Customer churn in online firms is difficult to manage because customers are so fickle. The ability to detect churn in the early stage is something every online firm would wish to achieve. It represents both a potential revenue source and a cost-saving benefit. Churn prediction models attempt to organize customer behaviors, transactions and demographics to reduce the possibility of churn within ...

The basic purpose of the economic design of the control charts is to find the optimum control charts parameters to minimize the process cost. In this paper, an R package, edcc (economic design of control charts), which provides a numerical method to find the optimum chart parameters is presented using the unified approach of the economic design. Also, some examples are given to illustrate how t...

Exponential CUSUM charts are used in monitoring the occurrence rate of rare events because the interarrival times of events for homogeneous Poisson processes are independent and identically distributed exponential random variables. In these applications, it is assumed that the exponential parameter, i.e. the mean, is known or has been accurately estimated. However, in practice, the in-control m...

We consider statistical process control (SPC) of univariate processes when observed data are not normally distributed. Most existing SPC procedures are based on the normality assumption. In the literature, it has been demonstrated that their performance is unreliable in cases when they are used for monitoring non-normal processes. To overcome this limitation, we propose two SPC control charts f...

Control charts based on time between events (TBE) data have been shown to be useful for monitoring production or failure processes where defect or failure occurrence can be recorded over time. One type of TBE chart is set up with probability control limits, e.g. the Cumulative Quantity Control (CQC) chart and its extension CQC-r chart, which monitors the quantity inspected until the occurrence ...

Process monitoring through control charts is a quite popular practice in statistical process control. From a statistical point of view, a superior control chart is one that has an efficient design structure, but having resistance against unusual situations is of more practical importance. To have a compromise between the statistical and practical purposes, a natural desire is to have a control ...

Dendrometers are devices, which measure continuously the stem radius of a tree. In this work, we studied the use of cumulative sum (CUSUM) charts for automatically and, thus, objectively determining the onset and cessation dates of radial increase based on dendrometer data. We used data measured in two forest stands in southern Finland to demonstrate the idea and to test the performance of the ...