A vehicle convertible roof including a rearmost roof member, a side roof rail, an actuator and a link having a length that varies between a first length and a second as the rearmost roof member moves between a nominal and raised position. In one embodiment, a semiconductor device comprises a semiconductor layer having a trench, charge storage layers formed at both side surfaces of the trench, a wordline buried in the trench in contact with the charge storage layers, and source-drain regions formed in the semiconductor layer at both sides of the trench. The circular accelerator produces stable closed electron orbits in respective regions with respective widths in the radial direction of the accelerator. The receiving subsystem classifies a connection received from the network MAC layer into a priority connection, fast connection or slow connection based on a pre-stored information, and activates its respective hardware circuit based on the connection classified in order to speed up data transmission of the connection. When the towel is not being used, the towel rack can be folded against the wall to decrease the total volume and easily stored.