A method of establishing a desired grade of an uncured concrete surface or subgrade surface includes providing a wheeled apparatus having a wheeled support and a plow assembly, which may include a plow member for establishing the desired grade andor a vibrating member for vibrating and smoothing the concrete. In a method of driving a laser diode, the laser diode is driven by a pulse current which is 10 or more times higher than a threshold current value. The system changes to a frequency of this transmitter, which was found by the search receiver, if the quality of the signal received by the audio receiver falls below a certain limit. The file generator also creates characters forming an arbitrary position of the file name. Then, the user introduces a selection command for a displayed identifier, the start or the end of said document being identified by the shot associated with the selected identifier.