• Steel and Composite Structures
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• 제38권6호
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• pp.739-749
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• 2021

This paper introduces an improved design equation to evaluate the resisting capacity of circular reinforced concrete (RC) columns partially strengthened with outer steel tube. When RC column members are required to be strengthened according to the change in the loadings considered and/or the deterioration progress in columns, wrapping up RC column with steel circular tube, which takes the form of concrete filled steel tube (CFST), has been popularly considered because of its structural advantage induced from the confinement effect. However, the relatively high construction cost of steel tube is restricting its use to the required region, while deriving the shape of a partial CFST column. To evaluate the resisting capacity of a partial CFST column, numerical analyses need to be performed, and a numerical model proposed in the previous study for the numerical analysis of full CFST columns is used to conduct parametric studies for the introduction of a design equation. The bond-slip effect developed along the interface between the in-filled concrete and the exterior steel tube is taken into consideration and the validity of the numerical model has been established through correlation studies between experimental data and numerical results for partial CFST circular columns. Moreover, parametric studies make it possible to introduce a design equation for determining the optimum length of outer steel tube which produces partial CFST circular columns.

• Interaction and multiscale mechanics
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• 제6권4호
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• pp.357-375
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• 2013

In this paper, the forced vibration problem of an Euler-Bernoulli beam that is joined with a semi-infinite field of a compressible fluid is considered as a boundary value problem (BVP). This BVP includes two partial differential equations (PDE) and some boundary conditions (BC), which are introduced comprehensively. After that, the closed-form solution of this fluid-structure interaction problem is obtained in the frequency domain. Some mathematical techniques are utilized, and two unknown functions of the BVP, including the beam displacement at each section and the fluid dynamic pressure at all points, are attained. These functions are expressed as an infinite series and evaluated quantitatively for a real example in the results section. In addition, finite element analysis is carried out for comparison.

• Journal of Computational Design and Engineering
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• 제1권4호
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• pp.289-297
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• 2014

Although big-sized markers are good for accurate marker recognition and tracking, they are easily occluded by other objects and deteriorate natural visualization and level of immersion during user interaction in AR environments. In this paper, we propose an approach to exploiting the use of rectangular markers to support tangible AR interaction based on fingertip touch using small-sized markers. It basically adjusts the length, width, and interior area of rectangular markers to make them more suitably fit to longish objects like fingers. It also utilizes convex polygons to resolve the partial occlusion of a marker and properly enlarges the pattern area of a marker while adjusting its size without deteriorating the quality of marker detection. We obtained encouraging results from users that the approach can provide better natural visualization and higher level of immersion, and be accurate and tangible enough to support a pseudo feeling of touching virtual products with human hands or fingertips during design evaluation of digital handheld products.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.332-337
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• 2001

The objective of research is to clarify the interaction between dislocations and precipitates during high temperature creep deformation behaviors of high Mn austenitic steels. After measuring the internal stress in minimum creep rate at 873K, a transmission electron microscope (TEM) observation was performed to investigate the interaction between dislocations and precipitates during high temperature creep deformation. The band width of effective stress and internal stress increased when the nitride precipitates distribute more densely. Fine nitrides disturbed the dislocation movement with pinning the dislocations and perfect dislocations were separated into Shockley partial dislocations by fine nitrides. Coarse nitrides disturbed the dislocation movement with climb mechanism.

• 아동학회지
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• 제36권2호
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• pp.1-16
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• 2015

The purpose of this study is to investigate the effects of father's play beliefs on father-child interaction and child's social skills. The subjects were 370 fathers of 1, 2 and 3 graders of elementary schools who lived in Seoul and Gyeonggi area. The results were as follows; First, the differences were found to be significant between the whole of father's play hours, play focus beliefs, study focus beliefs and father-child interaction, and their sub-variables of disciplinary action, sensitiveness, and affectionate expression; and between the whole of child's social skills and its sub-variables of cooperative action, self-assertion and self-control. Second, the higher play focus beliefs, the more positive interaction on the child, and specifically they use much democratic disciplinary action, sensitiveness and affectionate expression. Third, as to the effect of the father's play focus beliefs on the child's social skills, father-child interaction was found to act as a partial parameter, while as to the effect of the father's study focus beliefs on the child's social skills, father-child interaction was found to act as a full parameter.

