The IEEE Working Conference on Software Visualization (VISSOFT) is the main conference on Software Visualization. This year, the conference was held in Cleveland, OH, USA, co-located with ICSME between September 30th and October 1st, 2019. VISSOFT took place at the Hyatt Regency Cleveland at the Arcade. The program included two keynotes, one of them shared with SCAM’19, and the presentation of 8 full technical papers and 5 new ideas and emerging results / tool (NIER) demo papers (TD). As usual, the conference promoted lots of discussion and demos of visualizations. The shared keynote speech with SCAM was titled: “Visualization of Software-Clone Data: A Comprehensive Survey” and given by Rainer Koschke, who elaborated on the results of a survey of 68 papers of clone visualization techniques.
Software Evolution. The first session focused on software evolution and included the presentation of 2 full papers and 2 NIER/TD papers. In it, Juan Pablo Sandoval presented his work with Fabian Beck and Alexandre Bergel . The paper elaborates on the use of the matrix visualization technique for the analysis of performance variations along various versions of a software system. Next, Carol V. Alexandru presented Evo-Clocks , a visualization that employs a node-link diagram for the analysis of the evolution of software metrics. In the diagram, nodes are depicted by circular pie chart visualizations. Then, a short paper  was presented, which introduces the Macaw visualization tool. The tool provides users a visualization of program evolution to support automated program repair tools that use genetic algorithms, which is integrated to kGenProg. Finally, the last presentation of the session was given by Alexandre Bergel. He presented a short paper  that introduces a lightweight visualization technique to examine source code variations and memory consumption.
Meta-Analysis of Software Visualization. The second session was about meta-analyses of software visualization and included the presentation of 3 full papers. The first presentation was given by Fabio Petrillo, who presented a tertiary systematic literature review of software visualization . The survey includes the analysis of 48 papers and confirmed a lack of rigorous evaluations and the need for empirical studies as well as found a lack of collaboration amongst software visualization researchers. Next, I presented a paper  that introduces an ontology, called VISON, that encapsulates the main concepts that characterize software visualization. The paper also links 70 software visualization tools that are publicly available. Finally, there was a presentation of a paper  that reports on a user study that involved 5 software engineers of a large company and 4 researchers to examine the usefulness of visualization for requirements monitoring.
Eye Tracking, VR/AR. This year, I was invited to chair the last session of the first day that focused on the use of eye tracking and VR/AR in the context of software visualization. The session included the presentation of 1 full paper and 2 NIER/TD. The first presentation corresponded to a paper  that reports on the use of two linked views: one with a hierarchical edge bundling technique for context space and a graph visualization for embedded space, to visualize eye tracking data of source code exploration. Then, Sivasurya Santhanam from DLR presented a paper  that introduces an
architecture and an implementation of conversational interfaces for the Microsoft HoloLens device. In it, conversation interfaces are used for the exploration of visualizations of OSGi-based software architectures. Finally, the session ended with the presentation of a paper  that introduces CodeHouse, VR Code Visualization Tool.
Demo and Posters. At the end of the day, we had a Demo and Poster Session, in which we enjoyed to test some awesome visualizations. An especial interest got the ones displayed in immersive virtual and augmented reality.
Banquet. The traditional banquet was organized at The Butcher and The Brewer. The food and conversation was excellent. Many thanks to the organization!
Keynote. On the second day, we had a keynote speech titled “Algorithms and Metaphors for Graph Visualization” by Stephen Kobourov. In it, he presented his work using map metaphors, which shown to be intuitive, for visualizing relational data sets. He demoed the GMap framework, and discussed applications and experimental results.
Code Clones, Metrics, and Maintenance. Next, we had a session that included the presentation of 2 full papers and 1 NIERT/TD paper. The presenter of the first paper  introduced CloneCompass that uses combined views of a treemap matrix and an adjacency matrix to support the exploration of assembly code clones. Next, Craig Anslow presented a paper  to which I had the opportunity to contribute. In it, Craig introduced CorpusVis, a widget-based visualization to explore software metrics of systems in the Qualitas Corpus. The last presentation corresponded to a paper  that proposes using visualizations for exploring software maintenance activities.
Paper Awards. In 2019, the paper “Performance Evolution Matrix: Visualizing Performance Variations along Software Versions”  by Juan Pablo Sandoval Alcocer, Fabian Beck and Alexandre Bergel received the Best Paper Award. Excellent work!
Most Influential Paper Award. Finally, the conference concluded with the Most Influential Paper Award that went to
“A System for Graph-Based Visualization of the Evolution of Software”  by Collberg, C., Kobourov, S., Nagra, J., Pitts, J., & Wampler, K. The paper was presented by Christian Collberg.
All in all, VISSOFT 2019 was great! I enjoyed attending the talks and meeting people. I look forward to attending VISSOFT 2020 in Adelaide, Australia.
Guest Post by Leonel Merino
Visualization Research Center (VISUS)
University of Stuttgart
IEEE VISSOFT 2019 Proceedings
 Alcocer, J. P. S., Beck, F., & Bergel, A. (2019). Performance Evolution Matrix: Visualizing performance variations along software versions. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 1-11). IEEE.
 Alexandru, C. V., Proksch, S., Behnamghader, P., & Gall, H. C. (2019, October). Evo-Clocks: Software Evolution at a Glance. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 12-22). IEEE.
 Tomida, Y., Higo, Y., Matsumoto, S., & Kusumoto, S. Visualizing Code Genealogy: How Code is Evolutionarily Fixed in Program Repair?. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 23-27). IEEE.
 Alcocer, J. P. S., Jaimes, H. C., Costa, D., Bergel, A., & Beck, F. Enhancing Commit Graphs with Visual Runtime Clues. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 28-32). IEEE.
 Bedu, L., Tinh, O., & Petrillo, F. A Tertiary Systematic Literature Review on Software Visualization. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 33-44). IEEE.
 Merino, L., Kozlova, E., Nierstrasz, O., & Weiskopf, D. VISON: An Ontology-Based Approach for Software Visualization Tool Discoverability. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 45-55). IEEE.
 Kritzinger, L. M., Krismayer, T., Rabiser, R., & Grünbacher, P. A User Study on the Usefulness of Visualization Support for Requirements Monitoring. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 56-66). IEEE.
 Zhang, L., Sun, J., Peterson, C., Sharif, B., & Yu, H. (2019). Exploring Eye Tracking Data on Source Code via Dual Space Analysis. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 67-77). IEEE.
 Seipel, P., Stock, A., Santhanam, S., Baranowski, A., Hochgeschwender, N., & Schreiber, A. (2019, November). Speak to your Software Visualization — Exploring Component-Based Software Architectures in Augmented Reality with a Conversational Interface. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 78-82). IEEE.
 Hori, A., Kawakami, M., & Ichii, M. CodeHouse: VR Code Visualization Tool. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 83-87). IEEE.
 Wang, Y., Weatherston, J., Storey, M. A., & German, D. CloneCompass: Visualizations for Exploring Assembly Code Clone Ecosystems. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 88-98). IEEE.
 Slater, J., Anslow, C., Dietrich, J., & Merino, L. CorpusVis – Visualizing Software Metrics at Scale. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 99-109). IEEE.
 Levin, S., & Yehudai, A. (2019, October). Visually Exploring Software Maintenance Activities. In 2019 Working Conference on Software Visualization (VISSOFT) (pp. 110-114). IEEE.
 Collberg, C., Kobourov, S., Nagra, J., Pitts, J., & Wampler, K. (2003, June). A system for graph-based visualization of the evolution of software. In Proceedings of the 2003 ACM symposium on Software visualization (pp. 77-ff). ACM.