Heart sound occurs when the heart contracts and expands. It provides information on myocardial contractility and blood vessels, which is not obtainable from ECG. For this reason, stethoscopy of heart sound in anesthesiology is a very crucial means for acquiring cardiac information and preventing intraoperative medical accidents, and it requires a system for precise objective measurement and analysis of heart sound and murmur. Thus, this study purposed to develop portable digital esophageal stethoscope (PDES) that can objectify and quantify heart sound and murmur. In this study, we designed PDES for precise measurement and analysis of heart sound and murmur data. Heart sound information obtained by inserting the sensor of the PDES into the patient's esophagus can be transmitted to a terminal or a PC and displayed on the screen The amplitude and waveform of heart sound are displayed using self-developed software Heart Sound 1.0. The results of experiment with the developed PDES showed that data on the amplitude and waveform of heart sound and murmur were produced stably in real-time. In addition, when heart sound was heard using a headphone, the sound was clear without external murmur. The PDES developed in this study, which complements the disadvantages of traditional esophageal stethoscope while preserving its advantages, could not only examine heart sound and murmur using an esophageal catheter but also display the amplitude and waveform of heart sound and murmur and measure the patient's body temperature. Accordingly, the developed PDES is expected to be useful in the continuous stethoscopy of heart sound during operation and to contribute to research on heart sound by providing heart sound data.

DTV field tests have been performed to measure field strength and to check reception ratio on indoor and outdoor sites. They use an antenna of 9m to measure DTV signal in case of outdoor measurement on the road. Modern skyscrapers require the analysis of vertical-directional wave propagation by measuring vertical-directional DTV signal. Even if the field strength is above the reception threshold of 43dBμV/m, the reception is impossible in case of strong multi-path or high impulse noise. So, vertical-directional field measurement is essential in environment of tall buildings. In this paper, we developed an octo type multi-copter to measure vertical-directional DTV signal level. A compact and portable DTV signal level meter, an antenna, a microwave transmitter for data transmission, and a recording equipment are equipped in the multi-copter. Three different sites are selected to test the measurement system. Developed measurement system using the multi-copter is very useful in measuring vertical-directional DTV signal, especially in apartments, non-accessible area by vehicles, and forbidden areas.

IR-UWB has been developed as a standard of indoor ranging technology because it has robust and good transmission characteristics in indoor environments

IR-UWB has been developed as a standard of indoor ranging technology, because it has robust and good transmission characteristics in indoor environments and it can be operated with low power. In this paper, a IR-UWB packet analyzer is designed and implemented based on IEEE 802.15.4a, which is useful in developing IR-UWB real time location system with resolution of a few ten centimeters. A sniffer device of the packet analyzer monitors IR-UWB wireless networks, captures MAC packet frames, and transmits packet frames to the packet analyzing computer. The packet analyzing program in a computer analyzes received MAC packet frames and displays parsed packet information for developing engineers. Developed packet analyzer is used to analyze IEEE 802.15.4a MAC protocol, and also it can be used in other IEEE 802 series MAC protocol by modifying some functions.