In this paper, standard Cusum charts with head start value zero are compared with fast initial response (FIR) Cusum charts proposed by Lucas and Crosier (Technometrics 24: 199–205, 1982) from the viewpoint of the false alarm probability function. The focus in this comparison is...

A major resource for quality exists at Lockheed Martin Aeronautics - Fort Worth with the average age of the workers approaching 50 years with over 20 years employment. Realizing the asset present within this highly experienced work force became a major effort for improving quality at this plant....

Process capability indices Cp and Cpk are widely used in statistical quality control to assess the capability of a process. These indices are defined, based on the assumption that the quality characteristic follows a normal distribution. In this paper two new capability indices are considered,...

Some recent studies have proved that charts with variable sample size (VSS) detect moderate or larger shifts in normal and stable processes more quickly than the Standard Shewhart (SS) chart. But the statistical efficiency of charts, the speed at which they detect smaller shifts of the process...

A Markov Renewal Process (MRP) is used to obtain the time dependent probabilities and the availability of a K-out-of-N:G system with exponential failures and general repairs. A special case of Erlang-2 repairs is provided to illustrate the results.

We derive explicit formulas for availability and performance measures in complex degradable stochastic networks. The networks consist of interacting service systems (queues) where servers are unreliable and may break down. The breakdown and repair mechanisms are of rather general structure, and...

Suppose that a number of items is put on operation and that their life times are identically exponentially distributed up to a time a, when the operating conditions change resulting in a different failure intensity of the exponential distribution for those items which have survived the...

A rational selection of a probability distribution constitutes a major problem. Often a distribution function is selected which fits well to the observed data. In other cases the availability of statistical methods determines the model. Finally, in many fields of application there are certain...

Pearn et al. (Kotz and Johnson, Journal of Quality Technology 24: 216–233, 1992) proposed the process capability index Cpmk , and investigated the statistical properties of the natural estimator for stable normal processes with constant mean μ. Chen and Hsu (Communications in Statistics:...

Process capability indices Cp and Cpk have been widely used to provide numerical measures on process potential and process performance. While Cp measures process variation relative to the specification tolerance, which only reflects process potential, Cpk considers process variation as well as...