• Journal of Oriental Neuropsychiatry
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• v.21 no.2
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• pp.87-101
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• 2010

Objectives : The aim of this experiment was to investigate the influences of Autonomic Nervous System and EEG by conducting Reinforcement-Reduction(補瀉) acupuncture stimulation to compare the changes in acupoints on the body before and after treatment of acupuncture at Xingjian(LR2) being referred as Fire-point(火穴) and Ququan(LR8) being referred as Water-point(水穴) of Yin Liver Meridian(足厥陰肝經). Methods : This study was carried out on 30 healthy female volunteers in their 20's. There were four tests conducted throughout and the period for each test was between 2 to 5days. HRV and EEG were measured for 5 minutes before acupuncture stimulation was conducted on LR2-Reinforcement, LR2-Reduction, LR8-Reinforcement and LR8-Reduction at random. During the 20 minutes of acupuncture treatment, same subjects were measured simultaneously to observe any significant changes in acupoints. Again, the same subjects were measured for 5 minutes after removing the acupuncture in order to perform a comparative analysis. Results : The measurement of HRV showed that LF, LFnorm and LF/HF ratio increased significantly(p<0.05) while HF, HF norm decreased significantly in case of LR2-Reinforcement & LR8-Reduction. Both LR2-Reduction and LR8-Reinforcement induced a significant increase in HFnorm. EEG measurement indicated low $\alpha$ wave decreased and high $\beta$ wave increased significantly at LR2-Reinforcement during post-acupuncture period compared with acupuncture stimulation period. Both LR2-Reduction and LR8-Reinforcement developed significantly low $\alpha$ wave and high $\alpha$ wave. High $\beta$ wave increased significantly at LR8-Reduction during the acupuncture stimulation in comparison with pre-acupuncture period. Conclusions : The manipulation of acupuncture stimulation at LR2-Reinforcement and LR8-Reduction enhanced the activity of sympathetic nerves and the state of arousal while that of para sympathetic nerves declined. On the other hand, LR2-Reduction and LR8-Reinforcement developed the levels of para sympathetic nerves and relaxation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.667-678
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• 2002

In this paper, a new radiating structure with a multi-layered two-dimensional metallic disk array was proposed for shaping the flat-topped element pattern. It is an infinite periodic planar array structure with metallic disks finitely stacked above the radiating circular waveguide apertures. The theoretical analysis was in detail performed using rigid full-wave analysis, and was based on modal representations for the fields in the partial regions of the array structure and for the currents on the metallic disks. The final system of linear algebraic equations was derived using the orthogonal property of vector wave functions, mode-matching method, boundary conditions and Galerkin's method, and also their unknown modal coefficients needed for calculation of the array characteristics were determined by Gauss elimination method. The application of the algorithm was demonstrated in an array design for shaping the flat-topped element patterns of $\pm$20$^{\circ}$ beam width in Ka-band. The optimal design parameters normalized by a wavelength for general applications are presented, which are obtained through optimization process on the basis of simulation and design experience. A Ka-band experimental breadboard with symmetric nineteen elements was fabricated to compare simulation results with experimental results. The metallic disks array structure stacked above the radiating circular waveguide apertures was realized using ion-beam deposition method on thin polymer films. It was shown that the calculated and measured element patterns of the breadboard were in very close agreement within the beam scanning range. The result analysis for side lobe and grating lobe was done, and also a blindness phenomenon was discussed, which may cause by multi-layered metallic disk structure at the broadside. Input VSWR of the breadboard was less than 1.14, and its gains measured at 29.0 GHz. 29.5 GHz and 30 GHz were 10.2 dB, 10.0 dB and 10.7 dB, respectively. The experimental and simulation results showed that the proposed multi-layered metallic disk array structure could shape the efficient flat-topped element pattern.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.1
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• pp.28-39
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• 2019

In the design process of counter measures against the beach erosion, information like the main sediment transport mode and yearly net amount of longshore and cross shore transport is of great engineering value. In this rationale, we numerically analyzed the yearly sediment budget of the Mang-Bang beach which is suffering from erosion problem. For the case of cross sediment transport, Bailard's model (1981) having its roots on the Bagnold's energy model (1963) is utilized. In doing so, longshore sediment transport rate is estimated based on the assumption that longshore transport rate is determined by the available wave energy influx toward the beach. Velocity moments required for the application of Bailard's model (1981) is deduced from numerical simulation of the nonlinear shoaling process over the Mang-Bang beach of the 71 wave conditions carefully chosen from the wave records. As a wave driver, we used the consistent frequency Boussinesq Eq. by Frelich and Guza (1984). Numerical results show that contrary to the Bailard's study (1981), Irribaren NO. has non negligible influence on the velocity moments. We also proceeds to numerically simulate the yearly sediment budget of Mang-Bang beach. Numerical results show that for ${\beta}=41.6^{\circ}$, the mean orientation of Mang-Bang beach, north-westwardly moving longshore sediment is prevailing over the south-eastwardly moving sediment, the yearly amount of which is simulated to reach its maxima at $125,000m^3/m$. And the null pint where north-westwardly moving longshore sediment is balanced by the south-eastwardly moving longshore sediment is located at ${\beta}=47^{\circ}$. For the case of cross shore sediment, the sediment is gradually moving toward the shore from the April to mid October, whereas these trends are reversed by sporadically occurring energetic wind waves at the end of October and March. We also complete the littoral drift rose of the Mang-Bang beach, which shows that even though the shore line is temporarily retreated, and as a result, the orientation of Mang-Bang beach is larger than the orientation of null pont, south-eastwardly moving longshore sediment is prevailing. In a case that the orientation of Mang-Bang beach is smaller than the orientation of null pont, north-westwardly moving longshore sediment is prevailing. And these trend imply that the Mang-Bang beach is stable one, which has the self restoring capability once exposed to erosion.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.05a
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• pp.78-83
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• 2003

