• Title/Summary/Keyword: 흘수/수심 비(R)

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The Best Estimation of Float Correction Factor According to River Scale (하천규모에 따른 최적 부자 보정계수 추정)

  • Jung, Moon Soo;Lim, Hyeok Jin;Kim, Sam Eun;Kim, Chi Young
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.205-209
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    • 2017
  • 최근 우리나라의 수자원 관련 기술의 발전과 연구는 상당한 속도로 이루어지고 있다. 그 중 유량측정 분야는 모든 수자원계획과 관리의 근간이 되는 분야로 그 중요성이 상당한 부분을 차지한다. 대부분의 자연하천에서 저평수기는 물의 흐름이 비교적 안정된 정상류 흐름이므로 유속계를 통해 유속분포 및 평균유속의 비교적 정확한 측정이 가능하다. 반면, 홍수기 유량측정은 하천의 수리특성이 급변하고 인력, 장비, 안전 등의 문제로 소극적인 측정을 할 수 밖에 없는 것이 현실이다. 홍수기 유량 측정방법은 부자 측정방법과 전자파 표면유속계와 같은 비접촉식 측정방법에 의존하고 있다. 부자법과 전자파 표면유속계는 평균유속과 유량을 계산하기 위해 측정 유속의 보정계수를 활용하여 평균유속으로 환산하여 사용한다.

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Determining Input Values for Dragging Anchor Assessments Using Regression Analysis (회귀분석을 이용한 주묘 위험성 평가 입력요소 결정에 관한 연구)

  • Kang, Byung-Sun;Jung, Chang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.6
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    • pp.822-831
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    • 2021
  • Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.