Vol. 4 No. 4 (2015)
This issue contains extended papers that were initially submitted to the IMEKO TC21 (Mathematical Tools in Measurements) International Conference “Advanced Mathematical and Computational Tools in Metrology and Testing” (AMCTM) which was held in September 2014 in St. Petersburg, Russia. Some other papers published in this last issue of 2015 are related both to IMEKO TC1 and TC12 and to another scientific event that took place in Italy (the 2015 Italian Conference on electrical and electronic measurements organized by GMEE and GMMT). The last paper in this issue is a freely submitted paper.