• 대한산업공학회지
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• 제23권3호
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• pp.609-619
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• 1997

The concept of human emotion is recently demanded to be imbedded in industrial product and environment for enhancing quality of life. Human emotion is attempted to be qualified and quantified by physiological measurements. EEG variation, one of the physiological measurement, is observed to characterize psychological response in this study. This study is to find function and process of brain according to emotion. Twenty university students participated in this study and experienced positive and negative emotion by auditory stimulus. Delta, theta, alpha and beta waves showed characteristic variation in normalized sense according to positive and negative emotion. Local area showing significant difference between positive and negative emotion decreases with stimulus duration. Delta, theta and beta waves increase with negative emotion while alpha wave does with positive emotion.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 춘계 학술대회 및 국제 감성공학 심포지움 논문집 Proceeding of the 2000 Spring Conference of KOSES and International Sensibility Ergonomics Symposium
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• pp.58-61
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• 2000

The purpose of this study is to investigate the characteristics of electroencephalogram (EEG) during emotional occurrence of likes and dislikes in humans subjected to visual stimuli. Fifteen healthy male subjects participated in the study. Portrayals of females and cars on a visual screen, one photographic display at a time. were used as the stimulus. The subjects, with their EEGs concomitantly monitored, were asked to record their likes and dislikes for each portrayal of a total of 50 sequential displays. The results indicated that beta ($\beta$)=wave was more prevalent with dislikes than likes, and the arousal level was higher when dislikes predominated over likes, implying that more cerebral information processing activity was involved in answering dislikes than likes. In the case of cars, the difference between likes and dislikes was focused within a frequency band of 15-20 Hz in the right cerebral hemisphere. Our findings suggest that the activity in the right brain predominates with increases in negative emotion.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.18-22
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• 2000

This paper is transient motions of a very large floating structure subjected to dynamic load induced by wave. A time domain method is applied to the hydroelasticity problems for this purpose. The method is based on source-dipole and FEM scheme and on Newmark $\beta$ method to pursuit time step process taking advantage of the memory effect. The present method is appied to hydroelastic response analysis in regular waves and impact responses due to dropping aircraft.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.685-699
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• 2014

In this study, the dynamic responses of a riser under the combined excitation of internal waves and background currents are studied. A modified Taylor-Goldstein equation is used to calculate the internal waves vertical structures when background currents exist. By imposing rigid-lid boundary condition, the equation is solved by Thompson-Haskell method. Based on the principle of virtual work, a nonlinear differential equation for riser motions is established combined with the modified Morison formula. Using Newmark-${\beta}$ method, the motion equation is solved in time domain. It is observed that the internal waves without currents exhibit dominated effect on dynamic response of a riser in the first two modes. With the effects of the background currents, the motion displacements of the riser will increase significantly in both cases that wave goes along and against the currents. This phenomenon is most obviously observed at the motions in the first mode.

• 수면정신생리
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• 제29권1호
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• pp.1-3
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• 2022

Sleep is associated with Alzheimer's dementia. Many previous researches have shown that inadequate sleep is one of the risk factors that predict Alzheimer's dementia. The causal mechanism of this association is not clear. Slow wave sleep and REM sleep are critical stages in memory consolidation, and by sequential hypothesis both stages are important. Deposition of amyloid beta and tau, the main pathology of Alzheimer's dementia, are also associated with sleep. This review provides the association of sleep and Alzheimer's dementia, and future research is necessary to examine the specific mechanism of this association between sleep and Alzheimer's dementia, which may lead to an early intervention in sleep.

• 대한조선학회논문집
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• 제49권2호
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• pp.109-115
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• 2012

Slamming phenomenon may occur when a ship navigates a high sea region, where the response of ship can be expected as elastic behaviour and the resultant wave loads may increase. In this paper, numerical analysis of ship motions and wave loads including momentum slamming was performed using the strip theory with regular waves. In order to analyze the effect of slamming force on the global ship motions, time histories of each mode of displacement and forces were simulated by using Newmark-beta time integration scheme. The added mass and damping coefficients calculated by Lewis form method were compared with the results of given references. For verification of numerical results, the motion RAOs of a S175 containership were calculated as an example of application and time histories of respective displacement and vertical bending moment were compared with the results of ITTC workshop benchmark test.

• KIEAE Journal
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• 제9권1호
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• pp.47-53
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• 2009

To know the effect of smells from eco-friend and existing interior construction materials to human response, EEG of subjects' were measured. EEG signals were measured from 8 electrodes according to the international 10-20 system (Fp1, Fp2, F3, F4, Fc3, Fc4, P3, P4) from 10 healthy subjects in seven odor construction material. Followings are results. When stimuli of smell were suggested, non-stimuli pattern of ${\alpha}$-wave is largely in right occipitallobe part and rare in frontallobe part respectively. In case of eco-friend materials' smell, there is a activation of EEG in right occipitallobe part for every stimuli. But in case of eco-friend paint and Hwang-to, ${\alpha}$-wave is appeared in most part of brain even in frontallobe part. Especially for wet cedar case, activation of brain is very positive in right occipitallobe part and in frontallobe part. When comparing the normalized sensitivity of ${\beta}$-wave which appears in negative response, the preference ratio order is like this. Normal paint ${\rightarrow}$ MDF ${\rightarrow}$ Eco-friend paint ${\rightarrow}$ Gypsum board ${\rightarrow}$ Cedar ${\rightarrow}$ Wet cedar ${\rightarrow}$ Hwang-to.

• 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.

• 대한인간공학회지
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• 제22권4호
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• pp.1-13
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• 2003

This study has investigated psychological responses to various TV advertisements by using EEG(electroencephalogram). In particular, it was assumed that the brain wave would show different patterns depending upon the style of the advertisement that could be categorized into two such as 'information transfer' type and 'emotional reaction' type. Ten healthy males participated in the experiment. EEG signal was extracted from six lobes such as right and left frontal, right and left occipital, right and left temporal while the subjects were watching TV advertisements. Alpha and beta relative power spectrum, and beta/alpha parameter were calculated to compare two kinds of advertisement each other. Additionally, subjective questionnaire was used to examine subject's response by using adjective words and preference test. In result, significant differences were found in left frontal and right occipital lobe in terms of beta/alpha between two different advertisements. And, subjects showed different preference between two advertisements. It was shown that the current method could analyze the brain reaction to advertisement quantitatively, that presented the possibility of using it to marketing research.

• 한국세라믹학회지
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• 제47권6호
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• pp.503-508
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• 2010

$Eu^{2+}$-doped $\beta$-SiAlONs ($Si_{6-z}Al_zO_zN_{8-z}:Eu_y$) are recognized as promising phosphor materials to build an white LED for lighting application due to its excellent absorption/emission efficiency in the long wave length region. In this research, the fabrication of $\beta$-SiAlON:Eu plate phosphor by sintering was investigated with fixed Eu content(y) and varied composition of the host lattice(z). The addition of the activator $Eu_2O_3$ lead to enhanced densification by forming the transient liquid phase. The refinement of a composition by the calculated lattice parameter indicated that the measured composition of the fabricated specimens is nearly same to that of designed one. The single phase $\beta$-SiAlON:Eu plate with relative density of 96.4% was achieved by addition of 2 wt% CaO, which implies the possibility of full densification by adjusting the processing variables.