A predictive method is used to compensate for intermediate batch sensitivities which inevitably occur during resist batch changeover. The system may include, a security policy server, a network server at a client network and one or more client workstations on the client network. The position sensor also includes a compensation winding which is arranged to have a common coupling with the field modifying member whereby a signal output from the compensation winding can be used to compensate for variations in the signal level output by the sensor winding caused by, for example, temperature variations of the system. A detecting unit detects whether there is a vacant position in the placement area in which the element is placed by the placing unit, and a bypass-element placing unit places a bypass element at the vacant position detected by the detecting unit, the bypass element propagating the predetermined signal by bypassing the element located adjacent to the vacant position. Consequently, the present invention has the effect of accomplishing various applications and providing more pleasant air conditioned circumstances. The computer includes a sensing plane; a sensor unit sensing a moving sensed unit contacting the sensing plane; an image generator generating a trace image along the movement of the sensed unit as sensed by the sensor unit; and an image storage storing a predetermined image password based upon a predetermined image.