• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.125-131
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• 2005

The purpose of this study is an optimization of gate valve made by forging method instead of welding method. In this study, we propose an optimal shape design to improve the mechanical efficiency of gate valve. In order to optimize more efficiently and reliably, the meta-modeling technique has been developed to solve such a complex problems combined with the DACE (Design and Analysis of Computer Experiments). The DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the function. Also, we prove reliability of the DACE model's application to gate valve by computer simulations using FEM(Finite Element Method).

• Journal of the Korean Geophysical Society
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• v.8 no.1
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• pp.23-33
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• 2005

The digital surface model (DSM) is used for several purposes in photogrammetry, remote sensing and laser scanned data such as orthoimage production, contours erivation, extraction of height information. Creation of a surface model from point-clouds (3-D sparse points) that can be derived from stereo imagery and range data (e.g. laser scanned data) can be done with several mathematical interpolation models. In this paper, thin-plate-spline (TPS) is used for digital surface modeling. Determination of suitable weight is an important problem in thin-plate function for a surface. The Voronoi algorithm has been proposed as a method for determination of the weight in thin-plate-spline. In this paper, methods has been tested for different surfaces. The results show that thin-plate-spline can be independent of weight.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.2895-2897
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• 1999

화상을 확대함으로써 생기는 화상 몽롱화 (blurring) 현상과 블럭화 현상을 제거하기 위해 본 논문에서는 방향성을 고려한 B 스플라인 함수를 이용하여 화상을 보간하는 방법을 제시한다. 이 방법은Hermite 3차 스플라인 함수나, Bezier 곡선 함수를 이용한 방법 보다 적은 차수를 가질 수 있으므로 계산 량을 줄일 수 있다 또한 화소를 중심으로 수직, 수평 대각선 방향의 분산값을 구하여 변화가 적은 방향으로 보간을 실행함으로써 블럭화 현상과 몽롱화 현상을 감소시켜 확대 화상을 보간 시킨다.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.277-279
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• 2000

This paper proposes two kinds of the eddy current brake which uses permanent magnet. The one, like multipolar excitation consists of hexahedron shape of a segmented permanent magnetic and iron situated in the air-gap. The other, like multipolar excitation consists of only a segmented permanent magnetic. We use a finite element method to compute the flux distribution in the model. Also, we use the Galerkin-FEM with linear interpolation function may oscillate between the adjacent nodes to calculate the braking and attraction force. The advantages of the Halbach array are discussed.

• Journal of Welding and Joining
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• v.9 no.2
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• pp.37-43
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• 1991

In order to analyze the mechanical phenomena of three dimensional elato-plastic behavior caused by welding of thick plate, it is necessary to solve exactly the three dimensional unstationary heat conduction problem considering the moving effect of heat source and the temperature-dependence of material properties. In this paper, the three-dimensional unstationary heat conduction problem is formulated by using an isoparametric finite element method. Thereafter, the transient temperature distributions, according to time, of thick plate during welding are defined from the results calculated by the developed computer program.

• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.113-116
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• 2006

AC-electroosmosis is one of the electrokinetic forces leading to phenomena peculiar in the microfluidics. This paper shows particle deformation in the microchannel with rectangular electrodes on the bottom wall for the AC-electroosmotic flows. We make a PDMS microchannnel with ITO electrodes To measure velocity distributions of the particles we used a three-dimensional particle tracking velocimetry (micro-PTV) technique this method is Particle tracking by interpolation the diffraction pattern ring diameter variations with the defocusing distances of base particle locations. we induce a function of frequency at the electrode. We find the velocity of particles is the most at the edge of the electrodes and Particles move to side wall or center of the channel for the bottom and middle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.708-713
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• 2000

Finite element analysis is frequently used to get dynamic characteristics of complex structures. Since the results often show differences from experimentally measured ones, updating of finite element models is performed to make the FE results agree with measured ones. Among several model updating methods, one is to use frequency response function data. This paper investigates characteristics of the model updating method using simulated and experimental data for a cantilever beam. Damping effect is included in FE models, and FRFs for rotational displacements are calculated from FRFs for translational displacements using interpolation.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.223-239
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• 2014

New IIR digital differintegrators (differentiator and integrator) with very minor absolute relative errors are presented in this paper. The digital integrator is designed by interpolating some of the existing integrators. The optimum value of the interpolation ratio is obtained through linear programming optimization. Subsequently, by modifying the transfer function of the proposed integrator appropriately, new digital differentiator is obtained. Simulation results demonstrate that the proposed differintegrator are a more accurate approximation of ideal ones, than the existing differintegrators. Furthermore, the proposed differentiator has been tested in an image processing application. Edges characterize boundaries and are, therefore, a problem of fundamental importance in image processing. For comparison purpose Prewitt, Sobel, Roberts, Canny, Laplacian of Gaussian (LOG), Zerocross operators were used and their results are displayed. The results of edge detection by some of the existing differentiators are also provided. The simulation results have shown the superiority of the proposed approach over existing ones.

• Korean Journal of Remote Sensing
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• v.11 no.2
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• pp.43-57
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• 1995

This paper presents reconstruction of disparity in images. To achieve this, the algorithm was made up of two different procedures - one is extraction of boundaries for man-made structures and the other is matching of the structures. In the extraction of boundaries for man-made structures, we assume that man-made structures are composed of lines and the lines make up closed polygon. The convertional algorithms of the edges extraction may not perceive man-made structures and have problems that matching algorithms were too complex. This paper proposed sub-pixel boundaries extraction algorithm that fused split-and-merge and image improvement algorithms to overcome complexity. In matching procedure, feature-based algorithm that minimize the proposed cost function are used and the cost fuction considers movement of mid-points for left and right images to match structures. Because we could not obtain disparity of inner parts for the man-made structures, interpolation method was used. The experiment showed good results.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.835-851
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• 2022

This paper analyzes the variation law of the pipe lateral vibration characteristics, it was treated as a beam model, and was dispersed into several subunits based on the FEM. The corresponding stiffness and mass matrix of the pipe was deduced by using Hermite interpolation function, and the overall dynamic balance equation was established. The lateral vibration under different pipe lengths, thicknesses and towing speeds are solved by integral method. The results show that the pipe vibration trend decreases first and then increases, and the vibration value at the ore bin is larger than that at the pump set, and the value at the top is the largest, and the least value location can change with the length increase. Increasing length and thickness can reduce lateral vibration value, while increasing speed can increase the value. Neither the thickness nor the towing speed will change the location where the least value occurs. The vibration intensity will increase with the decrease of pipe length and thickness and the increase of towing speed.