Institution: | 1.Instituto de Sistemas Elétricos e Energia, Universidade Federal de Itajubá, Avenida BPS 1303, Pinheirinho, CEP 37.500-903, Itajubá, MG, Brazil ;2.Instituto de Ciências Exatas, Universidade Federal de Itajubá, Avenida BPS 1303, Pinheirinho, CEP 37.500-903, Itajubá, MG, Brazil ;3.Department of Economic Sciences, University of Craiova, A.I. Cuza 13, Craiova, Romania ;4.Department of Mathematics and Computer Sciences, University of Craiova, A.I. Cuza 13, Craiova, Romania ; |