Statistical Process Control Analysis

Sheikh Abdul Kadir Hagi, Ibrahim (1999) Statistical Process Control Analysis. Masters thesis, Universiti Pertanian Malaysia.

[img] PDF
829Kb

Abstract

This thesis is concerned with the investigation of the two key aspects of statistical process control. The first aspect is maintaining a stable process so that the pattern of variation of process out-put is not changing. In order to maintain a stable process, the study includes an examination of the state of control of the process. A traditional variable control charts, x and R charts and also the x control chart based on sample median and median control chart in conjunction with a chart for sample range were used for both normal and non-normal process. The second aspect depicts the process capability. Assuming that the processes have reached the state of statistical control, capability measurements were proceeded in this study for both normal and non-normal processes. A simulation studies are carried out to compare the performance of the traditional and the robust control chart. Likewise, the classical capability index is compared to two robust capability index. The results of the study indicate that the traditional and the robust control chart are equally good when no contamination in the data. However, the later performs better than the former in the presence of outliers in the data. Similarly, the traditional process capability index are almost as good as the robust capability index as proposed by Clement (1989) and John Kot (1993) in a well behaved data. Nevertheless, the robust capability index were found to be better compared to the traditional index when contamination occurs in the data. The study also carried out an investigation of properties of the three types of bootstrap confidence interval for estimating the process capability index (Cpk)' namely the standard, percentile and bias corrected and accelerated for two processes (normal and skewed). The average lengths displayed a consistent pattern where the longest intervals were the standard intervals, and with the shortest intervals being the percentile and bias corrected and accelerated intervals for both normal and highly skewed processes. The results of the study seem to be consistent for sample size n = 25 to n = 50.

Item Type:Thesis (Masters)
Subject:Process control - Statistical methods
Chairman Supervisor:Habshah Bt Midi, PhD
Call Number:FSAS 1999 35
Faculty or Institute:Faculty of Science and Environmental Studies
ID Code:9497
Deposited By: Laila Azwa Ramli
Deposited On:10 Feb 2011 07:16
Last Modified:26 Sep 2013 00:33

Repository Staff Only: Edit item detail

Document Download Statistics

This item has been downloaded for since 10 Feb 2011 07:16.

View statistics for "Statistical Process Control Analysis"


Universiti Putra Malaysia Institutional Repository

Universiti Putra Malaysia Institutional Repository is an on-line digital archive that serves as a central collection and storage of scientific information and research at the Universiti Putra Malaysia.

Currently, the collections deposited in the IR consists of Master and PhD theses, Master and PhD Project Report, Journal Articles, Journal Bulletins, Conference Papers, UPM News, Newspaper Cuttings, Patents and Inaugural Lectures.

As the policy of the university does not permit users to view thesis in full text, access is only given to the first 24 pages only.