In many industrial manufacturing processes, the quality of products can depend on relative amount between two characteristics X and Y. Often, this calls for on-line monitoring ratio Z=X/Y as a characteristic itself by means control chart. A large number charts have been investigated in literature under assumption independent normal observations characteristics. practice, due to high frequency s...

The Shewhart control chart is for many people the embodiment of statistical process control (SPC). In the past, many modifications and improvements have been devised (see Woodall and Montgomery [1999] for a brief overview). Several modifications or additions were aimed at more power for out-of-control situations. Among the earlier additions belong the runs rules from the Western Electric Compan...

The characteristic of software processes, unlike manufacturing ones, is that they have a very high human-centered component and are primarily based on cognitive activities. As so, each time a software process is executed, inputs and outputs may vary, as well as the process performances. This phenomena is better identified in literature with the terminology of “Process Diversity” (IEEE, 2000). G...

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...

Most commonly used control charts for monitoring quality characteristics of the processes were developed under the assumption that the observations are randomly sampled from a normal population. It is well known that these control charts have more false alarms than usual when processes are positively autocorrelated. One remedy is to adjust the control limits such that the modified control chart...

In order to monitor a process, quality practitioners frequently use Shewhart control charts (e.g. X –R, P-charts, etc.), so named after the pioneering work of Dr. Walter Shewhart. It can be shown that if there are sharp, intermittent changes to a process, these types of charts are highly effective. However, if one is interested in a small, sustained shift in a process, other types of control ch...