His research interests include the design, analysis and optimisation of algorithms for distributed and ubiquitous systems. Especially, his work covers proactive computing, distributed adaptive beamforming, context-based secure key generation and device-free passive activity recognition. Stephan is an editorial board member of the Elsevier Journal on Computer Communications and has been a guest editor for the Springer Personal and Ubiquitous Computing Systems Journal. He has served on the organizing and technical committees numerous prestigious conferences including IEEE PerCom, ACM Ubicomp. Short CV: