A Single CUSUM Chart for Monitoring Time Interval and Magnitude of Critical Events  
Author Liang Qu




Abstract This article presents a single CUSUM scheme (called the GCUSUM chart) for simultaneously monitoring the time interval T and magnitude X of an event. Since the GCUSUM chart is developed based on a synthetic statistic G which is a function of both T and X, this new chart is able to make use of the information about the event frequency, as well as the information about the event magnitude. Moreover, the detection power of the GCUSUM chart can be allocated in an optimal manner between that against T shifts and against X shifts, and between those against small shifts and against large shifts. The performance studies show that the GCUSUM chart is more effective than all other charts in the current literature for detecting the out-of-control status of an event. This chart is also easier to be designed and implemented than other CUSUM charts for monitoring both T and X. The GCUSUM chart has the potential to be applied to many different areas, especially to the non-manufacturing and service sectors, such as supply chain management, homeland security, office administration and health care industry.


Keywords Statistical process control; Quality control; CUSUM chart; Time between events; Magnitude of an event
    Article #:  1881
Proceedings of the 18th ISSAT International Conference on Reliability and Quality in Design
July 26-28, 2012 - Boston, Massachusetts, U.S.A.