• Proceedings of the KWS Conference
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• 2003.11a
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• pp.156-158
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• 2003

An implicit finite element implementation for Leblond's transformation plasticity constitutive equations, which are widely used in welded steel structure is proposed in the framework of parallel computing. The implementation is based upon the multiplicative decomposition of deformation gradient and hyper elastic formulation. We examine the efficiency of parallel computation for the finite element analysis of a welded structure using domain-wise multi-frontal solver.

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.161-163
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• 2002

An implicit finite element implementation for Leblond's transformation plasticity constitutive equations, which are widely used in welded steel structure is proposed in the framework of parallel computing. The implementation is based upon the updated Lagrangian formulation. We examine the efficiency of parallel compuatation for the finite element analysis of a welded structure using multi-frontal solver.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.278-285
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• 2011

This paper makes an analysis of the encoding structure and the decoding algorithm proposed by the DVB-S2 specification. The methods of implementing the LDPC decoder are fully serial decoder, the partially parallel decoder and the fully parallel decoder. The partial parallel scheme is the efficient selection to achieve appropriate trade-offs between hardware complexity and decoding speed. Therefore, this paper proposed an efficient memory structure for check node update block, bit node update block, and LLR memory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.275-276
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• 2009

• Bulletin of the Korean Mathematical Society
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• v.31 no.2
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• pp.215-236
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• 1994

The purpose of the present paper is to study generic submanifolds of a Sasakian space form with nonvanishing parallel mean curvature vector field such that the shape operator in the direction of the mean curvature vector field commutes with the structure tensor field induced on the submanifold. In .cint. 1 we state general formulas on generic submanifolds of a Sasakian manifold, especially those of a Sasakian space form. .cint.2 is devoted to the study a generic submanifold of a Sasakian manifold, which is not tangent to the structure vector. In .cint.3 we investigate generic submanifolds, not tangent to the structure vector, of a Sasakian space form with nonvanishing parallel mean curvature vactor field. In .cint.4 we discuss generic submanifolds tangent to the structure vector of a Sasakian space form and compute the restricted Laplacian for the shape operator in the direction of the mean curvature vector field. As a applications of these, in the last .cint.5 we prove our main results.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.249-256
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• 2000

Bond immunization model is used to minimize interest rate risk for investing in fixed-income market, the model equalizes asset and liability values using the duration which is the sensitivity of portfolio value with respect to the interest rate. However this model might generate an error in practice because the model is based on unreal hypothesis, so called "Parallel Shift Term Structure". In this paper, we use the neural network approach to overcome the parallel shift term structure and try to employ this term structure function to the traditional immunization model. Finally, we present some computational test results that show the superiority of the partial immunization model to the traditional methods.

• Journal of the Korean Mathematical Society
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• v.44 no.2
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• pp.307-326
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• 2007

We know that there are no real hypersurfaces with parallel Ricci tensor or parallel structure Jacobi operator in a nonflat complex space form (See [4], [6], [10] and [11]). In this paper we investigate real hypersurfaces M in a nonflat complex space form $M_n(c)$ under the condition that ${\nabla}_{\varepsilon}S=0\;and\;{\nabla}_{\varepsilon}R_{\varepsilon}=0,\;where\;S\;and\;R_{\varepsilon}$ respectively denote the Ricci tensor and the structure Jacobi operator of M in $M_n(c)$.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1426-1437
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• 2016

In different industrial and mission oriented applications, redundant or standby semiconductor systems can be implemented to improve the reliability of power electronics equipment. The proper structure for implementation can be one of the redundant or standby structures for series or parallel switches. This selection is determined according to the type and failure rate of the fault. In this paper, the reliability and the mean time to failure (MTTF) for each of the series and parallel configurations in two redundant and standby structures of semiconductor switches have been studied based on different failure rates. The Markov model is used for reliability and MTTF equation acquisitions. According to the different values for the reliability of the series and parallel structures during SC and OC faults, a comprehensive comparison between each of the series and parallel structures for different failure rates will be made. According to the type of fault and the structure of the switches, the reliability of the switches in the redundant structure is higher than that in the other structures. Furthermore, the performance of the proposed series and parallel structures of switches during SC and OC faults, results in an improvement in the reliability of the boost dc/dc converter. These studies aid in choosing a configuration to improve the reliability of power electronics equipment depending on the specifications of the implemented devices.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.453-456
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• 2000

고정금리 상품의 투자에서 이자율 변동 위험을 피할 수 있는 방법으로 많이 쓰이는 것은 듀레이션을 이용한 면역 모델(Bond Portfolio Immunization Model)로, 이것은 이자율 변동에 대해 포트폴리오의 가격 민감도인 듀레이션을 이용하여 자산과 부채의 변화를 일치시키는 방법이다. 그러나 이 전략은 수익률 곡선이 평형하게 이동한다는 가정(Parallel Shift Term-Structure)을 단점으로 가지고 있어 현실에 적용될 경우 오차가 발생하게 된다. 본 연구에서는 선험적(empirical) 방법으로 평형하지 않은 움직임을 가진 기간구조의 함수(Term-Structure Function)를 정의하고 면역 모델을 부채의 현금흐름에 대해 개별적으로 적용하는 새로운 면역 전략 모델을 구성하고 실험한다

• Journal of Power Electronics
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• v.11 no.6
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• pp.870-879
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• 2011

Regulated peak power tracking (RPPT) systems such as the series structure and the series-parallel structures are commonly used in satellite space power systems. However, these structures process the solar array power or the battery power to the load through two cascaded regulators during one orbit cycle, which reduces the energy transfer efficiency. Also the battery charging time is increased due to placement of converter between the battery and the solar array. In this paper a parallel structure has been proposed which can improve the energy transfer efficiency and the battery charging time for satellite space power RPPT systems. An analogue controller is used to control all of the required functions, such as load voltage regulation and solar array stabilization with maximum power point tracking (MPPT). In order to compare the system efficiency and the battery charging efficiency of the proposed structure with those of a series (conventional) structure and a simplified series-parallel structure, simulations are performed and the results are analyzed using a loss analysis model. The proposed structure charges the battery more quickly when compared to the other two structures. Also the efficiency of the proposed structure has been improved under different modes of solar array operation when compared with the other two structures. To verify the system, experiments are carried out under different modes of solar array operation, including PPT charge, battery discharge, and eclipse and trickle charge.