I am one of the persons in this picture, but I forgot which one.
My name is Zdenek Dvorak. I have obtained my PhD at Charles University, Prague, Czech Republic a few years ago -- the theme of my thesis was "Asymptotical structure of combinatorial objects"; it is mainly concerned with a recently developed concept of classes of graphs with bounded expansion. After spending two years doing postdocs in Atlanta and Vancouver, I came back to Prague. In 2012, I submitted a habilitation thesis New techniques in coloring embedded graphs.
I am interested in combinatorics, design of algorithms and especially data structures and many other topics in math and programming. You can find more in my curriculum vitae.
On a less serious note, I practice Shinto Muso Ryu Jodo (an old Japanese martial art of fighting with a stick). For general info about this martial art and possibility to train it in Czech Republic, especially close to Zlin, see the pages of Tenshin Dojo. Together with several other people we practice in Prague, see the schedule.
During my stay in Vancouver, there was no opportunity to practice jodo (except alone), so I started learning kendo in Sunrise club (now appears to be defunct, as unfortunately the main instructor passed away), to keep myself in shape. After returning to Prague, I was too busy to continue, unfortunately.
I also used to play go. I recommend the go club at Czech-Japanese society and the KGS internet server.