optimum generalized compound linear plan for multiple-step step-stress accelerated life tests

in this paper, we consider an  i.e., multiple step-stress accelerated life testing (alt) experiment with unequal duration of time . it is assumed that the time to failure of a product follows rayleigh distribution with a log-linear relationship between stress and lifetime and also we assume a generalized khamis-higgins model for the effect of changing stress levels. taking into account that the problem of choosing the optimal time for 3-step step-stress tests under compound linear plan was initially attempted by khamis and higgins [16]. we ever first have developed a generalized compound linear plan for multiple-step step-stress setting using variance-optimality criteria. some numerical examples are discussed to illustrate the proposed procedures.