End-to-end available bandwidth estimation is very important for bandwidth dependent applications, quality-of-service verification and traffic engineering. Although several techniques and tools have been developed in the past, producing precise estimations in real-time still remains challenging, mainly due to the lack of control on the measured network path and environmental conditions, such as ...

The Internet routers employing the random early detection (RED) algorithm for congestion control suffer from the problem of chaotic queue oscillation. It is well known that the slowly varying nature of the average queue size computed using an exponentially weighted moving average (EWMA) used in the RED scheme causes this chaotic behavior. This paper presents a new mathematical function to model...

(Correction made here after initial online publication.) Today's manufacturing environment has changed since the time when control chart methods were originally introduced. Sequentially observed data are much more common. Serial correlation can seriously affect the performance of the traditional control charts. In this article we derive explicit easy-to-use expressions of the variance of an EWM...

Recently, monitoring the process mean and variability simultaneously for multivariate processes by using a single control chart has drawn some attention. However, due to the complexity of multivariate distribution, the existing methods in the univariate processes can not be readily extended to the multivariate processes. In this paper, we propose a new single control chart which integrates the ...

Control charts with exponentially weighted moving average (EWMA) statistics (mean and variance) are used to jointly monitor the mean and variance of a process. An EWMA cost minimization model is presented to design the joint control scheme based on pure economic or both economic and statistical performance criteria. The pure economic model is extended to the economic-statistical design by addin...

EWMA control charts designed for monitoring the variance or the mean and the variance of a normally distributed variable are either based on the log transformation of the sample variance S or provide only rough ARL results. Gan (1995), as the most prominent example for the simultaneous case, calculated ARL values precisely for X̄-lnS EWMA schemes. The results in Knoth and Schmid (2002) for X̄-S o...

Control charts have been broadly used for monitoring the process mean and dispersion. Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are memory control charts as they utilize the past information in setting up the control structure. This makes CUSUM and EWMA-type charts good at detecting small disturbances in the process. This article proposes two new mem...

Background. Use of statistical process control (SPC) in healthcare is increasing but remains less common than in other industries. Healthcare-associated infections (HAIs) are important applications that can benefit from SPC methods, including use within existing surveillance programs to trigger investigation and intervention. The empirical value of SPC, however, typically is anecdotal and remai...