1. University of Trás-os-Montes and Alto Douro,Department of Engineering,Vila Real,Portugal
2. Institute for Renewable Energy, University of Applied Sciences Technikum Vienna,Vienna,Austria
3. University of Trás-os-Montes and Alto Douro,Department of Mathematics LIAAD-INESCTEC UTAD,Vila Real,Portugal
4. University of Trás-os-Montes and Alto Douro,Department of Engineering CPES-INESCTEC UTAD,Vila Real,Portugal