1. Faculty of Physics, Alexandru Ioan Cuza University of Iasi, 700506 Iasi, Romania
2. Department of Exact and Natural Sciences, Institute of Interdisciplinary Research, Alexandru Ioan Cuza University of Iasi, 700506 Iasi, Romania
3. National Institute of Research and Development for Technical Physics, Dimitrie Mangeron Blvd., 47, 700050 Iasi, Romania
4. Institute of Computer Science, Romanian Academy, Iași Branch, 700481 Iași, Romania