Supporting user tasks through visualisation of light-weight ontologies

This paper explores how to use visualizations in ontology-based semantic web. Based on their opinions, the authors first give two important features to visualize ontology-based semantic web: the ontology should be lightweight, that is, taxonomies with few cross-taxonomical links and logical relations between the classes; the number of instances should be far larger than the number of classes.

They first reviewed existing visualization work based on two criteria: how they support the ontological life-cycle stages and what ontological nature of the visualized data are exploited. They observed that while there are many existing tools provide “schema level” visualizations, few offer instance level visualizations; there is a “clear lack of visualization techniques that (a) display a simple schema with instances and (b) scale to a large number of instances”.

Cluster Map, a map with large sperepheres representing classes, connected with directed links indicating hierarchies and ballon-shaped edges overlapping instances, was then proposed as their techniques for visualizing light-weighted ontologies. Two real world application scenarios of Cluster Map follows; one in construction information portal, the other in peer-to-peer networks.

The authors future analyzed how Cluster Map can be used for a variaty of tasks, including analysis, monitors and query. For analysis, they considers scenarios resulting from different combinations of dataset, ontology and classifications. For querying, they discussed applications of Cluster Map in the four stages of a search task, namely, query formulation, initial of action, review of results and refinement. Most of the tasks scenarios are with an illustrasive graph of the Cluster Map.

The article is well written, without discussing much technique details. The analysis should give useful insiprations for those who will design visualizations for ontologies.