Steffen Hadlak

Research: Multi-faceted Graph Visualization

• capture social ties between persons
• classification of websites
• model the communication between households
• ontology based semantic knowledge base
• supply chain networks

• diversity regarding the facets of the graph
  • structure (nodes and edges)
  • partitions (grouping or clustering)
  • attributes (node properties or edge weights)
  • (geo)spatial context
  • temporal context
• scalability regarding the size of the graph
  • number of nodes and edges
  • number of attributes
  • amount of time steps
• flexibility regarding the foci on the graph
  • different characteristics of facets (linear or cyclic time)
  • different dependencies between facets (time varying structure and/or attributes)
  • different handlings of facets (clustering by node properties or similiar attribute time lines)
  • different views on facets (integrating time into structural visualization or vice versa)

Publications:

• Rebekka Alm, Mario Aehnelt, Steffen Hadlak and Bodo Urban: Annotated Domain Ontologies for the Visualization of Heterogeneous Manufacturing Data. Proceedings of the International Conference on Human-Computer Interaction, Springer, 2015.
• Rebekka Alm and Steffen Hadlak: Towards integration and management of contextualized information in the manufacturing environment by digital annotations. Proceedings of the VCRIC International Summer School on Visual Computing, Fraunhofer-Verlag, 2015.
• Steffen Hadlak, Heidrun Schumann and Hans-Jörg Schulz: A Survey of Multi-faceted Graph Visualization. State-of-the-Art Report at EuroVis, 2015.
• Hans-Jörg Schulz and Steffen Hadlak: Preset-based Generation and Exploration of Visualization Designs. Journal of Visual Languages and Computing, Vol. 31, Part A, 2015.

• James Abello, Steffen Hadlak, Heidrun Schumann and Hans-Jörg Schulz: A Modular Degree-of-Interest Specification for the Visual Analysis of Large Dynamic Networks. IEEE Transactions on Visualization and Computer Graphics, Vol. 20, No. 3, 2014.
• Steffen Hadlak: Graph Visualization in Space and Time. Doctoral thesis, University of Rostock, Germany, 2014.

• Steffen Hadlak, Heidrun Schumann, Clemens H. Cap, and Till Wollenberg Supporting the Visual Analysis of Dynamic Networks by Clustering associated Temporal Attributes. IEEE Transactions on Visualization and Computer Graphics, Vol. 19, No. 12, 2013.
• Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: A Visualization Approach for Cross-level Exploration of Spatiotemporal Data. Proceedings of the International Conference on Knowledge Management and Knowledge Technologies 2013 (i-Know'13).

• René Rosenbaum, Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: Visual Analysis of Spatiotemporal Multilevel Data. Workshop GeoVisual Analytics, Time to Focus on Time at the International Conference on Geographic Information Science (GIScience), Columbus, USA, 2012.

• Steffen Hadlak, Hans-Jörg Schulz and Heidrun Schumann: In Situ Exploration of Large Dynamic Networks. IEEE Transactions on Visualization and Computer Graphics, Vol. 17, No. 12, 2011.
• Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: Point-Based Visualization for Large Hierarchies (invited paper). IEEE Transactions on Visualization and Computer Graphics, Vol. 17, No. 5, 2011.
• Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: The Design Space of Implicit Hierarchy Visualization: A Survey. IEEE Transactions on Visualization and Computer Graphics, Vol. 17, No. 4, 2011.

• Steffen Hadlak, Christian Tominski, Hans-Jörg Schulz and Heidrun Schumann: Visualization of Attributed Hierarchical Structures in a Spatio-Temporal Context. International Journal of Geographical Information Science, Vol. 24, No. 10, 2010.
• Steffen Hadlak, Christian Tominski, Hans-Jörg Schulz and Heidrun Schumann: Visualization of Hierarchies in Space and Time. Workshop on Geospatial Visual Analytics: "Focus on Time" at the AGILE International Conference on Geographic Information Science, Guimarães, Portugal, 2010.
• Clemens Holzhüter, Steffen Hadlak and Heidrun Schumann: Multi-Level Visualization for the Exploration of Temporal Trends in Simulation Data. Poster presentation at the Winter Simulation Conference 2010 in Baltimore, Maryland, USA.

• Steffen Hadlak: Visualisierung von hierarchischen Strukturen auf einer Karte mit dem Point-Based Layout. Diploma thesis, University of Rostock, Germany, 2009.
• Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: Point-Based Tree Representation: A new Approach for Large Hierarchies. Proceedings of the IEEE Pacific Visualization Symposium 2009 in Beijing, China.

• Steffen Hadlak: Visualisierung großer hierarchischer Strukturen mit einem punktbasierten Baumlayout. Seminar thesis, University of Rostock, Germany, 2008.
• Hans-Jörg Schulz, Steffen Hadlak and Heidrun Schumann: A Point-Based Layout for Large Hierarchies. Poster presentation at the IEEE VisWeek 2008 in Columbus, U.S.A.

Presentations/Talks:

• A Survey of Multi-faceted Graph Visualization at EG / VGTC Conference on Visualization (EuroVis), Cagliari, Sardinia, Italy, 2015.
• A Modular Degree-of-Interest Specification for the Visual Analysis of Large Dynamic Networks at IEEE Conference on Information Visualization (InfoVis), Paris, France, 2014.
• Supporting the Visual Analysis of Dynamic Networks by Clustering associated Temporal Attributes at IEEE Conference on Visual Analytics Science and Technology (VAST), Atlanta, USA, 2013.
• In Situ Exploration of Large Dynamic Networks at IEEE Conference on Information Visualization (InfoVis), Providence, USA, 2011.
• Visualization of Hierarchies in Space and Time at Workshop on Geospatial Visual Analytics: "Focus on Time" at the AGILE International Conference on Geographic Information Science, Guimarães, Portugal, 2010.

Software:

• Implicit Tree Visualization Toolkit (meta-visualization for hierarchical structures)
• Two-Tone Pseudo Colored Spiral Display (visualization for cyclic time)

Videos of Techniques and Software:

• Clustering Dynamic Networks regarding Temporal Attributes (33.1MB)
• Exploration of the 3D Treemap Design Space (24.5MB)
• In Situ Exploration for a Model Versioning Use Case (15.8MB)
• In Situ Exploration for the Opennet Use Case (22.6MB)
• A Modular Degree-of-Interest Specification for Dynamic Networks (39.6MB)
• A Point-Based Layout for Large Hierarchies (47.5MB)
• Preset-based Generation of Hierarchy Visualization Designs (65.2MB)
• Preset-based Generation of Product Plot Designs (57.8MB)
• Visualization of Hierarchies in Space and Time (18.6MB)