• 한국안전학회지
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• 제33권2호
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• pp.132-137
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• 2018

Compared with general rivers, fluctuations of the water level and the river bed are severe in the tidal river. In hydro-dynamic aspect, such fluctuation gives different river-bed data to us according to observing period. The time-dependent river-bed data and pre-estimation of the Manning's roughness coefficient which is the key factor of numerical modelling induces uncertainty of evaluating the design flood level. Thus it is necessary to pay more attention to calculate the flood level at tidal rivers than at general rivers. In this study, downstream of the Imjin River where is affected by tide of the West Sea selected as a study site. From the numerical modelling, it was shown that the unsteady simulation gave considerable mitigation of the water level from the starting point to 15 km upstream compared to the steady simulation. Either making a detention pond or optional dredging was not effective to mitigate the flood level at Gugok - Majung region where is located in the downstream of the Imjin River. Therefore, a more sophisticated approach is required to evaluate the design flood level estimation before constructive measures adopted in general rivers when establishing the flood control plan in a tidal river.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.339-339
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• 2013

We study on the optical and electrical properties of indium-free ZTO(ZnSnO)/Ag/ZTO (ZAZ) multilayer electrodes for the low-cost transparent electrode. In the first step, each single layer was deposited using rf magnetron in-line sputter with various working pressure based on $O_2$/$Ar+O_2$ ratio (0~3%) and power at room temperature. Secondly, we studied the optical and electrical properties by analyzing the refractive index, extinction coefficient, transmittance and resistivity of each layer. Finally, we optimized the thickness of each layer using macleod simulation program based on the analyzed optical properties and fabricated the multilayer electrode. As a result, We achieved a low sheet resistance of $11{\Omega}$/sq and anaverage transmittance of 80% in the visible region of light (380~780 nm). This indicates that indium-free ZAZ multilayer electrode is a promising low-cost and low-temperature processing electrode scheme.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.25.2-25.2
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• 2008

Polar rain is a spatially uniform precipitation of electrons with energies around 100eV that penetrate into the polar cap region where geomagnetic field lines are connected to the Interplanetary Magnetic Fields (IMF). Since their occurrences depend on the IMF sector polarity, they are believed to originate from the field aligned component of the solar wind. However, statistically direct correlation between polar rain and solar wind has not been shown. In this presentation, we examined specifically the IMF strength influence on the polar rain flux variation by classifying of IMF sector polarities. For this study, we employed the polar rain flux data measured by STSAT-1 and compared them with the solar wind parameters obtained from the WIND and ACE satellites. We found the direct mutuality between polar rain flux and IMF strength with correlation coefficient above 0.5. This proportional tendency appears stronger when the northern hemisphere is in the away sector of the IMF, which could be associated with a favorable geometry for magnetic reconnection. Simple particle trajectory simulation clearly shows why polar rain intensity depends on the IMF sector polarity. These results are consistent with the direct entry model of Fairfield et al.(1985), while low correlation coefficient with solar wind density, the similarity between slops of both energy spectra shows that transport process occur without acceleration.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1361-1368
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• 2009

본 연구는 충청지역를 대상으로 하여 지역산업연관분석을 실시함으로써 지역경제활성화를 위한 산업선정과 투자우선순위 등을 제시하고자 함이다. RAS기법을 이용하여 2005년 전국산업연관표를 바탕으로 2006년 전국산업연관표를 작성한 후에, 입지계수법을 이용하여 2006년 충청지역산업연관표를 작성하여, 충청지역의 각종 파급효과들을 분석하였다. 생산유발효과, 부가가치 유발효과 분석결과는 제조업부문이 가장 높게 나타났으며, 취업유발효과의 경우 음식점 및 숙박업이 가장 높게 나타났으며, 감응도계수는 광업, 영향력계수는 제조업부문에서 높게 분석되었다.

• 한국컴퓨터산업학회논문지
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• 제3권9호
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• pp.1287-1294
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• 2002

본 논문에서는 DWT기반의 점진적 영상부호화를 위한 알고리즘 기법을 제안해보고자 한다. DWT와 에지부분을 추출하고 확장된 EZW 알고리즘을 이용하여 기존의 Embedded Coding 보다 효과적인 부호화 방법을 설계해 보았다. 일반적으로 에지 부분은 원 영상을 복원하는데 있어 매우 중요한 역할을 하게 된다. 영상에 대해 DWT를 거치게 되면 계수들은 중요계수와 비중요계수 두가지의 그룹으로 분류할 수 있다. 본 논문에서는 에지부분이 영상에서는 중요계수처럼 나타난다는 것을 이용하였다. 특히 DWT 영상에서는 방향성에 의해서 고주파 부대역에서 이러한 특성이 그대로 나타난다는 것을 확인할 수 있다. 또한 Embedded Coding에서 중요계수처럼 영상을 복원하는데 중요한 정보들은 전송순서에서 보다 우선순위를 가지게 된다. 따라서 본 논문에서 제안하려는 시스템은 영상의 점진적 전송이 요구되는 응용분야에 효과적으로 이용될 수 있을것으로 기대할 수 있을 것이다.

