The present invention provides improving agents of side-effects of chemotherapy agents. The downhole tool is positioned in a wellbore penetrating the subterranean formation. The controller includes a first actuator for locking or unlocking each of the lids, and a second actuator for unlocking the at least one of the trunks provided with the pop-up device and actuating the pop-up device. Multivariate periodograms or autocovariance functions are then calculated for each signal series.