This work shown as the fuzzy-EGARCH-ANN (fuzzy-exponential generalized autoregressive conditional heteroscedastic-artificial neural network) model does not require continuous model calibration if the corresponding DE algorithm is used appropriately. but other models such as GARCH. EGARCH. and EGARCH-ANN need continuous model calibration and validation so they fit the data and reality ... https://thebrickes.shop/product-category/sleeper-sectional/