• Title/Summary/Keyword: parameter calibration

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Dam Failure and Unsteady Flow Analysis through Yeoncheon Dam Case(II) - Unsteady Flow Analysis of Downstream by Failure Scenarios - (연천댐 사례를 통한 댐 파괴 부정류해석 및 하류 영향 검토(II) -시나리오에 따른 댐 하류 부정류 해석 및 범랑특성 연구-)

  • Jang, Suk-Hwan
    • Journal of Environmental Science International
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    • v.17 no.11
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    • pp.1295-1305
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    • 2008
  • This study aims at the analyze of unsteady downstream flow due to dam failure along dam failure scenario and applied to Yeoncheon Dam which was collapsed August 1st 1999, using HEC-RAS simulation model. The boundary conditions of this unsteady flow simulation are that dam failure arrival time could be at 02:45 a.m. August 1st 1999 and failure duration time could be also 30 minutes. Downstream 19.5 km from dam site was simulated for unsteady flow analysis in terms of dam failure and non-failure cases. For the parameter calibration, observed data of Jeonkok station were used and roughness coefficient was applied to simulation model. The result of the peak discharge difference was 2,696 to $1,745\;m^3/sec$ along the downstream between dam failure and non-failure and also peak elevation of water level showed meanly 0.6m difference. Those results of these studies show that dam failure scenarios for the unknown failure time and duration were rational because most results were coincident with observed records. And also those results and procedure could suggest how and when dam failure occurs and downstream unsteady flow analyzes.

Runoff Analysis of Modified TOPMODEL with Subsurface Storm Flow Generation Mechanism (지표하 흐름을 고려한 개선된 TOPMODEL의 유출분석연구)

  • Lee, Hak-Su;Han, Ji-Yeong;Kim, Gyeong-Hyeon;Kim, Sang-Hyeon
    • Journal of Korea Water Resources Association
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    • v.34 no.4
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    • pp.403-411
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    • 2001
  • This paper investigates the applicability of a modified version of TOPMODEL considering shallow subsurface storm flow in a forested mountaneous catchment. The macroporous soil structure provides a hydrological pathway for rapid runoff generation. A modified version of TOPMODEL introduces the two-storage system to analyze the hydrograph recession including rapid subsurface storm flow component. The two-month continuous hydrologic simulations of sulmachun watershed suggest that a modified version of TOPMODEL represents comprehensive and realistic flow generation mechanism comparing to those of an original version of TOPMODEL. The results of parameter calibration with Monte-Carlo method indicate a modified version of TOPMODEL produces a set of physically meaningful parameters.

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A Study on Development of Program for Estimating Reservoirs Outflow using Genetic Algorithm (유전자알고리즘을 이용한 저수지(貯水池)의 방류량(放流量) 추정(推定) 프로그램 개발 연구)

  • Ahn, Sang-Dae;Kim, Won-Il;Ahn, Byung-Chan;Ahn, Won-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.6
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    • pp.153-159
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    • 2009
  • In order to estimate release water from reservoirs located on ungaged watersheds, an algorithm was suggested based on hydrologic reservoir routing and real time calibrating watershed parameters. A prototype - simple computer program was developed to implement the algorithm with Genetic Algorithm technic. The program was applied to a mid-size reservoir and its ungauged watershed area using observed rainfall data, spillway gates operation data and reservoir water stage time series data under a existing storm event. The result shows that the algorithm and the prototype would be useful to simulate released water from reservoirs.

Calibration of Timetable Parameters for Rail-Guided Systems

  • Zhao, Weiting;Martin, Ullrich;Cui, Yong;Kosters, Maureen
    • International Journal of Railway
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    • v.9 no.1
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    • pp.1-9
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    • 2016
  • In order to achieve a comprehensive utilization of railway networks, it is necessary to accurately assess the timetable indicators that effect the train operation. This paper describes the parameter calibration for two timetable indicators: scheduled running time and scheduled dwell time. For the scheduled running time, an existing model is employed and the single timetable parameter (percentage of minimum running time) in that model is optimized. For the scheduled dwell time, two intrinsic characteristics: the significance of stations and the average headway at each station are proposed firstly to form a new model, and the corresponding timetable parameters (the weight of the significance and the weight of the average headway) are calibrated subsequently. The Floyd Algorithm is used to obtain the connectivity among stations, which represents the significance of the stations. A case study is conducted in a light rail transportation system with 17 underground stations. The results of this research show that the optimal value of the scheduled running time parameter can be automatically determined, and the proposed model for the scheduled dwell time works well with a high coefficient of determination and low relative root mean square error through the leave-one-out validation.

Calibration of Double-skin Simulation Model Depending on Configuration And Impact of Local Weather Information (이중외피 형상에 따른 모델 보정과 local 기상 정보의 필요성)

  • Yoon, Kyeong-Soo;Kim, Deuk-Woo;Lee, Keon-Ho;Park, Cheol-Soo
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.142-147
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    • 2009
  • In order to achieve performance assessment and optimal control of a double-skin system, an accurate simulation model is required. In the previous study, a lumped simulation model of such system was developed. As a follow-up of the previous research, the first objective of this paper is to investigate how the mathematical model should be calibrated according to system configuration(cavity width, depth, height, airflow pattern, local environment, etc.). And the second objective of this study is to discuss the effect of local weather information. In conclusion, this paper describes that the model should be recalibrated according to configuration. And it is necessary to have local weather information for accurate prediction and optimal control of the system.

