• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.4
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• pp.67-75
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• 2008

In construction facilities such as bridges, the fluid boundary layer(or water film) is formed at the structure-soil interface by the inflow into the system due to rainfall or/and rising ground-water. As a result, the structure-soil interaction(SSI) state changes into the structure-fluid-soil interaction(SFSI) state. In general, construction facilities may be endangered by the inflow of water into the soil foundation. Thus, it is important to predict the dynamic SFSI responses accurately so that the facilities may be properly designed against such dangers. It is desired to have the robust tools of attaining such a purpose. However, there has not been any report of a method for the SFSI analyses. The objective of this study is to propose an efficient method of finite element modelling using the new interface element named hybrid interface element capable of giving reasonable predictions of the dynamic SFSI response. This element enables the simulation of the limited normal tensile resistance and the tangential hydro-plane behaviour, which has not been preceded in the previous studies. The hybrid interface element was tested numerically for its validity and employed in the analysis of SFSI responses of the continuous bridge subjected to seismic load under rainfall or/and rising ground-water condition. It showed that dynamic responses of the continuous bridge resting on direct foundation may be amplified under rainfall condition and consequently lead to significant variation of stresses.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.208-213
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• 2003

Recently, Side-by-side mooring system of LNG FPSO and shuttle tanker is one of hot issues in offshore floating body dynamics, which requires accurate analysis of hydrodynamic interactions between side by side moored LNG FPSO and shuttle tanker than tandem moored vessels. This paper aims to investigate basic interaction characteristics of side-by-side moored multiple vessels both numerically and experimentally. A higher-order boundary element method combined with generalized nwde approach will be applied to analysis of motion and drift force of side by side moored multiple-body. Model tests were carried out for the same multiple floating bodies in regular and irregular waves. Motion responses and drift forces of vessels for two mooring situation(coupled & uncoupled) were compared with those of calculations. Discussions will be highlighted on applicability of numerical method to prediction of sophisticated multi-body interaction problem of which motion behavior is very important to analysis of mooring dynamics of deep sea floating bodies.

• Coupled systems mechanics
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• v.11 no.4
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• pp.315-333
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• 2022

Fluid-Structure Interaction (FSI) modeling is highly effective to reveal deformations, fatigue failures, and stresses on a solid domain caused by the fluid flow. Mechanical properties of the solid structures and the thermophysical properties of fluids can change under different operating conditions. In this study, we investigated the interaction of [45/-45]₂ wounded composite tubes with the fluid flows suddenly pressurized to 5 Bar, 10 Bar, and 15 Bar at the ambient temperatures of 24℃, 66℃, and 82℃, respectively. Numerical analyzes were performed under each temperature and pressure condition and the results were compared depending on the time in a period and along the length of the tube. The main purpose of this study is to present the effects of the variations in fluid characteristics by temperature and pressure on the structural response. The variation of the thermophysical properties of the fluid directly affects the deformation and stress in the material due to the Wall Shear Stress (WSS) generated by the fluid flow. The increase or decrease in WSS directly affected the deformations. Results show that the increase in deformation is more than 50% between 5 Bar and 10 Bar for the same operating condition and it is more than 100% between 5 Bar and 15 Bar by the increase in pressure, as expected in terms of the solid mechanics. In the case of the increase in the temperature of fluid and ambient, the WSS and Von Mises stress decrease while the slight increases of deformations take place on the tube. On the other hand, two-way FSI modeling is needed to observe the effects of hydraulic shock and developing flow on the structural response of composite tubes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.1
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• pp.23-28
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• 2022

Natural frequency variations in a vehicle-bridge interaction system is examined. The interaction system is designed for a simple beam subject to a moving vehicle. The equation of motion for the system is derived under the quarter-car condition, and numerical simulation is performed. Frequency amplification ratio (FAR) is defined as a ratio between the initial and the varying natural frequency of the system; a discontinuity in the FAR implies a resonance condition. Analysis is mainly focused on patterns, frequency variation characteristics, and discontinuity points of the FAR under the vehicle mass and tire stiffness variations. The result reveals that the interactions between the system affects the natural frequency of both the vehicle and the bridge in similar frequency regions that can be visually identified at the middle of the span using the FAR.

• Child Health Nursing Research
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• v.9 no.2
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• pp.149-161
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• 2003

Purpose: The purpose of this study is to identified patterns and trend of studies and to analyzed the nursing research related to the mother-child interaction in Korea and to improve direction of nursing research in mother-child interaction in Korea. Method: The research studies related to the mother-child interaction were selected from the Korean Nurses Academic Society Journal, and from dissertation, which were conducted between 1961 and 2002 with the consideration of the condition and the cultural specialty of Korea. The total numbers of the studies were 34. These studies were classified according to 1)time of publication or presentation, 2)research design, 3)type of interaction objects, 4)measurement tool, and 5)chief content of studies. Ressult: 1) Until 1984, there was no research studies related to mother-child interaction. The number of studies on the mother-child interaction on the mother-child interaction has been increased rapidly after 1985. The mother-child interaction studies were 13(38.2％) from the doctoral dissertation, 4(11.8％) from the Master's theses and 17(50％) other papers were published in academic journals. 2) Experimental studies of research design was used in these research studies was 13(38.2％). Descriptive studies was 8(23.6％), correlational studies was 4(11.8％) and comparative studies was 4(11.8％). Qualitative study was just one(2.9％) and literature review was 4(11.8％). Especially experimental studies has been increased. 3) Participants of these studies were mother and infant 29(85.5％), father and infant 2(5.9％), mother and fetus 2(5.9％) and nurse and infant 1(2.9％) 4) Utilization of instruments as follows: 13 studies used Walker et al(1986)'s MIPIS (Mother-Infant Play Interaction Scale), 6 studies used Barnard(1978)'s NCAFS (Nursing Child Assessment Feeding Scale), 4 studies used NCATS(Nursing child Assessment Teaching Scale) for assessing mother-infant interaction. 3 studies used Stainton(1981)'s Parent-Infant Interaction Scale. Choi(1987), Kim(1999) and Kim and Son(1997) used measurement tool researcher made which was modified from NCATS (Nursing child Assessment Teaching Scale) and AMIS(Assessment of Mother-Infant Sensitivity Scale). Other tools used to survey influencing factors of interaction. 5) Content of the research studies were classified 3 different types, such as ① studies about the mother-child interactions' pattern, ② studies about influencing factors of the mother-child interaction, ③ studies about effect of nursing intervention program to improve the mother-child interaction. Conclusion: Therefore we make following suggestions which are made based on the above research analysis : 1) In the future research studies need to compare with other area of discipline in mother-child interaction. 2) More attention and in depth research is needed to validate in terms of research design and statistical data analysis. 3) It is important to develop the instruments which is culturally acceptable in Korea society. 4) The results of correlational studies and experimental studies needs to the integrated by meta analysis.

