• Journal of Wetlands Research
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• v.21 no.spc
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• pp.39-50
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• 2019

This study aims to assess the influence of climate change on the hydrological cycle at a basin level in North Korea. The selected model for this study is MRI-CGCM 3, the one used for the Coupled Model Intercomparison Project Phase 5 (CMIP5). Moreover, this study adopted the Spatial Disaggregation-Quantile Delta Mapping (SDQDM), which is one of the stochastic downscaling techniques, to conduct the bias correction for climate change scenarios. The comparison between the preapplication and postapplication of the SDQDM supported the study's review on the technique's validity. In addition, as this study determined the influence of climate change on the hydrological cycle, it also observed the runoff in North Korea. In predicting such influence, parameters of a runoff model used for the analysis should be optimized. However, North Korea is classified as an ungauged region for its political characteristics, and it was difficult to collect the country's runoff observation data. Hence, the study selected 16 basins with secured high-quality runoff data, and the M-RAT model's optimized parameters were calculated. The study also analyzed the correlation among variables for basin characteristics to consider multicollinearity. Then, based on a phased regression analysis, the study developed an equation to calculate parameters for ungauged basin areas. To verify the equation, the study assumed the Osipcheon River, Namdaecheon Stream, Yongdang Reservoir, and Yonggang Stream as ungauged basin areas and conducted cross-validation. As a result, for all the four basin areas, high efficiency was confirmed with the efficiency coefficients of 0.8 or higher. The study used climate change scenarios and parameters of the estimated runoff model to assess the changes in hydrological cycle processes at a basin level from climate change in the Amnokgang River of North Korea. The results showed that climate change would lead to an increase in precipitation, and the corresponding rise in temperature is predicted to cause elevating evapotranspiration. However, it was found that the storage capacity in the basin decreased. The result of the analysis on flow duration indicated a decrease in flow on the 95th day; an increase in the drought flow during the periods of Future 1 and Future 2; and an increase in both flows for the period of Future 3.

• KDI Journal of Economic Policy
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• v.12 no.4
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• pp.3-20
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• 1990

The multisector model is designed to analyze and forecast structural change in industrial output, employment, capital and relative price as well as macroeconomic change in aggregate income, interest rate, etc. This model has 25 industrial sectors, containing about 1,300 equations. Therefore, this model is characterized by detailed structural disaggregation at the sectoral level. Individual industries are based on many of the economic relationships in the model. This is what distinguishes a multisector model from a macroeconomic model. Each industry is a behavioral agent in the model for industrial investment, employment, prices, wages, and intermediate demand. The strength of the model lies in the simulating the interactions between different industries. The result of its simulation will be introduced in the next paper. In this paper, we only introduce the structure of the multisector model and the coefficients of the equations. The multisector model is a dynamic model-that is, it solves year by year into the future using its own solutions for earlier years. The development of a dynamic, year-by-year solution allows us to combine the change in structure with a consideration of the dynamic adjustment required. These dynamics have obvious advantages in the use of the multisector model for industrial planning. The multisector model is a medium-term and long-term model. Whereas a short-term model can taken the labor supply and capital stock as given, a long-term model must acknowledge that these are determined endogenously. Changes in the medium-term can be analyzed in the context of long-term structural changes. The structure of this model can be summarized as follow. The difference in domestic and world prices affects industrial structure and the pattern of international trade; domestic output and factor price affect factor demand; factor demand and factor price affect industrial income; industrial income and relative price affect industrial consumption. Technical progress, as measured in terms of total factor productivity and relative price affect input-output coefficients; input-output coefficients and relative price determine the industrial input cost; input cost and import price determine domestic price. The differences in productivity and wage growth among different industries affect the relative price.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.696-703
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• 2014

Clostridium difficile causes mucosal damage and diarrhea by releasing two exotoxins: toxin A and toxin B. C. difficile colitis is associated with alterations in bowel flora and the failure to mount an effective antibody response. The aim of the current study was to investigate whether antitoxin sera prevent toxin-A-induced apoptosis, cytoskeletal disaggregation, cell detachment, and tight junction loss in cultured colonic epithelial cells. Serum samples were isolated from mice that survived a C. difficile infection following antibiotic treatment, and the antitoxin effects of these samples were investigated in toxin-A-exposed HT29 colonic epithelial cells and a toxin-A-induced animal model of gut inflammation. Unchallenged mice did not produce IgG against toxin A, whereas serum (antiserum) from C. difficile-challenged mice showed significant IgG responses against toxin A. Treatment with the antiserum markedly inhibited mucosal damage and inflammation in the toxin-A-treated mouse model. In contrast to control mouse serum, the antiserum also markedly inhibited toxin-A-induced DNA fragmentation, dephosphorylation of paxillin and Epo receptor (EpoR), deacetylation of tubulin, and upregulation of p21(WAF1/CIP1) and p53. Taken together, these results reveal that the generated antitoxin serum has biotherapeutic effects in preventing various C. difficile toxin-A-induced cellular toxicities.

