The electrical characteristics of biologically active points (BAPs) compared with those of the surrounding human skins are investigated. We confirm that BAPs have lower resistance and higher capacitance than the surrounding skins have. We find that BAPs have higher characteristic frequency than surrounding skins and sometimes the impedance spectra of BAPs have two semicircles on the complex impedance plane. Therefore, we propose the skin impedance model that is proper to the BAPs. This model describes our experimental results sufficiently.

A bi-directional and multi-channel wireless telemetry capsule, 11 mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.

The MPEG-2 Test Model 5 (TM5) algorithm describes a rate control method which consists of three steps: bit allocation, rate control and modulation. In TM5, however, buffer overflow and picture quality degradation may occur at the end of the GOP because the target bits and the actual coding bits for each picture do not match well. This paper presents a new bit rate control algorithm for matching the target and the actual coding bits based on accurate bit allocation. The key idea of the proposed algorithm is to determine quantization parameters which enable us to generate the actual coding bits close to the target bits for each picture, while improving the picture quality. The proposed algorithm exploits the relationship between the number of the actual coding bits and the number of the estimated bits of the previous macroblock within a picture.

An electroretinogram (ERG) represents the global responses of the retina to a visual stimulus and shows accumulated responses of each layer of the retina relative to the signal processing mechanisms occurring within the retina. Thus, investigating the reaction types of each ERG wave provides information required for diagnosis and for identifying the signal processing mechanisms in the retina. In this study, an ERG signal is generated by simulating the volume conductor field response for each retina layer, which are then summed algebraically. The retina model used for the simulation is Shah's Computer Retina model, which is the most reliable model developed so far. When the generated ERG is compared with a typical clinical ERG it exhibits a close similarity. Based on changing the parameters of the ERG model, a diagnostic investigation is performed with a variation in the ERG waveform.

An effective compensation method for the IR lamp deterioration in NDIR (non-dispersive infrared) capnograph system is proposed. The optical chamber with two IR (infrared) lamps has been designed newly and an electronic hardware for the control of lamp intensity has been implemented. After applying the proposed optical chamber and the reference lamp control circuit to the NDIR type capnograph system, it is identified that the proposed method can compensate the lamp deterioration effectively.