1. University of Genoa,Department of Naval Architecture, Electric, Electronic and Telecommunication Engineering (DITEN),GENOA,Italy,16145
2. Norwegian University of Science and Technology (NTNU),Department of Engineering Cybernetics,Trondheim,Norway,NO-7491
3. Norwegian University of Science and Technology (NTNU),Roger Skjetne is with the Department of Marine Technology,Trondheim,Norway,NO-7491