• Proceedings of the KSR Conference
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• 1999.11a
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• pp.391-397
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• 1999

Rails are produced by several rolling processes. These processes play an important role on the performance of rails. We analysed the rolling processes by finite element code, DEFORM. The distributions of temperatures and effective strains are obtained. After the rolling processes, the rails are sent to the cooling bed. During the cooling, the rails are bended and twisted. These bending and twisting should be minimized to produce a high quality rail. The analyses of cooling processes and residual stresses produced through the rolling processes will be Presented in the next paper.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.1029-1047
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• 2019

We are interested in the problem of determining the best fitted circle to a set of data points in space. This can be usually obtained by minimizing the geometric distances or various approximate algebraic distances from the fitted circle to the given data points. In this paper, we propose an algorithm in such a way that the sum of the squares of the geometric distances is minimized in ${\mathbb{R}}^3$. Our algorithm is mainly based on the steepest descent method with a view of ensuring the convergence of the corresponding objective function Q(u) to a local minimum. Numerical examples are given.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.2019-2031
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• 2004

The least-squares formulation for rigid-plasticity based on J$_2$-flow rule and infinitesimal theory and its meshfree implementation using moving least-squares approximation are proposed. In the least-squares formulation the squared residuals of the constitutive and equilibrium equations are minimized. Those residuals are represented in a form of first-order differential system using the velocity and stress components as independent variables. For the enforcement of the boundary and frictional contact conditions, penalty scheme is employed. Also the reshaping of nodal supports is introduced to avoid the difficulties due to the severe local deformation near the contact interface. The proposed least-squares meshfree method does not require any structure of extrinsic cells during the whole process of analysis. Through some numerical examples of metal forming processes, the validity and effectiveness of the method are investigated.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.14-21
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• 1985

In this paper, a new pitch extraction method, the area comparison method, is proposed. By the speech production model, the area of the first peak on a pitch interval of speech signals is emphasized. By using the above characteristics, this method have more advantages than the others for pitch extraction. The defective decision caused by an impulsive noise is minimized and the pre-filtering is not necessary for this rr ethos, because the integration of signals takes place in the process.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.534-538
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• 2004

On this study, we improved diaphgram for micro speaker performance using Taguchi method in discrete design space. The design of diaphgram has an effect on performance of micro speaker such as, thickness of diaphgram, shape of diaphgram, etc. Therefore this study carried to decide shape of diaphgram and thickness of diaphgram for minimizing 2nd natural frequency of diaphgram using Taguchi method. we showed improved design factors that minimized 2nd natural frequency of diaphgram. Also, 2nd natural frequency of diaphgram for micro speaker is reduced up to 37 percent maintaining twist mode shape. From the results of ANOVA, 2nd natural frequency of diaphgram for micro speaker have an effect on position of the outer curved shape and thickness of diaphgram.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.208-211
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• 2003

This paper presents an improved droop method of the high voltage DC power supply which minimizes the voltage droop of a parallel-connected power supply. Conventionally, the droop method has been used to achieve a simple structure and no-interconnections among the power sources. However, it has a trade-off between output voltage regulation and load sharing accuracy. In this paper, the droop is minimized with a current and droop gain control using steady-stage estimation. The proposed method can achieve both high performance voltage regulation and load sharing. Two 10kV, 100mA parallel power modules were made and tested to verify the proposed current-sharing method.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2702-2704
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• 2005

This paper proposes the genetic algorithm (GA)-based fuzzy modeling method for intelligent tracking of a maneuvering target. When the maneuvering to turn or taking evasive action, the performance of the standard Kalman filter has been degraded because residual between the modeled target dynamics and the actual target dynamics. To solve this problem, the state prediction error is minimized by the intelligent estimation method. Then, this filter is corrected by measurement corrections which is the fuzzy system. The performance of the proposed method is compared with those of the input estimation(IE) technique through computer simulation.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.434-440
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• 2007

The livestocks are sometimes infected with pathogenic microorganisms such as bird influenza, brucellosis, pig cholerae, and salmonella. However, it is difficult to predict the outcome of these diseases because the livestocks are mostly raised in the rural areas. Efficient systems for detecting and alerting the onset of livestock diseases are urgently required. In these studies, the fluorescent analysis method, luminescent analysis method, and frequently used gene amplification method (polymerase chain reaction) have been developed in order to detect the pathogenic microbes in the early stages of disease progression. By using these developed systems, damages due to the livestock diseases induced by microbes can be minimized. If we can detect livestock diseases in the early stage, the costs for diagnosis and treatment will be reduced, and the livestock can be quickly recovered.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.69-77
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• 2004

An efficient board-level interconnect test algorithm is proposed considering both the ground bounce effect and the delay fault detection. The proposed algorithm is capable of IEEE 1149.1 interconnect test, negative ground bounce effect prevention, and also detects delay faults as well. The number of final test pattern set is not much different with the previous method, even our method enables to detect the delay faults in addition to the abilities the previous method guarantees.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.147-152
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• 1992

This paper describes a new approach that can extract the relative shift vectors between two aerial image sequences for implementing the visual navigation system. This method minimizes the noise included in the aircraft attitude information that represents the changes of the aircraft attitude using the statistical method and Kalman Filtering method. This result can be used to find the relative shift vectors which are independent of the attitude changes indicating the true trajectories of aircraft. We applied this method to the image about which we had already known the information of aircraft attitude, and that result showed that the errors were minimized successfully.