An efficient approach for SAT-based quantifier elimination and pre-image computation using unrolled designs that significantly improves the performance of pre-image and fix-point computation in SAT-based unbounded symbolic model checking. The controller is electrically connected with the electronic devices to form two circuit terminals of the control circuit. Next, matrixes of biased coefficients are generated by adding a midpoint bias value to a DC coefficient of the matrix of scaled coefficients. Battery health is determined by monitoring the light transmitted through the optical fiber. Various flow-control devices, such as moveable plates, baffles, or other members are controlled to increase or decrease flow rate through the flow passages to control the relative pitch or inclination of the ramp. A panel is positioned in front of at least a portion of the camera and is operable to selectively switch between at least a substantially transparent state and at least a substantially opaque state.