TY JOUR TI JUSTIFICATION THE DIMENSION OF THE COMPLEX INDICATOR OF A TECHNOLOGICAL LEVEL AND ITS GRAPHICAL REPRESENTATION KW approximation KW hypersurface KW composite index technical level JO NATURAL AND MAN-MADE RISKS (PHYSICO-MATHEMATICAL AND APPLIED ASPECTS) AU Skripnik, I.L. AU Voronin, S.V. PY 2017 IS 2017 PB Saint-Petersburg University of State Fire Service of Emercom of Russia