A power amplifier having multiple solid state sub-amplifiers connected in parallel between the power amplifier input and the power amplifier output are described. A movable platform, to which the object subjected to movements or forces is fixed, is connected to a base of the apparatus by six links in parallel. A domain model may be included that has an extension relating to information on the independent computing device. In one example, a central processing unit performs encoding of I frames and P frames of a video and a graphics processing unit performs initial encoding of B frames of the video in connection with a fixed function video encoder configured to perform entropy encoding of the B frames. When the valve body is magnetized to magnetically attract the valve spindle, the valve spindle is moved within the valve body, and the muffling ring collides with the recess inner wall, thereby reducing collision noise. The method comprises: retrieving unique information corresponding to a first electronic device and a storage device; generating an encryption key according to the unique information; generating a password string for secure a data file; encrypting the password string with the encryption key; and locking and storing the data file together with the encrypted password string in the storage device.