• 대한기계학회논문집A
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• 제36권12호
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• pp.1613-1618
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• 2012

자동차용 휠 베어링은 동력을 전달하고 차량의 무게를 지지해주는 중요한 부품으로써 너클에 체결된다. 이때 체결 토크에 의하여 시일 압입부와 궤도부를 포함하는 휠 베어링 외륜의 변형이 발생한다. 본 연구에서는 휠 베어링 외륜의 변형을 유한요소법을 이용하여 해석하였다. 상용 소프트웨어 MSC.MARC 를 이용하였고, 외륜, 볼트, 너클의 체결거동을 보다 정확하게 예측하기 위하여 탄소성 해석과 접촉 해석을 수행하였다. 외륜 플랜지는 가공에 따라서 다소 오목하게 형성될 수 있으며, 이는 너클과의 체결 시 틈새 발생을 유발하여 변형에 영향을 줄 수 있다. 따라서, 본 연구에서는 외륜의 오목한 정도를 변화시키면서 변형 해석을 수행하였다. 해석 결과를 검증 하기 위하여 시험을 수행하였고, 해석과 시험 결과를 비교한 결과 비교적 유사함을 알 수 있었다.

• 치위생과학회지
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• 제15권4호
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• pp.518-526
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• 2015

본 연구는 2015년 5~6월 기간 동안 D지역 대학교 학생 483명을 대상으로 성별, 학년별, 전공계열별 자아존중감, 취업, 외모 관련성을 조사하였다. 자아존중감은 1, 4학년에서 높게 조사되었으며 소속계열별 군사경찰대학, 의과(학)대학이 높게 조사되었다. 취업스트레스는 4학년이 가장 높게 조사되었으며 세무경영대학, 의료공과대학이 높게 조사되었다. 취업준비행동은 4학년이 가장 높게 조사되었고 재활복지교육대학이 가장 높았다. 외모관심도와 외모관리행동은 여학생, 4학년이 높게 나타났고 세무경영대학에서 높게 나타났다. 자아존중감 상위군이 하위군보다 취업준비행동, 외모관심도, 외모관리행동 모두 통계적으로 유의하게 높게 나타났고 자아존중감, 취업, 외모의 상관관계 분석결과에서 자아존중감이 높으면 취업준비행동도 높은 것으로 나타났으며 취업 스트레스는 적은 것으로 조사되었다. 그리고 취업스트레스가 높으면 취업준비행동도 많이 하는 것으로 조사되었다. 결론적으로 대학생활에서 자아존중감을 높이는 교육이 취업스트레스를 감소시키고 취업준비행동을 높일 수 있을 것이다.

• 대한원격탐사학회지
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• 제35권5_2호
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• pp.831-840
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• 2019

최근 장대교량의 경간장이 길어지면서 주탑간 거리(span)가 기존의 한계를 넘는 교량에 대해 초장대교량이라는 개념이 새롭게 제시되었다. 또한 장대교량의 구조가 복잡해지고, 안전성이 중요해지면서 시공 중 계측의 필요성이 더욱 커졌다. 하지만 장대교량에 기존 계측센서를 지속적으로 적용하는 데는 한계가 있다. 이에 기존 계측센서들의 한계를 보완하고자 위성항법시스템(GNSS: Global Navigation Satellite System)을 활용하기 위한 연구가 진행되고 있다. 본 연구는 최종적으로 2축경사계, 변형률계, 풍향풍속계와 GNSS를 혼용하여 초장대현수교의 거동 특성을 파악하고, 세부 모니터링 방법을 제시하고자 하였다. 이를 위해 GNSS를 이용하여 주탑의 절대좌표와 교축진행방향을 산출하였고, 장기거동을 분석하여 시공 직후 주탑의 영구 변위와 안정화 여부를 평가하였다. 또한 풍향이 대상교량의 거동에 미치는 영향을 수치적으로 나타냈으며, 이를 통해 대상교량의 거동특성을 분석하였다. 본 연구 결과, GNSS를 활용한 교량 계측은 분석 목적에 따라 데이터 처리가 용이한 것으로 나타났다. 또한, 초장대교량의 유지관리에 있어 기존의 계측센서와 GNSS을 활용한다면 각 계측 데이터의 오차 파악 및 보정을 통한 모니터링 시스템의 개선과 정확한 변위관측, 그리고 거동특성을 함께 파악하는 효과적인 모니터링 시스템을 구축 할 수 있다는 점을 확인할 수 있었다.

