P.M. Dovgalyuk - Ph. D. (Eng.), Associate Professor, Novgorod State University. E-mail: pavel.dovgaluk@gmail.com M.A. Klimushenkova - Junior Research Scientist, Novgorod State University. E-mail: maria.klimushenkova@ispras.ru D.S. Dmitriev - Junior Research Scientist, Novgorod State University. E-mail: denis.dmitriev@ispras.ru V.A. Makarov - Ph. D. (Eng.), Associate Professor, Novgorod State University. E-mail: vladimir.makarov@ispras.ru