• Journal of Korea Spatial Information System Society
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• v.11 no.3
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• pp.1-8
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• 2009

In this study the concepts on the elongation, compactness and equivalent ellipse of catchment plan-forms are applied to the real basins considering their theoretical frameworks. The catchment plan-forms and corresponding equivalent ellipses, obtained from GIS, are inspected on downstream directions. As a result the catchment plan-forms seem to be the population of the basin shapes which come from the random interaction between two conjectures on Hack's law being controversial recently. The ratio of the maximum and minimum inertia moments of the catchment plan-form Ri is more sensitive to evaluate the elongation of the basin shapes than the ratio of the main channel length and diameter of circle which has the same area as the catchment plan-form E. The catchment plan-forms compactness measures show distinct aspects according to their different definitions. These results are caused by the difficulties to quantification of the shapes and the composite consideration with more than two compactness measures and the fractal analysis are therefore required to recover them.

• Tunnel and Underground Space
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• v.11 no.2
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• pp.167-173
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• 2001

The joint model has influence on the results of discontinuum analysis. In this study the results of discontinuum analysis with Barton-Bandis joint model(BB model) and with Mohr-Coulomb joint model(MC model) are compared. The results of continuum analysis under the same condition are compared with the results of discontinuum analysis to investigate the behavior of rockmass around tunnel. The result of continuum analysis and that of discontinuum analysis with BB model show similar distribution of displacement and stress. On the other hand, the discontinuum analysis with MC model shows different displacement distribution and stress distribution. Moreover, the displacement and minor principal stress of the discontinuum analysis with MC model are smaller than those of continuum analysis, although the joints are explicitly considered in the discontinuum analysis. These results are originated from the limitation of MC model in simulating joint deformation behavior, especially the assumption of constant dilation jingle independent of it)int 7hear displacement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.1
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• pp.58-65
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• 2007

Mixed mode interlaminar fracture behaviors of carbon fabric/epoxy composites were investigated through MMF (Mixed Mode Flexural) test by varying mixed mode ratio ranging from 20% to 90%. Mixed mode interlaminar fracture criteria based on NL point and 5% offset point were also suggested in order to predict mixed mode interlaminar fracture behaviors. Fracture surfaces and crack propagating behaviors were examined through a travelling scope and a scanning electron microscope. According to the results, mixed mode interlaminar fracture behaviors can be predicted by mixed mode interlaminar fracture criterion with m=1.5 and n=0.5 on the basis of NL point or mixed mode interlaminar fracture criterion with m=2 and n=3 on the basis of 5% offset point. Fracture surfaces and crack propagating behaviors are sensitive to mixed mode ratios. MMF test can be successfully applicable in evaluating mixed mode interlaminar fracture toughness of carbon fabric/epoxy composites.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.342-342
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• 2011

댐의 건설로 인해 자연적인 물의 흐름이 댐 운영에 의하여 조절되기 때문에 유사의 연속성 및 유량의 변화에 따른 지형 환경적 변화가 예상된다. 따라서 영향분석을 위한 체계적인 조사 및 연구가 필요할 것이다. 본 연구는 내성천 영주댐 건설 예정지로부터 48.4km 하류인 회룡포 구간에서 하상변동이 예상됨에 따라 현장 조사를 수행하고, 장래변화를 예측하기 위하여 수치모델을 수행하였다. 수리학적 변화량은 금회 수립중인 하천정비계획의 계획 홍수량인 댐건설 전 4,040cms, 댐건설 후 2,934cms로 구분하고, 유사변화량은 영주댐 실시설계 보고서결과를 적용하여 분석하였다. 한편 2001년과 2010년의 실측종단변화를 검토한 결과, 회룡포 구간에서 0.5m~1.7m의 퇴적이 진행되고 있음을 알 수 있었다. 수치모델 및 실측한 데이터를 종합적으로 판단한 결과, 단기호우사상에 대해 댐 건설 후 회룡포 구간의 사주퇴적능력은 -0.05m로 감소되어 그 영향은 비교적 미미할 것으로 분석 되었고, 대부분의 변화는 주수로에서 -0.5~0.5m로 변화될 것으로 예측되었다. 하상 변동의 양상은 실측한 10년간의 종단변화와 같은 경향성을 보이며, 횡단번호 No.15 이후로 0.5m이상 퇴적이 이루어 질 것으로 예측되었다. 본 연구결과는 댐건설로 인한 하천 하상변화에 대한 특성을 파악하고 하천공사 나 수리구조물 설계의 기초자료로 활용될 수 있을 것으로 판단되며, 향후 지속적인 모니터링 및 조사를 통하여 하상변동양상을 관측하고 분석할 필요가 있을 것으로 판단된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.8
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• pp.95-103
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• 2006

The compositions, the gas properties in motor chamber and the aluminum oxide (Al2O3) particle size for two kinds of solid propellants with approximately 20% aluminum powder have been investigated. The SEM photographs of $Al_2O_3$ taken from nozzle entrance liner show that the aluminized PCP propellant with 47% volumetric fraction AP/HNIW and bimodal oxidizer 200-5 ${\mu}m$ can offer greater possibility for increasing aluminum agglomeration than the aluminized HTPB propellant with 64% volumetric fraction AP and trimodal oxidizer 400-200-6 ${\mu}m$. The nozzle entrance liner of solid rocket motor with the PCP propellant shows greater erosion at 4 circumferential sections in line with grain slots due to the impingement of large particles, but that with the HTPB propellant shows uniform erosion with circumferential angle.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.787-804
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• 2013

