé Plugins which are available via the CO-ODE website)

Let’s get started with some basic knowledge.

Types of ontology modelling

There are two main approaches to model ontologies

• Frame-based
• OWL based

There some differences in used terminology , how implications are done, expressive power, consistency checking etc between the two. Here we are using the OWL based approach because, it has several advantages over frames based approach.

• It has more expressive and can support negation and disjunction.
• Can capture incomplete information.
• Use Open World Reasoning (Something is false only if it contradicts other information).
• Doesn’t Support Unique Name Assumptions(UNA where different names refer different(unique) things)

unique name assumptions example

Comparison of Vocabulary of Frames and OWL

If you want to know more about the differences between Frame ontology and OWL ontology please refer here.

Your first ontology

• Start Protégé
• Provide ontology IRI which can be fount in “Active Ontology” tab.

Initial view of the Protégé window

• Save the ontology in preferred place with a name. (eg: any_name.owl)
• Provide Annotations by clicking + icon next to(optional).

Next part of this short note will contain the information about creating classes, sub classes, disjoint classes etc for the ontology.