• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.252-254
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• 2008

In this paper, the PSCAD/EMTDC modeling of JeJu AC power system with wind farms will be discussed. And the modelling of the synchronous generator, exciter, governor will also be defined in the JeJu power system by using the PSCAD/EMTDC. At the same time the fault analysis and the power flow analysis in JeJu AC power system are presented to demonstrate the JeJu AC power system can perfectly simulate the real JeJu power system function. Through the simulation using PSCAD/EMTDC we have gained the same results compared with the results accomplished by the PSS/E. so the validity of the modelling for the JeJu power system by using PSCAD/EMTDC is confirmed.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.179-182
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• 2009

PSS (Product-Service Systems) 개발에 있어서 중요한 요소로서 사용자의 경험을 들 수 있다. 제품개발 시 가장 중요하게 고려되는 요소로서 고객의 요구 (customer requirement)와 니즈 (needs)가 언급되곤 한다. 고객의 요구나 니즈는 실제로 관련 제품이나 서비스를 사용해 본 고객의 경험에 근거하고 있다. 따라서 고객의 경험을 제대로 파악하고 이를 추출하는 것이 성공적인 제품개발의 시작이다. 본 연구의 목적은 사용자 경험을 활용하는 제품-서비스 시스템 (UXPSS)을 위한 프레임워크 모델을 개발하고 샘플 제품에 대한 구현을 실시한다. 이를 위해서 사용자 경험, 제품의 서비스화, 서비스의 제품화, 서비스 사이언스, 기능분석 및 모듈화를 결합한 통합 모델을 개발하고 이를 실험적으로 구현해 본다.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1038-1040
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• 1997

This paper describes dynamic characteristics test of distance relay and current differential relay using Real Time Digital Simulator on double circuit transmission line. First, The double circuit T/L modeling on RTDS was proposed and the results from the proposed model were compared with those of PSS/E. This comparison shows the possibility of dynamic test using the RTDS. The relay included about 20 test items which are apt to include maloperation of protective relays in critical situations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.487-492
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• 2003

This paper analyzes an eigenvalue distribution and enhancement of the small signal stabiligy when an Unified Power Flow Controller (UPFC) modeling is connected into the multi-machine power system. Recently a lot of attention has been paid to the subject of dynamic stability. It deals with analysis of eigenvalue sensitivities with respect to parameters of UPFC Controller and damping of interarea and local electromechanical oscillation modes using UPFC Controller. It provides an insight and understanding in the basic characteristics of damping effects of UPFC Controller and shows a very stable frequency response via UPFC in test model. The series branch of the UPFC is designed to damp the power oscillation during transients, while the shunt branch aims at maintaining the bus voltage and angle. Comprehensive time-domain simulation studies using PSS/E show that the proposed robost UPFC controller can enhance the small signal stability efficiently in spite of the variations of power system operating conditions.

• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.827-849
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• 2017

Self-sufficiency (SS), which is often used in the social welfare policy of the American welfare system, is an important concept in the field of social welfare and has been studied so much. Among such studies there are also studies on how the employment hope scale and the perceived employment barrier scale, which the psychological SS (PSS) consists of, affect the economic SS (ESS) for low-income job seekers in the United States. These studies are generally conducted using survey data, which are mainly analyzed by structural equation model (SEM) in the field of social science field. In the survey data, the number of measurement variables is generally large and there is a correlation between variables. In such cases, Principal Component Analysis (PCA) can be used. The purpose of this study is to compare the results of SEM and PCA on the survey data mainly dealt with in the social science field. We compare the performance of the two analyzing methods through a small simulation study. We also analyze a real survey data of the ESS and the PSS by using these two methods and compare the results.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.11
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• pp.625-631
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• 2003

The purpose of this paper is to assess experimentally system stability of the 154 ㎸ transmission system due to the current of the forthcoming AC High-Speed Railway (HSR) era. It introduces a simple method to evaluate the system stability The proposed method also shows the relationship between stability and power losses, and the stability indices made by the numerical process proposed in this paper will be used to assess whether a system can be stabilized or not. This paper also presents the improvement of the stability via loss reduction using STATCOM. Reactive power compensation is often the most effective way to improve both power transfer capability and system stability. The suitable modeling of the electric railway system should be applicable to the PSS/E. In the case study the proposed method is tested on a practical system of the Korea Electric Power Corporation (KEPCO) which will be expected to accommodate the heavy HSR load. Furthermore, it prove that the compensation of voltage drop and its by-product, loss reduction is closely related to improvement of system stability.

• Journal of Distribution Science
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• v.15 no.2
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• pp.101-109
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• 2017

Purpose - Previous studies related to emotional labor of salespeople have mainly focused on identifying the antecedents of emotional exhaustion and turnover intention and exploring the mitigating effects salespeople's motivation on emotional exhaustion and turnover intention. They also demonstrates that there are different roles for moderating in social support, which means mental/physical support related to the job in supervisors, colleagues and organizations. The purpose of this paper is to investigate how service employees' surface acting affect turnover intention through emotional exhaustion. Another important objective of this paper is to investigate whether perceived social support moderates 1) the relationship between surface acting and emotional exhaustion 2) the relationship between emotional exhaustion and turnover intention. Research design, data, and methodology - To test the hypotheses, we collected the data from Korean insurance company sales employees. A total of 235 responses were received, from which 220 usable responses were obtained after list-wise deletion. Working with a sample of 220 responses, structural equation modeling was employed to empirically test research hypotheses(

The relationship between surface acting and emotion exhaustion,

The relationship between emotion exhaustion and turnover intention,

The moderating effect of perceived social support(PSS) on the relationship between surface acting and emotion exhaustion, and

The moderating effect of perceived social support(PSS) on the relationship between emotion exhaustion and turnover intention. SPSS 22.0 and AMOS software were used in these data analysis. Results - The service employees' surface acting was positively related to the emotional exhaustion; in turn, the service employees' feelings on emotional exhaustion are positively related to turnover intention. In addition, Perceived Social Support significantly moderated the relationship between surface acting and emotional exhaustion. However, perceived social support has a non-significant moderating effect on the path from emotional exhaustion to turnover intention. On the basis of these results, the following conclusion can be drawn. First, distribution service companies will be needed the administrative efforts to offer counseling programs and space to provide their members with enough rest in experiencing psychological pain due to the salespeople's surface acting. Also, it is necessary for distribution service companies to identify and share the examples of successfully solving emotional exhaustion caused by salespeople's surface acting.