• Korean Journal of Social Welfare
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• v.56 no.1
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• pp.103-126
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• 2004

The court-mandated spouse abusers with drinking problems not only resist and complain about taking the court-mandate but also have the low motivation to change their problem drinking and violent behaviors. Therefore, in this study the program is developed to decrease violent behaviors of spouse abusers with drinking problems. Also, the usefulness of this program is examined by quantitative and qualitative methods. The results are as follows: The experimental group's pre-to-post variation is decreased by significant level statistically more than the comparison group's variation in drinking problems. Regarding violent behaviors among groups, the experimental group's pre-to-post and pre-to-followup variation are decreased significantly. It is assumed that Motivation Enhancement Therapy(MET) influences the differences of motivation to change violent behaviors in both groups. The reason is that MET is considered to have influences on the group's dynamics and interaction. Also, it is helpful to change the negative emotions to the positive emotions and to stimulate the group interaction and the participation. This study will be contributed to promote the speciality on providing services for family in a domestic violence in Korea. Through this study, I suggested future implications in research, practice, and political side on spouse abusers with drinking problems.

• Journal of Ocean Engineering and Technology
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• v.33 no.1
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• pp.1-9
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• 2019

This paper considers a numerical assessment of the self-propulsion performance of a damaged ferry carrying cars in irregular waves. Computational fluid dynamics(CFD) simulations were performed to see whether the ferry complied with the Safe Return to Port (SRtP) regulations of Lloyd's register, which require that damaged passenger ships should be able to return to port with a speed of 6 knots (3.09 m/s) in Beaufort 8 sea conditions. Two situations were considered for the damaged conditions, i.e., 1) the portside propeller was blocked but the engine room was not flooded and 2) the portside propeller was blocked and one engine room was flooded. The self-propulsion results for the car ferry in intact condition and in the damaged conditions were assessed as follows. First, we validated that the portside propeller was blocked in calm water based on the available experimental results provided by KRISO. The active thrust of starboard propeller with the portside propeller blocked was calculated in Beaufort 8 sea conditions, and the results were compared with the experimental results provided by MARIN, and there was reasonable agreement. The thrust provided by the propeller and the brake horsepower (BHP) with one engine room flooded were compared with the values when the engine room was not flooded. The numerical results were compared with the maximum thrust of the propeller and the maximum brake horse power of the engine to determine whether the damaged car ferry could attain a speed of 6 knots(3.09 m/s).

• Wind and Structures
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• v.34 no.1
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• pp.127-136
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• 2022

In this work a multi-fidelity non-intrusive polynomial chaos (MF-NIPC) has been applied to a structural wind engineering problem in architectural design for the first time. In architectural design it is important to design structures that are safe in a range of wind directions and speeds. For this reason, the computational models used to design buildings and bridges must account for the uncertainties associated with the interaction between the structure and wind. In order to use the numerical simulations for the design, the numerical models must be validated by experi-mental data, and uncertainties contained in the experiments should also be taken into account. Uncertainty Quantifi-cation has been increasingly used for CFD simulations to consider such uncertainties. Typically, CFD simulations are computationally expensive, motivating the increased interest in multi-fidelity methods due to their ability to lev-erage limited data sets of high-fidelity data with evaluations of more computationally inexpensive models. Previous-ly, the multi-fidelity framework has been applied to CFD simulations for the purposes of optimization, rather than for the statistical assessment of candidate design. In this paper MF-NIPC method is applied to flow around a rectan-gular 5:1 cylinder, which has been thoroughly investigated for architectural design. The purpose of UQ is validation of numerical simulation results with experimental data, therefore the radius of curvature of the rectangular cylinder corners and the angle of attack are considered to be random variables, which are known to contain uncertainties when wind tunnel tests are carried out. Computational Fluid Dynamics (CFD) simulations are solved by a solver that employs the Finite Element Method (FEM) for two turbulence modeling approaches of the incompressible Navier-Stokes equations: Unsteady Reynolds Averaged Navier Stokes (URANS) and the Large Eddy simulation (LES). The results of the uncertainty analysis with CFD are compared to experimental data in terms of time-averaged pressure coefficients and bulk parameters. In addition, the accuracy and efficiency of the multi-fidelity framework is demonstrated through a comparison with the results of the high-fidelity model.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3874-3897
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• 2023

