Vassilis Christophides is a professor of Computer Science at the University of Crete. He has been recently appointed to an advanced research position at INRIA Paris-Rocquencourt. Previously, he worked as a Distinguished Scientist at Technicolor, R&I Center in Paris. He studied Electrical Engineering at the National Technical University of Athens (NTUA), Greece, July 1988, he received his DEA in computer science from the University PARIS VI, June 1992, and his Ph.D. from the Conservatoire National des Arts et Metiers (CNAM) of Paris, October 1996. His main research interests include Databases and Web Information Systems, as well as Big Data Processing and Analysis. He has published over 130 articles in high-quality international conferences, journals, and workshops. He has been scientific coordinator of a number of research projects funded by the European Union, the Greek State, and private foundations on the Semantic Web and Digital Preservation at the Institute of Computer Science of FORTH. He has received the 2004 SIGMOD Test of Time Award and the Best Paper Award at the 2nd and 6th International Semantic Web Conference in 2003 and 2007. He served as General Chair of the joint EDBT/ICDT Conference in 2014 at Athens and as Area Chair for the ICDE "Semi-structured, Web, and Linked Data Management" track in 2016 at Bali, Indonesia. Vasilis Efthymiou is a Ph.D. candidate at the University of Crete and a member of the Information Systems Laboratory of the Institute of Computer Science at FORTH. The topic of his Ph.D. research is entity resolution in the Web of data. He got his MSc and BSc degrees from the same university in 2012 and 2010, respectively. He has received undergraduate and postgraduate scholarships from FORTH, working in the areas of Semantic Web, non-monotonic reasoning, and Ambient Intelligence.