• Journal of Korea Water Resources Association
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• v.46 no.3
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• pp.229-243
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• 2013

Hydrological simulation Program-Fortran (HSPF) model was used to simulate streamflow and snow depth at Pyengchang watershed. The selected Global Climate Models (GCMs) provided by the Coupled Model Intercomparision Project Phase 3 (CMIP3) were utilized to evaluate streamflow and snow depth driven by future climate scenarios, including A1, A1B, and B1. Bias-correlation and temporal downscaling processes have been performed to minimize systematic errors between GCMs and HSPF. Based on simulated monthly streamflow and snow depth after calibration, the results indicate that HSPF performs well. The correlation coefficient between the observed and simulated monthly streamflow is 0.94. Snow depth simulations also show high correlation coefficient, which is 0.91. The results indicate that snow depth in 2018 at Pyongchang winter olympic venues will decrease by 17.62%, 9.38%, and 7.25% in January, February, and March respectively, based on streamflow realizations induced by all GCMs ensembles.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.17-27
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• 2020

The objective of this study was to assess the flood probability based on temporal distribution of forecasted-rainfall in Cheongmicheon watershed. In this study, 6-hr rainfalls were disaggregated into hourly rainfall using the Multiplicative Random Cascade (MRC) model, which is a stochastic rainfall time disaggregation model and it was repeated 100 times to make 100 rainfalls for each storm event. The watershed runoff was estimated using the Clark unit hydrograph method with disaggregated rainfall and watershed characteristics. Using the peak discharges of the simulated hydrographs, the probability distribution was determined and parameters were estimated. Using the parameters, the probability density function is shown and the flood probability is calculated by comparing with the design flood of Cheongmicheon watershed. The flood probability results differed for various values of rainfall and rainfall duration. In addition, the flood probability calculated in this study was compared with the actual flood damage in Cheongmicheon watershed (R² = 0.7). Further, this study results could be used for flood forecasting.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.81-92
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• 2019

The objective of this study is to evaluate hydrologic impacts of climate change according to downscaling methods using the Soil and Water Assessment Tool (SWAT) model at watershed scale. We used the APCC Integrated Modeling Solution (AIMS) for assessing various General Circulation Models (GCMs) and downscaling methods. AIMS provides three downscaling methods: 1) BCSA (Bias-Correction & Stochastic Analogue), 2) Simple Quantile Mapping (SQM), 3) SDQDM (Spatial Disaggregation and Quantile Delta Mapping). To assess future hydrologic responses of climate change, we adopted three GCMs: CESM1-BGC for flood, MIROC-ESM for drought, and HadGEM2-AO for Korea Meteorological Administration (KMA) national standard scenario. Combined nine climate change scenarios were assessed by Expert Team on Climate Change Detection and Indices (ETCCDI). SWAT model was established at the Mankyung watershed and the applicability assessment was completed by performing calibration and validation from 2008 to 2017. Historical reproducibility results from BCSA, SQM, SDQDM of three GCMs show different patterns on annual precipitation, maximum temperature, and four selected ETCCDI. BCSA and SQM showed high historical reproducibility compared with the observed data, however SDQDM was underestimated, possibly due to the uncertainty of future climate data. Future hydrologic responses presented greater variability in SQM and relatively less variability in BCSA and SDQDM. This study implies that reasonable selection of GCMs and downscaling methods considering research objective is important and necessary to minimize uncertainty of climate change scenarios.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.367-367
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• 2021

최근 기후변화로 인해 극한 강우 사상의 빈도가 잦아짐에 따라 수공 구조물의 안전성이 저해되거나 인명 및 재산 피해가 발생할 가능성이 커지고 있다. 기후변화에 따른 기상현상의 변화 추세를 파악하고 대비하기 위해 CMIP (Coupled Model Intercomparison Project Phase)의 GCM(General Circulation Model) 기상자료 산출물이 활발하게 이용되고 있다. 기후변화 시나리오는 홍수기 방재 대책 수립 등의 연구에도 적용되고 있으나, GCM에서 산출된 기상자료의 시간 간격은 24시간 혹은 3시간 정도로 시간적 해상도가 낮아 홍수 모형의 입력자료로 사용되기 어려운 형태를 가지고 있다. 따라서 기후변화 시나리오를 홍수 모의 등의 분야에 접목하기 위해서는 GCM 자료의 시간적 해상도를 1시간 이하로 낮춤으로써 시나리오 산출물이 홍수모형과 적절하게 연결될 수 있도록 해야 한다. MRC (Multiplicative Random Cascade) 모형은 국내외에서 예보강우의 시간 분해 및 일강우 데이터 분해 연구에 활용된 바 있으며 관측 강우에 대하여 분해 성능이 준수함이 확인되었다. 이에 본 연구에서는 MRC 모형을 활용하여 미래 기후변화 시나리오 산출물에 적용함으로써 MRC 모형이 일단위 및 3시간 단위 기후변화 자료의 시간 분해에 대해 적절한 성능을 수행하는지 여부를 분석하고, 기후변화 자료의 최소 시간 간격별 강우 분해 결과를 비교·분석하고자 하였다. 본 연구의 결과는 향후 기후변화 시나리오 기반 기상자료 시간 분해에 대한 MRC 모형의 적용성을 평가하는 기초 자료로 활용될 수 있을 것으로 사료된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.187-187
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• 2022

