Provided is a seal ring that has low-leakage characteristics and low-friction characteristics and can improve the drive loss of the automatic transmission of an automobile to thereby contribute to an improvement in the fuel consumption of the automobile. The cover plate is adapted for covering a drain pipe end having a closet flange that extends perpendicular to the drain pipe end. Signals from each of the photosensitive elements in a set are electrically coupled or combined with corresponding photosensitive elements in other sets to produce a total of M independent group signals from M interlaced groups of photosensitive elements. Proxying the request to the network-access-control module may include assigning the virtual machine a virtual identifier.