Optimal Design of Modified Group Runs Scheme with Estimated Process Parameters Based on Expected Average Number of Observations to Signal The modified group runs (MGR) scheme has a superior performance to the Shewhart and synthetic control schemes, particularly in identifying small and moderate mean shifts in a process. Recently, the MGR scheme was studied using the average number of observations to signal (ANOS) criterion, under the scenario where the process parameters are unknown (CaseU). However, a setback of this study is that the exact shift size must be specified prior to the implementation of this scheme as this is required by the ANOS criterion. In most of the scenarios, practitioners do not have a good knowledge of the exact shift size. To tackle this issue, we propose the use of the expected average number of observations to signal (EANOS) criterion in evaluating the performance of the CaseU MGR scheme. We also proposed the optimal design of the MGR scheme with CaseU based on minimizing outofcontrol (OOC) EANOS. Finally, we present an example of application and demonstrate that the proposed procedure eases the implementation of the MGR scheme with CaseU as it minimizes the risk of misspecifying the shift size.

Timeminimal set point transition for nonlinear SISO systems under different constraints Abstract   Set point transition of nonlinear plants plays an important role in many applications where dynamic process management has to be considered. This transition should be rapid xe2x80x93 as operation in the new set point increases the economical benefit xe2x80x93 but in compliance with all safety regulations. We present a feedforward approach for a timeminimal set point transition of singleinput, singleoutput nonlinear plants with respect to input, state and output constraints. The conceptual idea is based on the design of an optimization problem utilizing a coordinate change of the plant and a special setup function for the output trajectory. This allows the simultaneous planning of the trajectory and determination of the corresponding control signal. The formulation of the set point transition as an optimization problem provides a flexible design with respect to the integration of inequality constraints. Additional flexibility is provided by the type of setup functions, which permit any adjustment of the output trajectory between the set points. In contrast to other works, we focus on the stationarity of the system output, which allows a faster transition compared to the requirement to reach a steady state of all states. Finally, we present an example from the field of process systems engineering to demonstrate the applicability of the proposed methodology.