Yannis received his Diploma in Physics from the University of Athens, his MSc in Computer Science from University College London, and his PhD in Informatics from the National Technical University of Athens. He worked as a software engineer at a private company (1993-1997), as a research associate at the National Center for Scientific Research "Demokritos" (1998-2003), and as an adjunct professor at the University of Thessaly and the University of Central Greece (2004-2006). Since 2007 he is a researcher at the Information Management Systems Institute of the "Athena" Research Center . He has participated as a scientific coordinator, technical manager, and developer in many research, commercial, and consulting projects. He has published more than sixty papers in international peer-reviewed journals and conferences on data management and information systems. His research interests include: methods and tools for supporting data analysis on Social Media, complex changes in evolving interrelated data on the Web, context-dependent Web data.