The effect of aggregation and defuzzification method selection on the risk level calculation

In this paper a fuzzy logic-based hierarchical multilevel risk calculation model will be introduced with different model parameters. On each occasion when a fuzzy-based simulation model is constructed, the appropriate aggregation and defuzzification method must be chosen. It is very difficult because it cannot be said generally, which is the best method, its depends on the current application. The model presented in the paper is a model for risk calculation of physical exercise, and it was constructed in Simulink - Fuzzy Logic Toolbox environment with Mamdani-type fuzzy evaluation and different aggregation and defuzzification operators. The test was performed for several typical groups of the patients. The results are compared with a previously implemented Analytic Hierarchy Process with Fuzzy Comprehensive Evaluation based model with similar purposes. The result of the comparison has been analyzed and the best methods have been selected.