• 가정과삶의질연구
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• 제32권3호
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• pp.157-177
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• 2014

The purpose of this study was to investigate the contexts in which employed mothers with young children consider leaving the labor force. We used a mixed methods design, which integrates the findings of quantitative and qualitative analyses, to better understand the dynamics underlying employed mothers' intentions to leave the labor force. The participants of both quantitative (N = 324) and qualitative (N = 16) data were married mothers who were employed full-time and had at least one child younger than elementary-school age at the time of data collection. Both the quantitative analysis of logistic regression and the qualitative thematic analysis revealed that the child's age, the husband's income, the utilization of child care by relatives, the mother's job involvement, family-to-work role conflict, and other costs and rewards of participation in the work force were the important contexts where employed mothers considered leaving the labor force. The quantitative analysis uniquely found that being employed at a workplace with flexible work hours were associated with lower odds of considering exit from the labor market. The qualitative analysis highlighted that the decision to leave the labor force or to stay in it is a complicated issue that almost all employed mothers potentially face at some point in their careers. These findings suggest that policy support is warranted to help employed mothers with young children remain in the workforce when they wish to.

• 한국실내디자인학회논문집
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• 제15권6호
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• pp.68-76
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• 2006

Founding himself on 'The Principle of Self-making' that is the instrument of 'the natural construction' and accomplishing the various interdisciplinary researches, Frei Otto could explicate the fundamental structure of life that is able to make visible the self-making processes in the nature, the technique and the architecture. It is the flexible pneumatic construction that is grounded on the fibrous organization. This was a milestone not only for him who wanted to put the idea of the new architectural form into practice, but also for the contemporary architecture that faces on the style-pluralistic disorientedness. The architectural form of the natural construction includes in itself three constitutional sub-ideas. One of them is 'the adaptable architecture', which is inclined to the architecture similar to the organization of human body, and the other 'the light architecture' that is in the pursuit of the optimal form through the minimal material. The last one is 'the ecological architecture' that aims to realize the optimal dwelling environment based on the effective energy consumption by accumulating knowledges of the always fluid and unstable nature. With these architectural ideas Frei Otto could develop a new architectural form language 'the light architecture of the natural construction'. This study is purposed to explain the various experiments that were made by his team and the basic principles of the structural dynamics of 'the architecture of the natural construction' and then to analyze the structures that were built on the ground of those principles.

• Structural Engineering and Mechanics
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• 제42권6호
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• pp.831-847
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• 2012

Impact from water-borne debris during tsunami and flood events pose a potential threat to structures. Debris impact forces specified by current codes and standards are based on rigid body dynamics, leading to forces that are dependent on total debris mass. However, shipping containers and other debris are unlikely to be rigid compared to the walls, columns and other structures that they impact. The application of a simple one-dimensional model to obtain impact force magnitude and duration, based on acoustic wave propagation in a flexible projectile, is explored. The focus herein is on in-air impact. Based on small-scale experiments, the applicability of the model to predict actual impact forces is investigated. The tests show that the force and duration are reasonably well represented by the simple model, but they also show how actual impact differs from the ideal model. A more detailed three-dimensional finite element model is also developed to understand more clearly the physical phenomena involved in the experimental tests. The tests and the FE results reveal important characteristics of actual impact, knowledge of which can be used to guide larger scale experiments and detailed modeling. The one-dimensional model is extended to consider water-driven debris as well. When fluid is used to propel the 1-D model, an estimate of the 'added mass' effect is possible. In this extended model the debris impact force depends on the wave propagation in the two media, and the conditions under which the fluid increases the impact force are discussed.

