• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.384-389
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• 2011

This article presents an ultra broadband resistive power divider circuit for smart grid applications. Since the future smart grid system is expected to deploy high speed power line communication, the frequency response of the resitive power divider circuit is naturally of significance. Employing a thin film technology, the resistive power divider was designed, measured, and fabricated. For the circuit design, the conductor-backed coplanar waveguide line was firstly designed and measured. The 3 dB cutoff frequency was 72 GHz and S11 remains <-20 dB upto 70 GHz. The fabricated resistive power divider shows the 3 dB cutoff frequency of 50 GHz. It was experimentally verified that the resistive power divider circuit shows the insertion loss of 6 dB for high-speed input signal (40 Gb/s).

• Journal of Technology Innovation
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• v.24 no.4
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• pp.127-158
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• 2016

Multinational corporations' overseas R&D activities bring host countries positive effects such as knowledge spillover, technology transfer, job creation and etc. For this reason, many countries have made efforts to attract foreign firms' R&D investment in their national territories. Korean government have also implemented some policy measures to expedite foreign firms operating in Korea to increase R&D activities. However, the firms' R&D investment in Korea has still been unsatisfactory, and only few studies have examined this issue. Therefore, this study attempts to explain the R&D investment of foreign firms operating in Kore, from the perspective Dunning's eclectic paradigm. Utilizing linear regression and Tobit model, this study analyzes the influence of OLI advantages on R&D intensity of foreign firms in Korea. The result shows that locational advantages of Korea (such as revealed technological advantage) had positive influences on foreign firms' R&D intensity. However, the influence of other OLI advantages were different by foreign firms' nationalities. For instance, internalization advantages had influences on R&D intensity, but the directions were different between Japanese and other nationalities. Based on the results, we provided some discussion and attempted to draw implications for Korean government's FDI and R&D policy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.40-46
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• 1984

The extraction ratio of oil using solvent from the muscle of sardine, Sardinops melanosticta, was studied. The results were critically evaluated in the light of the theory of oil diffusion in a porous solid model. In addition the effect of temperature and moisture on the extraction rate was examined. Sardine muscle was prepared in a manner to meet the conditions required by the diffusion theory from Fick's law. The results of the model were well coincidenced to the theory derived from Fick's law. Diffusion constants at the direction to muscle fiber($D_1$) and at direction perpendicular to fiber($D_2=D_3$) when extracted at $45^{\circ}C$ were $8.16{\times}10^{-8}cm^2/sec\;and\;4.12{\times}10^{-8}cm^2/sec$, respectivly. The extraction rate was linearly propotional to absolute temperature(T) by eleventh power under the constant condition of moisture contents and muscle size. A comparison of the experiments with the highest($74.22\%$) and the lowest ($32.48\%$) moisture indicated that difference of $1\%$ in moisture contents caused to change the slope(K) of the extraction curve $0.53{\times}10^{-6}sec^{-1}$ approximately.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.625-632
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• 2006

Dependence of the critical micelle concentration (CMC) on temperature is examined from a statistical-mechanical point of view. A simple and primitive model examined in this article yields ln CMC= A+BT+C/T+D ln T with T being temperature and A, B, C, D being constants depending on the properties of the surfactant molecules which comprise the micelles. The resulting equation combines Muller's and Lim's equations, which have already been proven to fit well measured CMC data with temperature. The statistical-mechanical model on micellization discussed in this article provides a theoretical basis on these equations.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.188-194
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• 1993

By applying the Nakayama's theory of saturation spectroscopy to 87Rb $D_2$ lines, taking into account the optical pumping process, the relative intensities of the resonance signals were calculated for various polarization combinations of pump and probe beams. The saturated absorption spectra were observed with a linewidth-narrowed semiconductor laser. As the result, it was found that the theoretical calculations were in good agreement with the experimental observations in the case where the geomagnetic field was- shielded.

• Journal of ILASS-Korea
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• v.1 no.1
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• pp.44-54
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• 1996

A theoretical and experimental study was carried out on the prediction of drop size distribution of the pressure swirl atomizer. Drop size distribution was obtained by using maximum entropy formal ism. Several constraints in the form of the definition of mean diameter were used in this formulation in order to avoid the difficulties of the estimating source terms. In this study $D_{10}$ was only introduced into the formulation as a constraint. A drop size obtained by using linear Kelvin-Helmholtz instability theory was considered as an unknown characteristic length scale. As a result, the calculated drop size was agreed well with measured mean diameter, particularly with $D_{32}$. The predicted drop size distribution was agreed welt with experimental data measured wi th Malvern 2600.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1037-1041
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• 2006

본 연구에서는 수질자료에 내재되어 있는 주기성 및 경향성 등을 파악하기 위해 웨이블렛 변환을 적용하였으며 비선형 시계열자료에 대한 예측력이 우수한 인공신경망을 적용하여 예측모형을 개발하였다. 대상자료는 섬진강 유역의 주암호 수질자동측정망 지점에서 측정되고 있는 수질자료 중 2002년 1월 1일 ${\sim}$ 2004년 12월 31일까지의 일 TOC 수질자료를 이용하였다. 웨이블렛 변환을 위해 사용한 기저함수로는 Daubechies의 10번 웨이블렛 함수('db10')를 사용하였으며, 각 스케일링 및 웨이블렛 함수를 이용하여 5단계까지 변환하였다. 최종 변환된 근사성분과 D5, D4, D3, D2의 상세성분 자료를 이용하여 1시간후 TOC 예측 모형을 구성하였으며 그 결과 은닉층의 노드의 수가 17개인 모형인 Model_5_17 모형이 가장 우수한 예측력을 보였다.

• Korean Journal of Optics and Photonics
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• v.8 no.2
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• pp.142-148
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• 1997

The new type of dispersion-free optical isolator is presented and it's performance is verified by theoritical and empirical method. The dispersion-free optical isolator consists of 2 wedged birefringent materials, faraday rotator, collimating unit and focusing unit. In the test it shows that isolation is 40dB, insertion loss is 0.55dB, dispersion is 0.02ps at 1550nm

• Journal of Korea Game Society
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• v.13 no.3
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• pp.131-140
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• 2013

The study analyzes how to create stereoscopic image in 3-dimension animation 'Yggdrasil', produced in Autodesk Maya(3D animation software), using Anaglyph method that is the oldest in 3-dimension stereoscopic video production. The anaglyph method help to produce stereoscopic images easily and to give effective 3D effect encoding each eye's image using filters of different colors. In addition, space direction applied visual perception theory expresses necessary distance, depth and speed effectively in 'Yggdrasil'

• Geophysics and Geophysical Exploration
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• v.3 no.1
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• pp.13-18
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• 2000

We describe the concept of the singularity in the integral equation of electromagnetic (EM) modeling in comparison with that in the integral representation of electric fields in EM theory, which would clarify the singular integral problems of the Green's tensor. We have also derived and classified the singular integrals of the Green's tensors in 3-D, 2.5-D and 2-D as well as in the thin sheet integral equations of the EM scattering problem, which have the most important effect on the accuracy of the numerical solution of the problems.