• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.22-24
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• 2003

In this work, in order to investigate the effect of multiple lightning impulse currents on zinc oxide arrester blocks. We have been designed and fabricated a multi-impulse generator which can produce quintuple voltages with $1.2/50{\mu}s$ to 100kV and quintuple currents with $8/20{\mu}s$ to 12kA and we have evaluated the characteristics of zinc oxide arrester block using several electrical and physical methods after the multi-impulse test. It was found that the multi-impulse failures of ZnO arrester blocks were mainly caused by surface flashover and the multi-impulse currents test would be more suitable than single impulse current test in evaluation of the characteristics of zinc oxide arrester blocks corresponding to actual situations.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.939-948
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• 2021

The purpose of the research is to examine whether government regulation on Covid 19 pandemic has had a significant impact in economic sectors, particularly on consumer behavior. Thus there are three hypotheses, 1) viral marketing has an effect on online trust during the Covid-19 Pandemic Era, 2) viral marketing has an effect on impulse buying during the Covid-19 Pandemic Era, and 3) Viral marketing has an effect on impulse buying in the Covid-19 Pandemic Era through online trust. To test the hypotheses, questionnaires were distributed to 150 respondents, however, only 110 were selected due to incomplete data. There are 3 variables, namely viral marketing, online trust, and impulse buying, where online trust is also a mediating variable. Once the assumption test is completed, the researcher employs path analysis to test the hypotheses. The results are 1) there is an effect of viral marketing on online trust in the Covid-19 Pandemic Era, 2) There is no effect of viral marketing on impulse buying in the Covid-19 Pandemic Era, and 3) Viral marketing has an effect on impulse buying in the Covid-19 Pandemic Era through online trust. This means online trust succeed in mediating viral marketing-impulse buying relationship. The findings emphasized that the credibility of online trust enforce consumers in making buying decisions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.659-664
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• 2009

This paper describes lightning impulse operating duty performance and temperature dependence of series gap type for transmission line arresters. The ageing parameters of lightning arresters are impulse current, moisture ingress, temperature ageing and so on. Especially it is important to estimate the change of electrical characteristics by lightning impulse current. In the discharge withstand test, total energy applied to the ZnO arrester each time is 4/10 ${\mu}s$, 30 kA. and in the operating duty test, the arrester has passed the test if thermal stability is achieved, if the residual voltage measured before and after the test is not changed by more than 5 %, and after the test reveals no evidence of puncture, flashover or cracking of the ZnO block. As a results, the residual voltage was in the range of 17.2${\sim}$20.3 kV and ZnO block bear up against at 2 shot of series impulse current of 30 kA. Also it was so excellent that the mechanical destruction does not occur at the 2 groups of 5 impulses current of 2/20 ${\mu}s$ 10 kA. According to the tests, it is thought that the ZnO arrester shows good stability with impulse current test. and it was found that the ambient temperature is increased resistive leakage current was increased in the range 47.3${\sim}$167.4 ${\mu}A$.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1632-1634
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• 2003

For lihgtning and switching impulse voltage performances in laboratories, impulse voltage measuring system, which is consisted of voltage divider, recording instrument and connecting system between divider and recording instrument, is used. In order to show reliability of test result in test laboratory, tracebility of these measuring system to be using in test laboratory is needed. In this paper, we describe tracebility and uncertainty of impulse voltage measuring system in test laboratory.

• Journal of the Korean Home Economics Association
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• v.45 no.3
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• pp.33-42
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• 2007

The purpose of this study was to examine the relationship between online apparel impulse buying behavior and product category/price of apparel items. The data were collected using an online survey with a structured questionnaire and a total of 731 responses were retained. Two hypotheses were put forward to test the relationships among the variables. Test of H1 showed that some product categories purchased by the respondents in the impulse purchase group were significantly different from those bought by the non-impulse purchase group. Categories such as shirt/blouse and belt were bought more frequently by the respondents in the impulse purchase group whereas shoes were bought more frequently by those in the non-impulse purchase group. The respondents in the impulse purchase group bought more items that cost less than $25 than those in the non-impulse purchase group. Based on the results, H1 and H2 were supported. From the results of the study, it is concluded that product categories and product price are closely related to the online apparel impulse buying behavior.

