• Title/Summary/Keyword: 중립위치

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Experimental performance evaluation and comparison for lightweight piezo-composite actuator LIPCA (압전 복합재료 작동기 LIPCA에 대한 성능 비교실험 및 분석)

  • 김균열;박기훈;윤광준;박훈철
    • Composites Research
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    • v.16 no.2
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    • pp.41-47
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    • 2003
  • This paper is concerned with the performance evaluation and comparison analysis fur several kinds of LIPCA (Lightweight Piezo-Composite Actuator) device system. LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer was sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. To investigate the effect of lay-up structure of the LIPCA on the actuating performance, four kinds of actuator with different lay-up stacking sequence were designed, manufactured, and tested. The performance of each actuator was evaluated using an actuator test system consisted of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system. From the comparison of the performance of the LIPCA prototypes, it was found that the actuator with higher coefficient of unimorph actuator can generate larger actuating displacement.

Behavior of Composite Structure by Nonlinearity of Steel-concrete Interface(II) -Behavior of Steel-Concrete Interface- (강·콘크리트 경계면의 비선형성에 따른 합성구조체 거동 (II) -강·콘크리트 경계면의 거동 특성-)

  • Jeong, Youn Ju;Jung, Kwang Hoe;Kim, Byung Suk
    • Journal of Korean Society of Steel Construction
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    • v.15 no.5 s.66
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    • pp.509-518
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    • 2003
  • In this study, we carried out nonlinear analysis according to various interface nonlinear models by interaction magnitude, and analyzed interface behavior such as distribution of tangential traction and relative slip in steel-concrete composite structure. As a result of this study, tangential traction and relative slip of interface is rapidly increased at the steel plate-concrete interface, especially at the neutral region, rather than tensile, as opposed to the T beam-concrete interface. In transverse direction, it has gradually reduced to go outside from loading position. In longitudinal direction, it was minimum at the central region near the loading point, maximum at 0.6-0.7L from support and gradually reduced as it nears support. Moreover, as the load is increased, the failure of interface gradually expands from the maximum tangential traction position to the entire region. It is expected to provide fundamentality for interface behavior and load-carrying mechanism, and for the design of bending and shear connection of steel-concrete composite structure.

Design of Pile Foundations Considering Negative Skin Friction (부마찰력을 고려한 말뚝기초 설계)

  • Kim Ju-Hyong;Kwon Oh-Sung;Kim Myoug-Mo
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.65-74
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    • 2005
  • The negative skin friction on piles, which are installed in currently consolidating soft deposits, creates significant problems on the stability of pile foundations. This study investigated whether or not the pile foundation designs were appropriate in soft deposits with large amount of consolidation settlement. The final settlements of the grounds along the pile depth were estimated by the soil parameters obtained from the laboratory tests and by the field-measured settlement curves, if they were available. The displacement of the piles along the pile depth was estimated by both the load transfer method and the numerical method. Both methods gave similar locations of neutral planes and magnitudes of the maximum axial forces on the piles. The movements of the ground and the piles were compared to calculate the down drag acting on piles. For the piles whose bearing capacities were less than the design loads including the down drag, slip layer coatings and/or incrementing of the pile penetration depth into the bearing stratum were proposed to improve the pile capacities.

Stability Analysis of Boundary Layers on Airfoils by using PSE (PSE를 이용한 익형 위 경계층 안정성 해석)

  • Park, Dong-Hun;Park, Seung-O
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.11
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    • pp.1055-1065
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    • 2009
  • In this study, stability analysis of boundary layers on airfoils is performed by using parabolized stability equations(PSE). Boundary layer edge conditions are obtained by compressible inviscid flow calculations. Mean velocity and temperature profiles of the laminar boundary layer are obtained by solving compressible boundary layer equations in generalized curvilinear coordinates with fourth order accuracy in the wall normal direction. Laminar mean flow profiles are used as input data for PSE to investigate growth rates of disturbances and stability characteristics. For the cases of boundary layer on NACA0012 and HSNLF(1)-0213 airfoils at Mach number 0.5, growth rates with respect to disturbance frequencies and profiles of disturbance amplitude are investigated. The effect of angle of attack on stability characteristics are examined at both upper and lower surfaces. The neutral stability curves, effect of Mach number and effect of airfoil section shapes are also analyzed.

The Representation of Memory and New Directions of Archival Description Discourse (기억의 재현과 기록 기술(archival description) 담론의 새로운 방향)

  • Jo, Minji
    • The Korean Journal of Archival Studies
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    • no.27
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    • pp.89-118
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    • 2011
  • This paper considers the relationship between memory and archives by exploring the concepts and meaning of archivist and archival description. The author considers the metaphor of archives as memory and relates our understanding of creation, arrangement, preservation, description, and use of records and archives. The author argues that archivists demonstrate their knowledge and background when they organizing and preserving records and archives.

A Study on Space in the Moveis of Hirokazu Koreeda (고레에다 히로카즈 감독 영화의 공간 연구)

  • Hwang, Woo-Hyun
    • The Journal of the Korea Contents Association
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    • v.18 no.12
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    • pp.343-363
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    • 2018
  • Classical film narrative fails to reflect the increasing complexity of modern society. In this era of film narrative crisis Hirokazu Koreeda presents a new solution. The director puts an emphasis on neutral valuation over subject matter rather than empathy of audiences which leads to a biased point of view. Thus Hirokazu Koreeda choose space over story as a critical narrative enabler. Two qualitatively opposite spaces are presented and the boundary space of the two are set as a main background where the valuation over the spaces waves up and down. Audiences who get accustomed to a one-sided value judgement led by storytelling can be neutralized by pendulum movement of valuation. The specific methods of using space as a main tool of value neutralization have changed through the director's filmography. Space had been thoroughly designed through the storyboard in early works. Later the director let audiences experience the spaces to evoke a sense of place.

