• Title/Summary/Keyword: Gap Effect

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Experimental Study of Motion Behavior of Side-by-Side Moored Two Floating Bodies Including Sloshing in Head Sea (선수파 중 슬로싱을 고려한 병렬배치된 두 부유체의 거동 특성에 관한 실험 연구)

  • Cho, Seok-Kyu;Sung, Hong-Gun;Hong, Jang-Pyo;Hong, Sa-Young;Hong, Seok-Won
    • Journal of Ocean Engineering and Technology
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    • v.26 no.6
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    • pp.46-52
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    • 2012
  • The motions and drift forces of side-by-side moored FSRU and LNGC including the sloshing effect, were studied using experiments. The FSRU and LNGC contained LNG cargo tanks and the LNG sloshing could affect the motions and drift forces of the structures due to its coupling with floating body motion. The effect of coupling can vary with the LNG filling level, and the effect of the filling level was investigated. The coupling effect was stronger at lower filling level. It was confirmed that longitudinal sloshing influenced the surge and surge mean drift force in head sea. In addition, gap flow affected the sway and mean drift forces. Sloshing attenuated the sway and yaw excited by gap flow in side-by-side configuration.

Inter-Regional Wage Gap and Human Capital in Korea - An Unconditional Quantile Regression Decomposition Approach - (수도권과 비수도권의 임금격차와 인적자본 - 무조건 분위회귀 분해법의 적용 -)

  • Kim, Minyoung;Lim, Up
    • Journal of the Korean Regional Science Association
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    • v.33 no.2
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    • pp.3-23
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    • 2017
  • This study aims to understand how human capital is related to the inter-regional wage gap between the capital region and the non-capital region in Korea. We focus more specifically on whether the inter-regional wage gap is due to high levels of human capital in the capital region or due to high returns to human capital in the capital region. The decomposition method based on the unconditional quantile regression was used to examine how the relationship between human capital and the inter-regional wage gap varies along the wage distribution. When first estimating earnings functions from the two regions to apply this decomposition method, we included not only conventional indicators of human capital, such as education and on-the-job training, but also occupational skills including cognitive-interactive skills, technical skills, and physical skills. As a result, other things being equal, a large part of the inter-regional wage gap was explained by the human capital variables. Although the composition effect of the human capital variables existed in all the wage quantiles, the more important factor was the wage structure effect of the human capital variables. In addition, among the various human capital variables, the wage structure effect of years of education was a key factor in explaining the inter-regional wage gap. This study is meaningful in that it shows that the relationship between human capital and the inter-regional wage gap may vary depending on the wage quantiles.

Power Loss Calculation of High Frequency Transformers

  • Choi Geun-Soo;Yoon Shin-Yong;Baek Soo-Hyun;Kim Yong
    • Journal of Electrical Engineering and Technology
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    • v.1 no.3
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    • pp.338-342
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    • 2006
  • This paper analyzed the power loss of transformers considering the magnetic component. For this, each winding strategy and the effect of air gap between the ferrite core have been an important variable for optimal parameter calculation. Inductors are very well known design rules to devise, but the performance of the flyback converter as a function of transformer winding strategy has not been fully developed. The transformer analysis tool used was PExpert. The influence of the insulator thickness, effect of the air gap, how the window height and variation of the capacitive value effects the coil and insulator materials are some of parameters that have been analyzed in this work. The parameter analysis is calculated to a high frequency of 48[kHz]. Therefore, the final goal of this paper was to calculate and adjust the parameters according to the method of winding array and air gap minimizing the power loss.

Investigation on the Flowfield Around a Square Cylinder near a Wall (지면에 근접한 정사각주 주변의 유동장 연구)

  • Hwang, Jae-Ho;Park, Young-Whe;Kim, Tae-Yun;Lee, Dong-Ho
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.754-759
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    • 2001
  • This paper presents unsteady computational investigations and wind tunnel tests on the flow field around a square cylinder with a gap between the body and the ground plane. Two-dimensional unsteady, incompressible Navier-Stokes codes are developed for the computation of the viscous turbulent flows. By computing the flow around a square cylinder without ground effect, three two-equation turbulence models are evaluated and the developed code is validated. The results show a good agreement with experimental values and other computational results. Critical gap height at which the formation of Karman vortex streets is interrupted, is demonstrated and another transition regime is pointed out

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Analysis of Skew Effects on Cogging Torque and BEMF for BLDCM (BLDCM의 코깅토크와 역기전력에 대한 스큐 영향의 해석)

  • Sim, Dong-Joon;Park, Hyun-Soo;Kim, Kwang-Heon;Won, Jong-Soo
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.58-62
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    • 1990
  • Air gap flux density is obtained strictly from air gap permeance and MMF distribution using the design parameter of BLDCM when the stator slot is considered. Then the theoretical equations representing the cogging torque and BEMF are proposed. The effect of skew is described analytically, and skew effect on air gap permeance and MMF is studied. Consequently we verified analytically that skew of slots and magnets influenced on the reduction of the cogging torque and BEMF ripple, and the shape of BEMF.

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Numerical Evaluation of a Radially Variable Cell Density Strategy for Improving Light-off Performance: Focusing on Light-off Catalyst (자동차용 촉매변환기의 활성화 성능 향상을 위한 횡방향 가변 셀 밀도법의 수치적 평가: 활성화 촉매변환기를 중심으로)

  • 정수진;김우승
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.1
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    • pp.115-124
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    • 2002
  • The optimum design of auto-catalyst needs a good compromise between the pressure drop and flow distribution in the monolith. One of the effective methods to achieve this goal is to use the concept of radially variable cell density. However, there has been no study of evaluating the usefulness of this method on light-off catalyst. We have computationally investigated the effectiveness of variable cell density technique applied to the light-off catalyst using a three-dimensional integrated CFD model. in which transient chemical reacting calculations are involved. Computed results show that variable cell density technique can reduce the accumulated emissions of CO and HC during the early 100sec of FTP cycle by 86.78 and 80.87%, respectively, The effect of air-gap between the monoliths has been also examined. It is found that air-gap has a beneficial effect on reducing pressure drop and cold-start emissions.

Analysis of Recurrent Gap Time Data with a Binary Time-Varying Covariate

  • Kim, Yang-Jin
    • Communications for Statistical Applications and Methods
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    • v.21 no.5
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    • pp.387-393
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    • 2014
  • Recurrent gap times are analyzed with diverse methods under several assumptions such as a marginal model or a frailty model. Several resampling techniques have been recently suggested to estimate the covariate effect; however, these approaches can be applied with a time-fixed covariate. According to simulation results, these methods result in biased estimates for a time-varying covariate which is often observed in a longitudinal study. In this paper, we extend a resampling method by incorporating new weights and sampling scheme. Simulation studies are performed to compare the suggested method with previous resampling methods. The proposed method is applied to estimate the effect of an educational program on traffic conviction data where a program participation occurs in the middle of the study.

Effect of a Gap of a 2-D Flap Rudder on the Lift (2차원 플랩타의 간극이 양력에 미치는 영향)

  • Chang-Gu Kang
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.31-38
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    • 1993
  • Horn rudders or flap rudders with a gap between forward and after part are used for effective steering of a ship or a submerged body. It is necessary to analyze the effect of a gap since it affects the performance of rudders. In this paper, an equation to calculate the lift acting on a two-dimensional flap rudder in uniform flow is derived by using the thin hydrofoil theory and the analytic solution of viscous flow in a channel formed by two coaxial cylindrical walls to which a pressure gradient is applied.

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