Metrology and Hydrology Department, Tbilisi State University, Chavchavadze Avenue, 1, 0128, Tbilisi, Georgia

Physics Department, Georgian Technical University, Kostava Street, 77, 0175, Tbilisi, Georgia

Institute of Cybernetics, S. Euli street, 5, 0186, Tbilisi, Georgia

Department of Electrical Engineering, University of Washington, FT-10 Seattle, Washington 98195, USA

I. Vekua Institute of Applied Mathematics, Tbilisi State University, 2 University str., 0186 Tbilisi, Georgia

Physics Department, Georgian Technical University, Kostava Street, 77, 0175, Tbilisi, Georgia