Process capability indices such as Cp, Cpk, Cpu and Cpl are common metrics to evaluate and predict the performance of a process. Although higher process capability indices indicate higher process “quality”, but a high quality process does not necessarily guarantee the fewer rates of rejects. Therefore, a process capability index based on rate of rejects or real losses is more reliable and prope...

1. Introduction A process capability index is a numerical summary that compares the behavior of a product or process characteristic to engineering specifications. These measures are also often called capability or performance indices or ratios; we use capability index as the generic term. A capability index relates the voice of the customer (specification limits) to the voice of the process. A ...

Finding a suitable multi-dimensional index structure for a data-intensive system is not a trivial task. The QuEval framework supports users in finding the best index structure from a list of candidates. Nevertheless, if an index structure shows itself superior to other index structures most oft the times, but fails for one data set, we want to know the reason for this phenomenon. To support an ...

Fuzzy process capability indices are used to determine whether a production process is capable of producing items within specification tolerance, where instead of precise quality we have two membership functions for specification limits. In practice these indices are estimated using sample data and it is of interest to obtain confidence limits for fuzzy capability index given a sample estimate....

During the past three decades, PCIs – process capability indices – have inspired hundreds of pages of scientific research. The trade-off between simplicity and precision in reproducing an overall process quality prediction is both the reason behind the criticism for Cp and Cpk and the motive for their widespread use. Indeed, their strength in simplifying the assessment of a process control stat...