• Title/Summary/Keyword: Chiu

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Study on River Water Usage Calculation Method using Surface Velocity Sensor(RQ-30) (전자파표면유속계를 활용한 하천수 사용량 산정방법에 관한 연구)

  • Oh, Se Hwan;Song, Jae Hyun;Yoon, Young Sun;Roh, Young Sin
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.255-255
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    • 2022
  • 안정적이고 효율적인 물 배분과 관리를 위해 하천유량 외에도 하천수 사용량 파악에 대한 관심이 높아짐에 따라 다양한 하천수 사용량 계측방법의 검증 및 표준화로 하천수 사용량 자료의 신뢰도 및 활용성을 개선할 필요가 있다. 다양한 계측방법 중에서도 전자파표면유속계는 비접촉식 유속계이므로 안전적인 측면으로 유리하고 실시간 자료처리 및 계측이 용이하여 활용도가 높다. 본 연구에서는 만경강의 하천수 사용량 파악을 위해 어우보 취수로에 설치된 전자파 표면유속계(RQ-30)를 활용하여 보정계수(K-factor)가 적용된 표면유속을 활용한 유량산정방법, 표면유속과 평균유속의 일정비율로 유량을 산정하는 방법(ISO 748), Chiu의 유속분포법을 활용한 유량산정방법, 지표유속과 인력(人力)에 의한 측정유속과의 관계인 지표유속-평균유속관계곡선식으로 환산된 유량산정 방법등을 비교·검토하고 최적의 유량산정방법을 제시하였다. 향후 전자파표면유속계를 활용한 하천수 사용량의 비교결과를 통하여 더욱 효율적이며 신뢰도 높은 하천수 관리와 실시간 물배분 효과를 기대할 수 있다.

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Liquid Crystal Display with High and Stable Color Gamut by Using Pre-compensated Tri-chromatic LED Backlight

  • Chiu, Tien-Lung;Lee, Jiun-Haw
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1515-1518
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    • 2007
  • We demonstrate a high color gamut liquid crystal display (LCD) system (>100 %) by using a precompensated tri-chromatic LED-backlight module over a temperature range of (25 to $70^{\circ}C$), whose pre-compensated optical characteristic balances the spectral redshift and intensity decrease due to the temperature rising during operation.

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3D display measurement for DEP

  • Huang, Kuo-Chung;Wu, Chou-Lin;Liao, Ching-Chiu;Lee, Kuen
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1018-1021
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    • 2009
  • Define a designated eye position (DEP) for the 3D displays is a critical issue. It shows the system performance without content issue. We use luminance meter to capture these optical characteristic and discuss between one point measurement, two points measurement and three points measurement situation.

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Improve the Gamma variation by monitoring the angle of the polarizer absorption axis

  • Wu, Chun-Wei;Huang, Chiu-Jung;Hu, Cheng-Chung;Cheng, Yao-Li
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.293-296
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    • 2007
  • Gamma curve is one of the most important optical performance characteristics of a liquid crystal display. we present investigations on the relationship between gamma and polarizer. The gamma curve is affected by the angle of the polarizer absorption axis. When the crossed angle between the two polarizers turns larger, gamma values will decrease. The gamma variation caused from each polarizer variation could be improved by monitoring and controlling the axial direction of the polarizers.

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The estimation of river discharge by using the mean velocity equation in a unsteady condition (평균유속공식을 이용한 부정류 하천유량 산정)

  • Choo, Tai Ho;Chae, Soo Kwon;Yoon, Hyeon Cheol;Yun, Gwan Seon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.12
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    • pp.6558-6564
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    • 2013
  • As the average indicator for amount of water flowing in any cross section of a river, the mean discharge has been reported to be a very important factor for examining water circle constructions in a river basin, the design and construction of a hydraulic structure, and water front area use and management. The stage-discharge curve based on discharge and stage data measured in a normal season were basically derived. Using this derivation, the necessary discharge data was obtained. The values produced in this manner corresponded to the measured data in a uniform flow state well, but showed limited accuracy in a flood season (unsteady flow). In the present paper, the mean velocity in unsteady flow conditions, which exhibited loop form properties, was estimated using the new mean velocity formula derived from Chiu's 2-D velocity. The results of RMSE and Polar graph analyses showed that the proposed equation exhibited approximately nineteen times the accuracy compared to the Manning and Chezy equations.

Applicability evaluation of velocity profile method by V-ADCP measuring real-time river water use (실시간 하천수사용량 계측을 위한 V-ADCP 유속분포법의 적용성 평가)

  • Song, Jae Hyun;Park, Moon Hyung;Cha, Jun-Ho;Kim, Chi Young
    • Journal of Korea Water Resources Association
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    • v.52 no.1
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    • pp.83-96
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    • 2019
  • In order to properly manage the river water use, it is necessary to collect reliable data of river water use. However, It is not easy to get credible river water use data in Korea because there are some difficultites in reporting and measuring river water use data. Thus, Han River Flood Control Office has installed and operated measuring facility using V-ADCP on the EOUBO intake open channel in the Gosan-Bongdong station section of the Mankyung river, where the use of agricultural water is large. In this study, the applicability of the V-ADCP velocity profile method was evaluated for real-time river water use. For this reason, the parameter sensitivity of Chiu's 2D velocity distribution equation was analyzed and the optimal parameters based on actual discharge data were calculated. In addition, the characteristics of the velocity profile method were analyzed by comparative evaluation of the rating curve method and the index velocity method.