I am writing my dissertation on "Visualization-Driven Data Aggregation", digging deep into several data management topics, such as dimensionality reduction, data aggregation, and relational algebra, but also in computer graphics topics, such as line rendering, line simplification, and data visualization in general. I publish scientific papers on top-level conferences, such as VLDB.
Open Source Software
I am not involved in any OSS project, but I use and advocate OSS for my job and at home. The two most important gems of open source software that I currently rely on are LyX and Inkscape. I use them for literally everything.