• Journal of the Korea Society of Computer and Information
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• v.23 no.10
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• pp.151-156
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• 2018

The purpose of this study was to find more effective method through comparison of manual chest compression and chest compression using $AutoPulse^{TM}$ device in pre-hospital simulation cardiac arrest. In order to achieve the purpose of the study, ambulance workers did two different style CPR in pre-hospital simulation cardiac arrest. Data analyzed by T test and ANOVA. Findings of this study are as follows. Firstly, manual chest compression is more effective than chest compression using $AutoPulse^{TM}$ device on scene. Secondly, chest compression using $AutoPulse^{TM}$ device is more effective manual chest compression in ambulance and in elevator. In conclusion, these findings provide strong evidence for the importance of hands off time and stable CPR before hospital arrival in explaining patient's prognosis. Therefore, strategies to conduct precise hands off time and stable CPR are needed to improve patient's prognosis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.442-445
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• 2003

In this study, we developed the 40 J-class MPC(magnetic pulse compression) system for exciting excimer laser and investigated the optimal conditions of each stage of MPC circuit. This system consists of a DC power supply, a pulse transformer and four saturable inductors. The number of turns of saturable inductors at each stage of MPC circuit are 140, 25, 5, 1 and the optimal storage capacitance of each stage are 34 nF, 28.9 nF, 22.1 nF, respectively. In the improvement MPC system, we have obtained an output voltage of 43 kV, a current of 8.25 kA and a pulse duration of 360 ns. Also, the maximum pulse compression ratio of 77.7 and the current gain of 71.7 were obtained.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.123-130
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• 1997

We determine the dispersion profile of a dispersion decreasing fiber(DDF) for optimum pulse compression from a trade-off between high pulse compression and low pedestal power/short DDF length. We find that the optimum vlaue of the exponential dispersion decreasing factor .alpha. is 0.95 and that the corresponding optimum fiber length is 1.5 times of the initial soliton period. Passing through the dDF, ~10 times of pulse comparession ratio can be achieved without significant increase in pedestal power. To compress relatively broad pulses using a given DDF optimized at a specific pulse width, we also detemrine the optimum input pulse amplitude, as a function of input pulse width.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.3
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• pp.185-193
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• 1994

Conventional ultrasonic flaw detection system uses a large amplitude narrow pulse to excite a transducer. However, these systems are limited in pulse energy. An excessively large amplitude causes a dielectric breakage of the transducer, and an excessively long pulse causes decrease of the resolution. Using the pulse compression, a long pulse of pseudorandom signal can be used without sacrificing resolution by signal correlation. In the present work, the pulse compression technique was implemented into an ultrasonic system. Golay code was used as a pseudorandom signal in this system, since pair sum of autocorrelations has no sidelobe. The equivalent input pulse of the Golay code was derived to analyze the pulse compression system. Throughout the experiment, the pulse compression technique has demonstrated for its improved SNR(signal to noise ratio) by reducing the system's white noise. And the experimental data also indicated that the SNR enhancement was propotional to the square root of the code length used. The technique seems to perform particularly well with highly energy-absorbent materials such as polymers, plastics and rubbers.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2182-2183
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• 2005

A pulse generator of one stage magnetic pulse compression modulator was simulated by electromagnetic transients program (EMTP). The pulse generator was expected to generate ${\sim}80kV$ peak voltage, ${\sim}140ns$ pulse width and about $70{\sim}75%$ energy delivery efficiency from initial charge capacitor $(0.2{\mu}F)$ to dummy load $(25{\Omega})$. From this simulation, the scheme of pulse circuit could be estimated as a practically reasonable design.

• Current Optics and Photonics
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• v.5 no.3
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• pp.250-260
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• 2021

A tapered As₂S₃ photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As₂S₃ PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 ㎛ propagating in the tapered PCF are located in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As₂S₃ PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.

• Korean Journal of Optics and Photonics
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• v.1 no.1
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• pp.40-45
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• 1990

Optical pulse compression in a high finesse nonlinear Fahry-Perot interferometer made hy a silicon is ohserved. The optical pulse compression and moclul,ltion in a such nonlinear Fabry-Perot interferometer is due to the refractive index change of the silicon hy absorbing the incicknt pulse and generating electron-hole pairs. The pulse is compressed to liS of width of the IIlcicient pulse. And the experimental results are consistent with the results of computer simulation.lation.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.4
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• pp.541-547
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• 2013

Range resolution is important performance parameter to distinguish a target accurately. The destination of modern radar systems, to overcome the limitations of existing analog radar systems, is to improve the range resolution of the distance with low transmission power. For that reason, the research on pulse compression techniques is briskly studying. In the Receiver, modulation system of transmitted signal which has used in pulse compression technique is divided PM and FM to distinguish a target. In this paper, We analysed and designed the pulse compression signal processing module using the Baker Code which is the one of PM method's.

• Journal of IKEEE
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• v.9 no.2 s.17
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• pp.115-122
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• 2005

We report 400 femto-second highly stable, nearly transform-limited, pulse generation at 10 GHz in $1540{\sim}1550$ nm wavelength region by adiabatic soliton pulse compression of an actively mode-locked fiber ring laser output. Without using any supermode selection device, supermode beating noise has been suppressed below -123 dB/Hz, resulting less than 100 femto-second timing jitters at the noise band of $1\;kHz{\sim}100\;MHz$.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.4
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• pp.66-74
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• 1997

Recently, high-developed domestic industry and environmental issues demand high-voltage short-pulse power supply(power, voltage, pulse width and repetition rate of 100KW, 150KV, 500ns and 500Hz, respectively) for electron beam process and puolse corona process. In such power supplies magnetic compression circuit can be one of the effectives solutions. In ths study design and operation principle of a pulse-power supply with a three-stage magnetic-compression circuit are described. A good agreement between simulation and experimental results verifies the validity of thescheme. The system delivers energy of 10[J/pulse] at the efficiency of 82%[%].