• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.295-297
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• 1998

This paper shows characteristics of fault current division factor $S_f$, which is a ratio of earth- return current to total fault current, at a substation fed exclusively by power cables under unsymmetrical fault condition, such as single line-to-ground fault. In substation grounding system design, $S_f$ is a very important factor determining GPR, touch and step voltage at a substation under fault condition. In case of substations fed by overhead lines, 40-60% of $S_f$ has been typically used, although it is a very conservative value with no other network conditions considered. It is authors' hope that $S_f$ presented in this paper could hopefully be a basic reference in designing of substation grounding system, especially for a substation fed exclusively by power cables.

• 산경연구논집
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• 제8권5호
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• pp.77-85
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• 2017

Purpose - The purpose of this study is to investigate the variables that lead consumers to visit traditional markets and buy market goods. Thus, the current research examined the relationship between satisfaction and return intention as among the factors influencing loyalty. Research design, data, and methodology - This study was conducted to examine the effects of the perceived level of factors on loyalty and how it influenced consumers' visits to traditional markets in 125 adult adolescents and women living in Mok-po area. The results of the questionnaire were obtained. The statistical data of the questionnaire were verified by SPSS. Results - In this study, consumers' perception level of eight loyalty factors can be perceived by the traditional Korean market. The empirical analysis is summarized as follows. First, by selecting five representative variables influencing intention to return to traditional markets, Mok-po area consumers were affected by the intention to revisit according to the intensity of recognition level among these variables. Second, the higher the perceived level of product price, quality of access (accessibility) among the factors that consumers perceive as important factors in visiting traditional markets were heightened. Third, Mokpo residents are aware of the main important factors of visiting the market such as receiving a friendly atmosphere (image) about traditional market, market environment (hygiene and cleanliness), connection with the local economy, and customer service such as kindness, refund and return. These loyalty factors did not affect consumers' intention to revisit. In other words, image, environment, regional economic linkage, and these factors did not have a positive effect on revisit intention. Conclusions - The empirical analysis of this study suggests that factors that directly affect loyalty among the key factors that play a major role in visiting traditional markets should be identified and developed as loyalty factors. It is necessary to identify the key factors influencing the satisfaction and loyalty of traditional market users, and operate a system that systematically and comprehensively manages and evaluates them. In order to do this, the government, the local governments, and related organizations should regularly conduct loyalty and satisfaction surveys on visa recognition levels and establish strategies for dramatic improvement measures.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.29-38
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• 2022

The enormous sway of COVID-19 on the international financial market has been felt across the globe. The financial markets of Bangladesh have also been similarly affected by the global epidemic and experienced a significant increase in volatility. To scrutinise the connection between COVID-19 and the Dhaka Stock Exchange (DSE) indices' return and instability, this study uses data of the DSE from February 2014 to September 2021. A comparative examination of the return and instability of the stock indices of the DSE has also been done considering the outbreak of the current COVID-19 situation. After using the GJR-GARCH (1,1) model, this review uncovers that the outbreak of COVID-19 has a statistically positive noteworthy association with the DSE stock indices' instability, which increases the market's volatility. Traders' fear and the rising frequency of COVID-19 reported patients could cause this. Besides, according to this study, COVID-19 shows a substantial positive linkage with stock market returns that increases the market's return. An appealing valuation, lower interest rates in the banking channel, economic rebound following the closure to prevent coronavirus transmission, improved remittance inflows, and a return of export revenues could all have contributed to this outcome. In addition, the findings also reveal that all market indices are in a mean-reverting phase.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.259-262
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• 2006

본 논문에서는 2.4 GHz ZigBee 응용을 위한 저전력 CMOS LNA(Low Noise Amplifier)를 설계하였다. 제안된 회로의 설계에서 TSMC $0.18{\mu}m$ CMOS 공정을 사용하였고 current-reused stage를 이용한 2단 cascade 구조를 채택하였다. 본 논문에서는 LNA 설계 과정을 소개하고 ADS(Advanced Design System)를 이용한 모의실험 결과를 제시하여 검증하였다. 모의실험 결과, 1.0V의 전압이 인가될 때 1.38mW의 매우 낮은 전력 소모를 확인하였다. 또한 13.83dB의 최대 이득, -20.37dB의 입력 반사 손실, -22.48dB의 출력 반사 손실 그리고 1.13dB의 잡음 지수를 보였다.

