• KCID journal
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• v.1 no.2
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• pp.48-59
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• 1994

여러가지의 유사이동 공식들은 각 저자들의 실험실이나 현장실측치를 바탕으로 발표되었다. 그리고 저자에 따라서 본인들의 공식의 적용한계를 명백히 명시한 것도 있지만 그렇지 않은 것도 많다. 동일한 수리학적 조건에서 이 공식들이 현장에서 적용될 때 이 공식에 의한 유사량은 공식에 따라서 유사한 것도 있고 차이가 많이 나는 것도 있다. 특히 St. Venant식(물의 연속 방정식과 물의 운동량 방정식)과 유사 연속방정식을 연립하여 컴퓨터 모의시험에 이용할 때

• Journal of Korean Society of Archives and Records Management
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• v.6 no.1
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• pp.43-63
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• 2006

This paper aims to analyze of the records schedule's transactions, identify problems of them and suggest improving requirements, especially focusing on similar institutions. The paper examines the process and principle of establishing transactions for the records schedule and analyzes the transactions on the records schedules at 59 national and public university libraries by retention, type, library size and administrative functions.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.87-87
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• 2019

흔히 진흙으로 대표되는 점착성 유사는 모래와 같은 비점착성 유사와 달리 응집 현상으로 인해 지속적으로 유사 입자의 크기가 변화한다. 응집 현상은 점착성 유사 입자의 응집 과정과 파괴과정으로 구성된다. 응집 현상 중 응집 과정은 유사 입자 간의 충돌로 인해 발생하는 것으로 이해되며, 충돌을 야기하는 메커니즘으로는 브라운 운동(Brownian Motion), 차등침강(Differential Settling), 난류 전단 (Turbulent Flow Shear)이 있다. 파괴 과정은 입자간 충돌로 인해 깨지는 것이 아닌 난류 전단(Turbulent Shear)로 인한 덩어리 분리(Massive Splitting)가 발생하는 것으로 이해한다. 이러한 유체의 특성, 흐름 특성 (난류 거동) 뿐만 아니라 유사 입자의 특성 모두의 영향을 받으며 지속적인 응집 현상을 겪는 점착성 유사 입자들은 하나의 커다란 덩어리인 플럭(Floc)을 형성한다. 형성된 플럭의 구조는 프랙탈 기하학을 따르는 것으로 이해된다. 따라서 플럭의 구조는 자기 유사성을 띠며, 플럭의 밀도는 형성된 플럭 크기의 함수가 된다. 플럭의 크기가 증가할수록 플럭의 프랙탈 차원이 감소하며, 플럭의 밀도는 감소한다. 많은 이전의 연구에서 플럭의 침강 속도를 농도에 따른 함수로 가정하고 경험식을 이용하여 산정하나, 유사 입자의 침강 속도는 크기와 밀도의 함수임을 Stokes Law를 통해 생각해 볼 수 있다. 이에 본 연구에서는 응집 현상의 결과물로 형성된 응집물의 크기와 밀도를 각각 산정하고, Stokes Law를 이용하여 침강 속도와 응집물 크기의 관계에 대한 연구를 수행하고자 한다. 보다 심도 있는 연구를 위해서는 응집 현상을 야기하는 메커니즘에 대한 이해가 필수적이다. 간소화된 응집 모형으로부터 얻어진 플럭 크기를 이용하여 프랙탈 차원, 플럭의 밀도를 산정한다. 형성된 응집물의 크기와 침강 속도의 관계에 대한 이해를 통해 보다 정확한 플럭의 침강 속도 산정이 가능할 것으로 생각된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.302-307
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• 2017

