• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1741-1743
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• 2001

This paper presents the induced ground potential rise distributions on several ground electrodes buried nearby. These experiments were conducted with the impulse currents as a function of the ground electrodes types and distances from the current injection point. The ground potential is significantly induced in the vicinity of ground electrodes, and the induced ground potential rises can caused unwanted erratic operation of electronic device.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.4
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• pp.277-282
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• 2008

A fully integrated inductorless CMOS impulse radio ultra-wideband (IR-UWB) receiver is implemented using $0.18\;{\mu}m$ CMOS technology for 3-5 GHz application. The UWB receiver adopts the non-coherent architecture, which removes the complexity of RF architecture and reduces power consumption. The receiver consists of inductorless differential three stage LNA, envelope detector, variable gain amplifier (VGA), and comparator. The measured sensitivity is -70 dBm in the condition of 5 Mbps and BER of $10^{-3}$. The receiver chip size is only $1.8\;mm\;{\times}\;0.9\;mm$. The consumed current is 15 mA with 1.8 V supply.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1658-1660
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• 1994

This paper describes the measurement system of the magnetic field waveforms generated by lightning return strokes. The frequency bandwidth of magnetic field measurement system is from 270[Hz] to about 2.3 [MHz]. As the application experiment, the magnetic field generated by simple impulse and oscillating impulse currents, which are measured by a current transformer (Tek. AM503), is observed by the trial magnetic field measurement system. The obtained results are agreement with each other. A typical magnetic field waveform associated with lightning return strokes was recorded and presented.

• Structural Engineering and Mechanics
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• v.39 no.2
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• pp.287-301
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• 2011

This paper is focused on the residual capacity of steel columns, as a damage criterion. Load-Impulse (P-I) diagrams are frequently used for analysis, design, or assessment of blast resistant structures. The residual load carrying capacity of a simply supported steel column was derived as a damage criterion based on a SDOF computational approach. Dimensionless P-I diagrams were generated numerically with this quantitative damage criterion. These numerical P-I diagrams were used to show that traditional constant ductility ratios adopted as damage criteria are not appropriate for either the design or damage assessment of blast resistant steel columns, and that the current approach could be a much more appropriate alternative.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1466-1467
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• 2007

A new parameter W/R for the class I test have been introduced in the IEC 61643-1 published in 2005. One of the possible test impulses which meets the parameters for class I test is the 10/350 [${\mu}s$] waveshape proposed in IEC61312-1. 10/350 [${\mu}s$] waveshape meets parameters for class I test in the IEC 61643-1. The impulse generator for making the 10/350 [${\mu}s$] waveshape is consist of IVG, ICG, crowbar coil and crowbar switch. The electric change Q and the specific energy W/R were measured and calculated using the exclusive use measuring software according to the formula of IEC 611643-1. We verified the correspondence between measured results using impulse generator and recommended parameters by IEC 61643-1.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.97-99
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• 1998

This paper presents a numerical study of the behavior of the transformer winding, when stressed by the standard impulse voltage. The mathematical model of the transformer takes several points into the account. Capacitance of not adjacent winding as well as adjacent winding, eddy current loss caused by self and mutual inductance given as the functions of frequency. Not like the previous approach where calculation of capacitance is performed, in average sense. In this paper, capacitance of both adjacent and not adjacent winding is calculated using the numerical approach(B.E.M.), so they can get the more accurate value of capacitance. Because of frequency dependency of inductance, numerical-laplace-transform technique is required. Finally, to validate this approach, a simple test winding is simulated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.79-86
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• 2008

This paper presents the experimental results of impulse breakdown characteristics in $SF_6/N_2$ gas mixtures under a highly non-uniform electric field with a change in temperature. The test temperature ranges from -25[$^{\circ}C$] to 25[$^{\circ}C$]. The processes of impulse preliminary breakdown developments were analyzed by the measurements of current pulse and luminous signals. As a result, the temperature dependance of breakdown voltage for the negative polarity was much stronger than that for the positive polarity. When increasing the temperature, The leader stepping time for the negative polarity was shown to be longer than that for the positive polarity. The results presented in this paper can be used as a useful information in designing the gas insulation lines with prominent ability for lightning surge.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.6
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• pp.793-803
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• 1998

Since most clothing research has still centered around buying behavior, the importance of consumer behavior which exists outside the purchase context has been neglected. This orientation focusing solely on purchase-related processes is deficient as it cannot account for consumer behavior that is recreational or that occurs without a recognized consumption need. In this vein, clothing browsing behavior can be a significant variable that has effects on clothing purchase-related variables. So to speak, browsers do make purchases at times; delayed-action purchases, impulse purchases and browsers may provide other less informed people with product information. In this study, we used definition proposed by Bloch and Richins(1983), which defines non purchase shopping(browsing) as 1,he examination of merchandises of a store for recreational or informational purposes without a current intention to buy. The specific objectives of the study were to identify the dimensions of clothing non -purchase shopping and to determine the causal relationship among clothing involvement, non-purchase shopping, impulse buying, purchase quantity, opinion leadership. The questionnaire method was used and 366 questionnaires were analyzed. Results can be summarized as follows. First, the non-purchase shopping was divided into two dimensions such as recreational non-purchase shopping and informational non-purchase shopping Of the two dimensions, recreational dimension explained the greater part than informational one. Second, it was revealed that clothing involvement was strongly positively related to non-purchase shopping, which influenced considerably on impulse buying, purchase quantity, and opinion leadership. In other words, clothing non-purchase shopping behaivor is very significant concept of clothing product category and has considerable effects on clothing buying though it occurs independently of purchase, so it seems that much more concern will be needed on this concept.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1302-1307
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• 2013

MOV(Metal Oxide Varistor) is the most important part of SPD(Surge Protective Device) which can protect electric facilities from an impulse current such as a lightning. So far, the fault of MOVs have decided only by surge count without considering magnitude of surge current and an amount of input energy. This paper proposed the fault prediction algorithm for the MOV using look up table made by surge count and input current data which have non-linear characteristics for input current and are estimated by high voltage experimental results. Proposed algorithm was proved by experiment on verification at a high voltage laboratory.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.289-292
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• 2008

This paper describes the electrical characteristics of the ZnO surge arrester according to the variation of surrounding conditions. To investigate the characteristics of degraded ZnO surge arrester, 8/20 [${\mu$s], 2.5 [kA] impulse currents were applied to the ZnO surge arrester to be test. To present the effect of the surrounding con야tions, the leakage currents of ZnO surge arrester were measured to the surrounding temperature and wet conditions. As a result, the increase of ambient temperature causes the increase of resistive leakage current of ZnO surge arrester. Also, in the wet test, the outside leakage current through the ZnO surge arrester housing is much larger than the intrinsic leakage current.