Phase-II monitoring and diagnosing of multivariate categorical processes using generalized linear test-based control charts

ABSTRACT

In this paper, two control charts based on the generalized linear test (GLT) and contingency table are proposed for Phase-II monitoring of multivariate categorical processes. The performances of the proposed methods are compared with the exponentially weighted moving average-generalized likelihood ratio test (EWMA-GLRT) control chart proposed in the literature. The results show the better performance of the proposed control charts under moderate and large shifts. Moreover, a new scheme is proposed to identify the parameter responsible for an out-of-control signal. The performance of the proposed diagnosing procedure is evaluated through some simulation experiments.

KEYWORDS:

• Contingency table
• Exponentially weighted moving average
• Generalized linear test
• Multivariate categorical process
• Statistical process control

Acknowledgement

The authors are thankful to the anonymous reviewers for precious and constructive comments which led to significant improvement in the paper.