• 대한조선학회지
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• 제11권2호
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• pp.7-14
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• 1974

Hydrodynamic moments produced by the rolling oscillation on the free surface and the associated swaying force were exactly calculated by Ursell-Tasai method for the cylinders with Kim's chine form sections($a_1,\;a_7$). The coefficient of the added moment of inertia $K_{\varphi^{\tau}}$, the progressive wave height ratio $\bar{A}$, the coefficient of swaying forces $K_{RS}$, ${\alpha}_{RS}$ of rolling oscillations are shown in the several figures. The results of the computation were compared with those of lewis form sections. It is concluded that the effect of the section form on the added moment of inertia is significant for the cylinder with the section of same beam-draft ratio and sectional area coefficient, on the other hand, a little effect appears on the wave damping.

• 설비공학논문집
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• 제10권3호
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• pp.368-377
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• 1998

The purpose of this study was to examine theory about indoor thermal comfort-environment as well as to determine thermal sensation and physiological responses for men in summer indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart Rate(Electrocardiogram), Electroencephalogram(EEG) were examined. We found that comfort of people was achieved at SE $T^{*}$ 24.7$^{\circ}C$, -0.82＜PMV＜0.93, subject's clothing(0.41c1o)and the difference of skin temperature was found at the calf area as air temperature changes. At low SE $T^{*}$, heart rate was decreased and at high SE $T^{*}$, heart rate was increased but there was no change EEG(keeping $\alpha$-wave).wave).

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.95-96
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• 1999

The authors have considered the 1/f fluctuation of vial rhythm with $1/f\beta$ spectrum of $\alpha$ wave in relation to the invigoration for the learning memory by paid their attention to the hippocampus protocol in this paper. At the first clinical experiment, the data of the remembrance test at short period is able to make as the foundation of the repeat memory. It can replace this memory with long period memory through the hippocampus by the superposition of the same memory-nerve circuits.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2002년도 춘계학술대회 논문집
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• pp.107-113
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• 2002

We examined the psychophysiological effects of navigation in a virtual reality (VR). Subjects were exposed to the VR, and required to detect specific objects. Ten electrophysiological signals were recorded before, during, and after navigation in the VR. Six questionnaires on the VR experience were acquired from 45 healthy subjects. There were significant changes between the VR period and the pre-VR control period in several psychophysiological measurements. During the VR period, eye blink, skin conductance level, and alpha frequency of EEG were decreased but gamma wave were increased. Physiological changes associated with cybersickness included increased heart rate, eye blink, skin conductance response, and gamma wave and decreased photoplethysmogram and skin temperature. These results suggest an attentional change during VR navigation and activation of the autonomic nervous system for cybersickness. These findings would enhance our understanding for the psychophysiological changes during VR navigation and cybersickness.

• 대한의용생체공학회:의공학회지
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• 제27권2호
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• pp.47-52
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• 2006

The purpose of this study was to predict successful defibrillation in ventricular fibrillation using parameters extracted by wave analysis method and neuro-fuzzy. Total 15 dogs were tested for predicting successful defibrillation. Feature parameters were extracted for return of spontaneous circulation (ROSC) and non-ROSC by wave analysis method, and these parameters are an irregularity factor, spectral moments, mean power of level-crossing spectrum, and mean of alpha-significant value. Additionally, two parameters by analyzing method of frequency were extracted into a mean of power spectrum and a mean frequency. Then extracted parameters were analyzed in which parameters result to have high performance of discriminating ROSC and non-ROSC by a statistical method of t-test. The average of sensitivity and specificity were 62.5% and 75.0%, respectively. The average of positive predictive factor and negative predictive factor were 61.2% and 75.8%, respectively.

• 접착 및 계면
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• 제10권1호
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• pp.17-22
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• 2009

Polymer thin films were prepared by radio frequency (RF) plasma polymerization of phthalic anhydride (PA). First, monomer vaporization temperature ($100{\sim}160^{\circ}C$) was optimized by evaluating the thermal properties of thin films using differential scanning calorimeter (DSC) and measuring the root-mean-square (RMS) roughness with atomic force microscope (AFM) at the fixed plasma power of 10 W and time of 5 min in a continuous-wave (CW) mode. Plasma power (5~20 W) was then optimized by measuring the film solubility in solvents such as toluene, acetone, dimethylsulfoxide (DMSO) and 1 methylpyrrolidine (NMP). Next, pulsed mode plasma polymerization was also studied by varying the duty cycle of on-time (5, 20%) under optimized conditions of continuous-wave (CW) mode ($120^{\circ}C$, 10 W) in order to increase the anhydride functional groups. Finally, polymer thin films were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA) and ${\alpha}$-step.

