Visualisation of Transition Systems

State transition graphs are fundamental to computer science and engineering, where they are used to conceptualise and study the behaviour of computer-based systems. Nodes represent states a system can be in and directed edges represent transitions between states. Large state transition graphs often contain tens of thousands of nodes, or more, and tens to hundreds of thousands of edges. They also describe system behaviour at a low abstraction level. This hinders analysis and insight. This research presents a number of techniques for the interactive visualisation of state transition graphs, many of which take advantage of multivariate data associated with nodes and edges: selection and projection, attribute-based clustering, user-defined diagrams, multiple views on traces, and querying nodes and edges by direct manipulation. Several new methods were developed in close collaboration with users, and demonstrated in case studies with system analysts. It was carried out as doctoral research at Eindhoven University of Technology.