The present invention presents methods for reducing the amount of noise inherent in the reading of a non-volatile storage device by applying an episodic agitation to some terminal of the cell as part of the reading process. The method may include adaptively limiting a change of the QP between frame intervals based on a difference between the QP and the threshold value. Based on this sensed movement, the sensor generates a signal that is used to drive a control system to minimize the off-track motion. The location of the device is then based on the RSS levels and the final path loss coefficients. The present invention can achieve optimal fiber opening results in a relatively short period of time and at the same time does not cause loose grain, and meanwhile the pollution or impact on the environment is reduced in a maximum way. A second member includes magnet coils, and is designed to be changeable in position relative to the first member.