Monitoring of Multivariate Profiles in Multistage Process

Bahrami, Hassan | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50642 (01)
  4. University: Sharif University of Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Akhvan Niaki, Taghi
  7. Abstract:
  8. Nowadays, due to the advancement in manufacturing technology and increasing use of information technology in the services and industries, most of production proccess consist of complex and high-dimensional data. These processes include multivariate processes, complex profiles and multistage processes. In some quality control applications, processes consist of multiple components, stations or stages to finish the final product or service which are called multistage processes. In addition, some quality characteristics in each stage can be represented by a relationship between a response variable and one or more explanatory variables which is named as profile. In this research, a general model is proposed for monitoring the multivariate profiles in multistage process. First, the multivariate form of U transformation is used to eliminate the effect of the cascade property between stages. Then, two control schemes are used to monitor the parameters of multivariate simple linear profiles in multistage processes in Phase II. These methods include a single MEWMA and a combination of Chi-square statistic and MEWMA. The performance of the methods are evaluated in terms of the average run length criterion using 10,000 simulation experiments. The results show that both methods perform well in different conditions and the model has effectively eliminated the effect of the cascade property in multistage process
  9. Keywords:
  10. Statistical Quality Control ; Multistage Process ; Cascade Property ; Autocorrelation ; Multivariate Profiles

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