• Journal of Ginseng Research
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• 제44권5호
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• pp.690-696
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• 2020

Background: As the main metabolites of ginsenosides, 20(S, R)-protopanaxadiol [PPD(S, R)] and 20(S, R)-protopanaxatriol [PPT(S, R)] are the structural basis response to a series of pharmacological effects of their parent components. Although the estrogenicity of several ginsenosides has been confirmed, however, the underlying mechanisms of their estrogenic effects are still largely unclear. In this work, PPD(S, R) and PPT(S, R) were assessed for their ability to bind and activate human estrogen receptor α (hERα) by a combination of in vitro and in silico analysis. Methods: The recombinant hERα ligand-binding domain (hERα-LBD) was expressed in E. coli strain. The direct binding interactions of ginsenosides with hERα-LBD and their ERα agonistic potency were investigated by fluorescence polarization and reporter gene assays, respectively. Then, molecular dynamics simulations were carried out to simulate the binding modes between ginsenosides and hERα-LBD to reveal the structural basis for their agonist activities toward receptor. Results: Fluorescence polarization assay revealed that PPD(S, R) and PPT(S, R) could bind to hERα-LBD with moderate affinities. In the dual luciferase reporter assay using transiently transfected MCF-7 cells, PPD(S, R) and PPT(S, R) acted as agonists of hERα. Molecular docking results showed that these ginsenosides adopted an agonist conformation in the flexible hydrophobic ligand-binding pocket. The stereostructure of C-20 hydroxyl group and the presence of C-6 hydroxyl group exerted significant influence on the hydrogen bond network and steric hindrance, respectively. Conclusion: This work may provide insight into the chemical and pharmacological screening of novel therapeutic agents from ginsenosides.

• 한국해양환경ㆍ에너지학회지
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• 제17권1호
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• pp.20-26
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• 2014

조류발전 터빈의 효과적인 설계를 위해서는 날개의 변형을 고려한 해석이 필요하다. 날개에 가해지는 유체 하중은 날개 구조를 변형시키고, 터빈의 성능에 영향을 초래한다. 본 연구에서는 수평축 조류발전 터빈의 단독성능을 해석하는 전산유체역학 해석 절차를 개발하였다. 개발한 절차를 이용하여 조류발전 터빈의 성능을 예측하였고 실험결과와 비교하여 검증하였다. 검증된 전산유체역학 방법을 이용하여 복합재 터빈 날개에 대한 유체-구조 연성해석을 수행하였고 강체로 이루어진 터빈 날개에 대한 전산유체역학 해석 결과와 비교하였다.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.121-128
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• 2005

In most researches on the ride comfort analysis of passenger vehicles, the flexibility of the vehicle body has been not considered as an important factor, because the resonance frequencies of the vehicle body related to pitching, yawing and rolling motions are below 10Hz while the resonance frequencies of the vehicle body related to the flexibility are above 20Hz approximately. Nevertheless, the paper shows that the consideration of the local flexibility (or local stiffness) of the 4 corners on which shock absorbers are mounted influences the ride comfort. A simple beam model is devised to qualitatively examine the effect of the change of the local stiffness of the vehicle body on the ride comfort. Based on the results obtained from the analysis of the one-dimensional model, multi-body dynamic analysis considering the flexibility of the vehicle body is performed using ADAMS and MSC/NASTRAN. Natural frequencies and mode shapes computed by MSC/NASTRAN are used as input data for multi-body dynamic analysis in ADAMS. Through simulations using ADAMS, it has been found that the ride comfort can be improved by changing the local stiffness of the vehicle body and that the simulation results agree with experiment results.

• 정보화정책
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• 제20권1호
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• pp.61-84
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• 2013

이 연구는 중국이 인터넷에서 반체제 정보유입을 어떻게 차단하는지 기술적인 부분에 초점을 두어 인터넷 통제 메커니즘을 규명하였다. 중국은 경제적 이익 때문에 북한이나 쿠바처럼 전면적으로 인터넷 통제를 하기보다는 하드웨어 기반의 기술 통제와 노동 집약적인 물리적 통제를 병행함으로써 당-국가 체제를 위협할 수 있는 행위자 출현에 대비하고 있다. 이에 대한 일환으로 중국 정부는 인터넷을 이용해 시위 확산에서 민주화로의 이행에 연결고리가 될 수 있는 반체제 정보 차단에 심혈을 기울이고 있다. 본 논문은 우선 보편적인 인터넷 통제의 개념과 국가별 유형에 대해 알아보았다. 그런 다음 중국의 인터넷 통제 기술이 어떤 과정을 거쳐 발전되었는지, 90년대부터 현재까지 인터넷 통제 방법을 다각도로 고찰해 보았다. 마지막으로 집단시위 이슈에 따라 인터넷 정보가 어떻게 차단되고 표출되는지 중앙정부와 지방정부 간의 역학 관계로 분석하였다. 이러한 분석을 바탕으로 향후 중국에서 정보화 기기를 이용한 파급적인 인민의 저항이 발생한다 하여도 대규모 물리력과 기술력을 동원한 중국정부의 유연한 통제를 전망할 수 있을 것이다.

