The present invention is a fence assembly comprising fence segments and connectors. Data of a flow waveform indicating the flow of gas between the ventilation device and the patient is accessed. This problem is addressed by the use of phosphors that emit radiation of longer wavelength. The clutch transmits rotation of the rotatable shaft to the worm shaft and prevents transmission of rotation of the worm shaft to the rotatable shaft. The feedback path feeds back the output of the second inverting circuit to the input side of the first inverting circuit.