• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.569-576
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• 2011

In this paper a new analysis procedure for evaluation of progressive collapse resisting capacity of a structure was proposed based on the nonlinear static analysis procedure. The proposed procedure produces analysis results identical to those obtained by the linear static analysis procedure specified in the GSA guidelines without iteration, therefore saving a lot of computation time and excluding the possibility of human errors during the procedure. To verify the validity of the proposed procedure, the two methods were applied to the analysis of a reinforced concrete moment frame and a steel braced frame subjected to loss of a first story column and the results were compared. According to the analysis results, the two methods produce identical results in the prediction of progressive collapse and the hinge formation. As iterative analysis is not required in the proposed method, significant amount of analysis time is saved in the proposed analysis procedure.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.1-17
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• 2009

In recent years, most of flood damage is associated with the levee failure. The objective of this study is to predict flow depths, flood area, flooding time and flood damage through flood inundation analysis considering the overflow of levee and the characteristics of levee failure. The hydrological parameters were extracted from GIS data such as DEM, land cover and soil map to estimate levee failure discharge. In addition, the characteristics of flood wave propagation could be accurately predicted as flood inundation analysis was accomplished considering the affection of structure within protected lowland and hourly prediction of flooded areas and estimation of flood strength will be utilized as basic data for the flood defence and establishment of measure to reduce flood damage.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.141-154
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• 1993

In this paper, a method to calculate the ultimate compressive strength of welded one-sided stiffened plates simply supported along all edges is proposed. At first initial imperfections such as distortions and residual stresses due to welding are predicted by using simplified methods. Then, the collapse modes of the stiffened plate are assumed and collapse loads for each mode are calculated. Among these loads, the lowest value is selected as the ultimate strength of the plate. Collapse modes are assumed as follows ; (1) Overall buckling of the stiffened plate$\rightarrow$Overall collapse due to stiffener bending (2) Local buckling of the plate part$\rightarrow$Local collapse of the plate part$\rightarrow$Overall collapse due to stiffener yielding (3) Local buckling of the plate part$\rightarrow$Overall collapse due to stiffener berthing (4) Local buckling of the plate part$\rightarrow$Local collapse of the plate part$\rightarrow$Overall collapse due to stiffener tripping. The elastic large deflection analysis based on the Rayleigh-Ritz method is carried out, and plastic analysis assuming hinge lines is also carried out. Collapse load is defined as the cross point of the two analysis curves. This method enables the utimate strength to be calculated with small computing time and a good accuracy. Using the present method, characteristics of the stiffener including torsional rigidity, bending and tripping can also be clarified.

• The Korean Journal of Zoology
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• v.37 no.1
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• pp.58-65
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• 1994

Phosphatase의 저해제로 알려진 okadaic acid(OA)가 한국산 개구리(북방산개구리 참개구리) 난자의 성숙에 미치는 효과를 조사하였다. 북방산개구리 난자에 약 50 nl의 okadaic acid(0 5-500 mM)를 미세주입한 후 18시간 배양한 결과 0.5 mM의 농도에서 부터 난자의 핵붕괴를 일으키기 시작하였다 동면초기에 처리한 progesterone에 반응하지 않는 난자들도 OA에 의하여 성숙을 일으켰으며. 이 성숙은 배양액에 첨가한 cycloheximide(10 mg/ml)에 영향을 받지 않았다 또한 OA의 처리를 받고 일정시간 배양한 난자의 세포질에는 미성숙 난자의 성숙을 유도하는 maturation promoting factor (MPF)의 활성이 생기었다 참개구리의 난자도 역시 OA에 의해 성숙이 유도되었으며, 주입 후 6시간에서부터 핵붕괴가 일어나기 시작하였다 참개구리에서도 OA의 처리가 MPF의 활성을 촉진하는 것을 세포질내에 Hl histone kinase의 활성도가 증가하는 것으로 확인할 수 있었다 참개구리에서도 OA에 의한 성숙은 cycloheximide나 CAMP에 의해 영향을 받지 않았다 이러한 결과들은 개구리 난자의 MPF 활성화와 성숙과정에 phosphatase가 관여함을 보여주는 것이다.

• The Korean Journal of Zoology
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• v.29 no.3
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• pp.181-189
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• 1986

The present study was undertaken to investigate whether the known adenylate cyclase activators, forskolin and cholera toxin, would affect the germinal vesicle breakdown (GVBD) and the production of cAMP in mouse oocytes in vitro. To do this, in vitro oocyte culture method and adenylate cyclase assay were employed. In response to different concentrations of forskolin (20 to 80 $\\mu$g/ml) added to a culture medium, the percentage of GVBD significantly decreased (56 to 31%) in a dose-dependent manner as compared to that of control (63%). This inhibitory phenomenon by forskolin was reversible since the rate of GVBD was returned to the control level when the oocytes were transferred to a control medium following exposure to forskolin (80 $\\mu$g/ml). Treatment of cholera toxin (10 to 1, 000 ng/ml) was, however, ineffective in suppressing GVBD. When forskolin (10 to 80 $\\mu$g/ml) was added to the mouse oocyte extracts, cAMP production significantly increased by 5 to 18 fold, whereas cholera toxin (10 to 1, 000 ng/ml) was no longer effective. In addition, treatment of guanidyl-imidodiphosphate (GppNHp, 100 $\\mu$M), which is an activator of the regulatory unit of adenylate cycleas, with forskolin did not exhibit any changes in cAMP production as compared to that induced by forskolin alone. Neither cholera toxin nor cholera toxin plus GppNHp (100 $\\mu$M) exhibited any differences in mouse oocytes. From the above results, the suppression of GVBD by forskolin may be mediated by a high level of intracellular cAMP in mouse oocytes. It appears that the changes in intracellular cAMP level may an important role in the mouse oocyte maturation.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.1-11
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• 2012

