Results 211 to 220 of about 420,626 (277)

The Misguided Adaptive EWMA Chart

Quality and Reliability Engineering International
A new adaptive EWMA (AE) chart has been recently introduced for monitoring the mean of a normally distributed process. Using this variant of the AE chart, numerous papers have been written in statistical process monitoring literature.
Abdul Haq
semanticscholar   +2 more sources

An adaptive multivariate EWMA chart

Computers & Industrial Engineering, 2019
Abstract The adaptive multivariate EWMA (AMEWMA) and adaptive multivariate CUSUM (AMCUSUM) charts are recently proposed as they provide an overall good detection over a range of mean shift sizes than their non-adaptive conventional counterparts. In this paper, we propose an adaptive MEWMA (AMEWMA) chart for monitoring the infrequent changes in the ...
A. Haq, M. Khoo
semanticscholar   +2 more sources

CS‐EWMA Chart for Monitoring Process Dispersion

Quality and Reliability Engineering International, 2013
Control charts are the most extensively used technique to detect the presence of special cause variations in processes. They can be classified into memory and memoryless control charts. Cumulative sum and exponentially weighted moving average control charts are memory‐type control charts as their control structures are developed in such a way that the ...
N. Abbas, M. Riaz, R. Does
semanticscholar   +3 more sources

Beyond the EWMA chart: Critiquing hybrid approaches

Quality and Reliability Engineering International, 2023
This study reveals that recent variants of the EWMA chart have problematic weighting functions. These functions assign more weight to past data values than to the most recent ones, a practice that is less advisable.
Abdul Haq
semanticscholar   +1 more source

An improved exponential EWMA chart for monitoring time between events

Quality and Reliability Engineering International, 2022
Many control charts have been developed for monitoring the time between adverse events (TBE) to improve the quality of processes. In practice, the decrease in the TBE mean usually implies a deterioration of the process, while the increase indicates an ...
Yang Zhang, Yanfen Shang, Xuelong Hu, An-Da Li   +3 more
semanticscholar   +1 more source

Robust online detection on highly censored data using a semi-parametric EWMA chart

Journal of Statistical Computation and Simulation, 2022
For time and cost considerations, high censoring rate is quite common in life tests, which is a critical issue in lifetime monitoring. Conventional control charts designed for highly censored data are commonly based on the Weibull distribution.
Miaomiao Yu, Wei Zhao, Yong Zhou, Chunjie Wu   +3 more
semanticscholar   +1 more source

A parameter-free adaptive EWMA chart with variable sample sizes and variable sampling intervals for the process mean

Journal of Statistical Computation and Simulation, 2022
In this article, a parameter-free adaptive EWMA (AE) chart, which adopts the variable sample size (VSS), variable sampling interval (VSI) or both (VSSVSI) features, is developed to monitor the mean of a normal process.
A. Haq, Haleema Sadia, M. Khoo
semanticscholar   +1 more source

Max‐EWMA chart for time and magnitude monitoring using exponentially modified Gaussian distribution

Quality and Reliability Engineering International, 2021
Monitoring time and magnitude jointly is an attractive field due to their vast applications in different industries. This article presents a new maximum exponentially weighted moving average (Max‐EWMA) chart assuming exponentially modified Gaussian (EMG)
Ayesha Talib, Sajid Ali, Ismail Shah
semanticscholar   +1 more source

Moving average EWMA chart for the Weibull distribution

Communications in statistics. Simulation and computation, 2021
A new control chart is being presented using an exponentially weighted moving average (EWMA) statistic and moving average (MA) statistic to monitor the number of defective counts before specified time which follows Weibull distribution.
Nasrullah Khan, M. Nawaz, R. Sherwani, Muhammad Aslam   +3 more
semanticscholar   +1 more source