• 한국도로학회논문집
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• 제19권4호
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• pp.1-7
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• 2017

PURPOSES : This study aims to improve complex modeling of multivariable, nonlinear, and overdispersion data with an artificial neural network that has been a problem in the civil and transport sectors. METHODS: Deep learning, which is a technique employing artificial neural networks, was applied for developing a large bus fuel consumption model as a case study. Estimation characteristics and accuracy were compared with the results of conventional multiple regression modeling. RESULTS : The deep learning model remarkably improved estimation accuracy of regression modeling, from R-sq. 18.76% to 72.22%. In addition, it was very flexible in reflecting large variance and complex relationships between dependent and independent variables. CONCLUSIONS : Deep learning could be a new alternative that solves general problems inherent in conventional statistical methods and it is highly promising in planning and optimizing issues in the civil and transport sectors. Extended applications to other fields, such as pavement management, structure safety, operation of intelligent transport systems, and traffic noise estimation are highly recommended.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.59-64
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• 2017

As the demand on displays increases, new thin-film transistors such as metal oxide transistor are continuously being invented. When designing a circuit consisting of such new transistors, a new transistor model based on proper charge transport mechanisms is needed for each of them. In this paper, a modeling framework which enables to choose charge transport mechanisms that are limited to certain operation regions and assemble them into a transistor model instead of making an integrated transistor model dedicated to each transistor. The framework consists of a graphic user interface to choose charge transport models and a current calculation part, which is also implemented in AIM-SPICE for circuit simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.333-334
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• 2006

A novel mathematical modeling in web transport systems for Continuous Annealing Processes (CAP) is proposed. Despite of thermal and weight effects in dynamics of web transport systems, the conventional mathematical model does not consider those effects. Disregard of these effects causes the low manufacturing quality of webs in CAP. In order to improve the manufacturing quality of webs in CAP, moreover, precise tension control is required based on the mathematical model. Therefore, an advanced mathematical model considering thermal and weight effects in CAP should be established. The effectiveness of a novel mathematical model is evaluated by comparing the performances of the PI tension control system based on the proposed mathematical model with that based on the conventional one through the computer simulation.

• 한국환경과학회지
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• 제1권1호
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• pp.19-33
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• 1992

The high oxidants, which occur the daily maximum concentrations in the afternoon, are transported into the other region via long range transport mechanisms or trapped within the shallow mixing boundary layer and then removed physically (deposition, transport by mountain wind, etc.) and chemically (reaction with local sources). Therefore, modeling formation of photochemical oxidants requires a complex description of both chemical and meteorolog ital processecs . In this study, as a part of air quality studies, we reviewed various aspects of photochemical modeling on the basis of currently available literature. The result of the review shows that the model is based on a set of coupled continuity equations describing advection, diffusion, transport, deposition, chemistry, emission. Also photochemical oxidant models require a large amount of input data concerned with all aspects of the ozone life cycle. First, emission inventories of hydrocarbon and nitrogen oxides, with appropriate spatial and temporal resolution. Second, chemical and photochemical data allowing the quantitative description of the formation of ozone and other photochemically-generated secondary pollutants. Third, dry deposition mechanisms particularly for ozone, PAN and hydrogen peroxide to account for their removal by absorption on the ground, crops, natural vegetation, man-made and water surfaces. Finally, meteorological data describing the transport of primary pollutants away from their sources and of secondary pollutants towards the sensitive receptors where environmental damage may occur. In order to improve our present study, shortcomings and limitation of existing models are pointed out and verification Process through observation is emphasized.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.324-327
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• 2005

지하수와 지표수를 연계하여 flow와 transport를 모의하는 프로그램인 HydroSphere를 Canada Ontario주의 Canadian Forces Base Borden에서의 실험 (Abdul ,1985) 자료를 이용하여 평가해 보았고, 유성지역 소유역에서의 강수, 지표수, 지하수의 수소동위원소 모니터링 (박준형, 고용권, 박경우, 정형재, 김교원, 2003) 자료를 이용하여 평가해 볼 예정이다.

• 한국수자원학회논문집
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• 제43권6호
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• pp.543-557
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• 2010

본 논문에서는 2차원 하상변동 수치모형인 CCHE2D 모형을이용하여 유사량 공식과 유사이송형태별 이류-확산 방정식의 선택이 하상변동 수치모의결과 값에 미치는 영향을 분석하고 실제 현장자료와 비교하였다. 또한 이러한 분석을 기초로 낙동강하구둑 상류 접근수로에서의 최적의 유사량 공식과 유사 이송형태별 이류-확산 방정식을 제안하였다. 낙동강하구둑 상류 접근수로에 대해 Ackers and White와 Engelund and Hansen의 유사량 공식과 소류사와 부유사 유사 이송형태에 따른 이류-확산 방정식을 각각 다르게 적용하여 모의한 결과, Engelund and Hansen 공식을 적용한 경우에는 Ackers and White 공식을 적용한 경우와 비교했을 때, 평수 및 홍수 조건에서 모두 하상변동량이 거의 없는 것으로 나타났다. 또한 Ackers and White 공식으로 2002년에 발생한 실제 수문사상을 적용하여 하상변동 모의한 결과, 소류사 이송형태의 이류-확산 방정식을 적용한 모의결과가 부유사 이송형태를 적용했을 경우 보다 실제 하상변동에 더 근접한 것으로 나타났다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.101-113
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• 2016

