Abstract: A method is devise for retaining data. In the method, threshold voltage and a corresponding retention time limit are read from a current block. Then, retention time is calculated. Then, it is determined whether the retention time is longer than the retention time limit. A swapping routine is executed if the retention time is longer than the retention time limit. The process returns to the step of calculating the retention time if the retention time is no longer than the retention time limit.

Abstract: An interactive method to be performed by a digital signage for interaction with a portable electronic device includes configuring the digital signage to establish a wireless communication link with the portable electronic device, to generate playback signals associated with advertisement contents stored in the digital signage, to transmit the playback signals to the portable electronic device, wherein the playback signals enable the portable electronic device to display the advertisement contents and to enable transmission of a corresponding select signal to the digital signage in response to user operation associated with a selected displayed one of the advertisement contents, and to process the select signal.

Abstract: A load dependent braking pressure regulating device for railway vehicles comprises an auxiliary reservoir (8), a brake cylinder (10) and a control valve (9). A regulating valve (2), a sensor valve (4), a triggering board transmission mechanism (5) and a stop disc (6) are provided between the control valve (9) and the brake cylinder (10). A triggering head at the lower end of the stop disc (6) is right opposite the center of the triggering board of said transmission mechanism (5). The sensor valve (4) is connected with the control valve (9), the regulating valve (2), the brake cylinder and the pressure reduction reservoir(7). The device according to the present invention can prevent flat wheel accidents, enhance train operation safety, reduce operation cost and reduce the longitudinal impact between differently loaded cars in a train upon braking.