• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1445_1446
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• 2009

This paper represents the step response characteristics of shunts for impulse current. This work is aimed at the development of the reference measuring system(RMS) for impulse current rated 10 kA at 1/$20{\mu}s$, 100 kA at 4/$10{\mu}s$, 20 kA at 8/$20{\mu}s$, 40 kA at 30/$80{\mu}s$. According to the IEC 60060-2, the step response characteristics was assessed. As results of the test, the step response characteristics of newly developed shunts for impulse current satisfied requirements of RMS.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1305-1306
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• 2008

In this work, in order to investigate the effect of lightning impulse currents on ZnO surge arrester. and the deterioration characteristics of ZnO surge arrester, 8/20 [${\mu}s$], 2.5 [kA] impulse currents were applied to the ZnO surge arrester under test. The leakage currents of ZnO surge arrester were measured and ZnO element was analyzed by X-ray photoelectron spectroscopy. As a result, the resistive leakage current of ZnO surge arrester was increased with the injection number of lightning impulse currents.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1633-1635
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• 1994

This paper presents the development technology of standard resistor divider for full lightning impulse voltage. The ability of high voltage bulk power equipment to withstand lighting stroke is usually evaluated by means of full lightning impulse voltage. Lightning impulse voltage test has been essential to evaluate the insulation performance of electrical power apparatus. Recently International standard (IEC 60) on high voltage measurement techniques is being revised and requests a formal traceability of high voltage measurements. Therefore, general interest for this area has grown considerably during last years, and several international intercomparisions have been completed already worldwide, i.e. Europe, Japan, America etc.. In this viewpoint, we have also investigated the standard resistor divider with shield, which satisfies the IEC recommendation.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.904-906
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• 1995

Based on the detection of the size of datas of multipath channel characterization, we propose a new algorithm. called the impulse size based adaptive median filter(ISMF), for ghost cancellation system. The ISMF consists of two levels. The first one is the impulse noise size detection level and the second one is the adaptive median filtering level to remove the impulse noise detected. Test results confirm that the proposed ISMF removes impulse noise due to multipath channel characterization while preserving signal as well as ghosts so that the LMS algorithm performs effectively.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.29-34
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• 2009

In this paper, we design RF transceiver architecture and building blocks for impulse radio UWB system. Impulse radio UWB signal occupies the wide frequency band which is very low transmission power. So, it can minimize the interference effect with the other system. Using UWB technology, we obtain position awareness service. Therefore, we describe the RF transceiver architecture of direct conversion receiver and define the requirement of RF transceiver. Moreover, we implement a prototype RF transceiver based on the presented standard and verify a function and performance through the wireless data communication and ranging test.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.152-158
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• 2000

This paper deal with the experimental discussion about the impulse and AC dielectric strength of SF6 gas insulated transformer. Test sample is measured the dielectric breakdown voltage about modeling of the first and second section which is the weakest for surge voltage. The AC breakdown voltage is appeared 1.4 times than impulse breakdown voltage, so we can estimate that the impulse breakdown voltage is severe to AC breakdown voltage, and when the impulse is applied, in case of lmm tapping with Nomex paper, the characteristics of dielectric breakdown voltage is same to that in oil immersed transformer when SF6 gas pressure is 2.2kg/$cm^2$G.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.565-569
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• 2004

This paper deals with the characteristics of potential rise and effective impulse impedance of deep-driven ground rods that are used in high resistivity soil or in confined places such as downtown. Also the effects of the impulse and fault currents on the deep-driven ground rods combined with different type grounding electrodes like as mesh grids and counterpoises are described. The $8/20{\mu}s$ impulse current and other wave currents with different rise times are injected into the test ground rod and the effective impedances are examined. The most effective way to obtain the fine transient impedance behaviors of deep-driven ground rods is to reduce the inductive component of grounding electrode systems combined with other ground electrodes.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2235-2237
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• 2005

This paper presents the transient impedance behaviors of grounding systems to lightning impulse current. The potential rise and effective impulse ground impedance of the test grounding electrodes were measured as a function of the rise time of impulse currents and lengths of down conductor. The transient ground impedances strongly depend on the configuration and size of grounding electrodes, the impulse current shapes and lengths of down conductor, and the inductance of reduce of grounding electrode inductance is an important factor to improve the transient ground impedance.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1455-1456
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• 2007

This paper presents the experimental results on impulse breakdown characteristics under a highly non-uniform electric field in $SF_{6}/N_{2}$ gas mixtures according to a change in temperature. Test temperature ranges from $-25^{\circ}C$ to $25^{\circ}C$. The impulse predischarge breakdown developments are investigated by the measurements of current pulse and discharge luminous events. As a result, the predischarge development mechanisms for both positive and negative polarities are same. When increasing the temperature, breakdown voltage due to lightning impulse voltage is increased in negative polarity. On the other hand, when increasing the temperature, breakdown voltage due to lightning impulse voltage is not changed in positive polarity.

• Journal of Industrial Convergence
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• v.21 no.10
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• pp.81-89
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• 2023

The aim of this study was to explain the mediating effects of self-control in the relationship between academic stress and impulse buying tendency. Participants were recruited from one nursing university student located in Gwangju and J city. Data were collected from 145 nursing university student. The SPSS WIN 23.0 version was used with Sobel test and Baron and Kenny's mediating effect. It was investigated whether there was a mediating effect of self-control on academic stress and impulse buying tendency. First, academic stress showed a significant effect on impulse buying tendency. Second, Self-control had a partial mediating effect in the relationship between academic stress and impulse buying tendency(z=-2.69, p<.001). To reduce the impulse buying tendency among nursing university student, it is necessary to develop education·non-education interventions that promotion self-control in addition to decreasing academic stress.