A high-fidelity computational fluid dynamics (CFD) analysis was performed using the Large Eddy Simulation (LES) model for the lower plenum of the High-Temperature Test Facility (HTTF), a ¼ scale test facility of the modular high temperature gas-cooled reactor (MHTGR) managed by Oregon State University. In most next-generation nuclear reactors, thermal stress due to thermal striping is one of the risks to be curiously considered. This is also true for HTGRs, especially since the exhaust helium gas temperature is high. In order to evaluate these risks and performance, organizations in the United States led by the OECD NEA are conducting a thermal hydraulic code benchmark for HTGR, and the test facility used for this benchmark is HTTF. HTTF can perform experiments in both normal and accident situations and provide high-quality experimental data. However, it is difficult to provide sufficient data for benchmarking through experiments, and there is a problem with the reliability of CFD analysis results based on Reynolds-averaged Navier-Stokes to analyze thermal hydraulic behavior without verification. To solve this problem, high-fidelity 3-D CFD analysis was performed using the LES model for HTTF. It was also verified that the LES model can properly simulate this jet mixing phenomenon via a unit cell test that provides experimental information. As a result of CFD analysis, the lower the dependency of the sub-grid scale model, the closer to the actual analysis result. In the case of unit cell test CFD analysis and HTTF CFD analysis, the volume-averaged sub-grid scale model dependency was calculated to be 13.0% and 9.16%, respectively. As a result of HTTF analysis, quantitative data of the fluid inside the HTTF lower plenum was provided in this paper. As a result of qualitative analysis, the temperature was highest at the center of the lower plenum, while the temperature fluctuation was highest near the edge of the lower plenum wall. The power spectral density of temperature was analyzed via fast Fourier transform (FFT) for specific points on the center and side of the lower plenum. FFT results did not reveal specific frequency-dominant temperature fluctuations in the center part. It was confirmed that the temperature power spectral density (PSD) at the top increased from the center to the wake. The vortex was visualized using the well-known scalar Q-criterion, and as a result, the closer to the outlet duct, the greater the influence of the mainstream, so that the inflow jet vortex was dissipated and mixed at the top of the lower plenum. Additionally, FFT analysis was performed on the support structure near the corner of the lower plenum with large temperature fluctuations, and as a result, it was confirmed that the temperature fluctuation of the flow did not have a significant effect near the corner wall. In addition, the vortices generated from the lower plenum to the outlet duct were identified in this paper. It is considered that the quantitative and qualitative results presented in this paper will serve as reference data for the benchmark.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.357-365
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• 2024

The purpose of this study is to investigate the effects of children's robot-based play on sequential thinking through appreciation of picture books. For this purpose, 15 children aged 5 years old in each kindergarten located in Seoul were selected and J kindergarten (experimental group) supported <Picture book appreciation robot play> and C kindergarten (comparison group) supported <Picture book appreciation free play>. In order to examine the difference in play experience between the two groups, the score data before and after play support was collected using the sequential thinking test tool, and the collected data were analyzed using SPSS 28.0 program to perform ANCOVA (Covariance Analysis). As a result, the experimental group that experienced robot-based play through picture book appreciation showed significant improvement in the total score of sequential thinking and the sub-areas of dynamics, behavior, and intention compared to the control group.The results of this study are valuable as a play study to discover the value of robots as a creative play medium led by young children and to promote sequential thinking ability, which is emphasized as the capacity of future society.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.165-174
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• 2010

The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

• Journal of the Korean earth science society
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• v.32 no.3
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• pp.276-293
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• 2011

In this study a modeling system consisting of Weather Research and Forecasting (WRF), Sparse Matrix Operator Kernel Emissions (SMOKE), the Community Multiscale Air Quality (CMAQ) model, and the CMAQ-Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) model has been applied to estimate enhancements of $PM_{10}$ during Asian dust events in Korea. In particular, 5 experimental formulas were applied to the WRF-SMOKE-CMAQ (MADRID) model to estimate Asian dust emissions from source locations for major Asian dust events in China and Mongolia: the US Environmental Protection Agency (EPA) model, the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model, and the Dust Entrainment and Deposition (DEAD) model, as well as formulas by Park and In (2003), and Wang et al. (2000). According to the weather map, backward trajectory and satellite image analyses, Asian dust is generated by a strong downwind associated with the upper trough from a stagnation wave due to development of the upper jet stream, and transport of Asian dust to Korea shows up behind a surface front related to the cut-off low (known as comma type cloud) in satellite images. In the WRF-SMOKE-CMAQ modeling to estimate the PM10 concentration, Wang et al.'s experimental formula was depicted well in the temporal and spatial distribution of Asian dusts, and the GOCART model was low in mean bias errors and root mean square errors. Also, in the vertical profile analysis of Asian dusts using Wang et al's experimental formula, strong Asian dust with a concentration of more than $800\;{\mu}g/m^3$ for the period of March 31 to April 1, 2007 was transported under the boundary layer (about 1 km high), and weak Asian dust with a concentration of less than $400\;{\mu}g/m^3$ for the period of 16-17 March 2009 was transported above the boundary layer (about 1-3 km high). Furthermore, the difference between the CMAQ model and the CMAQ-MADRID model for the period of March 31 to April 1, 2007, in terms of PM10 concentration, was seen to be large in the East Asia area: the CMAQ-MADRID model showed the concentration to be about $25\;{\mu}g/m^3$ higher than the CMAQ model. In addition, the $PM_{10}$ concentration removed by the cloud liquid phase mechanism within the CMAQ-MADRID model was shown in the maximum $15\;{\mu}g/m^3$ in the Eastern Asia area.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.535-543
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• 2022

