• 국제초고층학회논문집
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• 제3권1호
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• pp.21-33
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• 2014

The tied braced frame (TBF) system was developed to achieve uniform seismic inelastic demand along the height of multi-storey eccentrically braced steel frames. A modular tied braced frame (M-TBF) configuration has been recently proposed to reach the same objective while reducing the large axial force demand imposed on the vertical tie members connecting the link beams together in TBFs. M-TBFs may however experience variations in storey drifts at levels where the ties have been removed to form the modules. In this paper, the possibility of reducing the discontinuity in displacement response of a 16-storey M-TBF structure by introducing energy dissipating (ED) devices between the modules is examined. Two M-TBF configurations are investigated: an M-TBF with two 8-storey modules and an M-TBF with four 4-storey modules. Three types of ED devices are studied: friction dampers (FD), buckling restrained bracing (BRB) members and self-centering energy dissipative (SCED) members. The ED devices were sized such that no additional force demand was imposed on the discontinuous tie members. Nonlinear response history analysis showed that all three ED systems can be used to reduce discontinuities in storey drifts of M-TBFs. The BRB members experienced the smallest peak deformations whereas minimum residual deformations were obtained with the SCED devices.

• Steel and Composite Structures
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• 제20권5호
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• pp.1155-1171
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• 2016

Post-tensioned (PT) steel moment resisting frames (MRFs) with semi-rigid connections (SRC) can be used to control the hysteretic energy demands and to reduce the maximum inter-story drift (${\gamma}$). In this study the seismic behavior of steel MRFs with PT connections is estimated by incremental nonlinear dynamic analysis in terms of dissipated hysteretic energy ($E_H$) demands. For this aim, five PT steel MRFs are subjected to 30 long duration earthquake ground motions recorded on soft soil sites. To assess the energy dissipated in the frames with PT connections, a new expression is proposed for the hysteretic behavior of semi-rigid connections validated by experimental tests. The performance was estimated not only for the global $E_H$ demands in the steel frames; but also for, the distribution and demands of hysteretic energy in beams, columns and connections considering several levels of deformation. The results show that $E_H$ varies with ${\gamma}$, and that most of $E_H$ is dissipated by the connections. It is observed in all the cases a log-normal distribution of $E_H$ through the building height. The largest demand of $E_H$ occurs between 0.25 and 0.5 of the height. Finally, an equation is proposed to calculate the distribution of $E_H$ in terms of the normalized height of the stories (h/H) and the inter-story drift.

• Smart Structures and Systems
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• 제26권1호
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• pp.89-102
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• 2020

Shape memory alloy (SMA)-based Superelasticity-assisted Slider (SSS) is proposed as an engineering solution to practically exploit the well-accepted advantages of both sliding isolation and SMA-based recentering. Self-centering capability in SSS is provided by austenitic SMA cables (or wire ropes), recently attracting a lot of interest and attention in earthquake engineering and seismic isolation. The cables are arranged in various novel and conventional configurations to make SSS versatile for aseismic design and retrofit of structures. All the configurations are detailed with thorough technical drawings. It is shown that SSS is applicable without the need for Isolation Units (IUs). IUs, at the same time, are devised for industrialized applications. The proof-of-concept study is carried out through the examination of mechanical behavior in all the alternative configurations. Force-displacement relations are determined. Isolation capabilities are predicted based on the decreases in seismic demands, estimated by the increases in effective periods and equivalent damping ratios. Restoring forces normalized relative to resisting forces are assessed as the criteria for self-centering capabilities. Lengths of SMA cables required in each configuration are calculated to assess the cost and practicality. Practical implementation is realized by setting up a small-scale IU. The effectiveness of SSS under seismic actions is evaluated using an innovative computer model and compared to those of well-known Isolation Systems (ISs) protecting a reference building. Comparisons show that SSS seems to be an effective IS and suitable for earthquake protection of both structural and non-structural elements. Further research aimed at additional validation of the system are outlined.

• 한국강구조학회 논문집
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• 제28권4호
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• pp.223-229
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• 2016

이 연구에서는 고무 스프링과 자력마찰을 조합한 스마트 댐퍼의 동적 실험을 수행하여 스마트 댐퍼의 깃발모양 (flag-shaped) 거동을 확인하고자 하였다. 스마트 댐퍼 동적실험을 수행하기 위하여, 네오디뮴 (NdFeB) 자석을 사용하였으며 $50mm{\times}50mm{\times}25mm$ ($B{\times}L{\times}H$)의 크기를 사용하였다. 또한 폴리우레탄 고무를 사용하였으며 길이 80mm 외경 80mm 내경 20mm의 크기의 원주형 고무스프링을 사용하였다. 동적 실험에서 자석의 개수와 진동수를 제어하여 수행하였으며, 자석의 개수는 0, 4, 8, 12개의 순서로 증가하였으며, 이는 자력 마찰력이 증가함을 의미하였다. 진동수는 0.1부터 2.0Hz까지 증가시키면서 진행하였다. 실험의 진행은 고무 스프링이 장착되지 않은 자력마찰 댐퍼의 자력 마찰력 평가 실험, 고무 스프링의 기압축량 평가 실험 및 최종적으로 자력 마찰력과 기압축 고무스프링이 합성된 스마트 댐퍼의 동적 실험 순서로 진행하였다. 실험 결과를 통하여 스마트 댐퍼의 깃발모양 거동을 평가하고 에너지 소산능력, 감쇠비를 평가하여 스마트 댐퍼로서의 성능을 확인하였다.