본 연구에서 퇴사량조사 실적 및 유량-유사량 관측 자료, 상 하류 수위-유량 자료를 보유하고 있는 B 저수지를 대상으로 3차원 수치모형을 이용하여 저수지 퇴사분포를 분석해 보았다. 또한 수치모형의 검증을 위하여 저수지내 6개 지점에 대한 시추 샘플링을 통해 퇴적토의 깊이를 측정하였다. 퇴적토 샘플링시 시료의 교란을 방지하기 위하여 동일지점에서 2회 샘플링 작업을 수행하였다. 샘플링 시료는 원지반과 퇴적지반의 구분을 위하여 시료분석 이전에 각 단면별 깊이를 측정하였으며, 시료는 각 단면별로 물리적 특성시험을 통해 압밀도를 측정하여 퇴적토의 깊이를 산정하고 수치모형시 검증 자료로 사용하였다. 본 연구에서는 3차원 수리해석과 함께 유사의 이송, 침식, 퇴적현상을 연동하여 모의 가능한 Delft3D 모형을 이용하여 B 저수지에 대한 유사 이송모의를 수행하였다. 모의 결과 저수지의 하폭이 넓어지는 지형 및 만곡부 인근에서 퇴적이 진행되는 결과를 보였으며, 퇴적토 시료와 비교한 결과 퇴적토 깊이는 일부 차이가 있었으나, 퇴적분포 양상은 유사한 결과를 보였다.

• Journal of KIISE:Software and Applications
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• v.31 no.1
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• pp.82-88
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• 2004

Comparing many programs like programming assignments one by one requires many costs. Moreover, if the checker would evaluate or grade assignments, much more time will be required. Even through the checker invest much time, fairness is not always guaranteed. These problems can be solved easily by grouping similar programs. So, programs after grouping can be easily evaluated and graded. In this paper, we propose and implement algerian performing grouping by similarity on many programs. The grouping algorithm evaluates similarity using algorithm proposed in (9), and performs a grouping following high similarity order. By using this grouping algorithm, the number of comparison among N programs can be reduced from N-1 times to N(N-1)/2 times. In the part of experiment and evaluation of this paper, we actually showed evaluation result by similarity using randomly 10 programming assignments at the university.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.249-257
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• 2005

There are basically two methods for the seismic design of underground structures ; analytical or pseudo-static, and dynamical method. In pseudo-static analysis approach, the ground deformations are imposed as a static load and soil-structure interaction does not include dynamic or wave propagation effects. However the behavior of soil structure interaction is nonlinear, it needs to consider nonlinear soil-structure interaction effects. In this study simplified seismic analysis method to consider soil-structure interaction by iterative procedure is proposed and the results are compared and analyzed by a finite difference computer program.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.6
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• pp.340-348
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• 2015

Removal efficiency of PCBs in contaminated marine sediments treated by Fenton-like oxidation combined with surfactant was investigated in this research in order to achieve remediation of PCBs. A washing treatment using various concentrations of hydrogen peroxide (1% and 15%) and surfactants (Triton X-100, Tween 60 and Tween 80) was evaluated at various conditions in laboratory scale experiments. The mean removal efficiencies of tPCBs varied from 24.1 to 46.7% in the sediments for 1 hour duration of the treatments. The concentration of tPCBs in contaminated marine sediments after the simultaneous treatment with hydrogen peroxide and surfactant satisfied the domestic environmental standards for the beneficial use of sediments. When suitable surfactant was used for Fenton-like oxidation, the removal efficiency of tPCBs at low concentration of hydrogen peroxide was similar to that at high hydrogen peroxide concentration. Thus the efficient removal of PCBs in contaminated marine sediments could be achieved through treatment with Fenton-like oxidation combined with surfactant washing.

