• Journal of the Korean Burn Society
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• v.24 no.2
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• pp.43-45
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• 2021

Magnetic Resonance Image (MRI) has been used as a safe, conventional and harmless diagnostic tool. However, thermal injuries have frequently been reported during MRI scanning due to the heat generated by the reaction with the magnetic field. It is recommended that metal-containing monitoring devices such as pulse oximetry and ECG monitoring leads should be removed prior to the start of the MRI scan, but these monitoring devices are inevitably placed in children or patients in the intensive care unit who have low compliance with the scan. Since the interaction between the metal probe or wire loop of pulse oximetry and the magnetic field can result in high thermal conduction, full-thickness burn can occur over the entire body surface during the MRI examination. Several cases of thermal burns from pulse oximetry on the fingers have been reported. However, we present a case of a full-thickness burn arising left earlobe in a 2-month-old child caused by the high conduction heat from pulse oximetry metal probe.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.151-155
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• 2016

In this paper, we present the LED dimming control system by using ADPCM (Adaptive Differential Pulse Code Modulation). This ADPCM apparatus accurately controls the LED current with high resolution reducing the RFI (radio frequency interference) due to the spreading out of the harmonics of current of pulses. Additionally, this makes it easier to increase the accuracy of control operation. This study introduces to make a digitally controlled circuit for controlling LED with high-energy efficient by adopting pulse current to LED. The LED current drive system we designed are two systems, the digitally-controlled unit and analog switching mode power supply unit, can be developed separately. The simulation shows the sigma delta modulation of digital to analog converter's output when the input level is 0.7. From this simulation, the output is approached to accurately 0.15% to target value with 510 pulses.

• Journal of Korean Critical Care Nursing
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• v.16 no.1
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• pp.1-14
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• 2023

Purpose : This study aimed to compare peripheral pulse oxygen saturation (SpO₂) values, measured at different monitoring sites, and arterial oxygen saturation (SaO₂) of neurocritical patients. Methods : The study included 110 patients admitted to the neurosurgical intensive care unit of a university hospital. The patients' SpO₂ values were measured in their index fingers, both second toes, both earlobes, and foreheads, using the patient monitoring system. These values were compared with the standard value of SaO₂ measured using a blood gas analyzer. Data were analyzed using descriptive values, Pearson's correlation coefficients, Lin's concordance correlation coefficients (CCC), and Bland-Altman plots. Result : Regardless of the measuring site, SpO₂ was correlated with the paired measurements of SaO₂ (r=.40~.60, p<.001, CCC range=.40~.58). No significant bias in paired measurements of SpO₂ and SaO₂ was observed at all sites (-0.06~0.19%, p>.05). SpO₂ values at the left finger and right earlobe had the narrowest range, with a 95% limits of agreement (LOA) (left finger -3.04~2.93% and right earlobe -3.18~2.79%). SpO₂ at the index finger, on the side without an arterial catheter, had a narrower range of 95% LOA than that of the opposing finger (-3.00~2.97% vs. -3.73~3.26%). Conclusion : SpO₂ at the finger without an arterial catheter had the highest level of precision. This study suggests using the index finger, on the side without an arterial catheter, for pulse oximetry in neurocritical patients.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.762-767
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• 2010

This paper describes characteristic of a light triggered thyristor investigated by experiment to adopt it into a main switch of a pulsed power unit. Triggering principle of the light triggered thyristor are referred with its structure and equivalent circuit. Operational principle and simulation result of a capacitive pulsed power circuit are explained. A variety of triggering conditions of triggering circuit and characteristics on turn-on, turn-off, voltage dividing in series operation, overvoltage protection function of the light triggered thyristor are investigated by experiments. Experimental result of 40 kJ pulsed power unit using the light triggered thyristor is presented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.245-248
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• 2008

This paper gives a description of the mode'ling and control of a single phase PWM(Pulse Width Modulation) converter for HEMU-400X(High-speed Electric Multiple Unit - 400 km/h experiment). The converter is part of a Auxiliary power unit supplied by the 25[kV], 60[Hz] overhead line. A model of the converter in a synchronously rotating reference frame of coordinates is used to develop a new type of control. The control system has separate controllers for the active and reactive current, permitting the free choice of the power factor. This paper proposes a new control method of PWM converter for Auxiliary power unit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.154-158
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• 2003

In this study, to measure the density of compaction, it is designed to use the 5 gamma-ray detectors. The developed instrument consists of measuring circuits for gamma-rays and thermal neutrons, a high voltage supply unit, stable circuit unit, count circuit unit and a microprocessor. To read count pulse from gamma-ray detectors are very accurate and it can be count to data calibration excluded count of ripple.

