• Journal of Korea Water Resources Association
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• v.36 no.3 s.134
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• pp.399-411
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• 2003

An approach determining a confidence interval of Nash's observed mean instantaneous unit hydrograph is developed. In the approach, both two parameters are treated as correlated gaussian random variables based on the theory of Box-Cox transformation and the regional similarity relation, so that linear statistical parameter estimation is possible. A parametric bootstrap method is adopted to give the confidence interval of the mean observed hydrograph. The proposed methodology is also applicable to estimate the parameters of Nash's model for un-gauged basins. An application to a watershed has shown that the proposed approach is adequate to assess the uncertainty of the Nash's hydrograph and to evaluate parameters for un-gauged basins.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.41-47
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• 2006

A liquid rocket thrust chamber should have a high confidence in its combustion performance and combustion stability. Expecially, the injector of which function is spraying and mixing propellants plays an important role in getting the confidence. This study was carried out to evaluate combustion stability of a double swirl coaxial injector by using the model similarity method. Besides, in case of a baffle which was used to improve combustion stability, the length and gap effects of the baffle were investigated.

• Fire Science and Engineering
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• v.28 no.4
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• pp.29-34
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• 2014

In this study, to assess the validity of scaling law which was based on the ventilation factor and utilized in fields of compartment fires, numerical simulations were conducted on full- and 2/5 reduced-scale compartment fires using FDS and simulation results were compared with the previously published experimental data. The numerical modeling used in this study was verified by comparing the predicted temperature at several points of the upper layer with the experiment data. Temperature and concentration distribution inside of compartments and velocity profile at door of compartment are analyzed to assess the validity of scaling law. Comparison between the predicted results on the full- and reduced-scale compartments shows good agreements on the inner compartment flow patterns, outflowing flame patterns from the compartments, and vertical temperature distributions.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.721-728
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• 2006

Earthquakes are reported thai building structures have been colossal damaged, but before 1988 designed structures which were not applicate seismic design code have no seismic performance. Especially, for the apartment structures were indicated that it have no resist wall element of earthquake before 1988 designed structures. We have to evaluate for seismic performance this structures, therefore it will be retrofitted for seismic index sufficient structures. We performed seismic performance evaluation for model structures by MIDAS which is general structure analysis software. In this study, it was performed shaking table test to evaluate model structure which is reinforcement concrete and 5 floors for seismic performance index. We made specimens by similar's law and tested shaking table test. In the shaking table test it is not performed prototype model test because of space and equipment condition. So we had made scale-down model for 1/5 by similar's law. That's why it needs for the evaluation of performance. However, it is not possible to do an experiment of prototype owing to the shortage of space and the limit of an experimental instrument in the shaking table test. Then, modeling and reducing the part of prototype do the experiment. In this experiment a shaking table test is done and seismic performance of model structures is evaluated by using similitude laws for scale down specimen. As a result it is proved that non-seismic design structures need to retrofit since seismic performance shows life safe grade in 0.12g of an earthquake.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.1-8
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• 2013

A pilot scale coagulation system, which has a function of physicochemical treatment, was developed to treat Combined sewer overflows(CSOs). This coagulation system requires evaluation of optimum design factors whether it has reflected those of lab scale system, moreover, the pilot scale system can be evaluated differently according to the characteristics of influent CSOs even though it has reflected lab scale's design factors. We conducted an experiment using lab scale system that could treat $1m^3$ of CSOs in a day, and also pilot-scale system with $100m^3/day$ CSOs flowed into the Cheongju sewage treatment plant. Therefore the aim of this study is to evaluate a hydraulic similarity between the design factors of pilot scale and those of lab scale coagulation system, and to evaluate feasibility of the coagulation system for the CSOs treatment with optimum operation conditions. From the result of pilot-test, we drew the optimum operation factors of in line mixer and flocculator having similarities with those of lab scale system as well as the optimum coagulant dose. Finally we confirmed that the coagulation system has feasibility to treat the CSOs with high removal efficiency.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.197-203
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• 2023

Callus cultivation is a method for producing a large amount of tissue of a plant in the laboratory, regardless of the environment. Lycoris chejuensis, a plant species native to jeju island, is a member of the Lycoris family has been used as a traditional medicine for the treatment of diverse diseases. In this study, we evaluated anti-inflammatory effect of biorenovated Lycoris chejuensis callus (LCB) in lipopolysaccharide (LPS)-induced RAW264.7 cells. As a result, LCB was less toxic to the cells in the concentration range of 25, 50, and 100 ㎍/mL as shown by the improved viability of LCB treated cells than compared to Lycoris chejuensis callus (LC) treatment. In addition, LCB inhibited the generation of NO and prostaglandin E₂ through the suppression of inducible nitric oxide synthase and cyclooxygenase-2 protein expression. LCB also attenuated the expression of interleukin-1β, interleukin-6 and tumor necrosis factor-α induced by LPS. The results suggest that LCB has anti-inflammatory activity on the LPS-induced inflammatory response and may be suitable for the development of potent functional cosmetic material.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.49-59
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• 2011

