• 의학교육논단
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• 제11권1호
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• pp.21-33
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• 2009

The purpose of this study is to review a variety of e-learning use in medical education, and to analyze the e-learning related research in medical education, finally to discuss possibilities and limitations of e-learning in future. Subjects of this research are 46 papers published in Korean Medical Database, PubMed, MEDLIS, RISS4U. Content analysis of 46 papers have been conducted based on the period of research, research methods, research subjects, study personnel, effectiveness. The results are as follows. First, various e-learning, such as hyper-media, simulation-based medical education (SBME), game-based learning, web-based learning, computer-based test (CBT) are implemented in medical education. Second, 35 research (76.1%) has verified the positive effect of e-learning. Third, in the case of Korean studies, experimental studies (46.2%) in a short period (46.2%) of 50-100 people (42.3%) to take the most. As a result, it is reported a lack of theoretical discussion and insight on e-learning compared to foreign research. Educational paradigms are currently shifting from off-line to on-line, from traditional classroom lecture to e-learning. But e-learning is not a substitution to traditional teaching, but a matter of choice. The choice is up to medical professors and students.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.120-124
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• 2007

Helicopters and rotary-wing vehicles encounter a wide variety of complex aerodynamic phenomena and these phenomena present substantial challenges for computational fluid dynamics(CFD) models. This investigation presents the rotor aerodynamic analysis items for the helicopter development and variety aerodynamic analysis methods to provide the better solution to researchers and helicopter developers between aerodynamic problems and numerical aerodynamic analysis methods. The numerical methods to make an analysis of helicopter rotor are as below - CFD Modelling : actuator disk model, BET model, fully rotor model,... - Grid : sliding mesh, chimera mesh / structure mesh, unstructure mesh,... - etc. : panel method periodic boundary, quasi-steady simulation, incompressible,... The choice of CFD methodology and the numerical resolution for the overall problem have been driven mostly by available computer speed and memory at any point in time. The combination of the knowledge of aerodynamic analysis items, available computing power and choice of CFD methods now allows the solution of a number of important rotorcraft aerodynamics design problems.

• 한국태양에너지학회 논문집
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• 제23권3호
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• pp.55-61
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• 2003

This paper represents the effect of rotor geometry on the performance of a small-scale Wells turbine for wave energy conversion. In this study, four kinds of blade profile were selected from previous studies with regard to the blade profile of the Wells turbine. The experimental investigations have been performed for two solidities by model testing under steady flow conditions, and then the effect of blade profile on the running and starting characteristics under sinusoidal flow conditions have been investigated by a numerical simulation using a quasi-steady analysis. In addition, the effect of sweep on the turbine characteristics has been investigated for the cases of CA9 and HSIM 15-262123-1576. As a result, a suitable choice of these design factors has been suggested.

• 한국태양에너지학회 논문집
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• 제23권2호
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• pp.99-105
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• 2003

This paper presents the effect of rotor geometry on the performance of a small-scale Wells turbine for wave energy conversion. In this study, four kinds the Wells turbine of blade profile were selected from previous studies. The types of blade profile included in the papers are as follows: NACA0020 ; NACA0015; CA9; and HSIM 15-262123-1576. The experimental investigations have been performed for two solidities by testing model under steady flow conditions. The effect of blade profile on the running and starting characteristics under sinusoidal flow conditions have also been investigated by a numerical simulation based on a quasi-steady analysis. In addition, the effect of sweep on the turbine characteristics has been studied for the cases of CA9 and HSIM 15-262123-1576. Based on the evaluation, a suitable choice of these design factors has been suggested. As a result, it seems that a suitable choice of the sweep ratio of 0.35 for the blade profile of the Wells turbine.

• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1351-1358
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• 2009

Parentage tests using polymorphic DNA marker are commonly performed to avoid incorrect recording of the parental information of livestock animals, and single-nucleotide polymorphisms (SNPs) are becoming the method of choice. In Japanese Black cattle, parentage tests based on the exclusion method using microsatellite markers are currently conducted; however, an alternative SNP system aimed at parentage tests has recently been developed. In the present study, two types of simulations were conducted using the pedigree data of two subpopulations in the breed (subpopulations of Hyogo and Shimane prefectures) in order to examine the effect of actual genetic and breeding structures. The first simulation (simulation 1) investigated the usefulness of SNPs for excluding a close relative of the true sire; the second one (simulation 2) investigated the accuracy of sire identification tests for multiple full-sib putative sires by a combined method of exclusion and paternity assignment based on the LOD score. The success rates of excluding a single fullsib and sire of the true sires were, respectively, 0.9915 and 0.9852 in Hyogo and 0.9848 and 0.9852 in Shimane, when 50 SNPs with minor allele frequency (MAF: q) of 0.25${\leq}$q${\leq}$0.35 were used in simulation 1. The success rates of sire identification tests based solely on the exclusion method were relatively low in simulation 2. However, assuming that 50 SNPs with MAF of 0.25${\leq}$q${\leq}$0.35 or 0.45${\leq}$q${\leq}$0.5 were available, the total success rates including achievements due to paternity assignment were, respectively, 0.9430 and 0.9681 in Hyogo and 0.8999 and 0.9399 for Shimane, even when each true sire was assumed to compete with 50 full-sibs.

