• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.357-359
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• 2009

In this paper, the 2.4GHz doppler radar system consisting of the doppler radar module and a baseband module were designed to detect heartbeat and respiration signal without direct skin contact. A bio-radar system emits continuous RF signal of 2.4GHz toward human chest, and then detects the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from quadrature signal of the doppler radar system are applied to the pre-processing circuit, amplification circuit, and the offset circuit of the baseband module. ECG(electrocardiogram) and reference respiration signals are measured simultaneously to evaluate the doppler radar system. As a result, the respiration signal of doppler radar signal is detected to 1m without complex digital signal processing. The sensitivity and calculated from I/Q respiration signal were $98.29{\pm}1.79%$, $97.11{\pm}2.75%$, respectively, and positive predictivity were $98.11{\pm}1.45%$, $92.21{\pm}10.92%$, respectively. The sensitivity and positive predictivity calculated from phase and magnitude of the doppler radar were $95.17{\pm}5.33%$, $94.99{\pm}5.43%$, respectively. In this paper, we confirmed that noncontact real-time heartbeat and respiration detection using the doppler radar system has the possibility and limitation.

• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.352-358
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• 2012

Purpose: The inexpensive black box system was developed to acquire and save driving information, to give the slope information, and to transmit SOS and theft signal. Method: The device consists of a main micro controller to acquire and save data, a GPS sensor module, a CDMA module, a touch LCD module, a RF (Radio Frequency) ID module, a SD (Secure Digital) card module, an emergency electric power source, a theftproof circuit, and a sensing device. The sensing device consists of a 8 bit micro controller, a accelerometer to detect impulse, two slope sensors to detect roll and pitch angle and a circuit to detect operation of 6 lighting devices. Results: Test results are as follows: 1) a tractor can be start up only with an electronic key (password or RFID card), 2) theft signal was transmitted when a tractor moved without an electronic key, 3) SOS was transmitted at conditions that rollover or crash happened. 4) 5 more than per 1s data are recorded at 5 minute intervals as new file name in SD card. Conclusions: This system can be used to save travelling record, reduce accident, prevent theft and rescue life in the accidents.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1281-1283
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• 1995

In this paper, we develop a prototype of the Optical SCM transmission module. This module is possible to application to electric facilities for control and measurements. Transmission channel number is two channels, namely, image and digital signal. In the image transmission, modulation method is AM, baseband signal is NTSC video signal and demodulation use PLL. Modulation of digital signal is QPSK, 1.544Mbps and demodulation use PLL. First, we calculate theoretical analysis about RF and Optical link in the transmission. This calculation is well correspond with practical system and transmission experiment is excellent, but this is only two channel model. And now, we plan to multichannel transmission to measure intermodulation, frequency assignments and optimal channel numbers et al.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.337-340
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• 2004

Upper stage telemetry system of KSLV- I (Korea Space Launch Vehicle I) is composed of MDU (Master Data Unit), RDU (Remote Data Unit), SRU (Shock Recorder Unit) and Transmitter. RDU is the front-end telemetry data acquisition unit which gathers analog/discrete signals from various sensors and other units, and transmits the processed data to MDU via MIL-STD-I553B data bus. In order to acquire useful data from analog signal, signal conditioning circuits, such as anti-aliasing or amplifying, should be implemented. For this purpose, SCM (Signal Conditioning Module) had been developed. This paper describes hardware structure of SCM and analog signal conditioning circuits for various sensors. Also, sampling time scheme for different sampling rates were designed and tested.