• International Journal of Aerospace System Engineering
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• v.9 no.2
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• pp.1-9
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• 2022

The NEA release mechanism is used to provide restraint and release functions with low shock for critical deployment operations on solar arrays after launch. The GK3 solar array consists of 2 wings and 6 hold down points per panel. The NEA SSD9103S1 is a part of the GK3 solar array hold-down and release mechanism. Each NEA unit is equipped with two Z-diodes which provide power to a NEA unit connected in series after actuation of the fuse wire. This paper presents the hot firing test results of a quadrature NEA SSD9103S1 configuration. One output powers a maximum of 4 NEA SSD9103S1 units simultaneously. The necessary actuation pulse duration has been determined to meet margin requirement for thermal energy of minimum 4. Actuation thermal energy difference is about 6.6% between each half of two fired serial NEAs. Thermal energy margin at worst case is minimum 5.9 in case of an actuation pulse duration of 500 ms. Two series Zener impedance depend on current applied has been characterized by an additional actuation after all fuse wires are open circuit. Total number of actuation commands to the GK3 NEA unit reduce drastically from 24 in case of single NEA configuration down to 8 in case of parallel and quadrature NEA configurations. It can be accommodated by the existing HP2U Pyro design without any impact.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.745-752
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• 2024

A method for gamma/neutron event classification based on frequency-domain analysis for mixed radiation environments is proposed. In contrast to the traditional charge comparison method for pulse-shape discrimination, which requires baseline removal and pulse alignment, our method does not need any preprocessing of the digitized data, apart from removing saturated traces in sporadic pile-up scenarios. It also features the identification of neutron events in the detector's full energy range with a single device, from thermal neutrons to fast neutrons, including low-energy pulses, and still provides a superior figure-of-merit for classification. The proposed frequency-domain analysis consists of computing the fast Fourier transform of a triggered trace and integrating it through a simplified version of the transform magnitude components that distinguish the neutron features from those of the gamma photons. Owing to this simplification, the proposed method may be easily ported to a real-time embedded deployment based on Field-Programmable Gate Arrays or Digital Signal Processors. We target an off-the-shelf detector based on a small CLYC (Cs2LiYCl6:Ce) crystal coupled to a silicon photomultiplier with an integrated bias and preamplifier, aiming at lightweight embedded mixed radiation monitors and dosimeter applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.353-368
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• 2023

The four wing unmanned aerial vehicle owns the characteristics of small size, light weight, convenient operation and well stability. But it is easily disturbed by external environmental factors during flight with these disadvantages of short endurance and poor attitude solving ability. For solving these problems, a microprocessor based on STM32 chip is designed and the overall development is completed by the resources such as built-in timer and multi-function mode general-purpose input/output provided by the master micro controller unit, together with radio receiver, attitude meter, barometer, electronic speed control and other devices. The unmanned aerial vehicle can be remotely controlled and send radio waves to its corresponding receiver, control the analog level change of its corresponding channel pins. The master control chip can analyze and process the data to send multiple sets pulse signals of pulse width modulation to each electronic speed control. Then the electronic speed control will transform different pulse signals into different sizes of current value to drive the motor located in each direction of the frame to generate different rotational speed and generate lift force. To control the body of the unmanned aerial vehicle, so as to achieve the operator's requirements for attitude control, the PID controller based on Kalman filter is used to achieve quick response time and control accuracy. Test results show that the design is feasible.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.59-64
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• 2024

The small tracking radar randomly changes the transmission period to avoid deceptive signals such as RGPO (Range Gaet Pull Off) operated on the target. Since the code repeats after a specific section, it becomes difficult to avoid a deceptive signal when the repetition is exposed. In this paper, a more realistic transmission pulse code is generated by adding random code generation through FPGA and system white noise. We present the research results of code generation that generates PRF that can avoid repetition while using pseudo-random code in EPROM using FPGA. Also, the result of designing random PRF pulse was confirmed by applying it to tracking radar.