A CPFD (Computational particle fluid dynamics) model of solar fluidized bed receiver of silicon carbide (SiC: average d_p=123 ㎛) particles was established, and the model was verified by comparing the simulation and experimental results to analyze the effect of particle behavior on the performance of the receiver. The relationship between the heat-absorbing performance and the particles behavior in the receiver was analyzed by simulating their behavior near bed surface, which is difficult to access experimentally. The CPFD simulation results showed good agreement with the experimental values on the solids holdup and its standard deviation under experimental condition in bed and freeboard regions. The local solid holdups near the bed surface, where particles primarily absorb solar heat energy and transfer it to the inside of the bed, showed a non-uniform distribution with a relatively low value at the center related with the bubble behavior in the bed. The local solid holdup increased the axial and radial non-uniformity in the freeboard region with the gas velocity, which explains well that the increase in the RSD (Relative standard deviation) of pressure drop across the freeboard region is responsible for the loss of solar energy reflected by the entrained particles in the particle receiver. The simulation results of local gas and particle velocities with gas velocity confirmed that the local particle behavior in the fluidized bed are closely related to the bubble behavior characterized by the properties of the Geldart B particles. The temperature difference of the fluidizing gas passing through the receiver per irradiance (∆T/I_DNI) was highly correlated with the RSD of the pressure drop across the bed surface and the freeboard regions. The CPFD simulation results can be used to improve the performance of the particle receiver through local particle behavior analysis.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.110-117
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• 2016

Litter fall is a source of nutrients and carbon transfer in terrestrial ecosystems. Litter decomposition provides nutrients needed for plant growth, sustains soil fertility, and supplies $CO_2$ to the atmosphere. We collected the leaf litter of evergreen broadleaf tree, Camellia japonica L., and carried out a decomposition experiment using the litterbag method in Ju-do, Wando-gun, Korea for 731 days from Dec 25, 2011 to Dec 25, 2013. The leaf litter of C. japonica remained 42.6% of the initial litter mass after experiment. The decay constant (k) of C. japonica leaf litter was $0.427yr^{-1}$. The carbon content of C. japonica leaf litter was 44.6%, and the remaining carbon content during the decomposition tended to coincide with the changes in litter mass. The initial nitrogen and phosphorus content was 0.47% and 324.7 mg/g, respectively. The remaining N in decaying litter increased 1.66-fold in the early decomposition stage, then gradually decreased to 1.18-fold after 731 days. The content of P showed the highest value (1.64-fold of initial content) after 456 days, which then fell to a 1.15-fold after 731 days. The remaining Ca, K, Mg and Na content in C. japonica leaf litter tended to decrease during decomposition. The remaining K showed a remaining mass of 8.9% as a result of rapid reduction. The initial C/N and C/P ratio of C. japonica leaf litter was 94.87 and 1368.5, respectively. However, it tended to decrease as decomposition progressed because of the immobilization of N and P (2.78 and 2.68-fold of initial content, respectively) during the leaf litter decaying. The study results showed that N and P was immobilized and other nutrients was mineralized in C. japonica leaf litter during experimental period.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.89-98
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• 2010

Sex and its tropic hormones influence the lacrimal system, corneal anatomy and disease, aqueous humor dynamics and glaucoma, crystalline lens and cataract, and retinal disease. Dry eye occurs especially frequently during pregnancy, oral contraceptive use, and after menopause, during which androgen levels decrease. Androgen control development, differentiation, and lipid production of sebaceous glands throughout the body, and androgen deficiency also leads to meibomian gland dysfunction and evaporative dry eye. On the other hand, estrogen causes a reduction in size, activity, and lipid production of sebaceous glands. Sex and its tropic hormones also influence the corneal anatomy and disease, and corneal thickening occurred on the second day of the menstrual cycle and around the time of ovulation and appeared to be related to estrogen levels. Fuchs' dystrophy is more commonly seen in postmenopausal women than men and may be linked to hormonal changes that occur with aging. In addition, overexpression of estrogen and progesterone receptors in the conjunctiva of vernal keratoconjunctivitis patients. Serum progesterone levels also may be associated with intraocular pressure especially in pregnant women, and for the women. For women with cataracts, hormone levels were typical of menopause, and there was a significant negative correlation between estradiol and follicular stimulating hormone levels. In addition, serum testosterone levels are associated with the development of diabetic retinopathy. Although the role of sex hormones on the eye is largely unknown, and the results should be interpreted with caution until replicated, the functions of sex hormones in ocular disease remains to be investigated, because they may be involved in structure and function of the ocular components, which are important in the pathogenesis of ocular disease.