Title: Economic design of two-stage control charts with asymmetric and dependent measurements
Authors: Nan-Cheng Su - National Taipei University (Taiwan) [presenting]
Abstract: In many instances, the cost is high to monitor primary quality characteristic called performance variable, but it could be more economical to monitor its surrogate. To cover asymmetric processes for two-stage charting methods using both performance and surrogate variables, bivariate skew normal distribution is considered as the underlying distribution of process variables. When the correlation relationship between the performance variable and its surrogate is specified, a charting procedure to monitor either the performance variable or its surrogate in an alternating fashion rather than monitoring the performance variable alone is proposed. The proposed two-stage control charts are constructed under an economic design using Markov chain approach. Two algorithms are provided to implement the proposed charting method. The application of the proposed charting method and its advantages over the existing methods are presented through an illustrating example.