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Monitoring of time between events with a double generally weighted moving average control chart
Author(s) -
Alevizakos Vasileios,
Koukouvinos Christos,
Lappa Angeliki
Publication year - 2019
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.2430
Subject(s) - chart , control chart , weibull distribution , x bar chart , control limits , statistics , log normal distribution , ewma chart , range (aeronautics) , moving average , shewhart individuals control chart , \bar x and r chart , mathematics , limit (mathematics) , computer science , reliability engineering , engineering , process (computing) , mathematical analysis , aerospace engineering , operating system
Monitoring of time between events (TBE) instead of the number of events is used in high‐quality processes where the events occur rarely. This article presents a double generally weighted moving average control chart with a lower time‐varying control limit to monitor the TBE (regarded as DGWMA‐TBE chart). The design parameters of the proposed chart are provided, and through a simulation study, it is shown that the DGWMA‐TBE chart is more effective than the DEWMA and GWMA charts in detecting moderate to large shifts. Furthermore, the DGWMA‐TBE chart is very robust for the same range of shifts when the TBE observations follow a Weibull or a lognormal distribution. Finally, examples are also presented to enhance the performance of the proposed chart.