In order to understand evaluation of the seismic stability of a reinforced earth retaining, we made chambers of 1:10 (the ratio of the miniature), considering the law of similarity based on drawings of representative cross sections. And we measured an increase in acceleration, earth pressure, and displacement after applying Hachinohe wave (long period), Ofunato wave (short period), and artificial wave, complying with the domestic standards, in order to evaluate the external stability of the reinforced earth retaining wall during earthquake based on the measurements. As a result, the unreinforced earth retaining wall collapsed at 2 g of seismic acceleration. But the reinforced earth retaining wall was evaluated to ensure proper stability as well, with respect to the earth pressure gauge, the increments of earth pressure tend to be raised significantly in the upper than the lower and showed a similar characteristic of behavior in previous theory.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.613-623
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• 2007

The main purpose of this study is to investigate the coordinate transformation based on two different systems between local geodetic datum(tokyo datum) and international geocentric datum(new Korea geodetic datum). For this purpose, three methods were used to determine seven parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. Also, we adopted multiple regression equation method to convert from Tokyo datum to KTRF. We used 935 control points as a common points and applied gross error analysis for detecting the outlier among those control points. The coordinate transformation was carried out using similarity transformation applied the obtained seven parameters and the precision of transformed coordinate was evaluated about 9,917 third or forth order control points. From these results, it was found that Bursa-Wolf model and Molodensky-Badekas model are more suitable than other for the determination of transformation parameters in Korea. And, transforming accuracy using MRE is lower than other similarity transformation model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.211-220
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• 2012

Coarse granular materials such as gravel, rubble is used as major fill materials in earth structures of railway, road and dam. Therefore, it is essential to accurately evaluate properties of these materials for reasonable design and construction. In the precedent study, we built large triaxial testing system and verified system compliance with a focus on the dynamic properties. And we could secured the reliability of the system. In this study, the cyclic triaxial tests were performed in various experimental conditions on coarse granular material. Two series of parallel graded samples are prepared by mixing crushed rock. The influence of grain size, loading pattern, loading frequency, and fine contents were analyzed and discussed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.82-82
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• 2018

본 연구는 국내에 자생하는 자원식물들의 살초활성을 조사하여 식물생장억제물질을 활용한 환경친화형 제초제 개발에 요구되는 기초 자료를 확보하기 위해 수행되었다. 국내 자생 식물 101종을 식물체 부위별로 나누어 MeOH로 추출하여 획득된 시료 129점에 대해 돌피(Echinocholoa crus-galli P.B. var. formosensis Ohwi)를 이용한 살초활성 검정을 실시하였다. 시료를 소량의 methanol로 녹여 직경 5.5cm petri dish 상의 Whatman No. 2 여지에 균일하게 흡착시킨 후, fume hood 내에서 용매를 제거하고 1mL의 증류수를 첨가하였다. 돌피 종자를 15립씩 3반복으로 파종하여 $28^{\circ}C$, 5,000lux의 growth chamber에 치상하고, 7일 후 시험구 당 균일하게 자란 10개의 유묘를 선발해 초장 및 근장을 조사하였으며, 살초활성 평가를 위해 대조구 개체의 초장과 근장에 대한 생장억제율을 산출하였다. $1,000{\mu}g/mL$ 농도에서 101종 129점 MeOH 추출물들의 돌피 유묘 뿌리 생장에 대한 억제율을 조사한 결과, 80% 이상을 나타낸 식물 시료는 가죽나무 줄기, 누린내풀 지상부, 단풍취 뿌리, 두릅나무 지상부, 백양꽃 전초, 백양꽃 지하부, 병조희풀 경엽부, 산사나무 잎 가지, 삽주 뿌리, 상사화 전초, 상사화 지하부, 석산 뿌리, 애기송이풀 전초 등 17점이었다. 이들 중 90% 이상 고활성을 나타낸 단풍취 뿌리, 두릅나무 지상부, 백양꽃 전초, 상사화 지하부, 석산 뿌리 유래의 추출물에는 새로운 환경친화형 제초제 개발소재로써 활용할 수 있는 살초활성물질들이 함유되어 있는 것으로 생각된다.