A vehicle body top structure for enhancing the rigidity and strength of the intersections of side rails and a front rail. The system accommodates virtually any signal voltage level commonly used for control of the tap-changing equipment, modifies the received signal to a desired format, and inputs the modified signal to a controller for decoding and actuation of the tap-changing motor. The classification can be performed with one or more trained classifiers that are trained using training images of fish having labels indicating species of the fish. Next, the defected substrate unit is separated from the packaging substrate, and at least one opening is formed in a frame of the first packaging substrate correspondingly. The meters collect data and the network server provides at least one metering application to the meters. Thus, the core provided at the opening formed by the skeleton is in substantial surface contact with the cylinder for heat release, so that heat received by the coil from the heat-generating bulb is directly exhausted to the cylinder through the core.