A retarding system for a mobile machine is disclosed. The fiber optic faceplate, comprising a closely packed bundle of optical fibers, permits efficient capture of light from the VCSELs. The loudspeaker portion comprises a loudspeaker body, a sliding member and a connecting portion. Furthermore, a screw rotational speed command in which the pressure deviation component between the set resin pressure and the current resin pressure is corrected from the screw rotational speed component that is decelerated in proportion to the positional deviation is determined and output. The method retrieves the street price corresponding to the old computer system and subtracts the price from the new computer price without the reused components in order to minimize the cost of the transaction.