National power measurement (case study: Oceania, Europa and North America) Samira Motaghi, Afshin Mottaghi, Dmitry Pletnev, Ekaterina Nikolaeva and Iuner Kapkaev E3S Web Conf., 175 (2020) 14020 Published online: 29 June 2020 DOI: 10.1051/e3sconf/202017514020