Deffuzification is the reverse operation of a
fuzzification process [15]. The output of the fuzzy inference
system must be crisp output because the value of fuzzy
inference engine result is fuzzy. Hence, the aim of
defuzzification process is transforms a fuzzy value into a
crisp value. There are popular methods in defuzzification
process such as centroid of area (COA) and Mean of
Maximum (MOM). In this paper we use the Mean of
Maximum because COA is computationally quite complex
and slow; being that involves finding the center of gravity,
known as the integration process [15]. The mean of
maximum (MOM) handles the calculation of the average of
all output values that have the highest degrees [13]. The
mean of maximum (ZMOM) of the area A is computed by
equation (1); where ZMOM is the defuzzified output, z’ is the
maximizing z at which the membership function reach its
maximum [14]