2)已知有如下不确定推理规则:r1:C11∨C12 T H1 0.7;r2: H1 T H 0.5;r3:C21∧C22 T H -0.6;r4:(C31∧C32)∨C33
根据MYCIN的确定性方法,首先需要计算每个规则的CF值,然后根据规则的CF值和置信度计算出结论的CF值。
计算规则CF值:
CF(r1) = min(CF(C11), CF(C12)) = min(0.8, 0.9) = 0.8
CF(r2) = CF(H1) = 1(因为H1是已知条件)
CF(r3) = min(CF(C21), CF(C22)) × T(r3) = min(0.3, 0.6) × (-0.6) = -0.36
CF(r4) = min(CF(C31), CF(C32), CF(C33)) × T(r4) = min(0.9, 0.5, 0.7) × 0.8 = 0.36
根据规则的CF值和置信度计算出结论的CF值:
CF(H) = (CF(r1) × T(r1) + CF(r2) × T(r2) + CF(r3) × T(r3) + CF(r4) × T(r4)) / (T(r1) + T(r2) + T(r3) + T(r4))
= (0.8 × 0.7 + 1 × 0.5 + (-0.36) × 1 + 0.36 × 1) / (0.7 + 0.5 + 1 + 1)
= 0.44
因此,根据给定的不确定推理规则和初始置信度,应用MYCIN的确定性方法得出CF(H)的值为0.44。
计算规则CF值:
CF(r1) = min(CF(C11), CF(C12)) = min(0.8, 0.9) = 0.8
CF(r2) = CF(H1) = 1(因为H1是已知条件)
CF(r3) = min(CF(C21), CF(C22)) × T(r3) = min(0.3, 0.6) × (-0.6) = -0.36
CF(r4) = min(CF(C31), CF(C32), CF(C33)) × T(r4) = min(0.9, 0.5, 0.7) × 0.8 = 0.36
根据规则的CF值和置信度计算出结论的CF值:
CF(H) = (CF(r1) × T(r1) + CF(r2) × T(r2) + CF(r3) × T(r3) + CF(r4) × T(r4)) / (T(r1) + T(r2) + T(r3) + T(r4))
= (0.8 × 0.7 + 1 × 0.5 + (-0.36) × 1 + 0.36 × 1) / (0.7 + 0.5 + 1 + 1)
= 0.44
因此,根据给定的不确定推理规则和初始置信度,应用MYCIN的确定性方法得出CF(H)的值为0.44。