A power supply for a plasma display device controls an output voltage by using a voltage divided by first resistors coupled to an output terminal, and outputs the output voltage as a driving voltage for driving a PDP. The system comprises a sensor which senses dangerous environmental conditions such as high temperatures within the vehicle. A reputation score associated with the host is generated based on the reputation information associated with a set of other entities. The cover defines a second cavity in communication with the passage and the tubes. In various embodiments, the user’s cellular phone may be configured to process a message that provides at least partial service context and autonomously authenticate the financial transaction. An electronic control unit controls the engine such that the detected value for the air-fuel ratio upstream from a front catalyst provided in an exhaust pipe reaches a value indicating a leaner air-fuel ratio when EGR is being executed than when not executed.