John Liagouris is a PhD candidate in the Knowledge and Database Systems Lab in NTU Athens under the supervision of prof. Yannis Vassiliou and prof. Timos Sellis. He is also a research assistant in the Information Management Systems Institute (IMSI) of the RC 'Athena' since 2009, and a recipient of the 'HERACLEITUS II' EU-funded research fellowship (2010-2013). Between September 2013 and July 2014, he was a visiting research fellow in the University of Hong Kong working with prof. Nikos Mamoulis. He received his diploma in Electrical and Computer Engineering from NTU Athens in 2008. His main research interests lie in the areas of privacy, graph databases, prototype system implementation (query optimization, indexing, memory management, etc.), and semantic web.