• Coupled systems mechanics
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• v.7 no.1
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• pp.79-93
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• 2018

The process of material failure i.e. cracks development and their propagation in an experiment related to the bending collapse of cross laminated timber plate with ribs is described. Numerical simulation of such an experiment by the nonlinear finite element method is presented. The numerical model is based on Hashin failure criteria, initially developed for unidirectional composites, and on material softening concept applied by the smeared crack approach. It is shown that such a numerical model can be used for an estimation of the limit load and the limit displacement of a cross laminated timber ribbed plate.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.85-93
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• 2004

Electric vehicle body has to be subjected to uniform load and requires auxiliary equipment such as air pipe and electric wire pipe. Especially, the cross beam supports the weight of passenger and electrical equipments. This need to use adaptive design in initial design stage to gain economy through interchangeability between many kinds of components. This study performs the topology optimization by the concept of homogenization based on optimality criteria method which is efficient for the problem with a number of boundary condition and design variable. Therefore this provides the method to determine the optimum position and the shape of circular hole in the cross beam and then can achieve the weight minimization of electric vehicle body.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.40-45
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• 1996

A new concept of equivalent homogenization is proposed. The concept employs new set of homogenized parameters: homogenized cross sections (XS) and interface matrix (IM), which relates partial currents at the celt interfaces. The idea of interface matrix generalizes the idea of discontinuity factors (DFs), proposed and developed by K.Koebke and K.Smith. The method of K.Smith can be simulated within framework of new method, while the new method approximates heterogeneous cell better in case of the steep flux gradients at the cell interfaces. The attractive shapes of new concept are: improved accuracy, simplicity of incorporation in the existing codes, equal numerical expenses in comparison to the K.Smith's approach. The new concept is useful for: (a) explicit reflector/baffle simulation; (b) control blades simulation; (c) mixed UO2/MOX core simulation, The offered model has been incorporated in the finite difference code and in the nodal code PANBOX. The numerical results show good accuracy of core calculations and insensitivity of homogenized parameters with respect to in- core conditions.

• Journal of the Korean earth science society
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• v.24 no.7
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• pp.614-624
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• 2003

The purpose of this study was to examine the effectiveness of utilizing a concept map as an instructional strategy to promote student achievement through semantical learning in elementary school on volcanoes. To analyze student achievement in understanding the concept of volcano, quantitative and qualitative analyses were performed through a written test for two different groups that were composed of 80 sixth-grade students: a control group that attended class using the conventional strategy and an experimental group that attended class using concept maps. The results of this study were as follows: First, the use of concept maps in class is effective in learning because of the higher understanding of the group that was using concept maps in the achievement assessment. Second, in their post-instructional understandings, no significant differences are shown between middle- and low-ranking students statistically, but a significant difference is shown between high- and low-ranking students or between high- and middle-ranking students. This indicates that the use of concepts maps in a class is more effective for the middle- and low-ranking students than for the high-ranking students. Third, in the repetitions of classes, the students learning with an aid of concept maps became accustomed to structuring the concepts of their learning subject in categories of relationships, hierarchies, cross-links, and examples easily.

• Korea Trade Review
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• v.44 no.1
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• pp.207-220
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• 2019

In the context of export-oriented growth strategy, Korea has promoted the conclusion of FTAs and 16 FTAs have entered into force or concluded so far. Despite of these efforts, the expansion of the global value chain (GVC) has resulted in fragmentation of production processes and international companies have been struggling to meet the criteria for determining the rule of origin. In order to overcome these difficulties, some foreign FTAs have been introducing cross-cumulation of origin. In this paper, we try to examine empirically whether the easing of the rules of origin using cross-cumulation contributes to the increase in actual value-added exports. we quantify the effects of cross-cumulation included in the EU-Vietnam FTA on Korean exports of the textile through a gravity model using the concept of value-added export. Based on the analysis results, the proportion of value-added exports in Vietnam increased by adoption of cross-cumulation of origin, which consequently resulted into an increase in total exports. This paper tries to draw several implications for the rules of origin in Korea's FTAs including cross-cumulation considering the export value chain of Korea.

