A cloud computing price model based on virtual machine performance degradation - Leite, Dionízio Machado; Peixoto, Maycon Leone Maciel; Ferreira, Carlos Henrique Gomes; Batista, Bruno Guazzelli; Segura, Danilo Costa Marim; Santana, Marcos José; Santana, Regina Helena Carlucci (International Journal of Computational Science and Engineering - IJCSE, 2019)