A power controlling method and corresponding base station for controlling the transmission power of each user terminal are disclosed, in which, each user terminal is paired into virtual MIMO transmission. In some examples, a device determines whether physical activity corresponds to a first type based on a first set of criteria, and whether physical activity corresponds to a second type based on a second set of criteria. An absorbent structure is disposed between the liner and the outer cover and extends from the crotch region to at least one of the front waist region and the back waist region of the article. Also included is a system to align the phase and amplitude modulation signals. The flanges are received in the groove and engageable with a shoulder formed at the rear end of the groove, thereby preventing excessive backward movement of the secondary piston.