SYSTAS: Density-based algorithm for clusters discovery in wireless networks - Apostolos Kousaridas; Stefanos Falangitis; Panagis Magdalinos; Nancy Alonistioti; Markus Dillinger (26th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2015, Hong Kong, China, August 30 - September 2, 2015, 2015)