1. Department of Electrical and Computer Engineering; Instituto Superior Técnico, Universidade Técnica de Lisboa; Lisbon Portugal
2. Department of Mechanical Engineering, Instituto Superior Técnico; Universidade Técnica de Lisboa; Lisbon Portugal
3. Department of Electrical and Computer Engineering, Instituto Superior Técnico; Universidade Técnica de Lisboa; Lisbon Portugal
4. Department of Electrical and Computer Engineering, Faculty of Science and Technology; University of Macau; Taipa Macau China