• 대한기계학회논문집B
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• 제30권9호
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• pp.905-912
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• 2006

Experiments in low strain rate methane-air counterflow diffusion flames diluted with $CO_2$ have been conducted to investigate the flame extinction behavior and edge flame oscillation in which flame length is less than the burner diameter and thus lateral conductive heat loss in addition to radiative loss could be remarkable at low global strain rates. The critical mole fraction at flame extinction is examined in terms of velocity ratio and global strain rate. It is seen that flame length is closely relevant to lateral heat loss, and this sheets flame extinction and edge flame oscillation considerably. Lateral heat loss causes flame oscillation even at fuel Lewis number less than unity. Edge flame oscillations are categorized into three: a growing-, a harmonic- and a decaying-oscillation mode. Onset conditions of the edge flame oscillation and the relevant modes are examined with global strain rate and $CO_2$ mole fraction in fuel stream. A flame stability map based on the flame oscillation modes is also provided at low strain rate flames.

• 한국가정과학회지
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• 제3권2호
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• pp.101-111
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• 2000

The purpose of this study is to examine needed abilities of Korean apparel merchandisers and to propose a basic design of textbook for an education of Korean apparel merchandisers. For this purpose. the role and needed abilities of Korean apparel merchandisers'. and the contents of other textbooks under same topic were examined. Data of Korean apparel merchandisers'abilities to execute their role were collected by interviewing 7 apparel merchandisers who work for major Korean apparel manufacturers. Korean apparel merchandisers are expected to have following abilities : comprehensive and analytic Judgement. knowledge of clothing and textiles. deep understanding of the apparel market, budget planning and accounting. cooperation in the execution of tasks, ability of summarizing data, healthcare, and computing skills. The textbook is divided into five parts. The titles and brief description of them are as follows : Part I - Introduction Basic concept and composition factors of apparel merchandising and the role of apparel merchandisers in Korean apparel industry will be discussed. Part II - Apparel Merchandising Environment The structure of apparel manufacturers and apparel industries In Korea. other environmental factors, and apparel consumer behavior will be investigated. Part III - Apparel Market Analysis Market segmentation. brand evaluation, product positioning. target market strategies, and market research will be investigated. Part IV- Apparel Merchandising Apparel merchandising processes will be introduced and explained in detail. Part V - Global Apparel Merchandising Global apparel merchandising environment and strategies. and global sourcing and marketing will be discussed.

• Corrosion Science and Technology
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• 제19권4호
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• pp.174-188
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• 2020

Atmospheric corrosion is a natural surface degradation process of metal due to changes in environmental parameters in the surrounding atmosphere. It is very sensitive to environmental parameters such as temperature, relative humidity, sulphur dioxide, and chloride, making it a major global economic challenge. Existing forecasting empirical corrosion models including the ISO standard are based on statistical analysis of experimental studies without considering the behavior of atmospheric parameters. The present study proposes a reliable global empirical model for estimating short and long-term atmospheric corrosion rates based on environmental parameters and corrosion mechanisms obtained from a parametric study. Repercussion of atmospheric corrosion rate due to individual and combined influences of environmental parameters specifies their importance in the estimation. New global empirical coefficients obtained for environmental parameters are statistically established (R² =0.998) with 95% confidence limit. They are validated using experimental datasets of existing studies observed at 88 different continental locations. The current proposed model can predict atmospheric corrosion by means of corrosion formation mechanisms influenced by combined effects of environmental parameters, further abating applicability limitations of location and time.

