The Research Group is Moving!

During winter term 2021/22, we move to University of Bamberg. From Oct. 15, 2021, Fabian Beck holds a full professor position on Information Visualization.

New webpage of the research group:

M.Sc. Hagen Tarner

Academic Staff

M.Sc. Hagen Tarner

S-GW 313
Universität Duisburg-Essen
Gerlingstraße 16
45127 Essen, Germany


I hold a Bachelor's degree in Medical Informatics and a Master's degree in Media Informatics. Currently I am pursuing my PhD in the field of Software Visualization.

Fields of Research:

Modern endeavors in the natural sciences create data in bigger quantities and higher complexity than ever before in human history. Space missions for example gather data on celestial bodies and the fundamentals of the universe, high-energy particle collision experiments amass petabytes of data per year, and even the annual check-up at a doctor’s office generates considerable quantities of data. Gaining insight and not just information from these datasets is a difficult task.

Modern techniques from the field of computer graphics provide tools to efficiently visualize datasets. With their abilities to do parallel computations on a massive scale, modern GPUs can enable interactive exploration and handling of datasets at interactive framerates. 

The combination of the natural science's data with the techniques of the field of computer graphics is Scientific Visualization. Algorithms for surface and volume rendering allow to create meaningful three-dimensional visualizations of experimentally gathered spatial data. Visualizing what's underneath a patient's skin in a non-invasive manner, simply by joining multiple MRI images is an example of these techniques.

A limiting factor for the usefulness and feasability of these approaches is performance. A simulation needs to terminate to provide results. A visual analytics system must respond to user input, no matter how big the underlying data is. Assessing and visualizing the performance of the rendering techniques are critical steps in increasing it, and thus the usefulness/feasability of applications using these techniques.

In my dissertation, I want to look at how to measure, gather, visualize, and then analyze performance data of current scientific visualization approaches. This not only requires a deep understanding of scientific visualization techniques (like volume and surface rendering), computer graphics (rendering techniques, rendering pipeline, software optimization), performance metrics (runtime statistics, profiling), but also knowledge about how to visualize complex information (information visualization, visual comparison, multivariate data, descriptive statistics). Benchmarking current rendering algorithms with actual datasets of the SciVis community, and using the results as the basis for developing a visual comparison system for multivariate runtime data might be one step to do this. I have already taken first steps in this direction by focussing my research so far on the visual comparison of multivariate runtime statistics and dynamic graphs.


SoftwareDynamics²: Fine-Grained Evolution of Software Behavior


  • Tarner, Hagen; Bongard, Daniel Van Den; Beck, Fabian: Visually Analyzing the Structure and Code Quality of Component-based Web Applications. In: VISSOFT 2021 - NIER/TD Track (Preprint). 2021. PDFCitationDetails
    Visually Analyzing the Structure and Code Quality of Component-based Web Applications

    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 JavaScript React applications. Our prototype implementation uses a node-link diagram for dependency visualization, tailored to the specific component structure of React applications and enriched with various visual cues. It is linked with different panels to show code quality and exact source code locations. Recommendations on how the quality of the system under analysis can be improved and refactored are provided. We evaluated our prototype in a small user study with four participants and found that it helped in program comprehension tasks and finding refactoring opportunities.

  • Latif, Shahid; Tarner, Hagen; Beck, Fabian: Talking Realities: Audio Guides in Virtual Reality Visualizations. In: IEEE Computer Graphics and Applications (2021). doi:10.1109/MCG.2021.3058129PDFFull textCitationDetails
    Talking Realities: Audio Guides in Virtual Reality Visualizations

    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.

  • Tarner, Hagen; Beschastnikh, Ivan; Beck, Fabian: Exploring a Multi-focus Visual Comparison of Dynamic Graphs. In: 2020 IEEE Visualization Conference (VIS), Posters (to appear). 2020. PDFCitationDetails
    Exploring a Multi-focus Visual Comparison of Dynamic Graphs
  • Tarner, Hagen; Frick, Veit; Pinzger, Martin; Beck, Fabian: Visualizing Evolution and Performance Metrics on Method Level as Multivariate Data. In: Seminar Series on Advanced Techniques & Tools for Software Evolution. 2020. PDFCitationDetails
    Visualizing Evolution and Performance Metrics on Method Level as Multivariate Data

    Visualizing the evolution of software metrics helps understanding the project progress of a software development team with respect to code quality and related characteristics. Blending this information with performance information can provide relevant insights into crucial changes in execution behavior and their respective context from code changes. We interpret this composition of evolution and performance metrics as multivariate data and map it to a fine-grained method level. This is the basis for investigating a multivariate visualization approach consisting of a visually enriched tabular representation that provides the method-level details for all the metrics across time, a projection view that shows clusters and outliers among the methods on a higher-level of abstraction, and a timeline view to find relevant temporal changes. Interactions connect the views and allow the users to explore the data step by step.

  • Tarner, Hagen; Frick, Veit; Pinzger, Martin; Beck, Fabian: Exploring Visual Comparison of Multivariate Runtime Statistics. In: 9th Symposium on Software Performance 2018. Hildesheim 2018. PDFCitationDetails
    Exploring Visual Comparison of Multivariate Runtime Statistics

    To understand program behavior or find performance bottlenecks in their software, developers need tools to efficiently compare runtime statistics collected across multiple executions. As there is a variety of useful metrics, a good visualization needs to be able to handle multivariate data and highlight the most important differences between multiple versions. We identify three scenarios for the comparison of execution-relevant changes, and explore possible visualizations of the gathered multivariate runtime statistics.


A list of courses I helped to realize:

  • Project Group ViVaSD - Visualizing Variability in Software Dynamics
  • Project Group Talking Realities
  • Lecture and Exercise Modelle der Informatik
  • Lecture and Exercise Computergrafik
  • Lecture and Exercise Informations- und Softwarevisualisierung
  • Seminar Software Performance Monitoring
  • Seminar Software Visualization
  • Seminar on Visualization of Graphs