• 전기의세계
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• v.25 no.5
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• pp.75-78
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• 1976

The most difficult problem encountered in impulse test of transformer is the determination of exact fauly for coil layer short. This paper is to establish one of improved standards in the above case by means of wave form analysis, based on the equivalent circuits and experimental investigation. During the fault occurs, the local oscillation in fault circuit is applicable where as the reflection wave is utilized to the main circuit. The result current wave form at neutral impeadance point is similar to the wave form by impulse test and has the singular wave form respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.484-485
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• 2007

This paper describes the series-gap characteristics of transmission line arrester with switching and lightning impulse flashover test. The transmission line arrester exhibited external gap because it is must not flashover with switching impulse on the other hand it is must flashover with lightning impulse. In accordance, minimum and maximum length of series-gap was determinated with these tests. As gap length is increased flashover voltage was increased in the range of 315.4 kV~496.3 kV and negative polarity exhibited a high voltage. As a result, It was thought tat the series-gap length of transmission line arrester exhibited in the range of 580 mm~1100 mm.

• International Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.25-29
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• 2016

This paper highlights the performance of an impulse turbine which is a part of turbopump in a liquid rocket first stage engine. The turbopump, currently under development at Korea Aerospace Research Institute, has an impulse type turbine with 12 nozzles and a single rotor. The impulse turbine can archive high specific power with the low gas flow rates. The supersonic impulse turbine with a single rotor can make a simple structure. High-pressure gases are converted into the dynamic energy with flows through the 12 nozzles and drive the rotor to make the power for the pumps. The turbine test was performed in the high-pressured turbine test facility with air gas instead of burned gas. A hydraulic dynamometer was used to absorb the power from the turbine and control the rotational speed and torque. The test points were at several pressure ratios with 7 different rotational speeds. Results showed the efficiency was highest at the design pressure ratio. The efficiency was insensitive to the pressure ratio variation than the rotational speed. It was a typical characteristic in an impulse turbine.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1368-1370
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• 1995

Lightning impulse voltage is essential to evaluate the insulation performance of electric power apparatus. Recently international standard(IEC-60) on high voltage measurement techniques are being revised. In the draft of this standard, a new calibration method is introduced and the accuracy of most industrial measuring systems is maintained by means of comparison test against the reference measuring systems. Intercomparison tests of dividers for lightning impulse measurement were carried out by KERI. The shielded resisitive divider with 700kV rating developed by KERI were done comparison test with PTB divider with 300kV rating which have the similar charateristics as that were circulated among the laboratories. This paper reports on the comparison test results with full lightning impulse voltages from 126kV to 240kV. It is demonstrated that KERI are capable of realizing the idea in the revision of the IEC standand, that is, to establish traceability.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.9_10 s.146
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• pp.1306-1315
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• 2005

Impulse buying has been considered a pervasive and distinctive phenomenon in the modern lifestyle and has been receiving increasing attention from consumer researchers and theorists. In the modern marketplace, spontaneous urges to buy and consume often compete with the practical necessity to delay the immediate gratification that purchasing provides. The purpose of this study is to conceptualize and test the framework of impulse buying behavior for fashion products using structural equation model. Data were obtained from 413 students attending universities during schedules classes in Busan. Analysis of the data, utilizing AMOS 4.1, supported most of the predictions. The results showed that situational variable(time available) and individual variable(fashion involvement) have direct effects on consumers' shopping emotions, including positive and negative emotion. Positive emotions had effects on all types of impulse buying(planned impulse buying, reminded impulse buying, and fashion-oriented impulse buying), while negative emotion affected two types of impulse buying(reminded impulse buying and fashion-oriented impulse buying). These emotional experiences influence impulse buying behaviors for fashion products serving as critical mediators. The findings suggest that time available and fashion involvement are good predictors mediated by shopping emotion to impulse buying behavior for fashion products. The implications of this research for future work on the shopping emotion and impulse buying behavior are discussed.