where yk represents the predicted response (e.g., IPC) of the k-th configuration (k = 1,..., N), and yˆk represents the actual response of the k-th configuration, which is obtained by cycle-by-cycle simulation. To compare the prediction accuracy of COAL
with that of the state-of-the-art (ANN), the MSE of COAL on the testing data will be normalized to that of the ANN DSE approach introduced by I¨pek et al. [2006].