| control performance index = (① × ③) + (② × ④)[(percentage increase/decrease in control quantity) × weighting with control quantity rate] + [(percentage increase/decrease in area) × weighting with area change rate]① percentage increase/decrease in control quantity : (rate of change in total control quantity + rate of change in victimized trees) ÷ 2② percentage increase/decrease in area : rate of change in damage area③ weighting with control quantity rate : 1 - weighting with area change rate④ weighting with area change rate : area weighting by damage grade × Coefficient of change distance in pine wilt disease boundary(0.7~1.3)※ Damage reduction if the control performance index is negative (−), and damage increase if positive (+) |