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Abstract
We propose the addition of a "cycle duration" constraint to the Lorenzen-Vance unified economic control chart model. This constraint consists of a specified upper bound on the 95th percentile of the distribution of out of control times. With the constraint added, the model serves to minimize long-run average costs while controlling for unacceptable short-term process behavior.
The constrained approach is applied to a wide variety of previously published examples. These examples illustrate situations where the out of control time variability can be substantially reduced at relatively Iow cost, demonstrating the practical appeal of the constrained model.
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A portion of this chapter is based on “Economic Control Chart Models with Cyclic Duration Constraints,” by Thomas P. McWilliams, Economic Quality Control, 1992, vol. 7, pp. 164-194.