• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.95-97
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• 1999

This paper describes electromagnetic repulsion force of multipolar axial magnetic field type electrodes for vacuum interrupter used in vacuum circuit breaker. It was distinguished that repulsion force of multipolar axial magnetic field type electrode in consideration of eddy current effect between upper electrode and lower electrode by finite element method. And it was found out that suitable contact weight of multipolar axial magnetic field type electrode for vacuum circuit breaker from repulsion force analysis results by finite element method.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.44.1-44.1
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• 2009

Identification of wave characteristics during current disruption events in the near-Earth geomagnetic tail region (~ 10 RE) is important to understand the substorm onset mechanism. In this paper, linear stability analysis in the ion-cyclotron grequency range, considering temperature anisotropy and cross-field flow is presented. It is found that the ion-cyclotron drift waves propagating in a quasi-perpendicular direction with respect to the ambient magnetic field are characterized by low frequencies ($\omega$ < $0.5{\Omega}ci$), while quasi-parallel waves have frequencies close to the ion-cyclotron frequency ($\omega{\sim}{\Omega}ci$). This finding is consistent with the observation by THEMIS spacecraft of a current disruption event in which a similar high- and low-frequency band structure is also present [A. T. Y. Lui, et al., J. Geophys. Res. 113, A00C06 (2008)]. It is also found that the quasi-perpendicular mode is excited by the ion cross-field flow.

• 한국자기공명학회논문지
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• 제24권1호
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• pp.16-22
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• 2020

Based on quantum transport theory, we investigated theoretically the magnetic field dependence of the quantum optical transition of quasi 2-dimensional Landau splitting system, in CdS and ZnO Through the analysis of the current work, we found the increasing properties of the cyclotron resonance line-profiles (CRLPs) which show the absorption power and the cyclotron resonance line-widths (CRLWs) with the magnetic field in CdS and ZnO We also found that that CRLWs, γ_total(B) of CdS < γ_total(B) of ZnO in the magnetic field region B < 15 Tesla.

• 한국운동역학회지
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• 제31권2호
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• pp.148-153
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• 2021

Objective: It is to extract training items that have a high relationship with the improvement of weightlifting records through correlation and regression analysis between training methods used commonly in the field and Snatch records and jerk records. Through this, it is intended to promote training efficiency to improve the records of weightlifters. Method: For 90 elite weightlifters of the professional teams, 4 groups (lightweight (30 people): 61 kg, 67 kg, 73 kg., middleweight (30 people): 81 kg, 89 kg, 96 kg., heavyweight (30 people): 102 kg, 109 kg, +109 kg., the whole group (90 people)) were divided. At the significance level of 0.05, correlation analysis and linear regression analysis were performed between record of training methods used widely in the field and Snatch records and Jerk records. Results: First, the better the record in Jerk, the better the Snatch record. Second, the three training methods HS, ForceS and WP performed in the field were all found to be important factors related to the improvement of Snatch record. Third, In the jerk where there are more types of training than Snatch, three training methods (HC, ForceS, BPP) appeared to be an important training method for improving the jerk record. Conclusion: While many training methods have been devised and carried out in the field, 3 types of training (HS, ForceS, WP) for improving Snatch record and 3 types of training (HC, ForceS, BPP) for improving Jerk record was found to be the most influential training method. Since all of them showed a large value of explanatory power by regression analysis, it is considered that this study is meaningful in that it can promote training efficiency by simplifying although there are many types of training for athletes.

• 한국지반공학회논문집
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• 제25권8호
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• pp.77-93
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• 2009

본 연구에서는 3차원 유한차분해석을 통하여 말뚝직경, 암반물성, 불연속면의 간격 및 방향 등 주요 인자가 암반근입 현장타설말뚝의 선단거동에 미치는 영향에 대한 분석을 수행하였으며, 이를 토대로 초기기울기 및 극한 단위선단지지력을 변수로 하는 쌍곡선형태의 선단하중전이(q-w)함수를 제안하였다. 제안식의 국내 암반지반에의 적용을 위하여 국내에서 수행된 14개 현장 23본의 시험말뚝의 재하시험자료를 토대로 제안식의 경험계수를 산정하였으며, 더불어 기존 초기기울기 및 극한단위선단지지력 산정식의 타당성 검토도 수행하였다. 현장재하시험 사례와의 비교분석 결과, 본 연구에서 제안된 산정식은 국내 암반지반에 근임된 현장타설말뚝의 선단거동을 비교적 잘 예측 가능하고, 말뚝지지력 및 침하량 예측값이 실측값에 가까움을 알 수 있었다.

