Title: A double neural network approach for the identification and parameter estimation of control chart patterns

Authors: Ahmed Shaban; Mohamed A. Shalaby

Addresses: Industrial Engineering Department, Faculty of Engineering, Fayoum University, Fayoum 63514, Egypt. ' Mechanical Design and Production Department, Faculty of Engineering, Cairo University, Giza 12613, Egypt

Abstract: The exhibited pattern on a control chart is classified as either natural or unnatural pattern. The presence of an unnatural pattern is evidence that a process is out of control. This paper devises neural networks as an intelligent tool to automate the identification of the different control chart patterns, and to accurately estimate their parameters. Two neural networks, named 'NN-1' and 'NN-2', are integrated together to perform the identification and the parameter estimation. The first stage 'NN-1' is developed to identify the existing pattern in the control data, and the second stage 'NN-2' is used to estimate the parameters of that pattern. NN-1 is developed to identify the five basic control chart patterns; namely: natural, upward shift, downward shift, upward trend, and downward trend. The probability of success in identifying the correct control charts pattern and its parameters is used to evaluate the performance of both NN-1and NN-2. Performance results of NN-1 and NN-2 are compared with other previous leading research work. Comparisons show that the proposed neural network approach yield better probability of success than the others.

Keywords: quality control; control chart patterns; control charts; natural patterns; unnatural patterns; upward shift; downward shift; upward trend; downward trend; pattern identification; parameter estimation; success probability; neural networks; statistical process control; SPC.

DOI: 10.1504/IJQET.2012.049681

International Journal of Quality Engineering and Technology, 2012 Vol.3 No.2, pp.124 - 138

Received: 10 Feb 2012
Accepted: 12 Mar 2012

Published online: 12 Oct 2012 *

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