Semiparametric regression control charts

Abstract

ABSTRACTControl charts are screening processes that have been widely used in many areas where monitoring product quality is required. Many methods have been proposed to construct charts with different types of data. A common point in most existing methods is to monitor the quality variable only. However, in many situations, the quality variable depends on other covariates, such as environmental factors. Thus, without adjusting charts by taking the effect of covariates into consideration, the traditional charts typically have a poor performance when the quality variable is highly dependent on covariates. To this point, we propose a new type of semiparametric regression control charts by integrating a regression model into a traditional control chart. The quality monitoring process stems from a newly developed nonparametric prior called the transformed Bernstein polynomial prior (TBPP), which provides a convenient and robust way to implement the pattern recognition by assuming the unknown pattern is centere...