Mohammad Esmail Dehghan Monfared

When a control chart indicates that the process is out of control. speed in determining the cause of The process out of control and elimination is of particular importance. if we can provide a good estimate of when the process goes out of control, we can more quickly identify and eliminate the cause of the process out of control . in this dissertation, we assume that a Poisson process is monitored by A multi­attribute control diagram. the control diagram warns that the process time out of control (change point) is estimated in different ways . in particular , we show how to use the information in the control diagram and the unknown change point estimators for when . step change with a linear trend is improved . Keywords: Change point estimation; Shewhart X control chart; Statistical process control; Quality control; Process improvement; Special­cause identification;Multivariate Poisson processes ; Change point estimation; Maximum likelihood estimator; Root transformation ;Square root transformation