• Journal of Biosystems Engineering
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• 제16권2호
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• pp.159-166
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• 1991

A simulation model was developed for analyzing a crop transport system using SLAMSYSTEM. The developed model could predict total delivered amount and delivery rate of a crop under various conditions of transport and analyze the effects of work factors on the efficiency of the crop transport system. A simulation model was also developed to analyze a rice transport system based on the generalized model of the crop transport system.

• 한국농공학회논문집
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• 제48권7호
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• pp.55-63
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• 2006

Bacterial transport models were evaluated in this study to determine the suitable model at describing bacterial transport in saturated column experiments. Four models used in the evaluation were: advective-dispersive equation (ADE) + equilibrium sorption/retardation (ER) + kinetic reversible sorption (KR) (Model I), ADE + two-site sorption (Model 2), ADE + ER + kinetic irreversible sorption (KI) (Model 3), ADE + KR + KI (Model 4). Firstly, analyses were performed with the first experimental data, showing that Model 4 is appropriate for describing bacterial transport. Even if Model 1 and 2 fit well to the observed data, they have a defect of not including the irreversible sorption, which is directly related to mass loss of bacteria. Model 3 can not properly describe the tailing observed in the data. However, further analysis with the second data indicates that Model 4 can not describe retardation of bacteria, even if the sorption-related parameters are varied. Therefore, Model 4 is modified by incorporating retardation factor into the model, resulting in the improved fitting to the data. It indicates that the transport model, into which retardation, kinetic reversible sorption, and kinetic irreversible sorption are incorporated, is suitable at describing bacterial transport in saturated column experiments. It is expected that the selected transport model could be applied to properly analyze the bacterial transport in saturated porous media.

• 한국물환경학회지
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• 제23권6호
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• pp.872-880
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• 2007

For effective management of sediment-related diffuse pollution, it is of utmost importance to estimate spatial variation of sediment transport processes within a catchment. A mathematical model can play a critical role in estimating sediment transport processes at the catchment scale provided that the model structure is appropriate for representing major sediment transport processes of the catchment of interest. This paper introduces a distributed catchment model River Basin Water Quality Simulator (RBWQS) and presents some results of its application to a small rural catchment in Korea. The model has been calibrated and validated for a wet period using hourly hydrographs and sediment concentrations observed at the catchment outlet. Based on the model simulation results, the spatial variation of sediment transport processes across the catchment and the effects of paddy fields and small reservoirs on hydrology and sediment transport have been analyzed at the catchment scale.

• Advances in environmental research
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• 제5권4호
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• pp.263-282
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• 2016

Contaminant transport in groundwater induces major threat and harmful effect on the environment; hence, the fate of the contaminant migration in groundwater is seeking a lot of attention. In this paper a two dimensional numerical flow and transport model through saturated layered soil is developed. Groundwater flow and solute transport has been simulated numerically using proposed model. The model implements the finite volume time splitting method to discretize the main equations. The performance, accuracy and efficiency of the out coming numerical models have been successfully examined by two test cases. The verification test cases consist of two-dimensional, groundwater flow and solute transport. The final purpose of this paper is to discuss and compare the shape of contaminant plume in homogeneous and heterogeneous media with different soil properties and control of solute transport using a zone for minimizing the potential of groundwater contamination; furthermore, this model leads to select the effective and optimum remedial strategies for cleaning the contaminated aquifers.

• 한국항해항만학회지
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• 제39권5호
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• pp.409-415
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• 2015

According to the globalization of world economy on distribution and sales, logistics and transportation parts are playing an important role. Especially, they have to decide what is the key factor of route choice model and how to choose the right transport route in multimodal transport system. By considering the key factors in rote choice model for freight forwarders between Mongolia and Korea, this paper propose 4 main factors: Cost, Delivery time, Freight and Logistics service with 13 sub factors. The importance of factors is surveyed base on AHP through interview with freight forwarders. In results, the empirical insights about current status of Mongolian forwarders are provided with different factors between transportation modes. Expecially, the Time factor is a role factor to choose transport route for air transportation forwarders.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.8-12
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• 2003

The centrifuge test result on capped sediment was compared to the advection- dispersion equation proposed for one layered to predict contaminant transport parameters. The fitted contaminant transport parameters for the centrifuge test results were one to three orders of magnitude greater than the estimated parameters from the advection-dispersion equation. This indicates that the centrifuge model over estimated the contaminant transport phenomena. Thus, the centrifuge provides a non-conservative approach to modeling contaminant transport. It should be also noted that the advection-dispersion equation used in this study is a one layered model. Two layered modeling approaches are more appropriate for modeling this data since there are two layers with different partitioning coefficients. Further research is required to model the centrifuge test using two-layered advection-dispersion models.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.241-242
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• 2015

