1. Control Research Laboratory, Department of Electrical Engineering; UNESP - Univ Estadual Paulista; Carlos Rossi Avenue, n° 1370 Ilha Solteira 15.385-000 São Paulo Brazil
2. Coordination of Mathematics and Natural Sciences; IFTO - Federal Institute of Education, Science, and Technology of Tocantins; Palmas 77.021-090 Tocantins Brazil