In the period January-June 2001, he visited the School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta GA, as a visiting researcher.
On September 2001 he joined the Istituto di Informatica e Telematica (IIT) of the Italian National Research Council (CNR).
In the period May-December 2003, he visited the Dept. of Computer Science at the Carnegie Mellon University, Pittsburgh, PA, as a visiting scientist.
He is/has been Associate Editor of IEEE Transactions on Mobile Computing, IEEE Transactions on Parallel and Distributed Systems, and Computer Networks (Elsevier), and Guest Editor of the Proceedings of the IEEE.