• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.334-336
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• 2003

This paper describes the influences of the large scaled wind farm interconnected with 154 kV power networks on the operational characteristics of distance relay applied in the transmission line. The wind farm composed of wind turbine generators are one of the great energy sources: they can supply the power into an interconnected network not only the normal conditions, but also the fault conditions of power network. Therefore, the distance relay applied in the transmission tine may mal-operate due to the contribution of wind farm. This paper presents the operational characteristics of distance relay for the fault occurred in the transmission line interconnected with wind farm. Simulation results show that it is difficult to recognize the fault location due to the power output of wind farm.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.642-649
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• 2010

LOS analysis is used for optimal deployment of mid-range guided weapon system or system engagement effectiveness simulation. Comparing to real-world, LOS analysis includes error sources such as coarse terrain data resolution, refraction of radio waves, and several ideal assumptions. In this research, exact LOS algorithm under assumption of constant earth curvature and error analysis of that is investigated. It proved that LOS algorithm under assumption of constant earth curvature has negligible error in mid-range guidance weapon system's scope.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.58-58
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• 2001

This paper shows a practical approach that is robust to the errors causing path-delay in mobile wireless location, and analyzes its performance by comparing with other methods. NLOS(non-line-of-sight) error and multipath are two big sources of positioning error in wireless location. Contrary to GPS(global positioning system), they result from the terrestrial propagation of a signal. Especially, since LOS(line-of-sight) path between a transceiver and a receiver is blocked by intermediate buildings and topography, NLOS causes a signal to be reflected and diffracted. This path-delay error is very localized, and so, it is not easy to be estimated and mitigated. To treat such localized error, therefore ...

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.43.2-43.2
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• 2018

The line-of-sight component in the relative motion of galaxy pairs sources the redshift space distortion (RSD) in galaxy surveys. By knowing the probability density function (PDF) of pair-wise motions and projecting it to the line-of-sight direction, one can compute the RSD effect precisely. I present the pair-velocity PDF of dark matter and galaxies in the Horizon-run 4 simulation. I also derive a model motivated by the perturbation theory which fits the results fairly well. I also discuss the application of the model in constraining the cosmology.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1836-1839
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• 1997

This paper presents machine vision technique with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.468-471
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• 2000

This paper investigates the harmonics of TCSC power transmission system having nonlinear VI characteristic loads. Nonlinear VI characteristic components are modelled with Nortons harmonic current sources. The system parameters such as line impedances admittances and node voltages and the thyristor switching action are described in complex Fourier series. EMTP simulation studies with a detailed three-phase TCSC power transmission system are also performed in order to verify the harmonic analysis at the steady state.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1528-1531
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• 1987

Two graphics simulators, SOFTGRA and RACA, have been developed. The SOFTGRA has been implemented by the scan line algorithm using 2 shading models with multi-light sources. The RACA is a ray casting simulator which produces shadowed images with realism. Above two simulators run on Sun micro system and MV10000 and produce image data which are transfered into IBM AT with Metheus' Omega graphics board and drawn there.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.55.2-55.2
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• 2017

We present a numerical code for the random scattering histories of Lyman alpha photons in the intergalactic medium. The numerical code calculates the radiative transfer under generic three dimensional density, ionization fraction, and peculiar velocity fields based on N-body + radiation transfer simulations of the epoch of reionization. The code is tested with models having analytical solutions, which have idealized geometry and simplified velocity fields. The emergent line profiles can give constraints to the ionization structure around Lyman alpha sources in the early universe.

• Asia pacific journal of information systems
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• v.12 no.2
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• pp.119-135
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• 2002

Those making decisions are no longer located in the same workplace. Wireless technology appears promising as a method to promote group performance in circumstances dependent on time, but not member proximity. However, the success of wireless technology in group decision-making situations has not yet been proven. This paper seeks to learn whether wireless technology affects the performance of group decision-making tasks that should be resolved urgently and/or sources of idea are disconnected with on-line network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.179-185
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• 1997

This paper presents machine vision technique with a camera modeling that accounts for major sources of camera distortion, namely,radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to varios degrees of decentering,that is,the optical centers of lens elements are not strictly collinear. Thin prism distortion arises form imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of and to apply the line of part manufacturing.