Development process and evaluation of the ontology visualization tool knoocks: a case study

Ontologies were becoming popular in various communities and disciplines over the past few years. The reason for their popularity is that they allow to specify concepts and their interconnections of a domain which are understandable by computers and by people. However without visualizations, ontologies - especially large ones - would be hard to comprehend by users. Visualizations are essential because they make ontologies with their structure more manageable. Furthermore, visualization tools are helpful to analyze the interconnections between concepts. For an effective usage of such visualization tools, it is necessary that the design is easy to understand, provides a good overview about the structure and allows fast access to detail information. Furthermore, it is necessary to consider the domain for which the ontology is developed along with its users and their needs. This paper presents the development process of Knoocks - a visualization tool for OWL Lite ontologies - where users were already involved during the process to improve the usability of the tool. Moreover, the presented case study underlines the importance of repeated usability evaluations during the development process to identify weak points of the design and missing features which are relevant for the intended users.