Journal of Modern Technology and Engineering, cilt.7, sa.2, ss.124-133, 2022 (Hakemli Dergi)
Fuzzy inference system (FIS) is one of the most used approaches in decision making and machine
learning models. The main advantage of this system is that it can process data in the fuzzy form whose exact
value is unknown. Various FIS models are available in the literature. The most common FIS models are Mamdani
and Sugeno type models. In Sugeno type FISs, the output of each rule should be given as a specific mathematical
function. Sometimes these functions can be difficult to identify. In the Mamdani model, it is sufficient to give an
approximate fuzzy set instead of the specific function as a rule output. The overall output of the Mamdani type
model is the aggregated fuzzy set, which is an aggregation of individual rule outputs. But in this composite set,
the contours of each rule output are lost and the effect on the overall output is not very obvious. A novel type FIS
with rule-based defuzzification (FIS-RBD) is proposed in this study. This model is a Mamdani type FIS, however,
the defuzzification process is applied to each rule’s output instead of the overall output. The overall output of
the system is calculated as the weighted average of the defuzzified values of the rule outputs. This approach is
a synthesis of a Mamdani type and Sugeno type models. In the study, the details of the proposed approach are
examined and the working principle is explained with numerical examples.