• Title/Summary/Keyword: Measure height

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In-Site Measurement and Analysis of Heat of Hydration for Kumdang Bridge (금당교 교대기초 수화열 계측 및 해석)

  • 안상구;이필구;차수원
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.363-368
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    • 2001
  • Abutments in Kumdang bridge are massive concrete structures of which total height is l0m, length is 30m, and width is 7m. Therefore, there is every probability that early age thermal cracking such as hydration heat occur. We measure heat of hydration, strains of rebar, and stresses of concrete abutment during construction. Using analysis of measuring data, we examine thermal stresses, and make use of results as method which control thermal cracking. Finally, we develope thermal stress analysis program which have pre/post processor to be easy of accessing and the usefulness of that is estimated through comparison of results.

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3D Inspection of Printed Circuit Boards (PCB의 3차원 검사)

  • 조홍주;박현우;이준재
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.2375-2378
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    • 2003
  • In manufacture of printed circuit boards, one important issue is precisely to measure the three-dimensional shape of the solder paste silk-screened prior to direct surface mounting of chips. This paper presents the 3D shape reconstruction of solder paste using the optical triangulation method based on structured light or slit beam and the measurement algorithm for height, volume. area, and coplanarity on component pads from the 3D range image. Futhermore, statistical process control function is incorporated for process capability analysis.

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A Study on the Noise Characteristics According to Bellmouth Inlet Shape (벨마우스 흡입구 형상에 따른 원심팬의 소음 특성에 관한 연구)

  • Lee, Hyun-Nam;Hong, Dong-Pyo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.809-812
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    • 2006
  • This article shows the study on the arresting sound occurrence due to the interaction of the centrifugal Fan and bellmouth suction flow with bellmouth height as variable. It has accomplished to measure of inlet noise and also to analysis suction pressure distribution through experiment and also using CFD. The main cause of sound occurrence was judged with the effect due to static pressure change of bellmouth surface.

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Experiments on Smoke Filling in a Large Space (대공간 축연실험)

  • Han, Yong-Sik;Kim, Myeong-Bae;Jang, Yong-Jae;Yun, Myeong-O;Kim, Jin-Gon
    • 한국연소학회:학술대회논문집
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    • 1998.10a
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    • pp.37-46
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    • 1998
  • In this experiments, smoke filling behaviors in a large space were investigated. Also, it found that the smoke filling time can be predicted with a simplified zone model. Thermocouples were used to measure the temperature of the hot gases layer and also later to determine the smoke layer depth. Height markers were also hung from the roof so that observers could visibly assess the smoke layer depth.

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Development of a Flow Sensor Using DBD (Dielectric Barrier Discharge) (DBD (Dielectric Barrier Discharge)를 이용한 유량 센서 개발에 관한 연구)

  • Kim, Tae-Hoon;Kim, Sung-Jin
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2076-2081
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    • 2008
  • In this study, a new concept of a flow sensor is developed using dielectric barrier discharge (DBD). Current of DBD generated between two electrodes is changed with varying flow rates. Therefore, it is possible to measure the flow rate by correlating generated DBD current with flow rates. The effects of flow rate, frequency, channel height, diameter of electrodes and distance between electrodes on the performance of the flow sensor using DBD are experimentally investigated.

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The Study on Effect of Local Schmidt Number on Lifted Flame and Its Propagation Velocity (국소 슈미트수가 부상화염 및 화염전파속도에 미치는 영향에 관한 연구)

  • Jeon, Minkyu;Lee, Min Jung;Jeong, Yong-Jin;Kim, Nam Il
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.75-76
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    • 2015
  • Lifted flame stabilization mechanism can be explained with constant Schmidt number from the equation of $H^{\ast}_L/d^2_o=const{\times}v_e^{(2Sc-1)/(Sc-1)}$. In this research, a method of local Schmidt number was applied in order to measure edge flame propagation velocities, and edge flame propagation velocity was calculated from the trend between lift-off height and nozzle flow rate.

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An Optimality Criterion for Median-unbiased Estimators

  • Sung, Nae-Kyung
    • Journal of the Korean Statistical Society
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    • v.19 no.2
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    • pp.176-181
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    • 1990
  • Sung [1990] presented an analogue of the classical Cramer-Rao inequality for median-unbiased estimators with continuous multivariate densities depending upon a vector parameter. In the process, diffusivity, a new dispersion measure relevant to median-unbiased estimators, was defined to be a function of median-unbiased estimator's density height. In this paper we shall elaborate these ideas by defining a second kind of diffusivity and discuss the role of model-unbiasedness in median-unbiased estimation in connection with this seconde kind of diffusivity. In addition, median-unbiased estimation will be compared to mean-unbiased estimation.

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A Study on Comparison of Acoustic Emission, Ultrasonic Testing and Crack Gauge Method in 3-point Bending Testing (3점 굽힘시험에 있어서 AE, 초음파, 크랙게이지법의 비교연구)

  • Han, E.K.;Kim, K.S.;Park, J.S.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.10 no.1
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    • pp.65-72
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    • 1990
  • Comparison of acoustic emission, ultrasonic testing and crack gauge in 3-point bending testing have been studied. As the results, COD is indirectly assumed by strain gauge rate and grid pitch width when crack gauge grid is out. Acoustic emission is qualitatively able to measure crack growth by total count but ultrasonic testing has a difficulty in measuring it because of echo height fluctuation according to the change and pressure of UT. probe.

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Development of Prototype Stylus Prototype for Large Optics Testing

  • Yang, Ho-Soon;Walker, David
    • Journal of the Optical Society of Korea
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    • v.5 no.2
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    • pp.60-66
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    • 2001
  • The authors discuss a prototype stylus profilometer designed to measure large optics. It consists of a low contact force type probe system, laser reference system, interferometric distance measurement system, and horizontal driving system. The probe contacts the surface ; the height and the horizontal distances of the measurement points are measured by the interferometer. The freely propagated laser beam provides the reference line during the measurement. The developed stylus profilometry shows only $\pm$60 nm of P-V error for the 157 mm diameter spherical mirror.

Comparisons of several measures related to k-anonymity algorithms (k-익명성 알고리즘 관련 측도들에 대한 비교 분석)

  • Youn-kyoung Shin;Ju-Sung Kang
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.1405-1408
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    • 2008
  • 개인정보 노출 위험을 최소화하면서 데이터 유용성을 최대화하기 위한 기법 중의 하나인 k-익명성 개념과 연관된 다양한 측도(measure)들을 비교 분석한다. 원본 데이터와 변형된 데이터가 주어졌을 때, 각각 다른 k-익명성 알고리즘들에서 제안된 높이(height), 정확도(precision), 손실측도(loss metric), 비용(cost), 점수(score) 등의 측도들이 데이터의 정확성(accuracy)을 측정하는 데에 대한 일관성과 개별성을 조사하고, 그 측도들의 특징에 따른 의미와 효율성을 비교분석한다.