우리나라의 농촌 유역은 크게 1) 상류에 위치한 농업용 저수지, 2) 저수지 방류부, 3) 저수지 하류하천, 4) 하류 농업 지대로 구성된다. 이들 모두 유역의 홍수·침수와 연관되어 있으나 각각의 설계 빈도가 서로 달라 일시에 수용 가능한 수자원의 양이 상이하다. 예컨대 극한 강우가 발생한 경우 PMP를 고려하여 설계된 저수지에서는 유입 홍수량이 통제될 수 있으나 50-200년 빈도로 설계된 하류하천에서는 측면 유입량 때문에 홍수가 발생할 수 있다. 따라서 유역의 홍수 확률을 산출할 때에는 유역 구성지역별 홍수 확률을 산정한 후 종합적으로 고려할 필요가 있다. 특히 농촌유역의 경우 하류하천 및 농경지의 설계 빈도 기준이 도시에 비해 낮아 유역 구성요소 간 처리 가능한 수자원 양의 차이가 크다. 따라서 본 연구에서는 농촌 유역을 대상으로 연구를 진행하였다. 한편, 최근 기후변화로 인해 극한 강우 사상의 빈도가 잦아짐에 따라 유역 내 홍수의 발생이 증가하고 있다. 따라서 기후변화에 따른 미래 농촌 유역의 홍수 발생 여부 파악이 필수적이다. 이에 본 연구에서는 CMIP 6 (Coupled Model Intercomparison Project Phase 6)의 GCM (General Circulation Model) 기상산출물을 농촌 유역에 적용함으로써 미래 농촌 유역의 홍수 발생 여부를 확인하고자 하였다. 또한, CMIP 6의 GCM 산출 기상자료의 시간 단위는 24시간 혹은 3시간으로 시간적 해상도가 낮으므로 유역 홍수 모의를 위하여 GCM 산출물의 시간 분해를 수행하였다. 본 연구에서는 MRC (Multiplicative Random Cascade) 모형을 기후변화 시나리오 기상자료에 적용함으로써 강우 자료의 시간 분해를 수행하고, 시간 분해 결과물을 활용하여 농촌 유역의 미래 홍수 확률을 산정해보고자 하였다. 본 연구의 결과는 향후 농촌 유역의 홍수 확률 산정 기법에 관한 기초 자료로 활용될 수 있을 것으로 사료된다.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.73-81
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• 2009

While various factors in passenger and freight demand analysis affect on destination choice, a key factor, in general. is an attractiveness measure by size variable (e.g., population. employment etc) in destination zone. In order to measure the attractiveness, some empirical studies suggested that disaggregate gravity model are more suitable than aggregate gravity model. This study proposes that truck travelers trip diary data among Korean commodity flow data could be used to estimate the behaviors of incorporating trip departure time, activity duration and attractiveness in destination. As a result, the main findings of size and distance variables coincide with the conventional gravity model having a positive effect of population variable and a negative effect of distance variable. Due to disaggregate gravity modeling, the unique findings of this study reports that small trucks are more likely to choose short distance and early morning, morning peak and afternoon peak departure time choice. On the other hand, large trucks are more likely to choose long distance and night time departure time choice.

• Applied Microscopy
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• v.14 no.2
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• pp.66-80
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• 1984

The organic phosphorus compounds have been widely used as an insecticide, since toxicity of these compounds is especially drastic to the insects than to men and other mammals. The organic phosphates are rapidly hydrolized and hence have little cumulative and ecologic effects. However, due to their acute toxic effects organophosphate have recorded rather high fatalities in men and domestic animals. The organic phosphorus compounds are powerful inhibitors to the carboxylic esterase enzymes such as acetylcholinesterase and pseudocholinesterase. As a result of firm binding characteristics of phosphate radicals to the active sites of enzyme, the activities of these enzymes are inhibited by the organophosphates. The organophosphates such as diazinon is easily observed from skin, gastrointestinal tract, conjunctivas and respiratory tract, and it is converted to more toxic form during metabolism in the liver The present study was carried out in order to investigate the hepatotoxicity of diazinon by observing the changes in the ultrastructure of cytoplasmic organelles of hepatic cells in albino mice. The animals were killed at 6, 12 and 24 hours after administration of 25mg/kg diazinon. The piece of hepatic tissue obtained from each animal was ultrathinly sectioned. The specimens stained by uranyl acetate and lead citrate double contrast methods were observed with JEM model 100B electron microscope. The results obtained were as follows: 1) A prominent dilatation and sacculation of the cisternae of rough endoplasmic reticulum associated with detachment of membrane bound-ribosomes, and disaggregation of the free ribosomes were recognized. 2) The hypertrophy of the smooth endoplasmic reticulum associated with depletion of the glycogen particles was observed. 3) The atrophy of cisternae of Golgi complex was observed. 4) A large number of secondary lysosomes (autophagic vacuoles and residual bodies) were formed. Consequently it is suggested that diazinon would induce disorganization of the cytoplasmic organelles of hepatocytes in albino mice.