• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.103-106
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• 2005

Lattice Boltzmann method is a new numerical method of investigating the fluid flow which have been solved by Navier-Stokes equation recently. It is known that making the single and parallel algorithms of the Lattice Boltzmann equation is easier than those of Navier-Stokes equations. Also, we can simulate the two phase flow using either the 'Interaction Potential model ' introduced by Shan and Chen. In this paper, we first compared the 3D cavity results of Lattice Boltzmann method with other numerical results for validation and showed the 3D phase transition and its simple application by using the ' Interaction Potential model'

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.220-220
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• 2015

Water, energy, and food security already became a risk that threatens people around the world. Increasing of resources demand, rapid urbanization, decreasing of natural resources and climate change are four major problems inducing resources' scarcity. Indeed, water, energy, and food are interconnected each other thus cannot be analyzed separately. That is, for simple example, energy needs water as source for hydropower plant, water needs energy for distribution, and food needs water and energy for production, which is defined as W-E-F nexus. Due to their complicated linkage, it needs a computer model to simulate and analyze the nexus. Development of a computer simulation model using system dynamics approach makes this linkage possible to be visualized and quantified. System dynamics can be defined as an approach to learn the feedback connections of all elements in a complex system, which mean, every element's interaction is simulated simultaneously. Present W-E-F nexus models do not calculate and simulate the element's interaction simultaneously. Existing models only calculate the amount of water and energy resources that needed to provide food, water, or energy without any interaction from the product to resources. The new proposed model tries to cope these lacks by adding the interactions, climate change effect, and government policy to optimize the best options to maintain the resources sustainability. On this first phase of development, the model is developed only to learn and analyze the interaction between elements based on scenario of fulfilling the increasing of resources demand, due to population growth. The model is developed using the Vensim, well-known system dynamics model software. The results are amount of total water, energy, and food demand and production for a certain time period and it is evaluated to determine the sustainability of resources.

• Structural Engineering and Mechanics
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• v.13 no.5
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• pp.505-532
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• 2002

In this study, the analysis of high-speed vehicle-bridge interactions by a simplified 3-dimensional finite element model is performed. Since railroads are constructed mostly as double tracks, there exists eccentricity between the vehicle axle and the neutral axis of cross section of a railway bridge. Therefore, for the more efficient and accurate vehicle-bridge interaction analysis, the analysis model should include the eccentricity of axle loads and the effect of torsional forces acting on the bridge. The investigation into the influences of eccentricity of the vehicle axle loads and vehicle speed on vehicle-bridge interactions are carried out for two cases. In the first case, only one train moves on its track and in the other case, two trains move respectively on their tracks in the opposite direction. From the analysis results of an existing bridge, the efficiency and capability of the simplified 3-dimensional model for practical application can be also verified.

• The Journal of Industrial Distribution & Business
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• v.9 no.4
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• pp.63-72
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• 2018

Purpose - The purpose of this paper is to investigate the effects of online game properties, social interaction, and player satisfaction on intention to online games in Chinese gamers. Research design, data, and methodology - This study is an empirical analysis assuming that properties of online games, social interaction and satisfaction will induce Chinese gamers' intention to play online games. We set the relationship between the six variables as follows. First, the properties of online games, exogenous variables, were identified by three factors: entertainment, security, participation and challenge. Second, we had input social interaction among gamers as another exogenous variables. Third, the gamer's satisfaction of online games was added to the research model as a mediating variable between exogenous variables and endogenous variables. Finally, gamer's intention to play influenced by satisfaction and social interaction was used as final endogenous variable. The data used for the empirical analysis were collected through questionnaires for Chinese under age 35 who enjoy the online games. The data used in the research were finally extracted from 195 questionnaires. The collected data were tested through the analysis of the measurement model (Step 1) and the analysis of the structural model (Step 2). The covariance structure equation model (SEM) was used for the analysis. The measurement model and structural model were evaluated by the maximum likelihood method. Results - The results of the empirical analysis are as follows. The satisfaction of online games were entertainment and security had a significant effect to satisfaction; but participation and challenge and social interaction had no significant effect on satisfaction. The social interaction among gamers and the satisfaction with online games have a significant influence on the intention to play online games. As a result, the attributes of the game were affecting the intention to play the game after satisfaction. Social interaction influenced the intention to play online games rather than satisfaction itself. Conclusions - This study provide some practical implications for the new companies who want to enter the online game industry and seek to competitiveness in China, and provide theoretical implications on the role of interaction among gamers in the study of online games.

• Journal of Information Technology Services
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• v.19 no.1
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• pp.159-172
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• 2020

The purpose of this study is to examine the structural relationship among factors affecting learning engagement, satisfaction, continuance intention in China-MOOC. For this study, data were collected from 334 students who were taking MOOC classes. and structural equation model ling analyses were employed to examine the causal relationships among variables. From the results of this study, First, self-regulated learning and interaction significantly affected learning engagement. Second, interaction had direct effects on satisfaction. Third, satisfaction significantly affect continuance intention. Furthermore, satisfaction mediated relationships between interaction and continuance intention. These results imply that self-regulated learning, interaction, learning engagement should be considered for designing and implementing China-MOOC learning. Further implication are discussed in the study.

