• Journal of Korean Classical Literature and Education
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• no.33
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• pp.5-44
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• 2016

This study focuses on Ko woo-young (1939-2005), a Korean representative cartoonist. I analyzed his work Nolbudyeon (1988), which is a retelling of Heungbu and Nolbu, a traditional Korean story. I consider Ko woo-young a creative observer who has popularized his perspective in modern society. His work is a good example of how a traditional folktale can be made relevant in modern society. I used three methods of adaptation to differentiate Nolbudyeon from Heungbu story: construction of events, characterizing, and space-time background. First, to aid character development, Nolbudyeon includes a prologue that focuses on conflicts between brothers with different personalities. At the same time, the ambiguous ending could be a response to Heungbu story, which has a didactic theme. Second, I found that the new characters, Nolsun and Yeonsaengwon, enhanced the differences between Heungbu and Nolbu by playing the role of mediators. Also, in Nolbudyeon, both Heungbu and Nolbu had positive as well as negative elements, in contrast with the original story's traditional point of view on good and evil. Finally, by exploring the space-time of Nolbudyeon, we can see that its world is combined with the contemporary world. In other words, Nolbu and Heungbu, though outwardly traditional, have a modern outlook. Therefore, readers can recognize that Nolbudyeon is a metaphor for modern life rather than just an old story.

• Nuclear Engineering and Technology
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• v.19 no.2
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• pp.85-98
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• 1987

To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.580-589
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• 2019

Indonesia has a very short supply of electricity. As a solution to this problem, plans for construction of thermal power plants are increasing. Thermal power plant require the cooling water system to cool the overheated engine and equipment that accompany power generation, and the circulation water pump chamber among the cooling water system are generally designed according to the ANSI (1998) standard. In this study, the design criterion $20^{\circ}$ for the spreading angle of the ANSI (1998) of the layout of the circulating water pump chamber can not be satisfied on the K-coal thermal power plant site condition in Indonesia. Therefore, 3-D numerical model experiment was carried out to obtain a hydraulically stable flow and stable structure. The Flow-3D model was used as numerical model. In order to examine the applicability of the Flow-3D model, the flow study results around the rectangular structure of Rodi (1997) and the numerical analysis results were compared around the rectangular structures. The longitudinal velocity distribution derived from numerical analysis show good agreement. In order to satisfy the design velocity in the circulating water pump chamber, a rectangular baffle favoring velocity reduction was applied. When the approach velocity into the circulating water pump chamber was occurred 1.5 m/s ~ 2.5 m/s, the angle of the separation flow on the baffle was occurred about $15^{\circ}{\sim}20^{\circ}$. By placing the baffle below the separation flow angle downstream, the design velocity of less than 0.5 m/s was satisfied at inlet bay.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.25-36
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• 2021

Hydrogen in hydrogen-electric vehicles has a wide range of combustion and explosion ranges, and is a combustible gas with a very fast flame propagation speed, so it has the risk of leakage, diffusion, ignition, and explosion. The fuel tank has a Thermally active Pressure Relief Device (TPRD) to reduce the risk of explosion and other explosions, and in the event of an accident, hydrogen inside the tank is released outside before an explosion or fire occurs. However, if an accident occurs in a semi-closed space such as an underground parking lot, the flow of air flow is smaller than the open space, which can cause the concentration of hydrogen gas emitted from the TPRD to accumulate above the explosion limit. Therefore, in this study, the leakage rate and concentration of hydrogen over time were analyzed according to the diameter of the nozzle of the TPRD. The diameter of the nozzle was considered to be 1 mm, 2.5 mm and 5 mm, and ccording to the diameter of the nozzle, the concentration of hydrogen in the underground parking lot increases in a faster time with the diameter of the nozzle, and the maximum value is also analyzed to be larger with the diameter of the nozzle. In underground parking lots where air currents are stagnant, hydrogen concentrations above LFL (Lowe Flammability Limit) were analyzed to be distributed around the nozzle, and it was analyzed that they did not exceed UFL (Upper Flammability Limit).

• Journal of Korean Society of Disaster and Security
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• v.15 no.2
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• pp.13-25
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• 2022

Public consent is essential to proceed with large-scale projects such as dam and hydroelectric power plant in the Carbon Neutral Era. In general, when designing facilities such as dams and river facilities, the impact due to constructing them is analyzed through numerical simulation in advance. Those facilities are built to cope with floods and usually HEC-RAS is used for numerical simulation in this process. The numerical simulation provides accurate data, but it is very difficult to persuade the public only with the data. Therefore, this study intends to consider the utilization of metaverse in the field of urban flooding and flood response. The applicability of metaverse was confirmed by emphasizing visual effects and providing easy-to-see data, using a kind of metaverse platform called Cities: Skylines. The functions and limitations of this platform were reviewed. A virtual flood scenario was applied after implementing real cities on a metaverse. The hazard map established in Korea and the results of applying the scenario of metaverse platform were compared. On the metaverse, not only the disaster situation caused by realizing the city and society as it is, but also the spread of social disasters after the disaster can be confirmed. Through this, countermeasures can be virtually implemented. If these social and humanistic data are also verified in the future, it is expected that the overall process for responding to urban flooding can be modeled.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.575-589
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• 2008

