A software andor hardware facility for scoring the quality of traffic to a site accessible via the Internet or other network. The propulsion unit can include a hollow support structure attached to the hull, a chamber attached to the support structure, an electric motor within the chamber, a propeller at the front end of the chamber, and a pivotably supported rudder at the rear end of the chamber. A data wire and a pixel electrode wire are formed thereon and covered with a passivation film. The bypass vent assembly may be configured to allow airflow to bypass the restrictor andor the drum. The electric discharge machining is completed when the machining time has elapsed from the start of electric discharge machining. A potential difference between two electrodes in communication with the optically sensitive layer associated with a pixel region exhibits a time-dependent bias; a biasing during a first film reset period being different from a biasing during a second integration period.