fuzzy-based functional capability indices for simple linear profile

The quality of some processes is defined by a simple linear function between a response and an explanatory variable, which is named a simple linear profile. various capability indices have been introduced in the literature for these processes. some of them are functional, that use all domain of the explanatory variable instead of its levels values. therefore, these methods may fail to account capability of the process and overstate it. this paper applies fuzzy logic to deal with the explanatory variable domain and introduces two capability indices. then, investigates and compares the performance of the proposed indices and some existing ones, using a simulation study. results show that one of the new proposed indices has the best performance based on the mean square error and mean absolute error criteria.