Optimal design of experiment based on the Wiener degradation model with covariate using conditional Fisher information matrix

The Wiener degradation models with covariates are widely used for reliability analysis by degradation index paths. In this paper, we suggest an algorithm for constructing the optimal design based on the Wiener degrada-tion model, which involves determining optimal stress levels, the number of objects under each stress level and the time moments for measuring degradation index, taking into account the limitation on the duration of the experiment and the critical value of the degradation index. The proposed algorithm is based on optimizing the sum of functionals from the Fisher information matrix (FIM) and the conditional Fisher information matrix (CFIM) under given restrictions on the stress levels, the duration of the experiment and the minimal interval between the time points of measuring the degradation index. As an example, the application of the developed algorithm is considered for the LED reliability analysis.