According to globalization of world economy on distribution and sales, logistics and transportation parts are play important role. Especially, it important to know and study how to choose right transport route and which is the key factor of route choice model in multimodal transport system. Thus this study aims to consider 4 main factors: cost, delivery time, freight, and logistics service factors additionally dividing into 13 sub factors and object is forwarders between Mongolia and Korean freight transport. The survey is based on AHP through interview with company officials. The paper provides empirical insights about current status of Mongolian forwarders and difference of the important factors between transportation modes. Result shows that time factor is role factor to choose transport route and then cost factors. Additionally, this study shows 2 different route choose factors between air transport and shipping transport forwarders.

• 한국해양환경ㆍ에너지학회지
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• 제5권1호
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• pp.19-29
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• 2002

본 논문에서는 운송시간과 운송비용으로 구성되는 희생량 모델과 각 운송경로별 CO₂배출량을 고려한 수출입 컨테이너화물의 운송경로 선택에 관하여 고찰한다. 먼저 부산항을 이용하는 수출입 컨테이너화물의 물동량과 운송경로별 분담, 국내외 CO₂배출량 현황, 희생량 모델, 수출입 컨테이너화물의 시간가치에 대하여 간단히 살펴본다. 그리고 서울에서 발생한 수출입 컨테이너화물을 부산항으로 운송하는 경우를 가정하고 희생량 모델을 이용하여 계산한 각 운송경로별 희생량에 기초한 운송경로의 선택에 대하여 고찰한다. 또한 화물의 운송에 의하여 발생하는 CO₂배출량을 고려하여 결정한 환경부하 희생량을 추가한 희생량 모델을 이용한 운송경로의 선택에 대해서도 고찰한다. 본 연구의 결과, 희생량 모델에 기초한 컨테이너화물의 운송경로 선택이 수출입 컨테이너화물의 국내 수송 현황을 잘 나타내고 있는 것을 확인하였다. 또한 연안운송의 운송분담율을 높이기 위해서는 운송시간의 단축이 가장 효과적인 것을 확인하였다.

• 약학회지
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• 제47권2호
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• pp.110-119
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• 2003

The purpose of the present study was to kinetically investigate the carrier-mediated uptake in the hepatic transport of organic anions, and to simulate the ″in vivo counter-transport″ phenomena, using kinetic model which was developed in this study. The condition that the mobility of carrier-ligand complex is greater than that of free carrier is not essential for the occurrence of ″counter-transport″ phenomenon. To examine the inhibitory effects on the initial uptake of a ligand by the liver, it is necessary to judge whether the true counter-transport mechanism (trans-stimulation) is working or not. The initial plasma disappearance curves of a organic anion were then kinetically analyzed based on a flow model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). Moreover, ″in vive counter-transport″ phenomena were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The ″in vivo counter-transport″ phenomena in the hepatic transport of a organic anion were well demonstrated by incorporating the carrier-mediated process. However, the ″in vivo counter-transport″ phenomena may be also explained by the enhancement of back diffusion due to the displacement of intracellular binding. In conclusion, one should be more cautious in interpreting data obtained from so-called ″in vivo counter-transport″ experiments.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.304-310
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• 2003

본 논문에서는 운송시간과 운송비용으로 구성된 희생량 모델과 운송경로의 환경비용을 이용한 수출입 컨테이너화물의 운송경로 선택에 관하여 고찰한다. 먼저 희생량 모델, 운송의 환경비용, 수출입 컨테이너화물의 물동량과 운송경로별 분담율에 대하여 간단히 살펴본다. 그리고 부산항의 수출입 컨테이너화물을 서울로 운송하는 경우를 가정하고 운송시간과 운송비용, 화물의 운송에 의하여 발생하는 환경비용에 대하여 고찰한다. 또한 환경비용을 고려한 희생량 모델을 이용하여 각 운송경로별 희생량을 계산한다. 마지막으로 계산된 운송경로의 희생량에 기초하여 수출입컨테이너 화물의 운송경로를 결정한다. 본 연구의 결과, 운송의 환경비용을 고려하는 경우 수출입컨테이너의 육상운송 분담율이 감소하며 연안운송 분담율이 증가하는 것을 확인하였다.