• Journal of The Korean Association For Science Education
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• v.36 no.6
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• pp.815-833
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• 2016

This study investigated children's (grade 3 to 9) responses to assessment items on energy as a cross-cutting concept in order to get basic information for a learning progression. The assessment consisted of 8 ordered multiple-choice items at the contexts of electric circuit, mechanical energy of falling objects, phase change of matter, dissolution, biological phenomena of a lizard, food chain, radiative equilibrium between Sun and Earth, and the system of water cycling. Children's responses to each item were analyzed with using cross-tabulations in terms of grades and item option levels and Wright map and Differential item functioning based on Rasch modeled item response analysis. The results offered empirical evidence of children's development of understanding energy from relation between energy and its phenomena, types of energy, transfer and conversion of energy, towards conservation and equilibrium of energy for all of eight contexts. Children of each grade did not fully understand energy conservation. As grade goes up, their understandings of energy transfer and conversion were differentiated across the contexts and topics of energy. According to Rasch analysis, children had easier understanding of energy on dissolution and poorer understanding of energy on water cycling than that on other contexts. It was discussed and suggested that the results of this study help us organize science topics with regard to energy when developing new national science curriculum.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.13-24
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• 2002

This study examined the knowledge structure constructed by children before formal instruction, and successive changes in the structural complexity of knowledge during the learning of the 'Structure and Function of Plants' unit. The researchers let the 5th graders draw the first draft of their concept maps in order to examine the pre-existing knowledge structure concerned with the unit and also four concept maps after completing every fourth lesson. Each concept map drawn by children on the basis of the previous one showed the degree of their current understanding on the structure and function of plants. The results revealed that only two levels of hierarchy and five relationships among the components of the first concept map(relationship, hierarchy, cross link and example) were proven to be valid in terms of conceptual relevance. According to the standard map, there was no change in hierarchy from the 2nd to the 3rd map, and in example from the 2nd to the 4th map. However, the gradual and successive increases of the scores in all components appeared in the children's maps throughout the unit. Knowledge restructuring occurred strongly in the early periods from the 1st to the 6th lesson, and the significant stable changes in tuning and accretion appeared throughout the whole lessons. The results also showed that there were no significant gender differences on the 5th grader's knowledge structuring.

• Management & Information Systems Review
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• v.32 no.3
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• pp.221-245
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• 2013

The purpose of this study is to examine the factors leading resilience and to investigate the impact of the adaptive performance. The results are as follows: First, Cognitive Flexibility, Self Concept Clarity and Learning Goal Orientation were proved as antecedents predicted to resilience. Second, Cognitive Flexibility had positive effects on all sub variables on adaptive performance and Prove Goal Orientation had positive effects on some sub variables on adaptive performance such as problem solving, cope with uncertainty, cross cultural adaptability. Self Concept Clarity had positive effects on some sub variables on adaptive performance such as problem solving, handle crisis, cross cultural adaptability. Third, Resilience mediated the relationship between Cognitive Flexibility and Adaptive Performance(problem solving, handle crisis, cross cultural adaptability). The hypotheses of the mediation effect of resilience between Goal Orientation, Self Concept Clarity and Adaptive Performance were rejected. Lastly, this study emphasized and verified the importance of resilience in process of adaptive performance. Future studies should be looked for broad variety of resilience factors.

• Journal of the military operations research society of Korea
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• v.33 no.2
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• pp.61-73
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• 2007

We examined technological forecasting of extended TFDEA(Technological Forecasting with Data Envelopment Analysis) and thereby apply the extended method to the technological forecasting problem of main battle tank. The TFDEA has the possibility of using comparatively inefficient DMUs(Decision Making Units) because it is based on DEA(Data Envelopment Analysis), which usually leads to multiple efficient DMUs. Therefore, TFDEA may result in incorrect technological forecasting. Instead of using the simple DEA, we incorporated the concept of Super-efficiency, Cross-efficiency, and CCCA(Constrained Canonical Correlation Analysis) into the TFDEA respectively, and applied each method to the case study of main battle tank using verifiable practical data sets. The comparative analysis shows that the use of CCCA with TFDEA results in very comparable prediction accuracies with respect to MAE(Mean Absolute Error), MSE(Mean Squared Error), and RMSE(Root Mean Squared Error) than using the concept of Super-efficiency and Cross-efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.821-826
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• 2016

The leak before break (LBB) concept is used in pipe line design for nuclear power plants. For application of the LBB concept, leak rates through cracks should be evaluated accurately. Usually leak late analyses are performed for through-thickness cracks with constant cross-sectional area. However, the cross-sectional area at the inner pipe surface of a crack can be different from that at the outer surface. In this paper, leak rate analyses are performed for the cracks with linearly-varying cross-sectional areas. The effect of varying the cross-sectional area on leak rates was examined. Leak rates were also evaluated for cracks in bi-material pipes. Finally, the effects of crack surface morphology parameters on leak rates were examined.