Sequential designs for estimating the operating window

In some industrial tests, the testing specimens are subjected to a variety of stress levels to generate observations. During the test, a prescribed stress level is applied to each experimental unit and the outcome is ternary: non-response, successful-response and over-response. Non-response and over-response are two failure modes. There is a operating window of stress levels in which successful-responses are excited with probability p. This article proposes two new sequential designs to estimate the boundaries of the operating window. Simulation study shows that the proposed procedures are efficient and robust.