A method classifies an object in a scene as either an ambulatory person or a wheelchair user. When the signal processing circuit of the optical drive detects a focus drop, the rotation speed of the spindle motor is detected and compared to a predetermined rotation speed. Additionally, a second privilege protection having at least two sub-privilege levels is further enforced for at least one privilege level of the first privilege protection to further differentiate the privileges otherwise afforded. The first operating unit has a first end and a second end, is pivotably coupled to the movable part at the first and second ends, and is configured to return the movable part from the clutch-off position to the clutch-on position. Memory devices may include bottom electrodes, electrical contacts having a cross-sectional area less than about 150 nm2 over and electrically coupled to the bottom electrodes, and a cell material over the electrical contacts. The fluorescent encapsulant includes at least a type of phosphor and at least a type of gel with the phosphor distributed over a surface of the LED chip.