Algorithm 1 Adaptive Adjustment Algorithm for Reduction Threshold

Input:  current threshold $e_{max}$, threshold minimum $erro{r}_{min}$, threshold maxmum $erro{r}_{max}$   1:while True do   2:    Call the CUSUM algorithm to determine if concept drift has occurred   3:    if Concept drift occurs then   4:        if $e_{max}$ > $erro{r}_{min}$ then   5:           Lower the current threshold $e_{max}$   6:           if $e_{max}$ < $erro{r}_{min}$ then   7:               $e_{max}$ = $erro{r}_{min}$   8:    else   9:        if c < $erro{r}_{max}$ then 10:           Raise the current threshold $e_{max}$ 11:           if $e_{max}$>$erro{r}_{max}$ then 12:               $e_{max}$ = $erro{r}_{max}$