Exploration of deep learning facial motions recognition technology in college students' mental health (딥러닝의 얼굴 정서 식별 기술 활용-대학생의 심리 건강을 중심으로)

  • Li, Bo;Cho, Kyung-Duk
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.3
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    • pp.333-340
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    • 2022
  • The COVID-19 has made everyone anxious and people need to keep their distance. It is necessary to conduct collective assessment and screening of college students' mental health in the opening season of every year. This study uses and trains a multi-layer perceptron neural network model for deep learning to identify facial emotions. After the training, real pictures and videos were input for face detection. After detecting the positions of faces in the samples, emotions were classified, and the predicted emotional results of the samples were sent back and displayed on the pictures. The results show that the accuracy is 93.2% in the test set and 95.57% in practice. The recognition rate of Anger is 95%, Disgust is 97%, Happiness is 96%, Fear is 96%, Sadness is 97%, Surprise is 95%, Neutral is 93%, such efficient emotion recognition can provide objective data support for capturing negative. Deep learning emotion recognition system can cooperate with traditional psychological activities to provide more dimensions of psychological indicators for health.

A Basic Study on Effect Analysis of Adjacent Structures due to Explosion of Underground Hydrogen Infrastructure (지하 수소인프라 폭발에 따른 인접 구조물 영향 분석에 대한 기초 연구)

  • Choi, Hyun-Jun;Kim, Sewon;Kim, YoungSeok
    • Journal of the Korean Geosynthetics Society
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    • v.21 no.3
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    • pp.21-27
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    • 2022
  • For carbon neutrality, interest in R&D and infrastructure construction for hydrogen energy, an eco-friendly energy source, is growing worldwide. In particular, for hydrogen stations installed in downtown areas, underground hydrogen infrastructure are being considered to increase a safety distance from hydrogen tank explosions to adjacent structures. In order to design an appropriate location and depth of the underground hydrogen infrastructure, it is necessary to evaluate the impact of the explosion of the underground hydrogen infrastructure on adjacent structures. In this paper, a numerical model was developed to analyze the effect of the underground hydrogen infrastructure explosion on adjacent structures, and the over pressure of the hydrogen tank was evaluated using the equivalent TNT (Trinitrotoluene) model. In addition, parametric analysis was performed to estimate the stability of adjacent structures according to the construction conditions of the underground hydrogen infrastructure.

A Study on an Ethnic Labor in Korea: Focused on Interpreting and Translation Job of Marriage Migrant Women (결혼이주여성 통번역사를 중심으로 본 한국의 에스닉(ethnic) 노동에 관한 연구)

  • Kim, Kyounghee;Heo, Youngsook
    • The Journal of Asian Women
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    • v.53 no.2
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    • pp.75-110
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    • 2014
  • This research examines marriage migrant women's interpreting and translation work as an ethnic labor, analyzing its creation and work experiences. Major findings about ethnic labor in the research are as follows: First, Korean gendered and discriminatory- exclusive immigration policy enables the creation of interpreting and translation job to marriage migrant women. While the policy limits settlement and employment fields of male immigrant workers, marriage migration women are allowed to settle and find any job. Second, job security and wage of marriage migrant women's interpreting and translation work are still low, although the job is considered a relatively decent one in foreign immigrant labor market. Finally, they experience conflicts between role as neutral interpreters and identity as migrant women, facing native Koreans' distrust and discrimination against them. In conclusion, this study suggests some issues on marriage migrant women's empowerment and their labor market prospect in terms of the sustainability of this job.

Analysis of solar power generation efficiency through spatiotemporal analysis of solar radiation on the Korean Peninsula using GK2A (천리안2위성을 활용한 한반도 일사량의 시공간적 분석을 통한 태양광 발전 효율 분석)

  • Hwang, Seunghyun;Baik, Jongjin;Kim, Hyeonjoon;Byun, Jongyun;Cha, Hoyoung;Jun, Changhyun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.457-457
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    • 2022
  • 최근 기후변화로 인한 위기가 인류의 생존을 위협하면서 전 지구적으로 기후변화에 대응하기 위한 탄소 중립 대책을 모색하고 있으며, 지속가능한 신재생에너지에 대해 주목하고 있다. 산업통상자원부는 2034년까지 총 발전량 중 신재생에너지의 비율을 25.8%까지 증가시키는 것을 목표로 신재생에너지의 발전 비율을 증가시키기 위한 다양한 노력을 기울이고 있다. 특히, 신재생에너지 중 가장 많은 비중을 차지하고 있는 태양광 발전은 비교적 광범위한 부지를 필요로 하고 있으며, 환경 및 지형적 영향이 크게 작용하는 만큼 발전 시설 부지 선정 및 운용 계획을 위한 면밀한 분석이 필수적이다. 그러나, 태양광 발전 활용 계획을 수립하기 위해 고려할 수 있는 지상 관측 일사량 및 일조량 데이터는 상당히 제한적이며 관측 밀도가 조밀하지 않다는 한계점이 있다. 본 연구에서는 천리안위성의 후속으로 발사된 천리안2위성의 산출물인 일사량 데이터를 활용하여 한반도 영역에서의 일사량에 대한 시·공간적 분석을 수행하였으며, 이를 기반으로 각 지역적 특성을 파악하고, 토지 피복 유형에 따른 태양광 발전의 효율 정도를 분석·평가하였다. 본 연구의 결과는 계측 지역 및 미계측 지역에서의 시공간적인 태양광 에너지의 효율성에 대한 정보를 제공함에 따라 태양광 발전을 위한 관련 시설물들의 최적 설치 위치 및 규모 등에 대한 설계 기준 마련에 활용될 수 있을 것으로 판단된다.

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