• Proceedings of the KIEE Conference
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• 2005.11c
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• pp.99-102
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• 2005

In order to development of diagnosis system for mold transformer, partial discharge measurement technique is recommended the best effective method for the evaluation of insulation condition on high voltage winding part. However, this technique was not applied to mold transformer yet. The purpose of this paper is to describe the method of partial discharge measurement for mold transformer with coupling sensor and measuring system. As we reviewed and developed the on-line partial discharge test technique, ceramic coupling sensor, measuring system, terminal box and index parameters.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.42-43
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• 2007

This paper proposes a parameter estimation technique of a power transformer. Based on the combined equation, it estimates separately the primary and secondary leakage inductances, winding resistances using the least square method from the instantaneous voltages and currents in the steady state. The performance of the proposed technique was investigated by varying the cut-off frequency of the filter and the number of samples per cycle. The technique estimates the parameters with higher sampling frequencies.

• Journal of the Korean Society of Costume
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• v.37
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• pp.149-162
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• 1998

This study is thed Embroidery, Cross-stitchery, Weaving, Wax-Printing of technique and design appeared in textile of Miaos dwells in south-west among the minority people of china. The study is as follows. First, the technique of textile1) satin stitch, couching stitch, french-knot stitch, etc. using anther silk thread or cotton thread color 2) cross-stitchery 3) hand-weaving technique which is shaped other warp or weft using simple loom 4) the technique of dyeing of pattern using effect with wax. These methods are singly used mixing together, therefore doubled beauty. Second, these technuque of ornament have other independence, specially ornament apron, sling, sleeve borders, slack borderss, edge of upper garment, take off and put on easily, heighten effect of various ornament, can preserve many years. Third, Maker, female born in this country fashion by need of herself, used liberal method shown in unique creativity of life. This texture make standards capable female proud of intelligent and skill of herself. Fourth, Design appeared in textile like as pattern flying bird in the sky, strolling beast in the field, lion rolling gem, laughing dragon winding snake at gem, birks, flowers, fish, butterfly is used as the wish of long life, a lucky sign. They expressed creativity and unique conception using formation : the technique transform other shape using by omitting or adding or overestimating. Geometric pattern of tartan, revealing, Fifth, composition structure having balance and symmetry or contradiction towards center and circumstance of the center harmonized repeatedly method, expressed unique artful attraction by full composition.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.49-52
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• 2000

A new composite manufacturing technique which combines winding and curing together is studied and analyzed. This method is especially suited to the manufacture of thick composite materials in which thermal spiking is a common problem. An experimental apparatus was designed and built for use with a filament winder to continuously cure a thick composite cylinder. A hoop-wound composite cylinder with 152 mm wall thickness was manufactured and embedded thermocouples and strain gages were monitored throughout the cure process. The experimental data were compared with analytical results.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1691-1692
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• 2008

In this paper, the adaptive neural network technique is proposed to control the speed of wind power generation system. For maximizing generated power effectively, adaptive neural algorithm based on SRWMM(Self Recurrent Wavelet Neural Network) is derived to on-line adjust the excitation winding voltage of the generator. Through computer simulations, it is shown that the proposed method can achieve smooth and asymptotic rotor speed tracking.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.128-131
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• 2005

In this paper a robust controller using adaptive backstepping technique is proposed to control the speed of a wind turbine system. To make wind power generation truly cost effective and reliable, advanced and robust control algorithms are derived to on-line adjust the excitation winding voltage of the generator based on both mechanical and electrical dynamics. This method is shown to be able to achieve smooth and asymptotic rotor position tracking, as justified by analysis.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1227-1229
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• 2007

In this paper a robust controller using adaptive backstepping technique is proposed to control the position of wind power generation system. To make wind power generation truly cost effective and reliable, advanced and robust control algorithms are derived to on-line adjust the excitation winding voltage of the generator based on both mechanical and electrical dynamics. This method is shown to be able to achieve smooth and asymptotic rotor speed tracking, as justified by analysis and computer simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.94-105
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• 2010

To detect faults in an inverter-fed permanent magnet synchronous motor (PMSM) drive under the circumstance having faults in a stator winding and inverter switch, an on-line basis fault detecting scheme during operation is presented. The proposed scheme is achieved by monitoring the second-order harmonic component in q-axis current and the fault is detected by comparing these components with those in normal conditions. The linear interpolation method is employed to determine the harmonic data in normal operating conditions. As soon as the fault is detected, the operating mode is changed to identify a fault type using the phase current waveform. To verify the effectiveness of the proposed fault detecting scheme, a test motor to allow inter-turn short in the stator winding has been built. The entire control algorithm is implemented using DSP TMS320F28335. Without requiring an additional hardware, the fault can be effectively detected by the proposed scheme during operation so long as the steady-state condition is satisfied.

• Journal of Conservation Science
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• v.31 no.3
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• pp.255-265
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• 2015

In this study, the potash glass beads of 281 samples in 30 sites analyzed until now were classified according to the chemical composition. And the color, size, manufacturing technique and distribution period were compared. Korea potash glass beads are divided into 3 types depending on the stabilizer content. I, II type is the CaO and $Al_2O_3$ content of less than 5%. Relatively, I type has a high CaO and II type has a high $Al_2O_3$. In contrast, III type comprises more than CaO 5%. I, II type is the saltpetre, III type is estimated using plant ash as row material of flux. A review of the properties by type, I type is cobalt blue, copper blue and purple beads. The outer diameter is sized to the range 1.4~7.4mm. Also it was produced by the drawing technique. It was used continuously from BC 1C until around AD 6C. On the other hand, II type is outer diameter of 1.9~3.6mm and a copper blue beads. manufacturing technique is the same as the I type. This seems to have been in use since around AD 1C to 4C. Finally, III type is brown, colorless, amber beads and an outer diameter of about 10mm. It was formed by winding technique and appeared in the tombs of Goryeo and Joseon Dynasty. As a result, 3 types of potash glass beads distributed in Korea is likely to flowing through the various trade routes from different provenances.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1320-1325
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• 1995

For hydrogen-cooled large turbine generators, partial discharges in ground wall insulations are suppressed by high hydrogen pressure. The first goal of the experiment is to investigate the effect of hydrogen pressure on partial discharge activity and aging rate in turbine generator winding insulations. A series of tests have been performed on two groups of the accelerated aging experiments. The first group of stator windings was aged under hydrogen pressure of 4 atm while the second group of stator windings was aged under air atmosphere. The stator windings aged under air atmosphere suffer from larger partial discharge magnitude with larger voids at high electrical stress than those under hydrogen pressure. The second goal of the experiment is to evaluate the validity of on-line measurement technique which is normally measured under hydrogen environment. The test results show that further experiments are needed to apply the on-line scheme to turbine generator being under high hydrogen pressure.