A pond heater with a water pump, the housing of the heater is provided with a holed seat for receiving the water pump; cold water enters the pond heater via a water inlet, and hot water generated by the heater is discharged from a water outlet to create convection in the pond to increase effect of ice removing. Further, the heating andor sanitation pipe is provided with a compressible andor expanded material between the inner pipe and the corrugated pipe for fixing the inner pipe inside the corrugated pipe. A first status message may be forwarded from the first edge node to the first core node. And the calculated shift amounts are converted to 3-dimensional coordinate shift amounts in the 3-dimensional space. When the eccentric lobe on the drive sleeve is in opposition to the eccentric lobe on the surrounding power transmission sleeve, the sprocket is disengaged from the wheel hub. The content distributing server selectively writes audio-video contents that have not been stored in the content distributing server of audio-video contents transmitted from the content accumulating server while the airplane is parked on the airport.