• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.440-447
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• 2002

This paper considerated about exact flow volume calculation method from factors having an influence on measurement and introduced in anesthesia ventilator realized spirometry system. System used differential pressure sensing method with factors, that is temperature, pressure, gas density, humidity and mucus etc. System optimized for low power system for mobile system. System composed analog interface part, signal processing part, display part. Analog interface part have differential pressure flow sensor and defferential pressure sensor. Signal processing part have AVR processor for low power system display part use serial port (RS232, SPT). so it display at pc monitor or send to anesthesia ventilator. System is stable by linearizing 2th characteristics of flow-differential pressure, auto correction of sensor. Noise reduced by algorithm with analog filter and digital processing. Small, light, low power system is good at mobile system and applied to patient in emergency or mobile. and, System is useful at anesthesia ventilator by using flow sensor.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.437-444
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• 2016

Most methods for detecting arrhythmia require pp interval, diversity of P wave morphology, but it is difficult to detect the p wave signal because of various noise types. Therefore it is necessary to use noise-free R wave. In this paper, we propose algorithm for premature contraction arrhythmia classification through ECG pattern analysis and template threshold. For this purpose, we detected R wave through the preprocessing method using morphological filter, subtractive operation method. Also, we developed algorithm to classify premature contraction wave pattern using weighted average, premature ventricular contraction(PVC) and atrial premature contraction(APC) through template threshold for R wave amplitude. The performance of R wave detection, PVC classification is evaluated by using 6 record of MIT-BIH arrhythmia database that included over 30 PVC and APC. The achieved scores indicate the average of 99.77% in R wave detection and the rate of 94.91%, 95.76% in PVC and APC classification.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2628-2635
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• 2010

This paper analyzes the detection probability of FMCW (Frequency Modulated Continuous Wave) radar based on Doppler frequency and analog-digital converter bit and designs and implements signal processing part of FMCW radar. For performance evaluation, the FMCW radar system consists of a transmitted part and a received part and uses AWGN channel. The system model is verified through analysis and simulation. Frequency offset occurs in the received part caused by the mismatching between the received signal and the reference signal. In case of Doppler frequency less than about 38KHz, performance degradation of detection does not occur in FMCW radar with 75cm resolution The analog-digital converter needs at least 6 bit in order not to degrade the detection probability. And, we design and implement digital signal processing part based on DDS chip of digital transmitted signal generator for FMCW radar.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.17-18
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• 2014

Wave energy generation system is sorted as oscillating water chamber type, over topping device type and wave activating body type. The wave activating body type converts from wave energy to kinetic of the machine one and the power generation amount increases while the motion of a activating body increases. In this paper the wave energy convertor consists of a main body which has a generation system and the activating body. They are connected by a bar type bridge. The twisting moment and angular velocity at a shaft of convertor are calculated when various condition of the incident wave, a diversity of connection methods between the main body and the activating body. It can be used as basic idea for determining the design of wave activating body type convertor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.834-837
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• 2015

In this paper, we designed the FPGA hardware-based real-time ECG simulator, which generates an analog ECG signal within the range of 0 to 5 volts and described function. The ECG signal generated by the simulator can be applied to laboratory tests, the medical device, and the calibration study in various ways. ECG signals generated by simulator are obtained with conventional 24bit quantization to generate the signal data, and they are sampled and quantized to 1kHz of the 8-bit resolution when used as actual data. The proposed simulator is implemented using xilix Spartan-3 and data are transmitted through an RS-232 between the PC and the FPGA simulator. The transmitted data are stored in the memory and the stored data are printed out with the analog ECG signal through DAC (0808). It can also control the heart rate (HR) via the two buttons level UP-DOWN. We used existing ECG input rating for the evaluation of the designed system and evaluated differential circuit for obtaining QRS waveform and the output signal. We finally could obtained proper the result.

