• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.629-642
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• 2021

Land-use change has an important role in the hydrologic characteristics of watersheds because it alters various hydrologic components such as interception, infiltration, and evapotranspiration. For example, rapid urbanization in a watershed reduces infiltration rates and increases peak flow which lead to changes in the hydrologic responses. In this study, a physical hydrologic model the soil and water assessment tool (SWAT) was used to assess long-term continuous daily streamflow corresponding to land-use changes that occurred in the Naesungchun river watershed. For a 30-year model simulation, 3 different land-use maps of the 1990s, 2000s, and 2010s were used to identify the impacts of the land-use changes. Using SWAT-CUP (calibration and uncertainty program), an automated parameter calibration tool, 23 parameters were selected, optimized and compared with the daily streamflow data observed at the upstream, midstream and downstream locations of the watershed. The statistical indexes used for the model calibration and validation show that the model performance is improved at the downstream location of the Naesungchun river. The simulated streamflow in the mainstream considering land-use change increases up to -2 - 30 cm compared with the results simulated with the single land-use map. However, the difference was not significant in the tributaries with or without the impact of land-use change.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.825-830
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• 2004

Kinematic calibration of Gough-Stewart platform using a new measurement device is presented in this paper. The device simultaneously measures components of position and orientation using commercially available gadgets. Additional kinematic parameters are defined to model the sources of inaccuracies for the proposed measurement device. Computer simulations reveal that all kinematic parameters of the Gough-Stewart platform and the additional kinematic parameters of the measurement device can be identified with the partial pose measurements of the device. Results also show that identification is robust for the initial errors and the noise in measurements. The device also facilitates the automation of easurement procedure.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.5
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• pp.94-101
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• 1996

When objects are scanned spatially by a laser-beam and mechanical mirror scanners, spatial information can be obtained, and then it is improtant to accurately obtain the parameters relating the light source and camera positions, etc.. In this paper, a calibration technique is presented for correction of measuremtn errors in a three-dimensional laser scanner system with two galvanometers. First, a model of the systematic errors is developed based on the geometry of the scanning system. Calibration parameter values are then iteratively adjusted with coarse-fine search in order to minimize errors (evaluation function) between measured and computed distances. It is shown that this correction method results in measurement precision suitable for practical use.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1140-1144
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• 2006

홍수를 예측하기 위해서 국내 5대강 유역의 홍수통제소는 저류함수모형을 사용하고 있다. 그러나 저류함수모형을 실제 홍수사상에 적용하기 위해 매개변수를 결정하여야 하는데 이는 매우 어려운 작업으로 지금까지는 저류함수모형의 매개변수 보정을 위해 시행착오에 의한 수동보정 방법을 사용하여 왔다. 이에 본 연구는 미호천 유역을 대상유역으로 하여 Pattern Search Multi-Start(P-S), SCE-UA와 유전자 알고리즘(GA)을 이용하여 매개변수 보정을 하고, 그 방법들에 대한 비교와 분석을 하였다. 그리고 최적화 기법을 통해 얻어진 매개변수를 사용하여 저류함수모형의 홍수수문곡선을 유도하고 이를 비교, 분석하였다. 또한 SSR과 WSSR의 목적함수를 사용하여 목적함수별 홍수수문곡선을 비교, 분석하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.298-302
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• 2002

Equivalent volume estimation of the coupler and two coupled microphones has a key role in standard microphone pressure calibration. The equivalent volume of the microphone is determined by the dynamic characteristics of the diaphragm system and front cavity. Therefore the modal parameters of diaphragm system - natural frequency and damping fatter - should be measured explicitly for the estimation of the equivalent volume. The diaphragm system is composed of the vibrating diaphragm, back slit behind diaphragm, pressure equalization vent, and front cavity which are acoustically coupled. In the measurement, the electrostatic actuator was used to excite the system with the swept sine, and the frequency response was obtained. The close actuator in front of the diaphragm must influence the radiation impedance of the system, and then the modal parameters. From the measured frequency response, the natural frequency and the damping factor could be estimated with the Complex exponential method based on the Prony model and the zero crossing real and imaginary plot.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.473-478
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• 2004

LIDAH data often include systematic errors, which should be removed by a calibration process. This paper proposes a robust approach to calibrating LIDAR data using natural surfaces as reference data. The uniqueness of this approach is to employ a sophisticated selection scheme so that only a portion of LIDAR points can be used to estimate the bias parameters generating the systematic errors. This approach was applied to calibrating simulated LIDAR data. The results show that the approach can successfully recover the bias parameters and calibrate the data with acceptable RMS errors. Particularly, the parameter recovery model can be easily extended to register image data with LIDAR data.

• ETRI Journal
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• v.36 no.6
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• pp.894-904
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• 2014

Blind mismatch correction of time-interleaved analog-to-digital converters (TI-ADC) is a challenging task. We present a practical blind calibration technique for low-computation, low-complexity, and high-resolution applications. Its key features are: dramatically reduced computation; simple hardware; guaranteed parameter convergence with an arbitrary number of TI-ADC channels and most real-life input signals, with no bandwidth limitation; multiple Nyquist zone operation; and mixed-domain error correction. The proposed technique is experimentally verified by an M = 4 400 MSPS TI-ADC system. In a single-tone test, the proposed practical blind calibration technique suppressed mismatch spurs by 70 dB to 90 dB below the signal tone across the first two Nyquist zones (10 MHz to 390 MHz). A wideband signal test also confirms the proposed technique.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.130-135
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• 2009

This study investigates the need of calibrating a nodal network ventilation simulation model (CONTAMW 2.4). For this purpose, the series of ventilation experiments were conducted and then compared to simulation outputs from an uncalibrated simulation model, resulting in a significant difference between two. Hence, an optimization routine was employed to estimate unknown parameters in the simulation model. In the paper, the authors presents 1.3 unknown parameters with the validated simulation model. It was found that the model with estimated unknown parameters predicts the ventilation phenomena accurately.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.95-98
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• 1996

In this paper, The vehicle's path construction method for motorized wheelchair's autonomous navigation in a building through analysis of a corridor image using vision system has been proposed and We detected lines of vertical axis through camera distortion parameter, which was measured by camera calibration in a corridor image. Then we got the feature points in the lines. We analyzed the distance of feature points and what is feature points. we reconstructed corridor image to vehicle's path.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.1032-1035
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• 2004

Pressure distribution is measured by way microphones to identify noise sources in the space. For example, beam-forming method or acoustic holography use phase information to identify the source. Therefore, the phase is significant information to correctly identify the source position. However, due to the microphone characteristics and measuring systems, measured signals always have errors, which make the identification difficult. Therefore, phase calibration of microphones is needed. Duct and speaker systems are generally used as calibrators. Acoustic characteristics of the calibrator are, of course, functions of many Parameters of the system: i.e. duct size, frequency, and microphone spacing. In this paper, design parameters which effect on the performance and size of the calibrators are considered. Then the parameters would be applied to design and real product of the phase-calibrator.