Abstract: A method, implemented by a computer, for determining a position of a personal mobility device (PMD) comprises: estimating a position of a PMD based on a first wireless signal; determining whether the PMD is within an intermediate area between a first area and a second area, based on an estimated position of the PMD; determining whether the PMD moves to the second area, by using both the first wireless signal and a second wireless signal; and determining position of the PMD by using any one of the first wireless signal and the second wireless signal based on a movement of the PMD to the second area.

Abstract: A method for controlling a video camera positioning system includes the steps of controlling a motor for driving a video camera to capture a panoramic frame, dividing the panoramic frame into a plurality of frames, controlling the motor for driving the camera lens to turn to the frame corresponding to an encoded command signal when the microcontroller receiving the encoded command signal, and zooming in the frame by the video camera. Furthermore, a video camera positioning system is also disclosed herein.

Abstract: A support structure is disclosed, which includes plural cylindrical joints. Each cylindrical joint includes a cylindrical joint body having a wire channel for being passed through by a wire, a cylindrical joint head disposed on one end of the cylindrical joint body and having the wire channel, a cylindrical joint socket disposed on another end of the cylindrical joint body and having the wire channel The cylindrical joints are connected one by one by coupling the cylindrical joint to the corresponding cylindrical joint socket and are rotated along the radial direction of the cylindrical joint head.

Abstract: A ball joint structure is disclosed, which includes a socket with a containing opening, a ball disposed in the socket, a cover disposed at the containing opening, a protrusion disposed at an outer surface of the ball, a concavity disposed at an inner surface of the socket, and plural adjustable elastic screws screwed on the socket. The protrusion is moved in the concavity when the ball is rotated in the socket. The ball is gripped in the socket with a force provided by the adjustable elastic screws.

Abstract: An automatic gain control circuit and method for stably maintaining received power in a mobile Internet system is disclosed. An efficient automatic gain control circuit structure is provided which uses no separate analog circuit elements in a process of detecting the level of a received signal. Therefore, it is possible to reduce a complexity of hardware, the size of the automatic gain control circuit and a manufacturing cost. Further, an automatic gain control (AGC) unit, which is made in a Fluctuating Gunn-Peterson Approximation (FGPA) type, performs an automatic gain control simply by referring to a lookup table based on the level of a received signal. Therefore, the present automatic gain control circuit can not only be more simply designed or modified than a conventional automatic gain control circuit, but also stabilize the level of the received signal simply without periodically checking the level of the received signal for the automatic gain control.

Abstract: Disclosed is an apparatus and a method for down-converting frequencies of an input signal by separating the signal to which at least two frequencies are allocated according to each frequency, and then outputting at least two digital IF signals in a communication system. The digital down-converting apparatus includes a band-pass filter, an analog-to-digital converter, down-converters, up-converters, and Serializer/Deserializeres, etc. First, the signal to which at least two frequencies are allocated is down-converted into baseband signals respectively. Then, the baseband signals are up-converted into signals of a predetermined frequency respectively.

Abstract: Disclosed is an apparatus and a method for up-converting frequencies of digital Intermediate Frequency (IF) signals input through at least two paths, and then outputting IF signals to which at least two frequencies are allocated in a communication system. The apparatus includes Serializer/Deserializers (SerDeses), down-converters, up-converters, a signal adder, a Digital-to-Analog Converter (DAC), and a Band-Pass Filter (BPF), etc. In relation to digital IF signals respectively input through at least two paths, first, the frequency down-conversion is performed, and then, the up-conversion to relatively low frequencies is performed.