TY JOUR TI MATHEMATICAL MODEL OF THE PROBLEM OF EQUIPMENT REPLACEMENT KW mathematical model KW hardware KW dynamic programming KW optimization KW hardware replacement KW Bellman's principle of optimality JO Vestnik of Kazan State Agrarian University AU Koroleva, V.V. AU Filippov, E.G. AU Yachmeneva, V.V. AU Ziganshin, B.G. PY 2022 IS 17 PB Kazan state agrarian University