The multivariate exponentially weighted moving average (MEWMA) control chart is one of the best statistical control chart that are usually used to detect simultaneous small deviations on the mean of more than one cross-correlated quality characteristics. The economic design of MEWMA control charts involves solving a combinatorial optimization model that is composed of a nonlinear cost function ...

ABSTRACT. Goal: The main objective of this research paper is to propose a chart, named  Modified Control Chart, where the process variance () allowed be larger than in-control value until maximum (), as long remains capable, in sense that it produces specified (tolerated) small fraction non-conforming items. Design / Methodology Approach: methodology was quantitative approach with statistical...

Control charts are one of the most important tools in statistical process control that lead to improve quality processes and ensure required quality levels. In traditional control charts, all data should be exactly known, whereas there are many quality characteristics that cannot be expressed in numerical scale, such as characteristics for appearance, softness, and color. Fuzzy sets theory is a...