• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.181-190
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• 2013

We propose an interpolation method considering barrel distortion of fisheye lens using nearest pixels on a corrected image. The correction of barrel distortion comprises coordinate transformation and interpolation. This paper focuses on interpolation. The proposed interpolation method uses nearest four coordinates on a corrected image rather than on a distorted image unlike existing techniques. Experimental results show that both subjective and objective image qualities are improved.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.397-403
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• 2010

The Immersed boundary method(IBM) is one of CFD techniques which can simulate flow field around complex objectives using simple Cartesian grid system. In the previous studies the IBM has mostly been implemented to fractional step method based Navier-Stokes solvers. In these cases, pressure buildup near IB was found to occur when linear interpolation and stadard mass conservation is used and the interpolation scheme became complicated when higher order of interpolation is adopted. In this study, we implement the IBM to an incompressible Navier-Stokes solver which uses SIMPLE algorithm. Bi-linear and quadratic interpolation equations were formulated by using only geometric information of boundary to reconstruct velocities near IB. Flow around 2D circular cylinder at Re=40 and 100 was solved by using these formulations. It was found that the pressure buildup was not observed even when the bi-linear interpolation was adopted. The use of quadratic interpolation made the predicted aerodynamic forces in good agreement with those of previous studies.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.553-556
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• 2002

A numerical study on the use of the momentum interpolation mettled for flows with a large body force is presented. The inherent problems of the momentum interpolation method are discussed first. Numerical experiments are performed for a typical flow involving a large body force. The tact that the momentum interpolation method may result in physically unrealistic solutions is demonstrated. Numerical experiments changing the numerical grid have shown that a simple way of removing the physically unrealistic solution is a proper grid refinement where there is a large pressure gradient. An effective way of specifying the pressure and pressure correction at the boundary by a local mass conservation near the boundary is proposed, and it is shown that this method can effectively remove the inherent problem of the specification of pressure and pressure correction at the boundary when one uses the momentum interpolation method.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.138-141
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• 2000

In this paper, we present a new interpolation algorithm for three-dimensional images. Generally, Image interpolation is carried out along the three orthogonal coordinates. However, such a interpolation algorithm along orthogonal coordinates do not utilize the contour of 3 dimensional objects. In this paper, we propose a new directional interpolation algorithm that searches the best interpolation direction for 3-dimensional objects. Experiments with brain MR images show promising results.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.78-83
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• 2008

Interpolation filters are widely used in symbol timing recovery systems to interpolate new sample values at arbitrary points between the existing discrete-time samples. Polynomial interpolation is interpolated by coefficient made inputted information. This paper presents an efficient way to implement polynomial base interpolation filters using support filter changing input. By an example, it is shown that the proposed structure out performs the conventional interpolation structure with less hardware cost.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.599-603
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• 2003

In this paper, the efficient channel estimationschemes for DRM system(AM band digital radio broadcasting standard) are investigated. In frequency domain, by means of the linear interpolation, the second order interpolation, cubic spline interpolation, and time domain interpolation, the channel impulse response is estimated respectively to compensate the attenuation due to the fading. And in time domain, the frequency channel impulse response is averaged to reduce the attenuation due to the AWGN. By the simulation, the performance of MSE, BER and the complexity of calculation is compared and analysized for each interpolation scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.672-675
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• 2001

In this paper, we propose that the calculation method for accurate wind speed using interpolation methods, and the finding method for accurate wind direction using interpolation polynomial, so we make better performance for 3-Cup Anemometer by the proposed methods. We embody the 3-Cup Anemometer with photo sensor to measure wind direction and wind speed. In order to more accurate wind speed and wind direction, we present the methods to overcome the limitations of system memory and of the sensor measurement error by 8 bit gray code (as substitute 360 degrees for 256 degrees data).

• Journal of Navigation and Port Research
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• v.36 no.9
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• pp.699-706
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• 2012

This paper describes Declination interpolation method in the application of Digital Magnetic Compass(DMC) with small capacity memory for relatively low-priced system. The purpose of this study is to find accurate declination values using Declination Lookup Table(DLT) and Secular Variation Table(SVT) with the Bilinear interpolation method having four points data only. World Magnetic Model with Gauss coefficients produced by NOAA is used in the calculation of DLT and SVT at desired years. To verify the applicability of the proposed method, the simulation tests and the error analysis are carried out in this work. As results from tests, the interpolation error is within 0.01 degree that is much enough to implement high accurate DMC comparing with commercial DMCs on the market. In summary, the declination interpolation method, proposed in this study, can be useful in the application of DMC.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.2
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• pp.81-90
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• 2017

This study aimed to construct an integrated database using the same spatio-temporal unit by employing various public-data types with different real-time information provision cycles and spatial units. Towards this end, three temporal interpolation methods (piecewise constant interpolation, linear interpolation, nonlinear interpolation) and a spatial matching method by district boundaries was proposed. The case study revealed that the linear interpolation is an excellent method, and the spatial matching method also showed good results. It is hoped that various prediction models and data analysis methods will be developed in the future using different types of data in the analysis database.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.217-222
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• 2004

In this paper, the efficient channel estimation schemes for DRM system(AM band digital radio broadcasting standard) are investigated. In frequency domain, by means of the linear interpolation, the second order interpolation, cubic spline interpolation, and time domain interpolation, the channel impulse response is estimated respectively to compensate the attenuation due to the fading. And in time domain, the frequency channel impulse response is averaged to reduce the attenuation due to the AWGN. By the simulation, the performance of MSE, BER and the complexity of calculation is compared and analyzed for each interpolation scheme.