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A Study of Progressive Parameter Calibrations for Rainfall-Runoff Models (강우-유출모형을 위한 매개변수 순차 보정기법 연구)

  • Kwak, Jae-Won;Kim, Duk-Gil;Hong, Il-Pyo;Kim, Hung-Soo
    • Journal of Wetlands Research
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    • v.11 no.2
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    • pp.107-121
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    • 2009
  • Many rainfall-runoff models have been used for the flood forecasting. However, the determination of rainfall-runoff model parameters is very difficult. In this study, we investigated the efficiency of flood forecasting models by studying the optimization techniques for parameter calibration of SFM, Tank, and SSARR models. We analyzed the correlations between parameters in optimization techniques, then classified the parameters into parameter groups. For this we applied the sequential calibration method through the sensitivity analysis. As the results of the analysis, the parameter groups clibration method showed better result for peak flow and clibtation time.

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Calibration and Sensitivity Analysis of LRCS Rainfall-Runoff Model(I): Theory (LRCS 강우-유출 모형의 보정 및 민감도 분석(I) : 이론)

  • O, Gyu-Chang;Lee, Gil-Seong;Lee, Sang-Ho
    • Journal of Korea Water Resources Association
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    • v.32 no.6
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    • pp.657-664
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    • 1999
  • This paper introduced the basic theory of LRCS(Linear Reservoir and Channel System) rainfall runoff model proposed by Korean researchers(Lee and Lee, 1995), and discussed the change of model output according to objective functions in sensitivity analysis and calibration process of model. It proposed "hat" matrix and affluence measures for affluence analysis of parameters in calibration, and investigated relationship between change of model output according to error propagation in parameter estimation, and sensitivity of model output according to variance of model output and change of parameters. Accuracy of parameter estimates was known by analysis of sensitivity coefficient, diagonal element $h_i$ and $D_i$._i$.

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Convergence Analysis of Kinematic Parameter Calibration for a Car-Like Mobile Robot (차량형 이동로봇의 기구학적 파라미터 보정을 위한 수렴성 분석)

  • Yoo, Kwang-Hyun;Lee, Kook-Tae;Jung, Chang-Bae;Chung, Woo-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.12
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    • pp.1256-1265
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    • 2011
  • Automated parking assist systems are being commercialized and rapidly spread in the market. In order to improve odometry accuracy, we proposed a practical odometry calibration scheme of Car-Like Mobile Robot (CLMR). However, there were some open problems in our prior work. For example, it was not clear whether the kinematic parameters always converged or not using the proposed calibration scheme. In addition, test driving had to be carried out "twice" without detailed explanation. This research aims to provide answers for the addressed questions though the convergence property analysis of the calibration scheme. In this paper, we evaluate on the effect of the kinematic parameter error on the odometry error at the final pose by numerical computation. The evaluation will show that the wheel diameter and tread of the CLMR can be calibrated by iterative test drives. In addition, the region of convergence in the parametric space will be discussed. Presented experimental results clearly showed that the proposed calibration scheme would be useful in practical applications.

A Study on the Determination of 3-D Object's Position Based on Computer Vision Method (컴퓨터 비젼 방법을 이용한 3차원 물체 위치 결정에 관한 연구)

  • 김경석
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.6
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    • pp.26-34
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    • 1999
  • This study shows an alternative method for the determination of object's position, based on a computer vision method. This approach develops the vision system model to define the reciprocal relationship between the 3-D real space and 2-D image plane. The developed model involves the bilinear six-view parameters, which is estimated using the relationship between the camera space location and real coordinates of known position. Based on estimated parameters in independent cameras, the position of unknown object is accomplished using a sequential estimation scheme that permits data of unknown points in each of the 2-D image plane of cameras. This vision control methods the robust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the robot, and correct knowledge of the relative positions and orientation of the robot and CCD camera. Finally, the developed vision control method is tested experimentally by performing determination of object position in the space using computer vision system. These results show the presented method is precise and compatible.

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Diesel SCR Development to Meet US Tier2 Bin5 Emission Regulation (북미 Tier2 Bin5 규제 대응을 위한 디젤 SCR 개발)

  • Lee, Kang-Won;Kang, Jung-Whun;Jo, Chung-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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    • pp.98-104
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    • 2011
  • The introduction of a diesel engine into the passenger car and light duty applications in the United States involves significant technical challenges for the automotive makers. This paper describes the SCR System optimization procedure for such a diesel engine application to meet Tier2 Bin5 emission regulation. A urea SCR system, a representative $NO_x$ reduction after-treatment technique, is applied to a 3.0 liter diesel engine. To achieve the maximum $NO_x$ reduction performance, the exhaust system layout was optimized using series of the computational fluid dynamics and the urea distribution uniformity test. Furthermore a comprehensive simulation model for the key factors influencing $NO_x$ reduction performance was developed and embedded in the Simulink/Matlab environment. This model was then applied to the urea SCR system and played a key role to shorten the time needed for SCR control parameter calibration. The potential of a urea SCR system for reducing diesel $NO_x$ emission is shown for FTP75 and US06 emission standard test cycle.