• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.115-120
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• 2000

Increasing demands on precision machining of free-form surface have necessitated that the tool to move not only position error as small as possible, but also with smoothly varying feedrates. This paper presents new algorithm for high precision 3D(3-dimensional) NURBS(Non-Uniform Rational B-Spline) interpolation in the reference-pulse technique. Based o the minimum path error strategy, interpolation algorithm was designed to follow the NURBS curve. Using this algorithm a real-time 3D NURBS interpolator was developed in software. The algorithm implemented in a PC showed promising results in interpolation error and speed performance. It is expected that this can be applied to the CNC systems for the high precision machining of complex shapes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.690-695
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• 2014

This paper presents a modified CCI image interpolation method based on the even-odd decomposition (EOD). The CCI method is a well-known technique to interpolate images. Although the method provides better image quality than the linear interpolation, its complexity still is a problem. To remedy the problem, this paper introduces analysis on the EOD decomposition of CCI and then proposes a reduced CCI interpolation in terms of complexity, providing better image quality in terms of PSNR. To evaluate the proposed method, we conduct experiments and complexity comparison. The results indicate that our method do not only outperforms the existing methods by up to 43% in terms of MSE but also requires low-complexity with 37% less computing time than the CCI method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5955-5977
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• 2018

Performance of the interpolation algorithm used in the technique of bi-dimensional empirical mode decomposition directly affects its popularization and application, so that the researchers pay more attention to the algorithm reasonable, accurate and fast. However, it has been a lack of an adaptive interpolation algorithm that is relatively satisfactory for the bi-dimensional empirical mode decomposition (BEMD) and is derived from the image characteristics. In view of this, this paper proposes an image interpolation algorithm based on the particle swarm and fractal. Its procedure includes: to analyze the given image by using the fractal brown function, to pick up the feature quantity from the image, and then to operate the adaptive image interpolation in terms of the obtained feature quantity. All parameters involved in the interpolation process are determined by using the particle swarm optimization algorithm. The presented interpolation algorithm can solve those problems of low efficiency and poor precision in the interpolation operation of bi-dimensional empirical mode decomposition and can also result in accurate and reliable bi-dimensional intrinsic modal functions with higher speed in the decomposition of the image. It lays the foundation for the further popularization and application of the bi-dimensional empirical mode decomposition algorithm.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.545-548
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• 2000

Adaptive array systems are hard to remove all the interferences when incident signals are coherent with a desired signal. In this paper, we propose a modified Duvall beamformer, which performs spatial smoothing using spatial interpolation technique to maintain the degree of freedom. The propose algorithm can minimize the loss on the degree of freedom due to spatial smoothing by forming subarrays with interpolated signals. Simulation results show that the proposed algorithm can remove all the interferences while conventional beamformer cannot.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.04a
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• pp.15-19
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• 1991

An attempt has been made to generate a cured boundary by using a transfinite interpolation technique. In the following sections, it will be shown how to construct transfinite interpolants both in h-version and in p-version over polygonal and nonpolygonal regions. Numerirical test cases validate the applicability and superior capability with the help of several structural problem.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.415-420
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• 2003

GIS technique was applied to the analysis of ambient air quality information. For this study, the air quality information was imported with the geographical information in Capital Area. This study well proves that GIS technique has a great deal of potential to analyze those air quality information, to produce useful information, and to ease the efforts for air quality improvement. Concerning about the data interpolation, the discrepancy caused by applying different method was ignorable, although Kriging method is further developed.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.214-217
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• 1992

This paper introduces a new methodology to apply the interpolation technique wi th optimum pattern to voltage-reactive power control of power system. The conventional tool for the optimal operation of power system is Optimal Power Flow(OPF) by standard optimization techniques. The achievement of solution through OPF programs has a defect of computation time, so that it is impossible to apply the OPF programs to the real-time control area. The proposed method presents a solution in a short period of time and an output with a good accuracy. The optimum pattern is a set of input-output pairs, where an input is a load level and a type of outage and an output is the result of OPF program corresponding to the input. The output in the OPF represents control variables of voltage-reactive power control. The interpolation technique is used to obtain the solution for an arbitrary input. As a result, the new technique helps operators in the process of the real-time voltage-reactive power control in both normal and emergency operating states.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.655-663
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• 2021

In this paper, DFT-Based channel estimation with channel response mirroring is proposed and analyzed. In General, pilot symbols for channel estimation in MIMO(Multi-Input Multi-Output) OFDM(Orthogonal Frequency-Division Multiplexing) Systems have a diamond shape in the time-frequency plane. An interpolation technique to estimate the channel response of sub-carriers between reference symbols is needed. Various interpolation techniques such as linear interpolation, low-pass filtering interpolation, cubic interpolation and DFT interpolation are employed to estimate the non-pilot sub-carriers. In this paper, we investigate the conventional DFT-based channel estimation for noise reduction and channel response interpolation. The conventional method has performance degradation by distortion called "edge effect" or "border effect". In order to mitigate the distortion, we propose an improved DFT-based channel estimation with channel response mirroring. This technique can efficiently mitigate the distortion caused by the DFT of channel response discontinuity. Simulation results show that the proposed method has better performance than the conventional DFT-based channel estimation in terms of MSE.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.510-518
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• 2000

A new video interpolation technique based on variable skip rate of video sequence is proposed in this paper. in the proposed technique. the determination whether a frame is skipped or not is done by the degree of motion complexity of the frame. If the motion complexity of a frame is low the frame is skipped. otherwise it is coded and transmitted. To determine the motion complexity of a frame a new technique using MEF (moving edge in frame),the set of pixels considered as moving edges in a frame. is introduced. In the course of decoding and interpolating of receiver., the motion field is segmented. For the purpose of dividing vector field morphological filtering is applied. Morphological filtering also used to smooth the boundaries between the changed and unchanged region. In the simulation results, the proposed technique shows higher quality and lower fluctuation of picture quality than the conventional techniques on conditioning of the same bit rate.

• Kyungpook Mathematical Journal
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• v.58 no.3
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• pp.453-462
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• 2018

In this paper, we present a symbolic formulation of the error obtained due to an approximation of a given function by the mixed-interpolating function. Using the proposed symbolic method, we compute the error evaluation operator as well as the error estimation at any arbitrary point. We also present an algorithm to compute an approximation of a function by the mixed interpolation technique in terms of projector operator. Certain examples are presented to illustrate the proposed algorithm. Maple implementation of the proposed algorithm is discussed with sample computations.