1. School of Computer Science & Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea
2. Universidad Politécnica de València, Camino de Vera, S/N, 46022 València, Spain
3. Department of Computer Science, San Diego State University, Campanile Drive, San Diego, CA 92115, USA
4. Department of Informatics, Electronic and Sistemistic, University of Calabria, 87036 Cosenza, Italy
5. Department of Electrical and Computer Engineering, Lawrence Technological University, Southfield, MI 48075, USA