• 한국전자통신학회논문지
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• 제10권6호
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• pp.757-762
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• 2015

본 논문은 색온도가 글씨 쓰기 과제 수행과 뇌파에 미치는 영향을 알아보고자 2013년 7월부터 9월까지 초등학생 아동 24명을 대상으로 실시하였다. 색온도의 고정과 유지를 위해 준비된 실험실에서 주황색등과 백색등에 따른 과제수행시간의 측정과 뇌파를 측정하여 분석하였다. 연구 결과 알파파, 베타파, 하이베타파의 출현이 백색등에서 높게 나타났으나 과제수행 시간은 주황색등에서 유의하게 빠른 수행을 보였다. 이는 기존의 낮은 색온도는 안정과 이완에 전형적인 색온도로 여겨졌으나 심인적인 요인과 과제의 특성과 종류에 따른 다양한 활용은 학습과 작업의 능률에 긍정적인 영향을 줄 수 있음을 제시했다.

• 한국전자통신학회논문지
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• 제9권12호
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• pp.1421-1426
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• 2014

현대의 복잡한 도시생활로 인하여 많은 이들이 크고 작은 정신적인 스트레스를 호소하고 있으며 이에 따라 각종 정신질환에 노출되어 있다. 특히, 학생이나 직장인 할 것 없이 많은 이들이 집중력 부족으로 인하여 일의 능률 저하나 양질의 생활 유지에 어려움을 가지고 있다. 이러한 집중력을 향상시키기 위해 명상이 대안으로 떠오르고 있으며, 이러한 명상이 집중력에 어떠한 형태로 영향을 미치는지 알아보기 위해 EEG 뇌파를 활용하여 실험하였다. 명상경험자를 실험대상으로 하였으며 뇌의 좌우반구의 전전두엽 영역에 배치된 AF3와 AF4영역을 중점적으로 관찰하고 분석하였다. 그 결과 리듬성 활동 뇌파의 특유한 패턴과 파워 스팩트럼의 변화를 관찰할 수 있었다.

• 한국세라믹학회지
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• 제32권6호
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• pp.659-668
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• 1995

Zirconium carbide was prepared from the mixture of metal zirconium and carbon powders in argon atmosphere by Self-propagating High-temperature Synthesis (SHS) in order to obtain the best carbon source and dilution contents. The most exellent result was obtained in the case that active carbon was added as a starting material, 20~30 wt% dilution content. From thermal profile analysis an apparent activation energy of 118 KJ/mol was calculated. The maximum heating rate achieved during 15 wt% ZrC reaction by product dilution method was approximately 1.54$\times$105 K/s. Coupling this value with the measured wave velocity of 1.026cm/s yielded a maximum thermal gradient fo $1.5\times$105 K/cm. Using the definition of t* and the measured wave velocity, the effective thermal diffusivity, $\alpha$, was calculated to be 0.62$\times$102 $\textrm{cm}^2$/s.

• 대한기계학회논문집B
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• 제27권5호
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• pp.655-667
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• 2003

Turbulent flow over a fully-developed wavy channel is investigated by the nonlinear $k-\varepsilon-f_\mu$ model of Park et al.⁽¹⁾ The Reynolds number is fixed at $Re_{b}$ = 6760 through all wave amplitudes and the wave configuration is varied in the range of $0\leq\alpha/\lambda\leq0.15$ and $0.25\leq{\lambda}/H\leq4.0$. The predicted results for wavy channel are validated by comparing with the DNS data of Maa$\beta$ and Schumann⁽²⁾ The model performance Is shown to be generally satisfactory. As the wave amplitude increases, it is found that the form drag grows linearly and the friction drag is overwhelmed by the form drag. In order to verify these characteristics, a large eddy simulation is performed for four cases. The dynamic model of Germane et al.⁽³⁾ is adopted. Finally, the effects of wavy amplitude on separated shear layer are scrutinized.