A fuel cell power system has a fuel cell capable of generating electrical power, a battery holder releasably mounting at least one rechargeable battery, and a power controller which receives the electrical power from the fuel cell and distributes the electrical power to an output bus for use by an external load and to the battery for charging the battery. According thereto, when an annular image of a side wall surface of a hole imaged by an omnidirectional imaging device is converted into a panoramic development image according to a polar coordinate conversion, a distortion resulted from a position deviation occurred between an optical axis of the omnidirectional imaging device and a central axis of the hole can be corrected. An advertiser cache can be checked to determine whether the advertiser cache in the BLE module contains an entry associated with an advertiser address from the advertiser packet. Electrons introduced into the gap are accelerated along the length of the slabs. The medical device also includes a collapsible barrier disposed between the first and second jaws of the tissue treatment device to direct tissue into the first and second jaws separately. The voltage of the control signal is varied from the initial voltage until an output clock signal from the voltage controlled delay line is detected by the bias generator.