Ontologies for the Semantic Web Prepared By: Tseliso Molukanele Rapelang Rabana Supervisor: Associate Professor Sonia Burman 20 July 2005

Overview Introduce the Field of Ontologies Approaches to Ontological Engineering Inspirational Toolkit Synthetic Toolkit Resources Required Work Allocation Milestones

What are Ontologies? “Ontology is a negotiated, agreed conceptualization of reality that is arrived at by consensus involving all stakeholders” An agreed upon description of information: -definition of terms - ‘is-a’ hierachy -‘has-a’ hierachy

Who uses ontologies? Philosophy AI WWW Library Science Office

Why use ontologies? A better WWW Automatic Machine processing Faster browsing/searching Realize difference/similarity of concepts

Evolution of OWL HTML XML RDF (Resource Description Framework ) OWL (Web Ontology Language)

Project Objectives Develop toolkits that aids the non- Computer Science user: - to create ontologies - to manage/use ontologies

Ontological Engineering Creating ontologies  Inspirational Approach  Synthetic Approach

The Inspirational Approach Own creativity/imagination Personal view of domain No prior constructs From scratch

Extensions to OWL UCT PhD Student Daniel Semwayo Extra features  Granularity  Realise niche of entity

Inspirational Toolkit Build ontologies from users specification Adhere fully to OWL Incorporate Daniel Semwayo’s Extension Be usable

Questions tackled Does a tool for building usable ontologies exist? Are simple specifications better then more constructs? Is Daniel Semwayo’s extension enforceable?

Success Factors Complete implementation that adheres to OWL Improved productivity in creation of ontologies Enforcement of extra methodology Improved productivity in the use of ontologies by extra methodology

The Synthetic Approach Identification of an ontology or set of ontologies Manipulation and merging of ontologies SYNTHESIS of ontologies

How is this approach useful? Embraces multiple ontologies Opportunity for interaction and sharing

Related Work ‘Ontology Applications & Design’ -Gruninger and Lee ‘OIL: Ontology Infrastructure to Enable the Semantic Web’ -Fensel and Horrocks

Gruninger & Lee Approach A Use consortia and standards organizations to develop comprehensive ontology requires collaborative design which is time- consuming and expensive Approach B Develop lots of lightweight and then merge them requires ontology mapping and merging, so ontologies must follow one standard

Objectives of Synthetic Toolkit Facilitate integrated usage of existing ontologies to produce a customized, more relevant ontology Be usable by non-Computer Scientists

The Synthetic Toolkit Allow for a base of ontologies to be selected and imported into Toolkit Provide supportive functions: browsing, modifying, manipulating, organising and merging Allow resultant ontology to be exported to an application to be used for a particular purpose, eg: search application

Limitations of Synthetic Toolkit Synthesis of ontologies built in compliance with a single web ontology language, OWL Merging cannot be fully automated

Major design Challenges Standardise presentation of diverse and/or large ontologies Importing and merging differing ontologies Ensuring ease of use for non-computer scientists

How will Toolkit be evaluated? Require: users with some expertise in a particular subjects Users select and synthesize ontologies to suit their needs Users export resultant ontology to search application to ascertain impact on search results

General Resources Required OWL Parsers Collection of ontologies Database for search application Test subjects

Work Allocation Inspirational Toolkit & Extensions: Tseliso Molukanele Synthetic Toolkit & Search Application: Rapelang Rabana

Major Milestones MilestoneDate of Completion Background & Literature Survey26 Aug Ontologies imported to Synthetic Toolkit and Search Engine Implemented Sept 7 Core functionality of Inspirational Toolkit Implemented Sept 12 Supportive Functions of Synthetic Toolkit & Extensions of Inspirational Toolkit Implemented Sept 22 TestingOct 3 Final ReportOct 7

Conclusion Ontologies play a key role in Knowledge Management Must provide better support for their creation and use Inspirational and Synthetic approaches adopted, explore the possibilities of greater support