Due to a heavy rain resulted from the global environmental change, collapse accidents happen annually and it is a tendency to increase the loss of life and economy. Thus, measures for the collapse of slope are required. If the slope can be simulated before cutting, the collapse can be predicted, and also the accident of the collapse can be minimized at the cost of recovery. This paper presents a simulation method of a slope which is important in cutting. The method is modeling and designing using Petri-Net and is implemented in the Windows XP using Arc GIS. Therefore, by means of cutting and reclamation based on GIS, this paper can contribute to saving a lot of time and money.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.605-615
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• 2001

SMAC method, one of the numerical simulation techniques, is modified from the original MAC method for the time-dependent variation of fluid flows. The Navier-Stokes equations for incompressible time-dependent viscous flow is applied, and marker particles which present the visualization of fluid flaws are used. In this study, two-dimensional numerical simulations of the water column collapse are carried out by SMAC method, and the simulation results are compared with Martin and Moyce's experimental data and result of the MPS method. A good results are obtained. This numerical simulation could also be applied to the breaking phenomenon of hydraulic structures such as dam break.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.481-481
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• 2023

제방은 홍수로부터 주변 주거지와 농경지를 보호하는 가장 전통적이고 기본적인 구조물이다. 개발된 제방보강기술은 파이오폴리머와 골재를 혼합하여 제방표면을 강화하여 월류 등으로 인한 제방붕괴를 대응할 수 있는 친환경 제방보강기술로 제방의 세굴 및 붕괴 등을 억제하는 목적이 있다. 개발 기술은 하천호안 사면 및 제방을 안전하게 보호하기 위한 기술로 치수방재사업과 자연재해 영향을 저감시키는 사업에 활용가능하며 시공성이 수월하여 월류파괴에 대한 대응 기술로 적용이 용이하다. 개발된 기술을 현장에 적용하기 위해서는 기술의 안전성을 확보해야 하므로 현장시범사업 등 실제 적용에 대한 연구가 필요하다. 하지만 월류 파괴는 현장에서 시범사업을 수행할 수 없으므로 본 연구에서는 실규모 실험을 통해 현장 적용성 연구를 수행하였다. 실규모 실험은 안동에 위치한 하천실험센터에서 수행하였으며, 인위적인 월류를 통하여 제방 세굴 및 붕괴 상황을 검토하였다. 실험결과 대조조건으로 식생 제방의 경우 25분경에 붕괴되었고, 개발 기술은 월류 발생 후 2시간 동안 제내지 경사면에서 균열이 발생하지 않았다. 개발기술이 월류파괴에 대해 대응 가능하고 붕괴를 억제할 수 있는 기술로의 실증 결과를 파악 할 수 있었다.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.335-342
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• 2009

The effects of bacterial lysis on the rate of quartz dissolution were investigated under pH 7 condition using Bacillus subtilis cells which were either irradiated or non-irradiated with gamma ray. The amount of dissolved organic carbon (DOC) which resulted from bacterial lysis increased in slurries of quartz and bacteria mixture over experimental period. Lysis of non-irradiated bacteria led to the elevated concentration of dissolved silicon when compared with abiotic control. Concomitant increase in the amounts of DOC and dissolved silicon over time indicated that lixiviation of silicon from quartz was due to bacterial lysis. Higher amounts of DOC and dissolved silicon were present in the irradiated bacterial slurries than those of non-irradiated bacteria. The enhancement of quartz dissolution in the irradiated bacterial slurries was likely attributed to disruption of organic molecules in the bacterial cells by gamma ray and formation of effective ligands for quartz dissolution. The results suggest that the effects of bacterial lysis on mineral weathering rate should be considered for prediction of time for released radionuclides to migrate to surface biosphere in high level radioactive waste disposal site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.439-447
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• 2019

In this study, experiments were conducted to establish appropriate measures for slopes with high risk of collapse and to obtain results for minimizing slope collapse damage by detecting the micro-displacement of soil in advance by installing a laser sensor and a vibration sensor in the landslide reduction model experiment. Also, the behavior characteristics of the soil layer due to rainfall and moisture ratio changes such as pore water pressure and moisture were analyzed through a landslide reduction model experiment. The artificial slope was created using granite weathering soil, and the resulting water ratio(water pressure, water) changes were measured at different rainfall conditions of 200mm/hr and 400mm/hr. Laser sensors and vibration sensors were applied to analyze the surface displacement, and the displacement time were compared with each other by video analysis. Experiments have shown that higher rainfall intensity takes shorter time to reach the limit, and increase in the pore water pressure takes shorter time as well. Although the landslide model test does not fully reflect the site conditions, measurements of the time of detection of displacement generation using vibration sensors show that the timing of collapse is faster than the method using laser sensors. If ground displacement measurements using sensors are continuously carried out in preparation for landslides, it is considered highly likely to be utilized as basic data for predicting slope collapse, reducing damage, and activating the measurement industry.