• 한국IT서비스학회지
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• 제12권2호
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• pp.195-214
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• 2013

The purpose of this study is to verify the mediating effect of interaction among learners in a Web Based Collaboration Learning (WBCL) environment. 254 Korean college students served as test subjects and during the 4 weeks of research period, they studied the Test of English for International Communication (TOEIC) in a web-based collaborative learning system. The interaction between learners was looked into by categorizing the concept into task oriented information sharing activities and relationship oriented communication activities and analyzing the causal relationship between the two activities. Learning performances were measured in individual level. The results are as follows. First, task oriented information sharing activities effect positively on relationship oriented information sharing activities. Second, the managerial characteristics of WBCL had a positive effect on interaction between learners but the systematic characteristics had partial influence on interaction between learners. Third, the interaction between learners completely interconnects the managerial characteristics of WBCL and learning performance but partially interconnects the systematic characteristic of WBCL and learning performance. In conclusion, this study implies that managerial and systematic characteristics of WBCL should be considered on the preferential basis for the WBCL to become successful and interactive activities such as information sharing and communication should be encouraged to be active from a small-size WBCL perspective.

• Ocean Systems Engineering
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• 제1권4호
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• pp.337-353
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• 2011

In the present study, an offshore platform having large partial porous cylindrical members, which are composed of permeable and impermeable cylinders, is suggested. In order to calculate the wave force on large partial porous cylindrical members, the fluid domain is divided into three regions: a single exterior region, N inner regions and N beneath regions, and the scattering wave in each fluid region is expressed by an Eigen-function expansion method. Applying Darcy's law to the porous boundary condition, the effect of porosity is simplified. Wave excitation forces and wave run up on the structures are presented for various wave conditions. For the idealized three-dimensional platform having large partial porous cylindrical members, the dynamic response evaluations of the platform due to wave forces are carried out through the modal analysis. In order to examine the effects of soil-structure interaction, the substructure method is also applied. The displacement and bending stress at the selective nodal points of the structure are computed using various input parameters, such as the shear-wave velocity of soil, the wave height and the wave period. Applying the Monte Carlo Simulation (MCS) method, the reliability evaluations at critical structure members, which contained uncertainties caused by dynamic forces and structural properties, are examined by the reliability index with the results obtained from MCS.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.861-866
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• 2004

A numerical flow analysis has been performed on the partial admission turbine of KARI turbopump to support the aerodynamic and structural dynamic assessments. The flow-field in a partial admission turbine is essentially three dimensional and unsteady because of a tip clearance and a finite number of nozzles. Therefore the mixing plane method is generally not appropriate. To avoid heavy computational load due to an unsteady three dimensional calculation, a frozen rotor method was implemented in steady calculation. It adopted a rotating frame in the grid block of a rotor blade by adding some source terms in governing equations. Its results were compared with a mixing plane method. The frozen rotor method can detect the variation of flow-field dependent upon the blade's circumferential position relative to the nozzle. It gives a idea of wake loss mechanism starting from the lip of a nozzle. This wake loss was assumed to be one of the most difficult issues in turbine designers. Thus, the frozen rotor approach has proven to be an efficient and robust tool in design of a partial admission turbine.

• 한국보육지원학회지
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• 제12권2호
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• pp.183-200
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• 2016

This study examined the mediating effect of emotional labor in the relations between teachers' emotional intelligence and teacher-child interaction of novice early childhood teachers. The sample consisted of 248 novice early childhood teachers in Gyeonggi Province. The structural equation modeling was conducted using AMOS to test the fit of a hypothesized structural model. The mediating effect of emotional labor was verified by the bootstrapping approach. The results were as follows: First, teacher-child interaction was positively associated with teachers' emotional intelligence and deep acting in emotional labor was negatively associated with surface acting in emotional labor. Next, surface acting in emotional labor had a mediating effect on the relations between emotional intelligence and teacher-child interaction. Finally, deep acting of emotional labor had a partial mediating effect on the relationship between emotional intelligence and teacher-child interaction. Based on these findings, ways to enhance teachers' emotional intelligence in relation to the novice teachers' emotional characteristics, and to improve recognition on emotional labor were discussed.

• 패션비즈니스
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• 제11권3호
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• pp.106-123
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• 2007

The purpose of this research is to study if the images that make-up advertisement tries to symbolize can be altered with changes only in the colors of make-up and without any changes in other factors and if colors can be tools of communication in image. Also, we studied the interaction between the partial changes of eyes and lips. The results are as follows. First, we studied if the images that make-up advertisement tries to symbolize can be altered with changes only in the colors of make-up and without any changes in other factors. The study revealed more or less differences, however, when we applied colors of each image on photos, people had higher recognition on that image more than other images. Therefore, we can conclude that the image can be changed merely with the change from colors of make-up. Second, we changed the make-up colors of lips and eyes separately and studied the interaction of the two. When natural colors and elegant color were applied, there was no interaction of color application between eyes and lips within 0.1 significance level. In the case of romantic colors, there was interaction of applying colors between lips and eyes within 0.1 significance level. When we applied gorgeous colors and modern colors, there was interaction of applying colors between lips and eyes within 0.1 significance level. Therefore, from the interaction of the two, it was recognized to be most gorgeous or most modern when gorgeous colors or modern colors were applied in both lips and eyes.