• Journal of IKEEE
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• v.24 no.2
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• pp.446-452
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• 2020

In this paper, we propose a energy-saving LED module using K-band microwave motion detecting sensor. To oscillate K-band microwave signal, An oscillator using a hairpin-type microstrip resonator was designed to increase stability and make fabrication easier. To radiate the microwave signal, a two-channel(TX/RX) patch antenna arrays was developed. Wilkinson power divider and ring hybrid mixer were developed and applied to obtain Doppler shift from the received signal. Shield cans were installed to protect the stability of the signals and unwanted external noise. The proposed motion detection sensor was mounted on a demonstration LED module and the energy saving performance through pre-test was verified.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.13-19
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• 2017

In this paper, study of vehicle fire cases caused by connector and power wiring of anti-lock brake system(ABS) module damage is presented. The purpose of ABS module is to improve braking and steering ability under sudden stop of the vehicle by repeatedly activating and releasing the brake with electric signal via electric control unit. The electric control unit for ABS may experience incomplete contact between power line and signal line or electrical breakdown on the printed circuit board by undergoing repetitive signal change which would consequently result in electrical heat and spark, eventually leading to automotive fire. Therefore, the purpose of this paper is to provide fundamental data by analyzing connector and power wiring of ABS module damage conducive to the precise investigation on the cause of vehicle fire.

• Smart Structures and Systems
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• v.13 no.6
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• pp.1041-1063
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• 2014

This work introduces a two-module robotic pipe inspection system with ultrasonic NDE device to evaluate the integrity of pipe structures. The proposed robotic platform has high mobility. The two module mobile robot platform overcomes pipe obstacle structures such as elbow, or T-branch joints by cooperative maneuvers. Also, it can climb up the straight pipeline at a fast speed due to the wheel driven mechanism. For inspection of pipe structure, SH-waves generated by EMAT are applied with additional signal processing methods. A wavelet transform is implemented to extract a meaningful and specific signal from the superposed SH-wave signals. Intensity ratio which is normalized the defect signals intensity by the maximum intensity of directly transmitted signals in the wavelet transforms spectrum is applied to evaluate defects quantitatively. It is experimentally verified that the robotic ultrasonic inspection system with EMAT is capable of non-destructive inspection and evaluation of defects in pipe structure successfully by applying signal processing method based on wavelet transform.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.776-779
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• 2004

A RF front-end module is designed for GIS(Gas Insulated Substation) which is employed for effective and efficient very high voltage transmission. Major advantage of the unit is improved PO detection sensitivity through minimizing the effect of surrounding interference signals, which is achieved by controlling the gain and the selection of the frequency band, for the precise detection of any UHF PO (Partial Discharge) disturbance occurred in the GIS due to some unwanted problems. For the development of the module, various switches for providing selected signal paths, wideband LNA, 3 BPF for selecting detection frequency band, and video detector are designed, fabricated and measured on 1 mm FR4 substrate with various RF components. The detection sensitivity of the unit was <-60 dBm that is sufficient to detect UHF PO signals as low as 1 pC. It is believed that the value is enough to detect the signal occurred in GIS.

• Journal of Digital Contents Society
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• v.11 no.2
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• pp.277-282
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• 2010

In this paper, the wireless transmission module is developed to transmit oxygen saturation(SpO2) signal, acquired from bio-signal measuring module, to PC. This wireless transmission module is designed with closed type protocol instead of open type protocol such as a zigbee or a bluetooth, considering of the security of personal medical informations. The display software is also developed to display transmitted SpO2 signals by various type data and graph without information loss for a emergency transfer.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.8
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• pp.836-844
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• 1991

PLC(programmable logic controller) system is widely used for the control of factory. PLC system receives ladder diagram which is drawn by the user to implement hardware logic, converts the ladder diagram into sequence program which is executable in the PLC system, and executes the sequence program indefinitely unless user breaks. The sequence program processes the data of on/off signal, and endures 1 scan delay and missing of pulse-type signal shorter than a scan time. So, data dependency doesn't exist. By applying theis characteristics to multiprocessor architecture, we design parellel PLC functionally and evaluate performance upgrade. Parallel PLC consists of central processing module, N general processing unit, and a shared memory by master-slave type. Each module executes allocated sequence program by the control of central processing module. We can expect performance upgrade by parallel processing, and reliability by relocation of sequence program when error occurs in processing module.