1. Semi-Automatic Data-Driven Ontology Construction System
Blaz Fortuna, Marko Grobelnik, Dunja Mladenic
Jozef Stefan Institute

2. Main features of OntoGen
Semi-Automatic
Text-mining methods provide suggestions and insights into the domain
The user can interact with parameters of text-mining methods
All the final decisions are taken by the user
Data-Driven
Most of the aid provided by the system is based on some underlying data provided by the system
Instances are described by features extracted from the data (e.g. bag-of-words vectors)

3. OntoGen v1.0 Designed for construction of topic ontologies
Clustering algorithms used for topic suggestion
Keyword extractions methods help the user to name the concept
Interactive user interface

4. OntoGen v2.0 Improved user interface New features:
Based on the feedback from users
New features:
Active Learning
Learning new concepts based on user queries and user classification of carefully selected documents
Simultaneous Ontologies
Optimization of similarity measure based on provided document categories
Concept’s Instances Visualization
Integration of Document Atlas visualization
Ontology Population
Interactive classification of new instances into ontology

5. Sub-Concept suggestion
Concept hierarchy
Sub-Concept suggestion
Ontology visualization

6. Concept’s documents management
Concept hierarchy
Concept’s documents management
Selected concept’s details

7. Active Learning
SVM hyperplane distance based active learning algorithm
First few labelled documents are bootstrapped using user query and nearest-neighbour search
In each step the unlabeled document closest to the hyperplane is chosen for user classification

8. New Concept

9. Simultaneous Ontologies
Data: Reuters news articles
Each news is assigned two different sets of categories:
Topics
Countries
Each set of categories offers a different view on the data
Topics view
Countries view
Documents

10. Concept’s Instances Visualization

11. Ontology Population One vs. All linear SVM used classification
Interactive user interface where user can finalize the classifications

12. Classification of the selected document
New documents
Classification of the selected document
Selected document