To properly manage and remediate groundwater contaminated with chlorinated hydrocarbons such as trichloroethylene (TCE), it is necessary to assess natural attenuation processes of contaminants in the aquifer along with investigation of contamination history and aquifer characterization. This study evaluated natural attenuation processes of TCE at an industrial site in Korea by delineating hydrogeochemical characteristics along the flow path of contaminated groundwater, by calculating reaction rate constants for TCE and its degradation products, and by using geochemical and reactive transport modeling. The monitoring data showed that TCE tended to be transformed to cis-1,2-dichloroethene (cis-1,2-DCE) and further to vinyl chloride (VC) via microbial reductive dechlorination, although the degree was not too significant. According to our modeling results, the temporal and spatial distribution of the TCE plume suggested the dominant role of biodegradation in attenuation processes. This study can provide a useful method for assessing natural attenuation processes in the aquifer contaminated with chlorinated hydrocarbons and can be applied to other sites with similar hydrological, microbiological, and geochemical settings.

• 한국해양공학회지
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• 제37권2호
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• pp.68-79
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• 2023

Even though submerged breakwater reduces incident wave energy, it redistributes the coastal area's wave-induced current, sediment transport, and morphological change. This study examines the coastal hydrodynamics and the morphological response of a wave-dominated beach with submerged breakwaters installed through field observation and quasi-3D numerical modeling. The pre-and post-storm bathymetry, water level, and offshore wave under storm forcing were collected in Bongpo Beach on the East coast of Korea and used to analyze the coastal hydrodynamic response. Four vertically equidistant layers were used in the numerical simulation, and the wave-induced current was examined using quasi-3D numerical modeling. The shore normal incident wave (east-northeast) generated strong cross-shore and longshore currents toward the hinterland of the submerged breakwater. However, the oblique incident wave (east-southeast) induced the southeastward longshore current and the sedimentation in the northeast area of the beach. The results suggested that the incident wave direction is a significant factor in determining the current and sediment transport patterns in the presence of the submerged breakwaters. Moreover, the quasi-3D numerical modeling is more appropriate for estimating the wave transformation, current, and sediment transport pattern in the coastal area with the submerged breakwater.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.243-247
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• 2004

Tile development of a porous iron-oxide coated sand filter system can be modelled with the analytical solution of tile transport equation in order to obtain the operating parameters and investigate the mechanism of arsenic removal. The adsorbed amount from the model simulation showed the limitation of adsorption removal during arsenic transport. A loss reaction term in the transport equation plays a role in the mass loss in column conditions, and then resulted into the better model fitting, particularly, for arsenate. Further, the competitive oxyanions delayed the breakthrough near MCL (10 $\mu$g/L) due to the competitive adsorption. This is the reason why arsenate can be strongly attracted in tile interface of an iron-oxide coated sand, and competing oxyanions can occupy the adsorption sites. Therefore, arsenic retention was regulated by non-equilibrium of arsenic adsorption in a porous iron-oxide coated sand media. The transport-limited process seemed to be affect the arsenic adsorption by coated sand.

• 대한토목학회논문집
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• 제30권1B호
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• pp.33-40
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• 2010

본 연구에서는 조석으로 인한 만에서 부유사 이동과 해저지형변화 예측에 대한 2차원 유사운송모형인 HSCTM-2D 모형의 적용성을 평가하였다. 또한, 보정된 모형을 이용하여 아산만 해역과 천수만 해역에서 점착성 부유사의 유입으로 인한 장기 퇴적량을 추정하였다. HSCTM-2D 모형을 보정하기 위하여 대상해역에 위치한 검조소의 실측조위자료와 모의기간 동안 측정한 유속 및 부유사농도 자료를 모의결과와 비교하였으며, 실측자료와 모의결과가 유사한 경향을 나타내는 것으로 확인되었다. 대상해역의 퇴적환경을 고려하여 외해유입 부유사 농도를 결정하고 장기간의 조석활동에 의한 점착성 부유사의 퇴적량을 추정하였으며, 아산만 해역에서는 연간 퇴적율이 8.1 cm/yr, 천수만 해역에서는 연간 퇴적율이 14.5 cm/yr를 나타냈다. 이와같은 연구결과로부터 적용된 모델링 시스템이 해역의 점착성 부유사 이동 및 퇴적과정에 대한 이해와 완화대책수립에 유용할 것으로 판단된다.