Hagen Tarner

In many graphics and visualization frameworks, directed acyclic graphs are a popular way to model visualization pipelines. Pipeline editors provide a visual interface to modify the underlying graph and use, e.g., a node-link diagram to visualize the data and program flow. This paper proposes an interactive tool for post-mortem performance analysis and comparison of pipeline variants. We extend the node-link representation of a visualization pipeline and enrich it with fine-grained runtime performance metrics. Annotating this static structure with dynamic performance information lets the developer evaluate performance characteristics in depth. Our approach further supports a visual comparison of two user-selected states of the graph. The comparison allows us to identify the impact of (topological) changes on the graph’s performance. We demonstrate the utility of our approach with different scientific visualization use cases and report expert feedback.

Runtime data of software systems is often of multivariate nature, describing different aspects of performance among other characteristics, and evolves along different versions or changes depending on the execution context. This poses a challenge for visualizations, which are typically only two- or three-dimensional. Using dimensionality reduction, we project the multivariate runtime data to 2D and visualize the result in a scatter plot. To show changes over time, we apply the projection to multiple timestamps and connect temporally adjacent points to form trajectories. This allows for cluster and outlier detection, analysis of co-evolution, and finding temporal patterns. While projected temporal trajectories have been applied to other domains before, we use it to visualize software evolution and execution context changes as evolution paths. We experiment with and report results of two application examples: (I) the runtime evolution along different versions of components from the Apache Commons project, and (II) a benchmark suite from scientific visualization comparing different rendering techniques along camera paths.

Monitoring code quality and dependencies is an important task to keep software maintainable. While generally well researched, only little work on visually analyzing code quality of component-based front-end web applications exists that considers the specifics of such software systems. We propose an approach to visualize dependencies and code quality metrics of component-based

Building upon the ideas of storytelling and explorable explanations, we introduce Talking Realities, a concept for producing data-driven interactive narratives in virtual reality. It combines an audio narrative with an immersive visualization to communicate analysis results. The narrative is automatically produced using template-based natural language generation and adapts to data and user interactions. The synchronized animation of visual elements in accordance with the audio connects the two representations. In addition, we discuss various modes of explanation ranging from fully guided tours to free exploration of the data. We demonstrate the applicability of our concept by developing a virtual reality visualization for air traffic data. Furthermore, generalizability is exhibited by sketching mock-ups for two more application scenarios in the context of information and scientific visualization.