• Journal of Computing Science and Engineering
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• v.8 no.1
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• pp.17-24
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• 2014

In this paper, we propose a new implementation of a failure detector. The implementation uses a dual model of heartbeat and interaction. First, the heartbeat model is adopted to shorten the detection time, if the detection process does not receive the heartbeat message in the expected time. The interaction model is then used to check the process further. The expected time is calculated using the exponential smoothing method. Exponential smoothing can be used to estimate the next arrival time not only in the random data, but also in the data of linear trends. It is proven that the new detector in the paper can eventually be a perfect detector.

• Korean Journal of Childcare and Education
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• v.15 no.2
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• pp.59-76
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• 2019

Objective: The purpose of this study was to analyze the structural relationship and influence of parents' family interaction, parenting efficacy, and child internalizing and externalizing problem behaviors. Methods: 1,418 children and their parents, and survey data from a panel study on Korean children (2014), were used to analyze the structural equation model. Results: First, the mother's family interaction had direct influence on their parenting efficacy, as well as their child's internalization and externalization. Second, the father's family interaction had a direct influence only on the internal problem behaviors of the child, and child external problem behaviors were influenced through the father's parenting efficacy. Third, parenting efficacy mediated the effects of family interaction on the problem behavior of children. Especially, the father's family interaction was found to affect child variables through the mother's parenting efficacy. Finally, the internalizing problem behaviors of the child mediated the effects of the parents' family interaction and parenting efficacy on child externalizing problem behaviors. Conclusion/Implications: The results of this study are significant in that the factors of father, mother, and child are interrelated, and that parent interaction has varying influence on the problems of their children.

• Coupled systems mechanics
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• v.7 no.6
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• pp.649-668
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• 2018

In this paper, we present a numerical model for fluid-structure interaction between structure built of porous media and acoustic fluid, which provides both pore pressure inside porous media and hydrodynamic pressures and hydrodynamic forces exerted on the upstream face of the structure in an unified manner and simplifies fluid-structure interaction problems. The first original feature of the proposed model concerns the structure built of saturated porous medium whose response is obtained with coupled discrete beam lattice model, which is based on Voronoi cell representation with cohesive links as linear elastic Timoshenko beam finite elements. The motion of the pore fluid is governed by Darcy's law, and the coupling between the solid phase and the pore fluid is introduced in the model through Biot's porous media theory. The pore pressure field is discretized with CST (Constant Strain Triangle) finite elements, which coincide with Delaunay triangles. By exploiting Hammer quadrature rule for numerical integration on CST elements, and duality property between Voronoi diagram and Delaunay triangulation, the numerical implementation of the coupling results with an additional pore pressure degree of freedom placed at each node of a Timoshenko beam finite element. The second original point of the model concerns the motion of the outside fluid which is modeled with mixed displacement/pressure based formulation. The chosen finite element representations of the structure response and the outside fluid motion ensures for the structure and fluid finite elements to be connected directly at the common nodes at the fluid-structure interface, because they share both the displacement and the pressure degrees of freedom. Numerical simulations presented in this paper show an excellent agreement between the numerically obtained results and the analytical solutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.4984-4993
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• 2012

This study was initiated with the need of studies to promote learning and use of collaboration skills that learners should have in collaborative learning in CSCL. The researcher carried out research on 96 students taking the course of 'educational methods and educational technology' in K collage to take a look at the impact of prior training on collaboration in CSCL and interaction of types of collaborative scripts. To answer the first research question, the scores of each group's chatting in collaborative learning process and messages represented in the process of task performance based on collaborative skills were measured and analyzed. In addition, to answer the second research question, the scores of each group's shared mental model formulation based on relevant evaluation standards were analyzed. This study results, First, there was no significant difference in the acquisition of collaboration skills caused by interaction of prior training on collaboration and collaboration skills and collaborative scripts. However, it turned out that types of collaborative scripts give significant impacts on acquisition of collaboration skills. Second, there was also no significant difference between prior training on collaboration and the formulation of shared mental model by the interaction of collaborative scripts. However, it is showed that types of collaborative scripts have significant impacts on the formation of shared mental model.

• Korean Journal of Childcare and Education
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• v.16 no.6
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• pp.185-202
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• 2020

Objective: The purpose of this study is to analyze the mediating effect of teacher's ego resilience in the relationship between the social support of colleague teachers and teacher-child interaction. Methods: A survey was conducted on 181 teachers working at early childhood education institutions located in Gyeonggi and Chungbuk regions. The structural equation model was verified with the Mplus 6.0 program. Results: First, the social support of colleague teachers directly affects teacher's ego-resilience and teacher-child interaction, and teachers ego-resilience has a significant effect on teacher-child interaction. Second, the teachers ego-resilience was found to be partially mediated in the relationship between the social support of fellow teachers and teacher-child interaction. With bootstrapping, the mediating effect of teachers ego-resilience was found to be statistically significant between the social support of colleague teachers and teacher-child interaction. Conclusion/Implications: Social support of fellow teachers plays an important role in the positive expression of teacher-child interaction, and the quality of relationships with children can be further enhanced by promoting teachers ego-resilience that mediates the two variables.