• 한국정보통신학회논문지
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• 제7권3호
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• pp.454-460
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• 2003

The modulated frequency dependence on the pyroelectric properties of LiTaO$_3$ single crystal was investigated by the dynamic method. The pyroelectric coefficient of LiTaO$_3$ single crystal was 2.1${\times}$$10^{-8}$/$\textrm{cm}^2$ㆍK. and figure of merits for the responsivity and the detectivity were 1.31${\times}$$10^{-10}$Cㆍcm/J and 1.47${\times}$$10^{-8}$C\ulcornercm/J. respectively. The voltage responsivity corresponded with the pyroelectric voltage exhibited the highest value as about 165V /W at 4Hz and then was in inverse proportion to the frequency over 20Hz. The noise equivalent power and the detectivity at 4Hz were 8.4${\times}$$10^{-9}$ W/Hz$^{1}$2/ and 2.2${\times}$$10^{7}$ cmㆍHz$^{1}$2//W, respectively. Therefore, we could found that LiTaO$_3$ single crystal shows a excellent pyroelectric properties in low frequency region for the human body detection.tection.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.166-170
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• 2008

The changing process from hovering mode to transition one is of importance to determine a stability of tilt-rotor aircraft, which is utilized in UAV(Unmaned Aerial Vehicle). The analysis on fluid flows and aerodynamic characteristics according to variation of tilting angle of rotor is essential step in development of tilt-rotor. In the present study, the computation domain is divided into the rotating and stationary regions in order to consider the rotating blades. For the convenient realization of various tilting angle as well as application of boundary condition, the whole computation region is constructed into sphere domain. The near farfield boundary condition is adopted. The airfoil used in computation is NACA 0012. The computation results for the hovering mode are validated by comparing with previously conducted experimental results. From the results, the flow fields around rotor blade and the aerodynamic characteristics in transition mode are observed. The computational result will provide the basis for development and performance evaluation of tilt-type aircraft.

• 대기
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• 제16권4호
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• pp.279-301
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• 2006

This study analyzed the characteristics of the wind waves near the Korean marginal seas in the 2002 - 2005 year using the third generation wave model, WAVEWATCH - III model. In order to investigate the model performance, model results were compared with the marine meteorological observation results. The 4 years average correlation coefficient between model and observation shows very high value of about 0.77. The model of this study represents very well the characteristics of wind waves near the Korean marginal seas. Simulated monthly sea surface winds and wind waves show the evident spatial variations and this model also simulates very well seasonal characteristics of wind waves in this region.

• BMB Reports
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• 제45권12호
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• pp.748-753
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• 2012

A sequence of 10 amino acids at the C-terminus region of methylglyoxal synthase from Escherichia coli (EMGS) provides an arginine, which plays a crucial role in forming a salt bridge with a proximal aspartate residue in the neighboring subunit, consequently transferring the allosteric signal between subunits. In order to verify the role of arginine, the gene encoding MGS from a thermophile species, Thermus sp. GH5 (TMGS) lacking this arginine was cloned with an additional 30 bp sequence at the 3'-end and then expressed in form of a fusion TMGS with a 10 residual segment at the C-terminus ($TMGS^+$). The resulting recombinant enzyme showed a significant increase in cooperativity towards phosphate, reflected by a change in the Hill coefficient (nH) from 1.5 to 1.99. Experiments including site directed mutagenesis for Asp-10 in TMGS and $TMGS^+$, two dimentional structural survey, fluorescence and irreversible thermoinactivation were carried out to confirm this pathway.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.124-130
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• 2001

The heat transfer and flow measurements were made on a cylindrical pedestal mounted on a flat plate with a turbulent impinging air jet. The heat transfer coefficient distributions on the flat plate were measured using the shroud-transient technique and liquid crystal was used to measure the surface temperature. The jet Reynolds number (Re) is 23,000, the dimensionless nozzle-to-surface distance (L/d) from 2 to 10, the dimensionless pedestal diameter-to-height (H/D) from 0 to 1.5, the dimensionless 2nd pedestal diameter-to-height ($H/D_2$) from 0 to 0.4 and the distance from the stagnation point to 2nd pedestal (p/D). The results show that for H/D = 0.5 to 1.5, the Nusselt number distributions on the plate surface exhibit a maximum between $r/d\;{\cong}\;1.0$ and 1.5. The presence of the pedestal appears to cause the flow separation and reattachment on the plate surface, which results in the maximum heal transfer coefficient. Also, for p/D = 2.5 and $H/D_2$ = 0.3, the local Nusselt number in the region corresponding to $r/d\;{\cong}\;1.1$ was increased up to 50% compared to that for $H/D_2=0$.