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Phase-I monitoring of general linear profiles in multistage processes

Khedmati, M ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1080/03610918.2015.1118507
  3. Publisher: Taylor and Francis Inc , 2017
  4. Abstract:
  5. In this article, the general linear profile-monitoring problem in multistage processes is addressed. An approach based on the U statistic is first proposed to remove the effect of the cascade property in multistage processes. Then, the T2 chart and a likelihood ratio test (LRT)-based scheme on the adjusted parameters are constructed for Phase-I monitoring of the parameters of general linear profiles in each stage. Using simulation experiments, the performance of the proposed methods is evaluated and compared in terms of the signal probability for both weak and strong autocorrelations, for processes with two and three stages, as well as for two sample sizes. According to the results, the effect of the cascade property is effectively removed and hence each stage can be monitored independently. In addition, the result shows that the LRT approach provides significantly better results than the T2 method and outperforms it under different shift and autocorrelation scenarios. Moreover, the proposed methods perform better when larger sample sizes are used in the process. Two illustrative examples, including a real case and a simulated example, are used to show the applicability of the proposed methods. © 2017 Taylor & Francis Group, LLC
  6. Keywords:
  7. Cascade property ; General linear profiles ; Multistage processes ; Phase I ; Signal probability ; Communication ; Computer simulation ; Statistics ; Likelihood ratio tests ; Linear profile monitoring ; Linear profiles ; Multistage process ; Nocv1 ; Sample sizes ; U-statistics ; Autocorrelation
  8. Source: Communications in Statistics: Simulation and Computation ; Volume 46, Issue 6 , 2017 , Pages 4465-4489 ; 03610918 (ISSN)
  9. URL: https://www.tandfonline.com/doi/full/10.1080/03610918.2015.1118507