the classical method of process capability analysis necessarily assumes that collected data are independent; nonetheless, some processes such as biological and chemical processes are autocorrelated and violate the independency assumption. many processes exhibit a certain degree of correlation and can be treated by autoregressive models among which the autoregressive model of order one (ar (1)) ...

Process capability indices Cp, Cpk, Cpm and Cpp fitting for nominal-the-best type quality characteristics, are effective tools to assess process capability since these indices can reflect a centering process capability and process yield adequately. The index Cpp introduced by Greenwith and Jahr-Schaffrath [Greenwith, M., Jahr-Schaffrath, B.L., 1995. A process incapability index. International J...

Process capability indices (PCIs) can be viewed as effective and excellent means of measuring product quality and performance, but they are not sufficient for evaluating an entire product with multiple characteristics. [Chen, K.S., Huang, M.L., Li, R.K., 2001. Process capability analysis for an entire product. International Journal of Production Research 39(17), 4077–4087] proposed the process ...

Statistical process control is a major part of industrial statistics and consists not only of control charting, but also of capability analysis, of design of experiments and other statistical techniques. This paper reviews and comments some available techniques for the univariate as well as for the multivariate case from the viewpoint of industrial application. 1 Distribution of a Quality Chara...

Process Capability indices have become popular for describing how well a process meets specified tolerances. The lack of affinity with the process nonconformance probability p and the difficulty of dealing with the sampling distribution of their natural estimators affect greatly the use of the traditional indices as Cp, Cpk, Cpm and Cpkm. In this paper, a capability index is proposed which is c...

in quality control charts, the problem of determining the optimum process mean arises when the deviation of a quality characteristic in one direction is more harmful than in the opposite direction. the failure mode in these two directions is usually different. a great majority of researches in this area have considered asymmet-ric cost function for processes with single quality characteristics....

The concept of process capability was proposed in early 1970 with the introduction of ‘capability ratio’ by Juran, a world known quality expert. Thereafter almost 40 years have been passed and many indices such as Cp, Cpk and Cpm were developed for measuring process performance. However, many researchers, for example, Kotz and Johnson [1-2] raised concerns about the application of the diversifi...