• 한국시스템다이내믹스연구
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• 제8권2호
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• pp.115-140
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• 2007

Changes in material use, energy use and emissions profiles of steel industry are the result of complex interrelationships among a multitude of technological and economic drivers. To better understand and guide such changes requires that attention is paid to the time-varying consequences that technology and economic influences have on an industry's choice of inputs and its associated outputs. We briefly review the range of policy issues in our paper and assess the impact that climate-change policies may have on energy use and carbon emissions in Korea steel industry. We then present the models of Korea steel industry's energy and product flow regarding environmental regulations by using system dynamics simulation methodology(SD). Time series data and engineering information are combined to endogenously specify changes in technologies, fuel mix, and production processes within dynamic simulation model. Through a various scenario, ramifications that the convention of climate change would to steel industry is analyzed, and based on the study results, strategies against environment changes is contemplated in various perspectives to contribute to minimize the risks concerning the uncertain future and to be conducive to Korea steel industry's sustainable development.

• 한국전산유체공학회지
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• 제16권4호
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• pp.7-13
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• 2011

A comparative analysis of thermal models in the lattice Boltzmann method(LBM) for the simulation of laminar natural convection in a square cavity is presented. A HYBRID method, in which the thermal equation is solved by the Navier-Stokes equation method while the mass and momentum conservation are resolved by the lattice Boltzmann method, is introduced and its merits are explained. All the governing equations are discretized on a cell-centered, non-uniform grid using the finite-volume method. The convection terms are treated by a second-order central-difference scheme with a deferred correction method to ensure stability of the solutions. The HYBRID method and the double-population method are applied to the simulation of natural convection in a square cavity and the predicted results are compared with the benchmark solutions given in the literatures. The predicted results are also compared with those by the conventional Navier-Stokes equation method. In general, the present HYBRID method is as accurate as the Navier-Stokes equation method and the double-population method. The HYBRID method shows better convergence and stability than the double-population method. These observations indicate that this HYBRID method is an efficient and economic method for the simulation of incompressible fluid flow and heat transfer problem with the LBM.

• Journal of the Korean Data and Information Science Society
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• 제26권1호
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• pp.261-269
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• 2015

Nowadays the application of change point analysis has been indispensable in a wide range of areas such as quality control, finance, environmetrics, medicine, geographics, and engineering. Identification of times where process changes would help minimize the consequences that might happen afterwards. The main objective of this paper is to compare the change-point detection capabilities of Bayesian estimate and maximum likelihood estimate. We applied Bayesian and maximum likelihood techniques to formulate change points having a step change and multiple number of change points in a Poisson rate. After a signal from c-chart and Poisson cumulative sum control charts have been detected, Monte Carlo simulation has been applied to investigate the performance of Bayesian and maximum likelihood estimation. Change point detection capacities of Bayesian and maximum likelihood estimation techniques have been investigated through simulation. It has been found that the Bayesian estimates outperforms standard control charts well specially when there exists a small to medium size of step change. Moreover, it performs convincingly well in comparison with the maximum like-lihood estimator and remains good choice specially in confidence interval statistical inference.

• Water Engineering Research
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• 제1권4호
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• pp.267-277
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• 2000

This study reports an examination of the sensitivity of water resources in the Keum River basin to climate change. Assuming a doubling in $CO_2$ concentrations, a cooperative study provided four climate change scenarios for this study, which have been translated into temperature and precipitation scenarios on a basin scale. The study utilized these temperature and precipitation data for each climate change scenario as inputs to the NWS-PC model to generate the corresponding streamflow scenario over the Keum River basin. A reservoir simulation model for the Dae-Chung Dam in the Keum River basin has been developed with an object-oriented simulation environment, STELLA. For each streamflow scenario, the performance of the reservoir was assessed in terms of reliability, resiliency, and vulnerability. Although the simulation results are heavily dependent on the choice of the climate change scenarios, the following conclusions can be clearly concluded: (1) the future streamflow over the Dae-Chung Dam tends to decease during the dry period, which seriously increases competitive water use issues and (2) flood control issues predominate under the $2CO_2$-High case.

• 산업경영시스템학회지
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• 제41권4호
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• pp.213-219
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• 2018

Mechanical components are to be produced with accurate dimensions in order to function properly in assemblies of a machine. Once designs of mechanical components are created, designers examine the designs by adopting many known experimental methods. A primary test method includes stress and strain evaluation of structural parts. In addition, fatigue test and vibration analysis are an important test method for mechanical components. Real experiments at a laboratory are established when products are manufactured. Since design changes should be done before producing the designs in factories, rapid modifications for new designs are required in production industries. FEM simulation is a proper choice for a design evaluation with speed at a detail stage in design process. This research focuses modeling and mechanical simulation of a mechanical component in order to ensure structural safety. In this paper, a universal joint, being used in driving axels of vehicles, is studied as a target component. A design model is created and tested in some ways by using commercial software of FEM. The designed component is being twisted to transmit heavy power and thus, torsional stress should be under strengths of the component's material. The next is fatigue analysis to convince fatigue cycles to be within the endurance limit of the material. Another test is a vibration analysis for rotational components. This research draws final conclusions from these test analyses and recommends whether the designed model is under safety condition in terms of mechanical structure.