TY JOUR TI APPLICATION OF THE MEAN ELLIPTICAL VALUE IN ASSESSING THE EFFECTIVENESS OF FIRE SAFETY KW central trend KW efficiency KW ellipse KW radius KW data array JO Scientific and analytical journal «Vestnik Saint-Petersburg university of State fire service of EMERCOM of Russia» AU Kozhevin, D.F. PY 2025 IS 2025 PB Saint-Petersburg University of State Fire Service of Emercom of Russia