Nikos Kremmydas is a MSc candidate in the Department of Computer Science at the University of Ioannina. He received his BSc degree in Computer Science, in 2004, from the University of Crete. During the first semester of 2004 2005, he had been a member of the Mobile Computing Group at F.O.R.T.H, Crete. From 2006, he has been a member of the Distributed Data Management Laboratory at the Univercity of Ioannina. His research interests include Databases and Peer-to-Peer Systems. Current research activities include the study of a structure, for the effective storage and retrieval of metadata, at schema-based Peer-to-Peer Systems.