1. Department of Electromechanical Engineering, Centre for Research in Engineering and Industrial Management_CAST, University of Beira Interior, Edifício 1 das Engenharias, Calçada Fonte do Lameiro, Covilhã, P-6201-001, Portugal.
2. Department of Aeronautic Sciences, University of Beira Interior, Edifício 1 das Engenharias, Calçada Fonte do Lameiro, Covilhã, P-6201-001, Portugal.