Informatics Center, Federal University of Pernambuco (CIn/UFPE), Recife, Brazil. fss3@cin.ufpe.br|Informatics Center, Federal University of Pernambuco (CIn/UFPE), Recife, Brazil. fss3@cin.ufpe.br|Informatics Center, Federal University of Pernambuco (CIn/UFPE), Recife, Brazil. fss3@cin.ufpe.br|Informatics Center, Federal University of Pernambuco (CIn/UFPE), Recife, Brazil. fss3@cin.ufpe.br|Informatics Center, Federal University of Pernambuco (CIn/UFPE), Recife, Brazil. fss3@cin.ufpe.br