Dana Simian , University Lucian Blaga of Sibiu, Faculty of Sciences, Department of Computer Science, Sibiu, Romania E-mail: dana.simian@ulbsibiu.ro Boldur Barbat , University Lucian Blaga of Sibiu, Faculty of Sciences, Department of Computer Science, Sibiu, Romania E-mail: bbarbat@gmail.com Dan Dumitrescu , University Babes-Bolyai of Cluj Napoca , Faculty of Mathematics and Informatics, Department of Informatics, Cluj-Napoca, Romania E-mail: ddumitr@cs.ubbcluj.ro Olga Miljkovic , Megatrend University of Belgrade, Serbia E-mail: olgamkg@sbb.co.yu Ioana Moisil , University Lucian Blaga of Sibiu, "Hermann Oberth" Faculty of Engineering, Sibiu, Department of Computer Science and Automatic Control, Sibiu, Romania E-mail: ioana.moisil@ulbsibiu.ro Milan Tuba , University of Belgrade, Serbia E-mail: tubamilan@ptt.yu