1. Department of Mathematics, Faculty of Basic ScienceBabol Noshirvani University of TechnologyBabol Iran
2. Department of Physics, Faculty of Basic ScienceBabol Noshirvani University of TechnologyBabol Iran
3. Department of Mathematics and Descriptive Geometry, Faculty of Civil EngineeringSlovak University of TechnologyBratislava Slovakia
4. Institute of Information Theory and Automation of the Czech Academy of SciencesPraha 8 Czech Republic