• Journal of Life Science
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• v.29 no.9
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• pp.1023-1026
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• 2019

The purpose of this study was to investigate the estrogen-like activities of eight oriental medicines, including red ginseng, fenugreek, and dandelion. Hot water and ethanol extracts were prepared from Cervus nippon temminck (Nokgaksang), Cynanchum wilfordii (Baeksuo), Lespedeza cuneata (Yagwanmun), Panax ginseng (red ginseng), Smilax china (Toryeong), Taraxacum platycarpum (Mindeulre, dandelion), Tribulus terresteis (Namgase), and Trigonella foenum-graecum (Horopa, fenugreek). Then, estrogen-like activities were verified by the in vitro transcriptional activity assay. The extracts showing estrogen-like activities were red ginseng, Baeksuo, fenugreek, Yagwanmun, and dandelion in the ethanol extracts, and red ginseng, fenugreek, and Baeksuo in the hydrothermal extracts. Red ginseng extract showed a higher activity than the standard $10^{-8}M$ $17{\beta}$-estradiol in both the hydrothermal and ethanol extract at $500{\mu}g/ml$, while the $50{\mu}g/ml$ of the red ginseng ethanol extract and the $500{\mu}g/ml$ of the Baeksuo hydrothermal extract showed estradiol activities between $10^{-9}$ and $10^{-8}M$ $17{\beta}$-estradiol. This shows that it would be possible to contribute to the development of functional materials using red ginseng, Baeksuo, fenugreek, and dandelion.

• Journal of Korea Water Resources Association
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• v.39 no.2 s.163
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• pp.99-108
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• 2006

To describe the behavior of suspended-sediment particles in turbulent open-channel flows, the advection-diffusion equation or its simplified form has been used. Though this equation was derived upon several assumptions, only a few studies tried to evaluate the limit of the assumptions. The reason is that it is very difficult to measure turbulence in open-channel flows and to discriminate the velocities of water and sediment particles. The present study aims to measure the velocity profiles of water and sediment particles in open-channel flows by using PTV (Particle Tracking Velocimetry), a kind of PIV (Particle Image Velocimetry). The measured results showed that sediment particles moved slower than water tracers did in the outer region. In the present study, the amount of velocity-lag reached about $5\%$ of the mom flow velocity and the position of the maximum velocity-lag was $g/h\approx0.05\;(g^{+}=30\~50)$ The main cause of the velocity-lag of sediment particles seems that the sediment particles have larger density than water has. On the other hand, in the viscous sublayer, sediment particle has a larger velocity than water tracers. The reason of the inversion of velocity-lag may be due to the no-sleep condition of water at the solid boundaries.

• Journal of Life Science
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• v.30 no.6
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• pp.550-554
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• 2020

The purpose of this study was to screen the testosterone-like activities of eight oriental medicines with an in vitro testosterone compound detection (TCD) system. Distilled water and 80% ethanol, both at 80℃, were used to obtain extracts from Cervus nippon temminck (Nokgaksang), Cynanchum wilfordii (Baeksuo), Lespedeza cuneata (Yagwanmun), Panax ginseng (Hongsam), Smilax china (Toryeong), Taraxacum platycarpum (Mindlre), Tribulus terresteis (Namgase), and Trigonella foenum-graecum (Horopa), and extracts at concentrations of 5, 50, and 500 ㎍/ml were assessed using the TCD system. The testosterone-like activities of the 80% ethanol extracts were seen to increase with concentration and ranged from 0.9 to 5.0 times higher than those of the negative control; Horopa and Yagwanmun exhibited superior testosterone-like activities, followed by Mindlre and Hongsam at the same concentration. Toryeong and Namgase, on the other hand, showed low activity with Nokgaksang and Baeksuo exhibiting very low levels. Compared with the activities of the positive control (5α-DHT), the 80% ethanol extracts of Horopa and Yagwanmun at a concentration of 500 ㎍/ml showed higher testosterone-like activities than 10^-8 M 5α-DHT. The water extracts showed lower activity levels than the ethanol samples, and the change of activity with concentration was also lower. It was confirmed that the 80% ethanol extracts of Horopa, Yagwanmun, and Mindlre etc. enhance the transcription efficiency of testosterone-related genes and may therefore be useful in developing health food or medicinal treatments for the improvement of male menopausal symptoms.