• Women's Health Nursing
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• v.12 no.1
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• pp.5-11
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• 2006

Purpose: The purpose of this study was to analyze the concept, palliation, in order to enhance understanding of palliative care and ultimately lead to the provision of timely quality palliative care. Method: This study used Walker and Avant s methods for concept analysis. Result: The defining attributes of palliation identified in this study were 1) being limited, 2) responsiveness, 3) leading to positive effects, 4) relativity, and 5) being unsettled. The antecedents of palliation were 1) a problematic condition, 2) appropriate management for the problematic condition, and 3) interaction between the problematic condition and the appropriate management. The consequences of palliation included 1) improvement of a problematic condition and 2) dependency on a management of the problematic condition. Conclusion: Although further studies are required to refine the diverse attributes of the concept of palliation, according to this concept analysis of palliation, palliative care should be introduced at the early stage of disease and constantly provided for the improvement of its negative symptoms.

• Women's Health Nursing
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• v.16 no.4
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• pp.381-389
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• 2010

Purpose: The purpose of this study was to analyze the concept seogueulpeum, in order to give a operational definition of middle-aged women's seogueulpeum. Methods: Walker and Avant's methods for concept analysis was used. Results: The defining attributes of seogueulpeum identified in this study were 1) time, 2) negativity, 3) vagueness, 4) passivity, 5) individuality. The antecedents of seogueulpeum were 1) a problematic condition, 2) past event, experiences for the problematic condition, and 3) interaction between the problematic condition and past event, experiences. The consequences of seogueulpeum included 1) to get worse for the problematic condition, 2) passive or active management for the problematic condition. Conclusion: Although further studies are required to refine the diverse attributes of the concept of seogueulpeum, according to this concept analysis of seogueulpeum, this study contribute to explain psychological health of middle-aged women. In addition to develop the adequate interventions decreasing seogueulpeum with aging in women is needed.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1330-1337
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• 2016

A visualization test of the fuel-coolant interaction in the Test for Real cOrium Interaction with water (TROI) test facility was carried out. To experimentally simulate the In-Vessel corium Retention (IVR)- External Reactor Vessel Cooling (ERVC) conditions, prototypic corium was released directly into the coolant water without a free fall in a gas phase before making contact with the coolant. Corium (34.39 kg) consisting of uranium oxide and zirconium oxide with a weight ratio of 8:2 was superheated, and 22.54 kg of the 34.39 kg corium was passed through water contained in a transparent interaction vessel. An image of the corium jet behavior in the coolant was taken by a high-speed camera every millisecond. Thermocouple junctions installed in the vertical direction of the coolant were cut sequentially by the falling corium jet. It was clearly observed that the visualization image of the corium jet taken during the fuel-coolant interaction corresponded with the temperature variations in the direction of the falling melt. The corium penetrated through the coolant, and the jet leading edge velocity was 2.0 m/s. Debris smaller than 1 mm was 15% of the total weight of the debris collected after a fuel-coolant interaction test, and the mass median diameter was 2.9 mm.

• Smart Structures and Systems
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• v.21 no.6
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• pp.777-791
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• 2018

This paper discusses the shape control of deformable mirrors for Adaptive Optics in the dynamic range. The phenomenon of control-structure interaction appears when the mirror becomes large, lowering the natural frequencies $f_i$, and the control bandwidth $f_c$ increases to improve the performance, so that the condition $f_c{\ll}f_i$ is no longer satisfied. In this case, the control system tends to amplify the response of the flexible modes and the system may become unstable. The main parameters controlling the phenomenon are the frequency ratio $f_c/f_i$ and the structural damping ${\zeta}$. Robustness tests are developed which allow to evaluate a lower bound of the stability margin. Various passive and active strategies for damping augmentation are proposed and tested in simulation.

• Korea-Australia Rheology Journal
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• v.21 no.2
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• pp.91-102
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• 2009

This paper describes an extension of viscoelastic Group Interaction Modelling (GIM) to predict the relaxation response of linear, branched and cross-linked structures. This model is incorporated into a Monte Carlo percolation grid simulation used to generate the topological structure during the isothermal cure of a gel, so enabling the chemorheological response to be predicted at any point during the cure. The model results are compared to experimental data for an epoxy-amine systems and good agreement is observed. The viscoelastic model predicts the same exponent power-law behaviour of the loss and storage moduli as a function of frequency and predicts the cross-over in the loss tangent at the percolation condition for gelation. The model also predicts the peak in the loss tangent which occurs when the glass transition temperature surpasses the isothermal cure temperature and the system vitrifies.