Abstract: A walking-assistant device is provided comprising a driving unit that includes four wheels and four actuators for adjusting heights of the four wheels, a mechanism unit that includes two vertical frames whose length is adjusted and connection frames for fixing and connecting the vertical frames, and a manipulation unit that includes a plurality of sensors for grasping a user's moving intention and controls the driving unit and the mechanism unit based on a signal detected by the sensors.

Abstract: Provided are a method for emulating a separate contents memory unit into an optical disk, an optical disk drive using the same, and an optical disk including a security zone. In the method, when an optical disk processing command from a host is present, whether an optical disk is present in the optical disk drive is judged. When the optical disk is not present in the optical disk drive as a result of the judgment, the contents memory unit is executed as a virtual optical disk. An application stored in the contents memory unit is displayed. The optical disk drive includes an optical disk storage unit, a contents memory unit, and a controller. The optical disk storage unit stores or reproduces contents using an optical disk. The contents memory unit stores contents therein and is executed as a virtual optical disk when the optical disk is not present. The controller controls the optical disk storage unit and the contents memory unit, and controls an access to be made, subject to the contents memory unit.

Abstract: A walking-assistant device is provided comprising a driving unit that includes four wheels and four actuators for adjusting heights of the four wheels, a mechanism unit that includes two vertical frames whose length is adjusted and connection frames for fixing and connecting the vertical frames, and a manipulation unit that includes a plurality of sensors for grasping a user's moving intention and controls the driving unit and the mechanism unit based on a signal detected by the sensors.

Abstract: Provided are a method for emulating a separate contents memory unit into an optical disk, an optical disk drive using the same, and an optical disk including a security zone. In the method, when an optical disk processing command from a host is present, whether an optical disk is present in the optical disk drive is judged. When the optical disk is not present in the optical disk drive as a result of the judgment, the contents memory unit is executed as a virtual optical disk. An application stored in the contents memory unit is displayed. The optical disk drive includes an optical disk storage unit, a contents memory unit, and a controller. The optical disk storage unit stores or reproduces contents using an optical disk. The contents memory unit stores contents therein and is executed as a virtual optical disk when the optical disk is not present. The controller controls the optical disk storage unit and the contents memory unit, and controls an access to be made, subject to the contents memory unit.