one of the most important problems of the designs proposed by traditional economic-statistical approaches of control charts is inefficiency in the face of uncertainty. uncertainty in the parameters of economic-statistical models may lead to failure in rapidly detecting changes in processes and impose greater costs to the organization. monitoring the machining process in an automotive industry e...

The control limits of an exponentially weighted moving average (EWMA) control chart should vary with time, approaching asymptotic limits as time increases. However, previous analytic analyses of EWMA charts consider only asymptotic control limits. In this article, the run length properties of EWMAs with time-varying control limits are approximated using nonhomogeneous Markov chains. Comparing t...

There are many situations for statistical process in which we have both random and vague information. When uncertainty is due to fuzziness of information, fuzzy statistical control charts play an important role in the monitoring process, because they simultaneously deal with both kinds of uncertainty. Dealing with fuzzy characteristics using classical methods may cause the loss of information a...

In this paper is presented the study of fuzzy logic power stabilizer for stability of a single machine infinite bus (SMIB). The performance of the system with fuzzy logic based power system stabilizer is compared with the system having conventional power system stabilizer and system without power system stabilizer. The results show that the system with fuzzy logic controller is capable of stabi...

This research proposes a vigorous methodology based on the fuzzy set theory to improve the facility layout process. Using natural language, the fuzzy set theory is an appropriate tool for controlling complex systems such as facility planning. The closeness rating between departments in a plant depends on qualitative and quantitative factors. Some of these factors may have a greater effect on th...