There have been changes since the companies realized important role of quality improvement in their success. If they are able to produce high products and satisfy demands, then can survive competitive global markets. Quality applications aim decrease variability, which leads less cost, production time, number defects, scrap, rework more customer satisfaction. be improved by reducing product var...

After the Shewhart method was suggested for industrial applications, other applications such as surveillance for bioterrorism and financial transactions have come into focus. Also other methods for surveillance have followed. The relation between the Shewhart method and the followers is examined. A uniform presentation of methods, by expressions of likelihood ratios, facilitates the comparisons...

in this paper, first the available single charting methods, which have been proposed to detect simultaneous shifts in a single process mean and variance, are reviewed. then, by designing proper simulation studies these methods are evaluated in terms of in-control and out-ofcontrol average run length criteria (arl). the results of these simulation experiments show that the ewma and ewms methods ...

in this research, an iterative approach is employed to recognize and classify control chart patterns. to do this, by taking new observations on the quality characteristic under consideration, the maximum likelihood estimator of pattern parameters is first obtained and then the probability of each pattern is determined. then using bayes’ rule, probabilities are updated recursively. finally, when...

Shewhart control charts are suitable for stable but repetitive production processes used the subsequent identification of random deviations while indicating breached quality limits. They provide information on process variability and, at same time, make it possible to obtain reliability monitored processes. The objective this paper is assess characteristics plastic mouldings needs automotive in...

control chart is the most well-known chart to monitor the number of nonconformities per inspection unit where each sample consists of constant size. generally, the design of a control chart requires determination of sample size, sampling interval, and control limits width. optimally selecting these parameters depends on several process parameters, which have been considered from statistical and...