Synopsis

Network structures (graphs) have become a natural part of everyday life and their analysis helps to gain an understanding of their inherent structure and the real-world aspects thereby expressed. The exploration of graphs is largely supported and driven by visual means. The aim of this thesis is to give a comprehensive view on the problems associated with these visual means and to detail concrete solution approaches for them. This is done on all three levels involved: the data level, the representation level, and the task level.

In a first step, the intricate dependencies on the representation level alone are discussed for the case of implicit tree visualizations. With the awareness of the representation issues involved, a second step takes the characteristics on data level into account, which are most importantly graph size and graph type. Their influence on the visualization design are discussed specifically for large trees and bipartite graphs. Finally, with bringing in the task level, the entire exploration workflow from computational preprocessing to the interaction with the visualization can be captured and thus discussed in terms of its consequences for the visualization design. This includes issues of necessary confirmative elements in the exploratory analysis, as well as selecting appropriate data sets from a heterogeneous data pool for an analysis.

Concrete visualization techniques are introduced to underline the value of this comprehensive discussion for supporting explorative graph visualization.

Important publications

• Hans-Jörg Schulz, Thomas Nocke and Heidrun Schumann (2006): A framework for visual data mining of structures. In: ACSC'06 Proceedings of the 29th Australasian Computer Science Conference, volume 48 of Conferences in Research and Practice in Information Technology, Hobart, Tasmania, Australia, ed. by Vladimir Estivill-Castro and Gillien Dobbie, pp. 157-166. Australian Computer Society.

• Hans-Jörg Schulz and Heidrun Schumann (2006): Visualizing graphs: A generalized view. In: Proceedings of the 10th International Conference on Information Visualisation, IV 2006, London, UK, ed. by Ebad Banissi, Remo Aslak Burkhard, Anna Ursyn, Jian J Zhang, Mark Bannatyne, Carsten Maple, Andrew J. Cowell, Gui Yun Tian and Ming Hou, pp. 166-173. IEEE Computer Society.