In the present work, we investigate the hydrodynamic behavior of a turbulent bore, such as tsunami bore and tidal bore, generated by the removal of a gate with water impounded on one side. The bore generation system is similar to that used in a general dam-break problem. In order to the numerical simulation of the formation and propagation of a bore, we consider the incompressible flows of two immiscible fluids, liquid and gas, governed by the Navier-Stokes equations. The interface tracking between two fluids is achieved by the volume-of-fluid (VOF) technique and the M-type cubic interpolated propagation (MCIP) scheme is used to solve the Navier-Stokes equations. The MCIP method is a low diffusive and stable scheme and is generally extended the original one-dimensional CIP to higher dimensions, using a fractional step technique. Further, large eddy simulation (LES) closure scheme, a cost-effective approach to turbulence simulation, is used to predict the evolution of quantities associated with turbulence. In order to verify the applicability of the developed numerical model to the bore simulation, laboratory experiments are performed in a wave tank. Comparisons are made between the numerical results by the present model and the experimental data and good agreement is achieved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4C
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• pp.231-238
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• 2008

A column testing device capable of measuring the electrical resistivity of soil at 3 different locations was developed to verify applicability of bulk electrical conductivity (BEC) breakthrough curves in monitoring contaminant transport. Tracer injection tests were conducted with three different types of saturated sands to obtain average linear velocities and longitudinal hydrodynamic dispersion coefficients based on BEC breakthrough curves and effluent solute breakthrough curves. Comparative analysis of transport parameters obtained from curve fitting the results into the analytical solutions confirmed the validity of resistance measurements in estimating time-continuous resident solute concentration. Under the assumption that a linear relationship exists between ${\sigma}_{sat}-{\sigma}_w-C$, the BEC breakthrough curves are able to effectively reduce the laborious and time-consuming processes involved in the conventional method of sampling and analysis. In order to reduce possible uncertainties in analyzing the BEC breakthrough curves, it was recommended that resistance measurements take place nearby the effluent boundary. In addition, a sufficient electrical contrast or difference in the electrical conductivity of the influent and the saturating solution is required to conduct reliable analysis.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.705-720
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• 2023

In South Korea, ongoing incidents related to drinking water quality have eroded consumer trust. Specifically, beyond quality incidents, there have been complaints about taste, odor, and other issues stemming from the presence of chlorine. To address this, water service operators are employing various management strategies from both temporal (scheduling) and spatial (rechlorination) perspectives to ensure uniform and safe distribution of chlorine residuals. In this study, we focus on the optimal monthly management of chlorine residuals, based on water distribution network analysis. Water quality reaction coefficients, including bulk fluid and wall reaction coefficients, were estimated through lab-scale tests and EPANET water quality simulations, respectively, accounting for temperature variations in a large-scale water distribution network. Utilizing these estimated coefficients, we examined the monthly variations in chlorine residual distribution under different chlorine injection conditions. The results indicate that the efficient concentration for chlorine injection, which satisfies the residual chlorine limit range, varies with temperature changes. Consequently, it is imperative to establish a specific and quantitative chlorine injection plan that considers the accurate spatial distribution of monthly chlorine residuals.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.12-18
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• 2023

The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.126-134
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• 2001

Several angular sandstone fragments (about 7 cm in longest diameter) occur in two piston cores, obtained from the submarine trough in the northeastern part of Korea Strait. The origin of the sandstone fragments and the paleoenvironment of trough sediment could be suggested from sedimentary facies analysis of cores and identification of ostracod within sandstone fragments. Echo characteristics around two core sites in submarine trough represent the prolonged bottom echoes with diffuse or no subbottom reflectors. The cores consist of a lower bioturbated mud and an upper gravelly sand sediments with sandstone/shell fragments. The bioturbated mud sediments show low water contents (27-44%) and high shear strength (19.2->37 kPa) compared with those of Holocene sediments (60-219% and 1.0-2.7 kPa, respectively) in the inner shelf and continental slope. However, clay contents (48-56%) of the bioturbated mud sediments are similar to those of fluviatile Holocene sediments in the inner shelf. The mean grain size of gravelly sand sediments ranges from 2.3 to 3.0 ${\phi}$ and shows coarsening upward with sandstone/shell fragments. The Holocene palimpsest in the continental shelf are composed of muddy sand sediments or sandy mud sediments (mean grain size: 4.6-7.6 ${\phi}$). Those suggest that two core sediments might be formed from Paleofluvial and paleocoastal deposits during sea-level lowstand. However, sandstone fragments mainly consist of quartz grains and bioclasts, with carbonate matrix, hollow pore, and glauconite. Two extinct ostracod species, Normanicythere sp. and Kotoracythere sp., are recovered in the sand-stone fragments of core EP-7, and they continued to exist from late Pliocene to early Pleistocene in cold water environment of this area. Thus, the sandstone fragments are interpreted to be formed at the paleocoastal environment derived from the Plio-Pleistocene outcrops exposed around the submarine trough during the LGM (Last Glacial Maximum) period.