The present thesis investigates a new variant for physics-based information visualization. The fundamental idea bases on a quantification of the similarity of related objects, expressed by the parameters of a mass-spring system. Since the spring stiffnesses correspond to the computed similarity measures, the system converges into an energy minimum, which reveals multidimensional relations and adjacencies in terms of spatial neighborhoods.
As a part of this work we develop a platform-independent framework, called IVORY, for physics-based visualization and analysis of multidimensional data relations. The software design follows strictly the theory of operator frameworks. It is fully implemented in JAVA and its architecture features client-server setup, which allows to run the visualization even on thin clients. In addition, VRML 2.0 exports can be viewed by any VRML enabled web browser. Individual visual metaphors and interaction paradigms are invoked into IVORY via an advanced plug-in mechanism. The configuration of IVORY is accomplished using a specialized high-level script language, the Information Visualization Modeling Language (IVML).
In order to simplify complex setups we suggest visual clustering algorithms for postprocessing. We present a set of three new visual clustering algorithms - called Ellipsoidal, BLOB and H-BLOB clustering - which group and visualize cluster hierarchies at multiple levels-of-detail. We propose that the algorithms are especially suited for the visualization of very large data sets and for visual decision making in information visualization.
The versatility of the framework and its algorithms is demonstrated by means of experimental results. They show the framework’s capability to visualize large and complex volumes of different types of abstract data. Furthermore, a usability test including daily-business cases in the areas of our cooperation partner validates IVORY’s performance in practice.

Thomas C. Sprenger received his master's degree in computer science (Dipl. Informatik-Ing. ETH) from the Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, in 1996. From 1996 to the end of 2000, he has been a research assistant and Ph.D. student with the Computer Graphics Laboratory at ETH Zurich where he received his PhD in Computer Science in 2002. His research interests include computer graphics in combination with physics based models and their application to information visualization. In 2002, he received his Ph.D. (Dr. sc. techn.) from ETH Zurich. Dr. Sprenger is currently with AdNovum Software Inc. in San Mateo (CA), USA.

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