• 대한기계학회논문집A
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• 제37권12호
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• pp.1559-1565
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• 2013

고가가이드웨이를 주행하는 상전도흡인식 자기부상열차(EMS-Type Maglev)는 가이드웨이의 유연성으로 인하여 전자석 현가시스템과 동적 상호작용을 일으켜 부상공극에 영향을 미친다. 특히, 전체 건설비를 줄이기 위하여 경량화 가이드웨이를 지향하면서 시스템 설계단계부터 차량과 가이드웨이 사이의 동적상호작용 해석에 의한 심도 있는 부상공극 분석이 더욱 필요하다. 본 논문에서는 보다 정교한 차량/가이드웨이 동적상호작용 해석모델이 제안된다. 제안된 모델은 가상시제 기반의 3 차원 전체차량, 모달합성법에 의한 유연 가이드웨이 및 피드백 제어기가 포함된 부상전자석의 동적 모델들이 하나로 통합된 것이다. 제안된 모델을 도시형 자기부상열차에 적용하여 차량의 속도와 레일조도가 부상공극 및 가이드웨이에 미치는 영향을 분석하였다.

• 한국항공우주학회지
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• 제47권10호
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• pp.705-711
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• 2019

전개형 반사판 안테나의 전개거동 특성을 해석적 그리고 실험적 방법으로 분석하고자 한다. Kane 방정식을 이용하여 전개형 안테나의 다물체 운동방정식을 공식화하였다. 복합재료 반사판의 구조변형 특성을 살펴보기 위해 FSDT(First-order Shear Deformation Theory)를 이용하여 빔 모델로 유한요소 정식화 하였다. 역진자 모델을 이용하여 안테나 전개시간에 따른 스프링 상수 그리고 댐핑 계수들을 결정하였다. 다물체 동력학 해석을 통하여 설계변수에 따른 안테나 반사판의 동적구조 특성을 확인하였고, 무중력 모사 전개실험을 통하여 해석결과 검증 및 거동특성을 실험적으로 관찰하였다.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.41-46
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• 2018

The context of innovation in which we evolve today, subtracts us in a spacial reality and virtuality (digital) that aimed less and less to interact with natural processes which could converge to new possible relationships in the world. We constantly live in presence of fluctuations and imperceptible natural energies (wind, solar radiation, etc.) defined by flows, their own physicality, which remains without being virtual, elusive. This study first outlines how these energies already exploited within the framework of production, could be thought as interactive of our habitat's space dimension, as a prolongation of a physical and material environment built by men and for men, giving rise to new social, cultural dynamics, and making natural complexity of our space vivid, comprehensible with new visual and physical clues. In recent days, where lifestyles are changing, architecture no longer needs to limit its scope of creation to only built structures. Based on a deeper understanding of human and through new potential advanced technologies (kinetic system, etc), it is time to fundamentally diagnose what environments or devices contribute to our lives. Architecture becomes ${\ll}interface{\gg}$, step up its fundamental role, and newly defines the sturdy image and tectonics of existing environment, establishing a stance to search for a new typology. In the end, building will show two simultaneous and distinctive connections related to its physical existence: reality in its function and irreductibility, in its ability to forge new dynamic connections with its environment, hybridizing the spatial dimension to a new form of physicality, adaptive and incessantly flexible in the dimension time, becoming a vessel for ever changing contemporary lifestyles.