Among other things, one or more techniques andor systems are provided for maintaining an electrical network model describing an electrical network. Accordingly, it becomes possible to light the discharge lamp when it is in a high temperature condition such as when turning on the discharge lamp again just after it was turned off, and the life time of the discharge lamp can be lengthened. Each first wafer includes a plurality of signal terminals and a grounding member mounted on opposite sides of a dielectric base thereof. The wafer surface is thoroughly cooled so as to as reduce the surface mobility of the impinging atoms during the subsequent metallic deposition. In a medium that recordsplays back data including video data and control information, the control information includes information for accessing a specific portion of the video data.