The purpose of this study is to explore the effect of 'World Cafe' conversations for collective intelligence. For this purpose, 'World Cafe' was applied to the class 'presentation and discussion' of university class. To explore the effect of 'World Cafe' conversations for collective intelligence I surveyed the responses of students participating in the class and analyzed results of the survey and class activities. The results are as follows: first, 82 percent of all students were actively involving in the class, second, topics were more discussed through World Cafe class than general discussion class. These results suggest 'World Cafe' class induced active participation of the students in class and have the effect producing the collective intelligence.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.158-172
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• 2000

In order to visualize mine cavities, 3D seismic reflection data were acquired at the ground subsidence sites near Nampung coal mine area, Neukguri, Dogye, Samchuck. Full range 3D array with complete range of azimuths on the bins was considered in the data acquisition design. Because of poor S/N data, we estimated the stacking velocities by CVS method, and we estimated the shot and receiver statics on the shot and receiver stack data. We could confirm that features of ground collapse that were expected from the subsidence. In order to visualize the cavities, we need to apply more sophisticated processing schemes, such as velocity analysis, residual statics correction.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.455-460
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• 2010

A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis was applied to detect and identify ten Weissella spp. frequently found in kimchi. The previously reported genus-specific primers designed from 16S rDNA sequences of Weissella spp. were adopted but PCR was performed at the increased annealing temperature by $4^{\circ}C$. The sizes of amplified PCR products and restricted fragments produced by AluI, MseI, and BceAI endonucleases were well correspond with the expected sizes. W. kandleri, W. koreensis, W. confusa, W. minor, W. viridescens, W. cibaria, and W. soli were distinguished by AluI and MseI and W. hellenica and W. paramesenteroides were identified by BceAI. W. thailandensis was distinguished when restriction pattern of other species was compared but identified by the single use of MspI.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.273-273
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• 2022

혼합층(Mixed layer)은 온도가 일정한 수심층으로, 해수표면에 작용하는 바람의 영향으로 인하여 해수가 위아래로 섞여 형성된다. 이러한 혼합층은 영양염의 순환과 산소의 공급 등과 함께 일차생산량을 결정하는 중요한 요인이 될 수 있으며 혼합층 두께의 변동은 양식 산업에 영향을 미칠 수 있다. 최근에는 기후변화로 인한 해수면 상승 및 해수온 상승 등이 지속되고 있으며, 이러한 현상은 해양생태계의 변화를 초래하여 수산업의 피해를 유발할 수 있다(강원연구원, 2017). 이에 국립수산과학원, 기상청, 국립해양조사원 등 유관기관에서는 정선해양 수온 관측 및 해수순환모델을 이용하여 혼합층의 분석을 수행하고 있으나 격자 구축 및 초기·경계장 설정의 한계가 존재하여 정밀하고 정확한 혼합층 분석에는 어려움이 있다. 이에 본 연구에서는 비정형격자를 사용하여 격자 구축에 제약이 없는 SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model)을 이용하여 우리나라 연안해역의 계절변화 및 기후변동성에 따른 혼합층 두께의 변화를 검토하고자 한다. 연구대상지는 서해·동해·남해를 포함한 우리나라 전체 연안 해역(위도: 32°N ~ 39°N, 경도: 124°E ~ 132°E)으로 선정하였으며, 격자크기 100 ~ 3,000 m인 삼각격자로 격자를 구축하였다. 혼합층을 분석하기 위하여 수직격자 층은 50층으로 SZ(Sigma Z coordinate system)좌표계를 사용하였다. 초기·경계장은 FES(Finite Element Solution)2014, HYCOM(Hybrid Coordinate Ocean Model) 및 대기모델 결과를 이용하여 설정하였다. 수치모형 검증을 위하여 수온관측소에서 수심별 측정한 수온 값과 SCHISM 결과 값을 비교하였고, 상대오차가 약 10% 이내로 나타나 모형의 정확도를 확인하였다. 최종적으로 해수면 상승 및 해수온 상승 시나리오를 고려하여 계절별 연안해역의 혼합층 두께의 변화 양상에 대하여 검토하였다. 향후에는 보다 정밀한 대기모델과의 혼합모형 구축 및 다양한 수심 별 관측자료를 활용한다면 실무에서 적용 가능한 혼합층 분석 및 수산업 피해 발생 지역에 대한 피해저감 대책 수립이 가능할 것으로 판단된다.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.77-85
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• 2009

This paper describes the findings obtained from a research project aimed at investigating, via 1 g laboratory model tests, the ground movements caused by multiple side-by-side (sbs) tunnel construction in clay. The ground movements above a second tunnel showed different trends from those observed above a first tunnel. These trends include an increase in the overall volume loss, and a widening of the settlement troughs on the near limb of the trough accompanied by a shift of the maximum settlement towards existing tunnel. This would suggest that the use of simple predictive methods of adopting a Gaussian curve for analysing the ground settlements associated with twin (sbs) tunnel construction is not appropriate. Therefore the current paper adopts a method that modifies the Gaussian curve approach in order to improve the predictions. This paper comments on the parameter selection involved with adopting this new method to apply it to full-scale field situations, and also discusses its limitations.