• 반도체디스플레이기술학회지
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• 제4권4호
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• pp.1-4
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• 2005

The chemical composition and uniaxial compressive stress are varied to observe their effect on the current-voltage characteristics of ZnO based ceramics. The variation of chemical composition produces two kinds of ceramics showing ohmic and nonohmic current-voltage characteristics. The current at a fixed voltage increased with the increase of the compressive stress for both ohmic and nonohmic ceramics. Ceramics showing nonohmic behavior exhibit better reversible return of current-voltage curve when the applied compressive stress is removed from the ceramics than those showing ohmic behavior do. We found an appropriate chemical composition showing linear relation between current and stress at a fixed voltage. The ceramic materials with an appropriate chemical composition can be used as a potential sensing material in pressure sensors.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.2050-2058
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• 2018

Impulse characteristic of transmission tower grounding grid is needed for lightning protection of transmission line. This paper describes an outdoor experimental test facility established for large-scale grounding grid of transmission tower, made up of four impulse current generators and a circle current return electrode. The amplitude of impulse current is up to 100 kA. The results of the CDEGS simulation and GPR measurement reveal the uniform current distribution in the test arrangement. An impulse test for a square electrode with extended conductors is carried out in condition of three current waveforms with different amplitude. Based on the electrical network model and iterative algorithm method, a calculation model is proposed to simulate the impulse characteristic of large-scale grounding grid considering soil ionization. The curve of impulse resistance against the current amplitude shows the soil ionization both from the simulation and test. Deviation between the simulation and test result is less than 15%.

• 대한전기학회논문지
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• 제36권1호
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• pp.3-8
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• 1987

The conventional autosequentially commutated current-fed inverter (ASCI) is widely employed with the induction motor drives for speed control. Howener, this inverter has a limit of high power and high frequency indution motor drives. One of the limitations is to be found in the commutation capacitors in the main circuit of this inverter. A new current-fed gate turn-off thyristor (GTO) inverter is developed. This inverter is composed of the main GTO bridge configuration and the improved energy rebound circuit (ERC)without the commutation capacitor. This inverter works stable at high frequency from light load to heavy one. The improved ERC is used not only to rebound the load reactive power to the dc link, but also to return the power in the load to the ac source. The new GTO inverter circuit and the characteristics of the inverter induction motor drives are explained and analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1083-1084
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• 2006

The wide spread of DC electric railway systems such as urban rapid transits including heavy rail and light rail transits has significant ramification as the stray currents from return conductor rails can cause the electrochemical interference, that is, the electrolytic corrosion of both rails and outside underground metallic infrastructures. The immature understanding of either the railway authority who is responsible for establishing the necessary provisions at the design stage or the affected parties makes it difficult to prepare the optimum range of solutions for the long-pending interference problem. In Japan, however, numerous assessment studies have been carried out on the stray current interference, by which protective guidelines are provided by "Electrolysis Committee". In this paper, we review a guide book from "Tokyo Electrolysis Committee", namely, "Protective Methods for Stray Current Corrosion".

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.816-818
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• 2003

Solenoid actuator's operating speed is affected by magnetic motive force, plunger mass, inductance, return spring constant, and eddy current. Recently, non-magnetic ring is generally used for improving the operational speed, because it is impossible that changing of any specified design factor and stacking of plunger steel. This paper represents the dynamic equations of solenoid actuator, simulations for the response characteristics, analysis of eddy current effect by using the induced time constant. And, we experiment for the operating characteristics in case of non-magnetic ring is exists and not exists in the plunger.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1694-1703
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• 2014

Lightning induced voltage is a major factor that causes interruptions on distribution lines. In this paper, analytical expressions are proposed to evaluate a lightning induced voltage on power lines directly in the time domain without the need to apply any extra conversions. The proposed expressions can consider the widely used current functions and models in contrast to the earlier analytical expressions which had a number of limitations related to the simplification of the channel base current and the current along the lightning channel. The results show that the simulated values based on the proposed method are in good agreement with the previous studies and the proposed expressions can be used for optimizing the insulation and protection level of existing and new lines being designed.