1. Interactive Technologies Institute (ITI/LARSyS and ARDITI), Caminho da Penteada, 9020-105 Funchal, Portugal
2. Universidade da Madeira, Caminho da Penteada, 9020-105 Funchal, Portugal
3. Institute for Technological Development and Innovation in Communications, Universidad de Las Palmas de Gran Canaria, C. Juan de Quesada, 30, 35001 Las Palmas, Spain