• 콘크리트학회논문집
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• 제18권4호
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• pp.497-506
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• 2006

본 연구에서는 주상복합건물에 적용가능한 건식공법에 의한 프리캐스트 콘크리트 보-기둥 연결부에 대하여 실험을 통하여 분석하였다. 현재 국내에 활용하고 있는 프리캐스트 콘크리트 보-기둥 연결부와 현재 미국에서 사용되고 있는 DDC 연결부, 그리고 DDC 연결부와 개선된 연결부에 포스트텐션을 도입한 시험체를 제작하였고, 실험을 통하여 그 거동을 평가하였다. 실험 결과 보-기둥 연결부에 DDC 시스템을 적용하게 되면 연결부의 강도와 연성능력의 향상을 기대할 수 있었으나 파괴 메커니즘이 보에 에너지를 분산시키지 않고, 연결부에서 사인장 균열에 의하여 에너지를 소산시키게 되어 연결부가 파괴되는 단점이 나타났다. 개량 DDC 연결부는 기둥에 사인장균열이 발생하지 않고 보다 연성적인 파괴거동을 보여주었다. 또한 보-기둥 연결부에 포스트텐션의 도입은 연결부 강도의 증가는 크게 기대할 수 없었으나 자가조정(self-centering) 등을 통하여 연결부의 안정성 및 연성능력에 기여하는 것으로 나타났다.

• 농촌지도와개발
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• 제17권4호
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• pp.957-984
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• 2010

The aim of this research is to delineate how daily living activities, depression, self-respect, and social activity participation affects the life satisfaction of the rural elderly. The subjects of the research were elderly over-65-year-olds living in Yeoju, Gyeonggido and conducted from November 15 to November 30, 2009. The sampling method was convenience sampling among non-probability sampling, a total of 339 were used as analysis data. The collected data were then put through-frequency analysis, correlation analysis, simple regression analysis, analysis of variance, Kruskal-Wallis, and feasibility verification through SPSS SAS 9.1.3 program. As a result of hypothesis verification, daily living activities have a positive influence over life satisfaction. And the higher the elderly's self-respect, the greater their life satisfaction, and it was verified that depending on social activity participation, there is a difference in their life satisfaction. The purpose of this study is to verify and carry out action plan and ital.

• 아동학회지
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• 제29권1호
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• pp.207-225
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• 2008

This study used content analysis to explore how experience and coping style affect burnout in child-counselors. Data were self-reports collected by interviews of with 30 child counselors. The contents of the interviews showedthe cause of, psychological and physical responses to, and the ways the subjects coped with burnout. The summarized results are that (1) they experience burnoutwhen they feel incompetent, when counseling is ineffective, when they are under-compensated and when they are poorly supervised, (2) The psychological and physical responses to burnout are diminished self-esteem, depression, incompetence, chilling effect on other fields, and digestive problems. (3) Child-counselorscope with burnout mostly by centering on the problems and by searching for social support.

• 한국가정과교육학회지
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• 제14권2호
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• pp.79-95
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• 2002

The Purposes of this study are first to develop the teaching and learning plan for the dress part in high school's Home Economics by the application of the values clarification theory then to apply it to the classroom activities. and lastly to analyze its effects. We developed the master plan for teaching and learning, and developed the 12 hour sub plans including 7 activities and learning materials. The effects of the teaching are as followings: First, When the self-esteem was compared with the whole classes, there was no difference between the twos, but a boy and a girl who were observed as not making a value-oriented life marked higher score in answering the self-esteem. Second. It was found that values clarification theory made student's degree of participation and interest higher and helped them to choose their dresses in the real life.

• Nuclear Medicine and Molecular Imaging
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• 제40권2호
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• pp.106-112
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• 2006

Tissue hyperplasia is one of the most frequently encountered complications when self-expanding metallic stents are placed in benign non-vascular luminal organ strictures, thus causing restenosis of the lumen. The investigators postulated that ionizing irradiation could be applied to prevent restenosis caused by tissue hyperplasia in non-vascular luminal organs as it reduced coronary or peripheral arterial narrowing successfully. The authors combined $\beta$-irradiation using $^{188}Re-MAG_3$ solution with balloon dilation for animal and clinical studies because this new treatment approach had the advantages such as low penetration depth of $\beta$-ray, self-centering irradiation, and mechanical effect of balloon dilation over using $\gamma$-irradiation with afterloading devices in this article, the concept and mechanism of radioisotope balloon dilation, and animal and clinical studies using radioisotope balloon dilation are reviewed.

• 한국정보시스템학회지:정보시스템연구
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• 제15권3호
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• pp.233-252
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• 2006

Recently, negative sides of internet, internet and/or game addiction and unethical behavior over internet, have been largely publicized in our society. There have been numerous studies to explore the problems and solutions, but these lack considering broader set of research variables. Therefore, this research investigated how i) internet users' self characteristics and ii) cognitive characteristics toward internet influence iii) internet addiction and iv) information ethics respectively. Especially, this study focused on college students, more mature beings than elementary, middle and high school students with whom most other researches have dealt so far. Major findings of this study are as follows: (1) Willingness to develop relationships over internet, usefulness of internet use, a degree to perceive the cyber space as real, and a degree to express self over internet have significant effects on disabled life style. Self respect willingness to develop relationships over internet, usefulness of internet use, a degree to perceive the cyber space as real, and capability of using internet have significant effects on the lack of control over internet. Willingness to develop relationships over internet, self control, and a degree to express self over internet have significant effects on the lack of control over internet. 2) Regarding the effects of independent variables(self characteristics and cognitive characteristics) on information ethics through internet addiction factors, self respect self control, a degree to perceive the cyber space as real, and capability of using internet have directly and indirectly significant effects on information ethics through internet addiction. Then we suggested four approaches to reduce the internet addiction and improve the information ethics based on the findings.