• Structural Engineering and Mechanics
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• 제58권4호
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• pp.731-743
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• 2016

Plastic behaviors, based on the von Mises yield criterion, of circular discs containing a purely elastic, circular inclusion under uniform temperature loading are studied with the finite element analysis. Temperature-dependent mechanical properties are considered for the matrix material only. In addition to analyzing the plane stress and plane strain disc, a 3D thin disc and cylinder are also analyzed to compare the plane problems. We determined the elastic irreversible temperature and global plastic collapse temperature by the finite element calculations for the plane and 3D problem. In addition to the global plastic collapse, for the elastically hard case, the plane stress problem and 3D thin disc may exhibit a local plastic collapse, i.e. significant pile up along the thickness direction, near the inclusion-matrix interface. The pileup cannot be correctly modeled by the plane stress analysis. Furthermore, due to numerical difficulties originated from large deformation, only the lower bound of global plastic collapse temperature of the plane stress problem can be identified. Without considerations of temperature-dependent mechanical properties, the von Mises stress in the matrix would be largely overestimated.

• Human Ecology Research
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• 제55권2호
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• pp.105-124
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• 2017

The recent global economic crisis has resulted in increased discussion and attention on the sharing economy, a form of economic activity where individuals share currently available products. This study investigates consumer sharing economy usage attitudes and usage intentions by applying rational choice theory. For this study, an investigation that had 400 adult consumers from across Korea answer a structured questionnaire was conducted. A statistical approach using SPSS ver. 22.0 was used to analyze the data. The study found that the consumer's sharing economy value and participation levels were higher than usual. Higher than usual consumption patterns were seen for the construct of rational behavior theory. An analysis of the relative influence of variables regarding sharing economy usage intention also found that usage intention was higher for those who had experienced using a sharing economy services rather than those who did not have experience. In addition, the sharing economy usage intention also increased along with the values for subjective norms, sharing economy usage attitudes, sharing economy participation, sharing economy emotional benefits, and increased values. This study found that fundamental materials for consumer education should be made to eliminate difficulties that consumers have when they use sharing economy services. It is also expected that economic policy will develop to stimulate the sharing economy in a stable manner, that sharing economy-related information will be provided to consumers, and that consumer policies will be prepared to prevent consumer problems before they occur.

• Structural Engineering and Mechanics
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• 제68권5호
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• pp.549-561
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• 2018

Sobol method is applied as a powerful variance decomposition technique in the field of global sensitivity analysis (GSA). The paper is devoted to increase convergence speed of the extracted Sobol indices using a new proposed sampling technique called genetic based Latine hypercube sampling (GBLHS). This technique is indeed an improved version of restricted Latine hypercube sampling (LHS) and the optimization algorithm is inspired from genetic algorithm in a new approach. The new approach is based on the optimization of minimax value of LHS arrays using manipulation of array indices as chromosomes in genetic algorithm. The improved Sobol method is implemented to perform factor prioritization and fixing of an uncertain comprehensive high speed rotor-bearing system. The finite element method is employed for rotor-bearing modeling by considering Eshleman-Eubanks assumption and interaction of axial force on the rotor whirling behavior. The performance of the GBLHS technique are compared with the Monte Carlo Simulation (MCS), LHS and Optimized LHS (Minimax. criteria). Comparison of the GBLHS with other techniques demonstrates its capability for increasing convergence speed of the sensitivity indices and improving computational time of the GSA.

• 무역학회지
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• 제44권6호
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• pp.327-344
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• 2019

This paper explores the hub-and-spoke system as the structure of the global economic network that presents obstacles for international cooperation. With its exclusive jurisdiction and control over the hub, a powerful state can employ coercive economic measures to compel and deter unwanted behavior of rogue states and even its allies. Against this backdrop, this study analyzes the cases of the US blocking access to its market by Chinese Huawei as well as the case of Japan in restricting trade for highly advanced goods to South Korea. This analysis reveals that both measures are forms of secondary boycotts, which affect not only the entities within their jurisdiction but also others located in third countries. In addition, this paper extends its findings to free trade agreements and offers implications on the outward processing scheme for the Gaeseong Industrial Complex in the KORUS FTA and the Korea-China FTA. These events result in a gray-risk for South Korea, a country that aims to resolve North Korea's denuclearization and inter-Korean economic cooperation.