• Membrane Journal
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• v.12 no.2
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• pp.55-66
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• 2002

fouling phenomena of ion exchange membranes were reviewed for improved design and operation of electodialysis. The membrane fouling index for electrodialysis (EDMFI) was defined for the quantitative analysis of fouling potential as an analogy to the pressure-driven membrane process. fouling phenomena were compared in the electrodialysis experiments with inorganic foulant (silica sol) and organic foulants (humate and bovine serum albumin (BSA)), and their fouling potentials were analyzed using the fouling index. The comparison showed that the EDMFI could be used as a quantitative measure of the fouling tendency in electrodialysis processes. As a novel fouling mitigation method, square wave power was reported to be effective in electrodialysis with organic foulants. The square wave powers having the pulsed electric field enabled to reduce the membrane fouling significantly at an optimal frequency.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.96-97
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• 2007

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.156-157
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• 2000

The amplification method using evanescent wave coupling has a long history and has been widely used as a new lasing method, especially, in the waveguide optics$^{(1)}$ . In particular, it has been observed experimentally that when the light wave propagating in a dielectric medium is totally reflected at the planar interface between the dielectric and a pumped active medium, the reflectance may be greater than unity, i.e., amplification is possible$^{(2)}$ . There were several attempts by other authors to explain this enhanced internal reflection (EIR) classically$^{(3)}$ . They commonly introduced a complex refractive index for the active medium with its imaginary part being negative, and this scheme was also used to describe an amplification process in a waveguide having active-cladding region$^{(4)}$ . However these theories are phenomenological, using macroscopic constants, and therefore a microscopic theory is needed to understand EIR in a fundamental level. (omitted)

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.250-253
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• 2015

High contrast grating (HCG) is the structure made up of the sub-wavelength grating of high-index and the surrounding layer of low-index, which reveals high contrast between two materials. Its advantages include high reflectivity over a broad bandwidth, polarization and wavelength selectivity, optical high-Q resonator, and phase modulation. In this work, the HCG structure comprising of indium tin oxide (ITO) and Silicon (Si), for the surrounding layer and the grating layer respectively, was studied. Its theoretical model was established, and transmittance, phase and optical behavior were calculated by rigorous coupled-wave analysis and finite element method. Furthermore, the established structure was fabricated to validate its feasibility. The fabricated structure shows the focusing capability whose length is about $10{\mu}m$, and the feasibility of the structure was demonstrated. It is also meaningful that ITO layer can contribute to the fabrication of the HCG structure, leading to enable the structure to be electrical-driven.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.4
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• pp.217-227
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• 2015

In this study, two-dimensional physical experiment was carried out to examine the applicability of the three formulas(Takahashi and Shimosako, 1994; Tabet-Aoul and Lambert, 2003; Li, 2007), which were proposed to calculate the wave forces acting on perforated caisson breakwaters. In order to quantitatively compare the measured with the estimated values based on the wave formulas, the refined index of agreement and the coefficient of determination were calculated, by which the degree of agreement was evaluated. Among the three wave formulas, DUT formula (Li, 2007) showed the smallest deviation from the measured forces, whereas Takahashi formula (Takahashi and Shimosako, 1994) showed the largest deviation. Meanwhile, comparison of the magnitude of the measured wave forces with those from the three formulas revealed that DUT formula slightly underestimate, while the others overestimate the measured forces.

• Management & Information Systems Review
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• v.36 no.2
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• pp.21-35
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• 2017

The Korea Wave has been spread out all over the world since 1990s. Therefore, it can be seen that the Korea wave phenomenon is one of determinants of international tourism demand for Korea in addition to the macro factors such as population, GDP per capita, exchange rate, distance, etc. Existing studies have focused on analyzing the impacts of the Korea wave on the international tourism demand for Korea by using the aggregated data. However, the impacts of the Korea wave inducing tourism vary in different age groups. In this study, we conduct empirical analysis in order to explore how different the effects of Korea wave on the demand of foreign tourists visiting to Korea in different age groups are. The estimation results show that the Korea Wave influences most on international tourism demand for Korea in the age group of the under-20s. Noticeable is that the estimated effects of the Korea Wave on international tourism demand for Korea in the age group of the over-50s are higher than those in the 30s and 40s. This indicates that the parent generations visit Korea together with their young children who are most affected by the Korea Wave. Through this study, it is necessary to develop strategies for tourism marketing linked to children and parents, and to develop tourism products to increase the number of foreign visitors to Korea in the 30s and 40s.

• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.121-126
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• 2008

Pulse diagnosis refers to the process of diagnosing a patient by feeling an artery on the wrist based on the shape that the pulse take s while the hold-down pressure increase. The styloid process artery on the wrist is usually felt, and the pulse is taken on Chon, Gwan and Cheok using three fingers. This study is to examine the structural difference in the location of pulse diagnosis by measuring and analyzing blood diameter, blood depth, and blood flow velocity of the location of pulse diagnosis by using ultrasonic wave (VOLUSION730 PRO, GE Medical, U.S.A). This study also attempted to grasp whether the characteristics of blood vessels differ depending on Body Mass Index (BMI) and analyzed their correlation with Oriental medical pulse diagnosis. The male subjects without cardiovascular diseases were divided into the normal BMI group, the underweight group and the overweight group and 10 people of each group were measured, Blood depth, blood diameter and blood flow velocity at the location of pulse diagnosis (Chon, Gwan, Cheok) of the wrists of left and right hands were measured and the pulse wave was measured by using pulse diagnosis instrument (3-D Mac, DaeyoMedi, Korea).The results of this study showed that the characteristics of blood vessels differ depending on the degrees of obesity, and the characteristics of floating pulse and sinking pulse of Oriental medical pulses were related to the degrees of obesity. This shows that the characteristics of the blood vessels of subjects and BMI information are the major indicators for diagnosis and are the matters that must always be considered when developing the algorithm of pulse diagnosis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.547-554
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• 2014

In this study, have researched 'a' index from three sound sources, effects on subject and finding optimal 'a' index, which can improve subject's stability, concentration and productivity. Check the health status of subjects who were selected 5 male and 5 female university students, and the period of this experiment was about two months. It were measured each subject's EEG, HRV and vibra image to analyze transition of stability, concentration, stress and heart beat. The results was measured in an environmental test room of temperature $25[^{\circ}C]$, the relative humidity 50 [%], illuminance 1,000 [lux] and air current speed 0.02[m/sec] with 'a' index of three sound sources which are a=1.106, a=1.749 and a=2.227. Results in a=1.106 compared to before exposure, relative $S{\alpha}$ wave, relative $L{\beta}$ wave and relative $M{\beta}$ wave have been revitalized, asymmetry index, stress and HRV have been decreased. Thus, to increase stability, concentration and productivity, also to decrease stress, changes in sound source of a=1.106 was found to be the most effective.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.327-333
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• 2001

Estimation of the frequency response of Ti:LiNb03 traveling-wave optical modulator with phase reversal electrodes is succinctly presented. The fact that such devices may have bandpass characteristics is demonstrated through simulations based on the derived equations. The influence of each parameter of traveling-wave electrodes on the frequency response is investigated in detail. It is shown that the center frequency and the bandwidth of response curves can be effectively adjustable by changing the MW effective index and the interaction length of the electrodes. rodes.

• Tunnel and Underground Space
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• v.25 no.1
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• pp.24-36
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• 2015

The Geochang granite widely used in construction works is one of the most popular dimension stones in Korea. In order to evaluate the physical properties of rock, a lot of laboratory tests for the Geochang granite were conducted to find unit weight, absorption ratio, P wave velocity, S wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, cohesion, friction angle and point load strength index. The uniaxial compressive strength of the Geochang granite was 19.5 times tensile strength and also 8.6 times cohesion, besides P wave velocity was 1.5 times S wave velocity. Correlation analyses were also conducted to find the correlation among 11 different physical properties, where the uniaxial compressive strength showed Pearson correlation coefficient of more than 0.8 with Poisson's ratio, point load strength index and Young's modulus, respectively. Regression analyses were finally conducted by means of both linear and multiple analysis and the brief results including coefficient of determination of more than 0.7 were presented.