A position determining system using a first communication network, a second communication network, and a positioning system. A receipt is associated with each ballot with the same individual serial number to be given to a voter using the ballot. The method and apparatus are equally applicable when resources of backhaul transmission channel of a relay cell in a cell are grouped. The reversed head portion can continue to acquire image data at the same scanning planes to the previous scanning planes of the rotation drive to the first direction. The microprocessor varies the threshold in accordance with electrical supply voltage, the electric motor temperature and the electric current drawn by the motor during a previous shredding operation, so that the maximum thickness the shredder will accept can be reduced automatically when motor temperature increases or as the effectiveness of the machine deteriorates throughout its working life. The collar portion may include an outer circumferential surface defining a second diameter that is greater than the first diameter.