Artículos de revistas
Attribute control charts for monitoring the covariance matrix of bivariate processes
Fecha
2018-03-01Registro en:
Quality and Reliability Engineering International, v. 34, n. 2, p. 257-264, 2018.
1099-1638
0748-8017
10.1002/qre.2253
2-s2.0-85040867787
Autor
Universidade Estadual Paulista (Unesp)
Universidade de São Paulo (USP)
Institución
Resumen
In this article, we consider the use of 3 attribute charts—the npxy, the npw and the Max D charts—to control the covariance matrix of bivariate processes. In comparison with the generalized variance |S| chart, the 3 attribute charts signal faster, with smaller samples, all kind of disturbances, except when the 2 variables are highly correlated. To compete with the VMAX chart, the Max D chart needs larger samples, but no more than twice bigger. An example illustrates the monitoring of the covariance matrix using the Max D and npw.