• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.450-453
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• 1988

A numerical scheme is considered for computing charge distributions and drawing equipotential lines for multiconductor transmission lines with arbitrary cross sections. Two-dimensional integral equation superposed by the charges is numerically calculated by the method of moments. Here in Galerkin's method special pulses cut into halves chosen for expansion and testing functions facilitate the numerical computations in solving the integral equation. Numerical examples are given for some system of which the shell conductor is grounded as the reference zero of potential.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.79-81
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• 1994

A solution of magnetic fields for amorphous core transformer has been tried using homogenization technique. The technique, which is derived by applying asymptotic expansion to the standard finite element method, is helpful to analyse a joint part of amorphous core transformer microscopically. A butt-lap-step joint type of lamination method is modeled and its equivalent reluctivity is calculated to analyse various quantities of the magnetic fields. The algorithm is also applicable to other electric devices which have complicated material structure with repeated patterns.

• The KSFM Journal of Fluid Machinery
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• v.5 no.2 s.15
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• pp.43-49
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• 2002

In this paper, the steady-state performances analysis of a tilting pad gas bearing(TPGB) we analyzed by using finite element method for compressible Reynolds' equation. TPGB is used in a high-expansion-ratio expander running at a speed of 230,000 rpm. In order to solve the nonlinear finite element equations, the Newton-Raphson method is applied. The variations of the loading capacity, friction force and tilting angle of a single pad v.s. eccentricity direction of eccentricity and bearing number are investigated. The condition for the equilibrium of a pad, which is important for safe working of the bearing, is stated. The performances of the three pad bearing such as loading capacity, friction moment are predicted.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.55-59
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• 2007

Wavelet Transform is amenable to efficient algorithms. So wavelet transform was adopted many signal processing and communication applications. For example, the wavelet transform was adopted as the transform for JPEG2000. However, Wavelet has weakness about smoothness along the contours and limited directional information. Hence, recently, some new transforms have been introduced to take advantage of this property. So we use to other transform, called contourlet transform in compression. In this paper, we propose a new method for image compression based on the contourlet transform, which has been recently introduced. Contourlet transform has a good result about images with smooth contours. Moreover, Contourlet is feasible multiresolution and multidirection expansion using non-separable filter bank. This treatise shows a good image representation after compressing using contourlet transform.

• Membrane Journal
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• v.8 no.3
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• pp.117-129
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• 1998

The atmospheric pollution by diesel emission is mainly attributed to particulate matters and NO$_x$. Their regulation limits have become tighter. This paper reviews the characteristics and the fabrication method of the diesd particulate filter(DPF) which is used to control the particulate matters of diesel emission. First the constituent of particulate matters and the regulation standard are discussed and then the state of the art post-treatment system is reviewed. The materials, the fabrication method and the control of thermal expansion of the ceramic honeycomb filter, which is widely used as the DPF, are also reviewed.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.25-31
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• 1997

현대적 노달방법은 다차원 중성자 확산방정식을 풀기 쉽고 계산시간을 단축시킬 수 있도록 각 방향에 대하여 횡방향으로 적분하여 등가인 차원 수 만큼의 1차원 중성자 확산 방정식을 만들어 풀고 있다 이 과정에서 횡방향 누출 중성자 적분항을 적절히 근사해야함이 필수적인데 이로 인하여 계산의 정확도를 손상하게 될 수가 있다. 이러한 횡방향 누출 중성자 근사를 제거하여 계산의 정확도를 향상시킨 것이 노달 해석함수 전개법(Analytic Function Expansion Nodal Method)이다. 그러나 이 방법은 기존의 노달 방법 보다는 계산시간이 다소 많이 소요되는 단점이 있었다. 본 논문에서는 소격격자 재균형 가속법(Coarse-Mesh Rebalance Acceleration Method)을 노달 해석함수 전개법에 적용하면 계산의 정확도는 그대로 유지되면서도 속도는 크게 향상시킬 수 있음을 보여 준다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.2
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• pp.241-246
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• 1986

A new method of on-line monitoring of spot weld quality is proposed by analysing weld votage signal. Weld voltage signal has been modeled by autoregressive model which is suitable for on-line modeling scheme, and order of the model is determined by F-test. From the chosen model, strength. Upon experimental results, it has been shown that fundamental frequency dispersion of weld voltage can be used as a good parameter like maximum thermal expansion in on-line monitoring of spot weld quality. Microcomputer implementation of the proposed monitoring method is also developed and presented.

• Korean journal of food and cookery science
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• v.17 no.5
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• pp.478-482
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• 2001

This experiment was carried out to clarify the effect of frying temperature and gelatinization method on the quality of popped rice for Salyeotgangjung. Frying at 220$^{\circ}C$ or 230$^{\circ}C$ gave a good expansion and score of sensory evaluation. But the frying oil began to smoke at 230$^{\circ}C$. There was no significant difference in the quality of popped rices between the treatments of minimum gelatinization after washing rice and moderate gelatinization after soaking for 80 minutes at 30$^{\circ}C$. In conclusion, frying washed rice with minimum gelatinization at 220$^{\circ}C$ would be considered as the best method for making Salyeotganagjung.

• Journal of Korean Elementary Science Education
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• v.19 no.2
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• pp.15-27
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• 2000

The purpose of this study was to survey the thinking of children, preliminary elementary teachers and elementary teachers in relation to the experiment of candle's combustion in a bottle on the water, to develop some supplementary experiments for the correction of the misconception on this experiment and to propose a new teaching method for this subject-matter The results of this study can be summarized as follows. 1. Most of the answers are related to the simple observation as the extinguishing of candlelight and the water rising in the bottle after a candle's combustion. And it is appeared that all the groups are similarly short of the ability of experimental design to verify the cause and effect. 2. from the results of the developed supplementary experiments, it is concluded that the main cause of the water rising is not the combustion of oxygen, but the expansion of volume and the releasing of air in the bottle in the bottle by heat of candle's combustion. 3. Based on the above results, a new direction for the teaching method of this subject is proposed.

• Journal of the Korea Society for Simulation
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• v.12 no.2
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• pp.55-62
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• 2003

The explosive Increase of wireless networks and the advancement of mobile devices lead to the expansion of mobile environment. In accordance with the development of mobile environment, the need to use mobile database is increased sharply, and also it accompanies the related problems. The current mobile database system is based on the centralized method from which a synchronized server manages multiple mobile database management system to synchronize. From this mobile system architecture, several kinds of problems can be detected such as the management of synchronization issues between mobile databases and the transaction management issues. Furthermore, the current mobile database management system does not consider any solution on the fault tolerance. To solve those problems, this paper proposes the mobile agent-based mobile database management system. The proposed system provide high confidence and efficiency by enhancing the network efficiency and fault tolerance through the mobile grouping.