• 대한기계학회논문집B
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• 제25권2호
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• pp.195-201
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• 2001

An inverse heat conduction problem(IHCP) arises when unknown heat fluxes and whole temperature field are to be found with temperature measurements of a few points. In this paper, observers are proposed as solution algorithm for the IHCP. A 1-dimensional heat transfer problem is modeled with modal analysis and state space equations. Position of the heat source is estimated through test heat inputs and the autocorrelation among a few of temperature data. The modified Bass-Gura method is used to design a state observer to estimate the intensity of heat source and the whole temperature field of a 1-dimensional body. To verify the reliability of this estimator, analytic solutions obtained from the proposed method are compared.

• 농촌지도와개발
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• 제28권4호
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• pp.215-229
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• 2021

This study aims to identify the factors influencing the registration of managers or co-managers in agricultural management in the field of work and life of female farmers and to derive implications for expanding the registration of female farmers as managers and securing the status of women. In this study, binomial logit analysis was conducted with 1,043 questionnaire responses collected on&offline to achieve the research purpose. As a result of the analysis, it was found that the duration of farming, decision-making initiative, the experience of the supporting policies for farming activity, the activities of the crop group/research or female farmer's group, and the experience of supporting policies for self-development and leisure activities had a statisticallty significant effect on the registration of female farmers.

• 공학교육연구
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• 제20권5호
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• pp.50-58
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• 2017

The purpose of this study is to explore the core competencies of the Fourth Industrial Revolution in the major newspaper articles of social network analysis and to examine the core competencies required by each field and target. To do this, we reviewed prior research focusing on core competency concepts and core competencies of engineering students, and analyzed 227 articles related to core competencies of the 4th Industrial Revolution, focusing on five major newspapers. Through analysis, we analyzed social network with 118 refined core competency keywords. As a result of the research, it was found that core competencies of the 4th Industrial Revolution are the degree centrality in terms 'creativity', 'problem solving ability', 'convergence ability', 'collaboration ability', 'conductivity', 'software ability', 'human literacy', 'personality' order. Also, as a result of the analysis of the ego centric network by field and target, the required core competencies of university and industry were found to be different. Through these discussions, it is necessary to restructure the core competence of engineering students in order to nurture the engineering talents necessary for the 4th Industrial Revolution.

• 한국기계가공학회지
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• 제19권1호
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• pp.56-62
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• 2020

The purpose of this study is to observe the visualization of the flow field for air flow distributed in the car from the ventilation fan installed in the ceiling of the passenger elevator car through the numerical analysis using computational fluid dynamics. STAR-CCM+, which is a code used for the numerical analysis, was used to predict the airflow distribution inside the elevator car. The numerical analysis of the distribution of the air current in the elevator was carried out. As a result, the analysis results for each point and the visualization of the air current distribution and the temperature distribution in the elevator car and were obtained. It was found that heat transfer was actively occurring inside the car due to the influence of the flow field discharged from the ventilation vent installed in the ceiling in the elevator car, and especially the convection heat transfer of Model-2 was more active than that of Model-1. As a result, the temperature distribution inside the car was found to be relatively low. In addition, the temperature distribution at a cross-section of 1700mm height in the elevator car shows that Model-2 is the location of the ventilation vent which makes people feel more comfortable.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.61-66
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• 1996

An overall feature to simulate composite behavior and to predict closed solution has been performed for the application to the stress analysis in a discontinuous composite solid. To obtain the internal field quantities of composite, the micromechanics analysis and finite element analysis (FEA) were implemented. For the numerical illustration, an aligned axisymmetric single fiber model has been employed to assess field quantities. Further, a micromechanics model to describe the elastic behavior of fiber or whisker reinforced metal matrix composites has been developed and the stress concentrations between reinforcements were investigated using the modified shear lag model with the comparions between reinforcements were investigated using the modified shear lag model with the comparison of finite element analysis (FEA). The rationale is based on the replacement of the matrix between fiber ends with the fictitious fiber to maintain the compatibility of displacement and traction. It was found that the new model gives a good agreement with FEA results in the small fiber aspect ratio regime as well as that in the large fiber aspect ratio regime. It was found that the proposed simulation methodology for stress analysis is applicable to the complicated inhomogeneous solid for the investigation of micromechanical behavior.