... Acosta and Pignatiello’s(1996) CUSUM scheme and EWMA charts, as shown in Tables 18.6(a) and (b), to Acosta and Pignatiello’s(1996) EWMA chart which adopts Roberts’ (1959) EWMA for mean and Wortham’s ... 18.1 and ρ is the variance shift magnitude in σ as definedin Table 18.3.TABLE 18.6 Comparisons between C-NN and Acosta’s CUSUM and EWMA(a) Comparisons between C-NN and Acosta’s CUSUM and EWMA ... Industrial Engineering, 28(1), 51-61.Crowder, S. T. and Hamilton, M. D. (1992) An EWMA for monitoring a process standard deviation,Journal of Quality Technology, 24(1), 12-21.Efron, B. and Tibshirani,...