• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.

• Geomechanics and Engineering
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• 제28권1호
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• pp.1-10
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• 2022

In Korea, accidents related to the collapse of deteriorated aging reservoirs occur every year. The grouting method is generally applied to reinforce an aging reservoir. However, when using this method, different reinforcing effects appear depending on the ground conditions. Thus, new construction methods and materials capable of providing consistent reinforcing effects are required. In this study, the direct shear test (DST), model test, and simulation analysis were performed to evaluate the impact of surface stabilizers, generally used to reinforce roads, rivers, and slopes of roads, applied using surface curtain walls on aging reservoirs. The DST results indicate that when the surface stabilizer was mixed with in-situ soil, the increase in cohesion was the highest at a mixing ratio of 9%. No changes in the friction angle were evident; therefore, 9% was determined to be the optimal mixing ratio. In addition, the model test and simulation analysis showed that when 9% of the surface stabilizer was mixed and applied to the aging reservoir, the seepage quantity of water and the saturated area were reduced by approximately 42% and 73%, respectively. Moreover, the comprehensive analysis of results showed that the grouting method could be completely replaced by surface stabilizers applied through surface curtain walls because the technique could secure stability by decreasing the seepage in the aging reservoir.

• Asian Journal for Public Opinion Research
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• 제12권2호
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• pp.75-101
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• 2024

This study investigates the variation in anxiety levels across income classes in the wake of the COVID-19 pandemic in Indonesia. The research is based on data from nationally representative surveys conducted in 2017 and 2021, and it employs a multilevel mixed-effects ordered logistic model. The unique aspect of this investigation lies in its utilization of the Cantril ladder, a commonly employed tool in public opinion research, to gauge anxiety levels. Participants are prompted to assess their present life circumstances concerning their daily worries and anxieties. The empirical findings provide evidence that individuals in provinces with higher exposures to COVID-19 reported heightened anxiety levels. Furthermore, the results highlight a consistent association between higher household income and lower levels of anxiety. Notably, individuals from the highest income group experienced a substantial decline in anxiety levels during the pandemic. When examining specific income classes, the study reveals heightened anxiety among women in higher-income brackets and among lower-income households residing in urban areas. Furthermore, regarding macroeconomic circumstances, the results illustrate a positive correlation between economic prosperity and anxiety levels among members of low-income households. The study also uncovers a positive connection between income inequality and self-assessed anxiety within upper-middle and high-income brackets.

• 한국의류학회지
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• 제28권6호
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• pp.854-861
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• 2004

To estimate dispersion stability of particles in anionic and nonionic surfactant mixed solution, suspending power was examined as functions of duration time of suspension, ionic and nonionic surfactant mixed ratio, surfactant concentration, kinds of electrolyte, ionic strength and mole numbers of oxyethylene additions to nonionic surfactant using $\alpha$-Fe$_2$O$_3$ particle as the model of particulate soil. The suspending power of anionic and nonionic surfactant mixed solution was relatively higher than that of anionic and nonionic surfactant single solution regardless of solution concentration. The suspending power was gradually decreased with increasing duration time of suspension. In the absence of electrolyte, the effect of surfactant concentration on suspending power was small but in solution with electrolyte, suspending power was lowest at 1 ％ surfactant concentration. With 1${\times}$10$^{-3}$ ionic strength and polyanionic electrolyte in solution, the suspending power was high but effects of oxyethylene mole number to nonionic surfactant on suspending power was small. Generally the suspending power was gradually increased with decreasing the particle size. Hence the suspending power was inversely related to the particle size.

• Journal of the Korean Data and Information Science Society
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• 제27권1호
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• pp.101-110
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• 2016

우울은 스트레스의 적응과정에서 나타나는 신체적 증상과 더불어, 근심, 침울함, 실패감, 무력감과 같은 심리적 증상을 나타내는 정신적 상태로, 우울의 경험 정도에 따라 개인에게 인지, 정서, 그리고 행동장애를 야기할 수 있다. 특히, 성장기에 경험하는 우울은 아동, 청소년들의 학업에 대한 집중력을 저하시키며, 폭력성 및 대인관계의 문제를 증가시켜 개인과 사회에 심각한 손실을 끼칠 수도 있다. 따라서 아동, 청소년들의 심리적 발달과정에 대한 사회적 관심과 적절한 대응방안이 요구된다. 본 연구는 이러한 배경을 근거로 여학생들의 성장과정에서 겪는 가정과 학교에서의 폭력 피해 경험이 우울에 어떠한 영향을 미치는지를 혼합모형을 이용하여 분석하였다.

• 응용통계연구
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• 제28권2호
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• pp.241-250
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• 2015

경시적 자료 연구의 중요한 주제 중의 하나는 시간이 지남에 따라 개인의 건강 상태가 어떻게 변하는지를 추적하는 확률이다. 질병의 상태를 시간의 흐름에 따라 추적하는 것은 장기간에 걸친 임상적 관찰 연구의 계획과 분석, 그리고 질병의 예방과 치료에 중요한 의미를 지닌다. 본 논문에서는 두 다른 시점에서 각 개인의 건강 상태에 대한 조건부 확률을 추정해내는 순위 추적 확률에 대하여 연구하였다. 순위 추적 확률과 순위 추적 확률비를 추정하기 위하여 선형 혼합 효과 모형을 고려하였다. 본 논문의 방법은 아동을 대상으로 심혈관계 질환의 위험요인을 연구하는 역학 자료에 적용되었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.134-141
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• 2000

The real area of contacts, average film thickness, mean real pressure, and mean hydrodynamic pressure are investigated numerically in this study, especially for the parallel thrust bearing. Model surface is generated numerically with given autocorrelation function and some surface profile parameters. Then the average Reynolds equation contained flow factors and contact factor is applied to predict the effects of surface roughness in mixed lubrication regimes. In this equation, flow factors are defined as correction terms to smooth out high frequency surface roughness and contact factor is introduced to relieve from obtaining the average film thickness. Therefore the computation time to obtain h can be reduced.

• Tribology and Lubricants
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• 제16권6호
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• pp.455-460
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• 2000

The real area of contacts, average film thickness, mean real pressure, and mean hydrodynamic pressure are investigated numerically in this study, especially for the parallel thrust bearing. Model surface is generated numerically with given autocorrelation function and some surface profile parameters. Then the average Reynolds equation contained flow factors and contact factor is applied to predict the effects of surface roughness in mixed lubrication regimes. In this equation, flow factors are defined as correction terms to smooth out high frequency surface roughness and contact factor is introduced to relieve from obtaining the average film thickness. Therefore the computation time to obtain barh h can be reduced.

• 아동학회지
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• 제20권4호
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• pp.3-24
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• 1999

The present study researched the development of a mixed-age after school program with a focus on the facilitation of emotional intelligence for low SES children. The model program was based on the Mayer and Salovey (1997) theory of emotional intelligence. Activities for 17 sessions were constructed on the basis of 43 objectives. The program was implemented with 53 children in the after school program classes of one elementary school in Kyuggi Province for 6 months. Participants were from low SES families, grouped into 3 mixed-age (K-3rd grade level) classes. Evaluation of the program showed positive effects on the development of children's emotional intelligence. Validity and appropriateness were discussed.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.194-197
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• 2005

In this work, a mixed beam approach is performed to identify the transverse shear behavior of thin-walled composite beams with closed cross-sections. The analytical model includes the effects of elastic couplings, shell wall thickness, and torsion warping. The distributions of shear flow across the section as well as the shear correction coefficients are obtained in a closed form in the beam formulation. The influence of transverse shear deformation on the static behavior of closed cross-section composite beams is also investigated in the analysis