• Composites Research
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• v.24 no.1
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• pp.10-16
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• 2011

Many tests are required to predict the fatigue life of composite laminates made of various materials and having different layup sequences. Aiming at reducing the number of tests, a methodology was presented in this paper to predict fatigue life of composite laminates based on fatigue life prediction of constituents, i.e. the fiber, matrix and interface, using micromechanics of failure. For matrix, the equivalent stress model which is generally used for isotropic materials was employed to take care of multi-axial fatigue loading. For fiber, a maximum stress model considering only stress along fiber direction was used. The critical plane model was introduced for the interface of the fiber and matrix, but fatigue life prediction was ignored for the interface since the interface fatigue strength was presumed high enough. The modified Goodman equation was utilized to take into account the mean stress effect. To check the validity of the theory, the fatigue life of three different GFRP laminates, UDT[$90^{\circ}2$], BX[${\pm}45^{\circ}$]S and TX[$0^{\circ}/{\pm}45^{\circ}$]S was examined experimentally. The comparison between predictions and test measurements showed good agreement.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.423-430
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• 2013

In this research, a paramteric study to account for the effect of interfacial strength and nanotube agglomeration on the elastoplastic behavior of carbon nanotube reinforced polypropylene composites is performed. At first, the elastoplastic behavior of nanocomposites is predicted from molecular dynamics(MD) simulations. By combining the MD simulation results with the nonlinear micromechanics model based on the Mori-Tanaka model, a two-step domain decomposition method is applied to inversely identify the elastoplastic behavior of adsorption interphase zone inside nanocomposites. In nonlinear micromechanics model, the secant moduli method combined with field fluctuation method is used to predict the elastoplastic behavior of nanocomposites. To account for the imperfect material interface between nanotube and matrix polymer, displacement discontinuity condition is applied to the micromechanics model. Using the elastoplastic behavior of the adsorption interphase zone obtained from the present study, stress-strain relation of nanocomposites at various interfacial bonding condition and local nanotube agglomeration is predicted from nonlinear micromechanics model with and without the adsorption interphase zone. As a result, it has been found that local nanotube agglomeration is the most important design factor to maximize reinforcing effect of nanotube in elastic and plastic behavior.

• Journal of the Korean association of regional geographers
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• v.9 no.3
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• pp.297-313
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• 2003

Problems caused by the U.S. military bases have attracted little attention until recently due to the national security of S.Korea and the peace of North-Eastern Asia, emphasized from the perspective of macro-geopolitics. However, since the political regime has been democratized and political discourses have been liberalized from the 1990s, those problems become a nation-widely serious social issue, though they have been brought about on the local areas. Thus, it can be suggested that micro-geopolitics is highly relevant and significant in approaching the local problems caused by the U.S. military bases, and ultimately resolving the macro-geopolitical problem of longstanding unfair relations in the SOFA and the withdrawal of U.S. troops. This paper aims to consider local problems caused by the U.S. military bases and resolving strategies from the perspective of micro-geopolitics. First of all, it discusses some significance of the micro-geopolitical perspective, as it has been recently emphasized in political geography in considering local problems and politics of life on the basis of place, then looks on empirically criminal and environmental problems caused by the U.S. military bases, analyses the questionnaire date on the perception of local dwellers around the military camps in Nam-gu Daegu, and finally suggests strategies to resolve those problems, which level up from the micro to the macro-scale of geopolitics.

• Journal of Hospice and Palliative Care
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• v.22 no.1
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• pp.30-38
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• 2019

Purpose: This study analyzed a path through which factors influencing death anxiety in the community-dwelling elderly, assuming personal organismic factors and microsystemic factors based on the ecology model purported by Belsky (1980). Methods: This study was performed with 189 elderly people. Data were collected through a self-report questionnaire. The data were analyzed using the SPSS and AMOS programs. Results: The factors influencing death anxiety in the elderly were depression, family support, social network, and familism value, and the explanatory power of these variables was 22%. Death anxiety increased with higher depression, higher familism value, larger social network, and lower family support. Spiritual well-being and elderly discrimination experience had indirect effects on death anxiety, and these effects were mediated by depression. Conclusion: Depression, family support, social network, and familism value were found to influence death anxiety in the elderly, and the strongest effect came from depression. To reduce death anxiety in the elderly, it is important to improve their relationship with their family and friends. Moreover, support should be provided by establishing local systems, and intervention should be provided to alleviate depression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.433-442
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• 2021

This study analyzed the housing market before and after the New Stay movement which was introduced in 2015. In this study, the territories having a New Stay Project and non-involved territories were analyzed based on the apartment price changes according to supply for 12 months before and after the movement date. This study used the difference-in-differences statistical technique. A comparison was carried out in Michuhol-gu, Incheon between Dowha-dong where a New Stay Project was executed, and Sungeui-dong where no project was executed, based on the movement date. It was seen that the price level in the former territory was higher than the latter demonstrating that the introduction of the New Stay Project in Dowha-dong lowered the apartment prices nearby (Sungeui-dong). A comparison in Gwonseon-gu, Suwon between Omogcheon-dong where a New Stay Project was executed and Gosaek-dong where there was no such project, based on the movement date showed that the introduction of the New Stay Project in Omogcheon-dong seemed to lower or stabilize the apartment prices nearby (Gosaek-dong). These results imply that the apartment prices in nearby areas can be stabilized if the supply volume of company-type rental houses is increased.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.109-119
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• 2018

This study investigates the effect of urban and architectural forms on the microclimate in urban areas. It applies urban and architectural elements such as urban form and tissue and building form and characteristics as the main influences on the microclimate within urban area. Among the 23 Automated Weather Stations (AWS) installed within Seoul city by the Korea Meteorological Administration, 6 sites were selected for the analysis, based on their different urban and architectural characteristics, and actual measurements were conducted in August 2017 using individual AWS equipment. Also, the measurements of microclimate and urban and architectural elements within a 500m radius of the AWS measurement points were collected and analyzed. The result of the analysis shows that the microclimate elements, such as wind speed, solar radiation, and temperature, were affected by the direction of the streets, the width, depth, and height of the buildings, the topographic elevation and direction and the traffic volume. This study is expected to contribute to mitigating urban heat island effect and setting the foundation for sustainable cities through development of urban management methods and techniques including the relationship between built environment elements and microclimate.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.356-357
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• 2009

• The magazine of the Korean Society for Advanced Composite Structures
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• v.4 no.3
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• pp.17-23
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• 2013

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.144-145
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• 1992

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2009.10a
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• pp.128-131
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• 2009