Abstract
A simple algorithm is introduced for computing the run length distribution of a monitoring scheme combining a Shewhart chart with an Exponentially Weighted Moving Average control chart. The algorithm is based on the numerical approximation of the integral equations and integral recurrence relations related to the run-length distribution. In particular, a Clenshaw-Curtis product-integration rule is applied for handling discontinuities in the integrand function due to the simultaneous use of the two control schemes. The proposed algorithm, implemented in R and publicy available, compares favourably with the Markov chain approach originally used to approximate the run length properties of the combined Shewhart-EWMA.
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References
Brook, D., Evans, D.: An approach to the probability distribution of CUSUM run length. Biometrika 59, 539–549 (1972)
Capizzi, G., Masarotto, G.: An adaptive Exponentially Weighted Moving Average control chart. Technometrics 45, 199–207 (2003)
Champ, C.W., Rigdon, S.E.: A comparison of the Markov chain and integral equation approaches for evaluating the run length distribution of quality control charts. Commun. Stat. Simul. Comput. 20, 191–204 (1991)
Champ, C.W., Rigdon, S.E., Scharnag, K.A.: Method for deriving integral equations useful in control chart performance analysis. Nonlinear Anal. Theory Methods Appl. 47, 2089–2101 (2001)
Clenshaw, C.W., Curtis, A.R.: A method for numerical integration on an automatic computer. Numer. Math. 2, 197–205 (1960)
Crowder, S.V.: A simple method for studying run-length distributions of Exponentially Weighted Moving Average charts. Technometrics 29, 401–407 (1987)
Imhof, J.P.: On the method for numerical integration of Clenshaw and Curtis. Numer. Math. 5, 138–141 (1963)
Kang, S.H., Koltracht, I., Rawitscher, G.: Nystrom-Clenshaw-Curtis quadrature for integral equations with discontinuous kernels. Math. Comput. 72, 729–756 (2002)
Knoth, S.: spc: Statistical Process Control (2004). R package version 0.2
Knoth, S.: Accurate ARL computation for EWMA-s 2 control charts. Stat. Comput. 15, 341–352 (2005)
Lucas, J.M., Saccucci, M.S.: Exponentially weighted moving average control schemes: Properties and enhancements quality. Technometrics 32, 1–29 (1990)
Luceno, A., Puig-Pey, J.: Evaluation of the run-length probability distribution for CUSUM charts. Technometrics 42, 411–416 (2000)
Luceno, A., Puig-Pey, J.: An accurate algorithm to compute the run length probability distribution, and its convolutions, for a CUSUM chart to control normal mean. Comput. Stat. Data Anal. 38, 249–261 (2002a)
Luceno, A., Puig-Pey, J.: Computing the run length probability distribution for CUSUM charts. J. Qual. Technol. 34, 209–215 (2002b)
Montgomery, D.C.: Introduction to Statistical Quality Control, 5th edn. Wiley, New York (2004)
Nelder, J.A., Mead, R.: A simplex algorithm for function minimization. Comput. J. 7, 308–313 (1965)
Piessens, R.: Computing integral transforms and solving integral equations using Chebyshev polynomial approximations. J. Comput. Appl. Math. 121, 113–124 (2000)
Piessens, R., de Doncker-Kapenga, E., Uberhuber, C.W., Kahaner, D.K.: QUADPACK. A Subroutine Package for Automatic Integration. Springer, Berlin (1983)
R Development Core Team: R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria (2008). URL http://www.R-project.org
Shu, L.: An adaptive Exponentially Weighted Moving Average control chart for monitoring process variances. J. Stat. Comput. Simul. 30, 415–428 (2008)
Sloan, I.H.: Quadrature methods for integral equations of the second kind over infinite intervals. Math. Comput. 36, 511–523 (1978)
Sloan, I.H.: Analysis of general quadrature methods for integral equations of the second kind. Numer. Math. 38, 263–278 (1981)
Sloan, I.H., Smith, W.E.: Product-integration with the Clenshaw and Curtis and related points. Numer. Math. 30, 415–428 (1978)
Sloan, I.H., Smith, W.E.: Product integration with the Clenshaw and Curtis points: implementation and error points. Numer. Math. 34, 387–401 (1980)
Sloan, I.H., Smith, W.E.: Properties of interpolatory product integration rules. SIAM J. Numer. Anal. 19, 427–442 (1982)
Trefethen, L.: Is Gaussian quadrature better than Clenshaw-Curtis? SIAM Rev. 50, 67–87 (2008)
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This research was partially funded by Italian MIUR-Cofin 2006 grants.
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Capizzi, G., Masarotto, G. Evaluation of the run-length distribution for a combined Shewhart-EWMA control chart. Stat Comput 20, 23–33 (2010). https://doi.org/10.1007/s11222-008-9113-8
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DOI: https://doi.org/10.1007/s11222-008-9113-8