1. Albacete Research Institute of Informatics, Universidad de Castilla-La Mancha, 02071 Albacete, Spain
2. Computer Science and Communications Research Centre, School of Technology and Management, Polytechnic Institute of Leiria, 2411-901 Leiria, Portugal
3. Institute of New Technologies—Leiria Office, INOV INESC INOVAÇÃO, Morro do Lena—Alto do Vieiro, 2411-901 Leiria, Portugal
4. Departamento de Sistemas Informáticos, Universidad de Castilla-La Mancha, 02071 Albacete, Spain