• Journal of the Korean Institute of Gas
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• v.8 no.3 s.24
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• pp.1-7
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• 2004

The polyethylene pipe can use semi-permanent because of the high corrosion resistance with chemical stability. In addition to, there is the merit that is an easy to establish and to maintain. However, as the reason that it is simply degraded when the polyethylene pipe was exposed to the outside, mainly it is used to lay under the ground with low-pressure gas transportation pipe. In this study, the nondestructive evaluation method was used to maintain the integrity of the polyethylene pipe. We simulated the various defects on the polyethylene pipes, and then the AE signal occurred according to the impact test of steel ball was evaluated by the acoustic emission method. From the results, the waveform and dominant frequency could be distinguishing from the defect shapes of polyethylene pipe. Especially, in the case of notch defect, the AE signals occur different by the angle and depth of the notch.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.1
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• pp.15-22
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• 1998

The goal of this paper is to propose analyzing and evaluating method of power parameters for motor drive system with various experimental graphic screens and numerical results and to develop the proposed system. A developed system is made up 586-PC and DSP board, motor drive system, power parameters analyzing and evaluating software for windows. Power parameters are analyzed using correlation signal processing techniques based on the correlation between voltage and current waveforms. Analysis results are visualized by 3-D current coordinates, and it is compared and evaluated with conventional time/ frequency domain. To verify the validity of the proposed system, capacitor run type single phase induction motor and thyristor speed controller is used for analyzing. Power and harmonic parameters of motor drive system is analyzed and verified, with varying fire angle of thyristor speed controller, and the proposed approach is to confirm validity.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.228-234
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• 2009

In this paper, we present an analytical method that provides fast and efficient evaluation of the power losses and the conversion efficiency for phase-shift controlled full-bridge converter. In the proposed method, the conduction losses are evaluated by calculating the effective values of the ideal current waveform first and incorporating them into an exact equivalent circuit model of the phase-shift controlled full-bridge converter that includes all the parasitic resistances of the circuit components. While the conduction losses are accurately accounted for the synchronous rectification, the core losses are assumed to be negligible in order to simplify the analysis. The validity and accuracy of the proposed method are verified with experiments on a prototype phase-shift controlled full-bridge converter. An excellent correlation between the experiments and theories are obtained for the input voltages of 400V, output voltage 12V and maximum power 720W.

• The Journal of the Acoustical Society of Korea
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• v.36 no.3
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• pp.179-185
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• 2017

The problem that occurred in the design/fabrication/testing of the wideband transmitting power amplifier for an embedded active SONAR (Sound Navigation and Ranging) system operating underwater was analyzed and the solution of the problem was proposed in this paper. Wideband acoustic SONAR systems had been developed in order to improve the underwater detection performance. The underwater acoustic transmission system had been also developed to achieve the wideband SONAR system. In this paper, the wideband acoustic transmission signal was generated using a 2 Level sawtooth type Class D PWM (Pulse Width Modulation) which was not complicated to implement. When the sonar signals having two or more frequencies were simultaneously generated, parasitic frequencies were added to the original signals by integer multiples of the frequency difference of the original signal. To cope with this problem, we proposed a way to remove the parasitic frequency from the source signal through modeling and simulation of the implemented power amplifier and PWM control hardware using MATLAB and Simulink.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.391-395
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• 2015

A 15-Lead ECG has been developed to diagnose posterior wall diseases of the heart that a 12-Lead ECG cannot diagnose. However, 15-Lead ECG data for developing heart-diseases-detecting algorithm are limited, and previous ECG simulators cannot predict the ECG waveform according to the changes in electrode. To solve these problems, the lumped parameter model (LPM), which divides the heart into 15 sections with varying electrical capacitance and electrical resistance. To imitate the electrical conduction in the heart, each node was connected to a current source and delivered the specific current considering the positions and time delay. The purpose of this study is to acquire the waveform that can be used in an ECG by delivering the specific current to LPM.