• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1269-1270
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.931-932
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• 2010

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2006.03a
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• pp.73-78
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.27-27
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• 1996

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.410-413
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• 2008

In this study, we compare the mechanical properties of forged and machined bushings for an excavator track chain. The manufacturing process is explained in detail together with the procedure of making the specimens. The longitudinal tensile strength and elongation and the radial ring compression strength are measured for this comparison. It has been shown that the forged is much better than the machined with regard to both longitudinal tensile strength and radial ring compression strength but that both are the same in terms of longitudinal elongation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.128-131
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• 2009

In this paper, three-dimensional finite element analysis of screw rolling process of a long shaft bolt is conducted by using a rigid-plastic finite element method based metal forming simulator AFDEX 3D. A whole sequence of cold forming processes of a long shaft bolt composed of forging and screw rolling processes is simulated to reveal the mechanism of screw formation. A mesh density control function is applied near the major plastic deformation region to achieve computational efficiency.

• Journal of the Korea Society of Computer and Information
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• v.4 no.1
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• pp.21-27
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• 1999

In this paper. we propose a new method for automatic classification of documents using the degree of similarity between words. First, we seek relevance terms using automatic indexing. Second, we found frequency in use words in documents and the degree of relevance between the words using probability model. Continuously, we extracted the set of words which is connected the relevance closely and created the profiles characterizing each classification And, with the profile we finally classified them. We experimented on classifying two groups of documents. Some documents were about Genetic Algorithm. The others were about Neural Network. The results of the experiments indicated that automatic classification with word accordance of degree enable us to manage the retrieved documents structurally.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.319-322
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• 2007

In the development of paralleling techniques, Multi-Phase Interleaved(MPI) converter constitutes one of the most promising alternatives reported in the last years. This technique consists of a phase shifting of the control signals of several cells in parallel operating at the same switching frequency. As a result, the aggregated input and output current waveform exhibit lower ripple amplitude and smaller harmonics content than in synchronous or stochastic operation modes. Based on the inherent advantages of the MPI converter, in this paper, a control scheme, which can reduce current and voltage rifle, is proposed for PEMFC generation systems. The MPI boost converter is composed of several identical boost converters connected in parallel.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.59-62
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• 2007

In this paper, we composed solar generation system with multi-phase interleaved boost converter Solar generated voltage is low, so it has need of the boost power conversion device for supply power to normal load. The multi-phase interleaved boost converter is easy to boost voltage and it can be reduced both input current ripple and output voltage ripple because it is composed with multi-phase. We simulated and tested multi-phase interleaved boost converter applied three-phase.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.49-52
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• 2007

In this paper, we proposed a design photovoltaic generation systems with SEPIC-Flyback converter. The SEPIC-Flyback converter is operated to SEPIC converter the state turn-on of the switch and the state turn-off the switch is operated Flyback converter. Therefore application rate of the core increases and voltage stress of switch and transformer decreases with active clamp operation. Also we performed MPPT(Maximum Power Point Tracking) control for efficient working of Photovoltaic Dower generation system.