We investigated the physiological patterns of cybersickness in a Virtual Reality(VR). Subject were exposed to the VR for 9.5 min, and required to detect specific virtual objects. Sixteen electrophysiological signals were recorded before, during, and after the virtual navigation. five questionnaires on the VR experience were acquired form 61 healthy subjects. During the virtual navigation, subjects with the high cybersickness susceptibility showed significant physiological changes, which included increased gastric tachyarrhythmia, eyeblink frequency, and EEG delta wave and decreased EEG beta wave. These results suggest that cybersickness may induce or accompany the changes in central nervous system and autonomic nervous system. Also, these results suggest that there may be increased sympathetic activation in autonomic drive for cybersickness.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.1
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• pp.39-42
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• 2002

For the purpose of modeling EEG signal which has nonstationary and nonlinear dynamic characteristics, this paper propose a state feedback real time recurrent neural network model. The state feedback real time recurrent neural network is structured to have memory structure in the state of hidden layers so that it has arbitrary dynamics and ability to deal with time-varying input through its own temporal operation. For the model test, Mackey-Glass time series is used as a nonlinear dynamic system and the model is applied to the prediction of three types of EEG, alpha wave, beta wave and epileptic EEG. Experimental results show that the performance of the proposed model is better than that of other neural network models which are compared in this paper in some view points of the converging speed in learning stage and normalized mean square error for the test data set.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1397-1398
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• 2015

본 연구에서는 뇌파를 이용하여 자동차에 HUD를 적용하였을 때, HUD의 위치와 이미지 컬러 변경 시 뇌 활성화 지수(Brain Activity Quotient)의 변화를 관찰하였다. 뇌파데이터는 Fp1, Fp2, O1, O2 총 4채널에서 얻었고, HUD위치는 좌측, 중앙, 우측으로 구성하였고 컬러는 초록, 주황, 빨강 총 3가지 색상을 사용하였다. HUD이미지의 크기는 $8{\times}4.5cm^2$로 구성하였다. 뇌 활성화 지수는 상대파워분석(Relative power analysis)를 사용하여 Slow beta wave(13~20 Hz)/alpha wave(4~7.99 Hz)로 계산하였다.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.721-733
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• 2007

The purpose of this research was to determine the effects of the functional lateralization of the brain variables related to the sex, the scientific attitude and the scientific exploration skills. The science instruction is divided in each type of the lecturing class with the experiment class. As for the degree of SMR brainwave activation in each stage are presented while accumulating the brain waves from the right, left and the whole brain waves are analyzed during the science learning activities. It is therefore reasonable to consider the science instruction types and brain lateralization to enhance the science learning effectiveness. Sensorimotor rhythm brainwave as the low Beta is represented well to show the thought process. Category quantification scores and objective scores are calculated to show the visual positioning map for the relationships of the categories by homogeneity analysis.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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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.

• Ocean Systems Engineering
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• v.4 no.4
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• pp.327-342
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• 2014

The tension leg platform (TLP) is one of the compliant structures which are generally used for deep water oil exploration. With respect to the horizontal degrees of freedom, it behaves like a floating structure moored by vertical tethers which are pretension due to the excess buoyancy of the platform, whereas with respect to the vertical degrees of freedom, it is stiff and resembles a fixed structure and is not allowed to float freely. In the current study, a numerical study for square TLP using modified Morison equation was carried out in the time domain with water particle kinematics using Airy's linear wave theory to investigate the effect of changing the tether tension force on the stiffness matrix of TLP's, the dynamic behavior of TLP's; and on the fatigue stresses in the cables. The effect was investigated for different parameters of the hydrodynamic forces such as wave periods, and wave heights. The numerical study takes into consideration the effect of coupling between various degrees of freedom. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables. Nonlinear equation was solved using Newmark's beta integration method. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e., 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether tension force, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations that is significantly dependent on wave height, and that special attention should be given to tethers fatigue because of their high tensile static and dynamic stress.

• Science of Emotion and Sensibility
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• v.14 no.2
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• pp.311-320
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• 2011

To quantitatively analyze the effects of color stimulation which is one of the major affecting factors on human emotion, we studied the relationship between color preference and the Electroencephalography (EEG) to 3 color stimuli; bright yellow red (BYR), deep green yellow (DGY), and vivid blue (VB). Physiological signal measured by EEG on the color stimulation was closely related with their well-known colorful images. The brain become more activated with decreasing the color temperature (BYR${\geq}$DGY>VB), and the right brain is more sensitive than the left. On the whole, the EEG values of the frequency bands are in order to beta ${\geq}$ theta and alpha > gamma. As decreasing the color temperature, beta wave increased (BYR${\geq}$DGY>VB), and alpha, beta and gamma waves increased with increasing the color temperature (BYR${\geq}$DGY>VB). The relationship between the color preference and EEG values showed EEG gets more activated at some frequency bands when the color preference becomes higher. In conclusion, the specific frequency band could be activating by a color stimuli which had showed higher the preference. It means that these color stimuli can apply for various industries such as beauty industry, interior design, fashion design, color therapy, and etc.