• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권3호
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• pp.133-139
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• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권3호
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• pp.277-282
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• 2005

This paper describes a step-down AC voltage regulator using an AC chopper and auxiliary transformer, which is a series connected to the main input. The detail design of the AC regulator, logic and PWM pattern of the AC chopper is described and the three-phase AC regulator using two single­phase AC choppers with a three transformer configuration is proposed for three-phase application. The proposed three-phase system has the advantages of lower system cost due to reduced switch number and gate driver circuit as well as advantages of decreased size and weight because it uses a series compensated scheme. The proposed AC regulator has many benefits such as fast voltage control, high efficiency and simple control logic. Experimental results indicate that it can be used as a step-down AC voltage regulator for power saving purposes very efficiently.

• 통상정보연구
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• 제4권2호
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• pp.233-252
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• 2002

This thesis is designed to draw up scheme for human resources development of the Korean software industry. Its concrete scheme is as follows. That is, IT professionals with international competitiveness should be cultivated, and a human resource development system, which can flexibly meet the market demands, has to be built. Pool of specialized programmers is necessary condition for achieving competitiveness in Korean software industry. Reeducation is also desirable to embody the agile productive capability into the existing human resources for new challenges in the industry. Well-organized human resources database will also make it easy to match new demand and to lower the transaction cost in switching jobs. To cope with the rapidly changing environment actively, human resource development and training system improvement through the cooperation with the concerned industries, universities, research centers and the government must be settled immediately.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.59-63
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• 2005

전력계통을 효율적으로 운용하려면 관련량을 정확하고 신속히 계산하는 좋은 알고리즘이 필요하다. 최근 IEEE Transaction on Power System에 위상각 이동을 이용한 손실 최적화 알고리즘이 발표되었다. 동일한 손실최적화 문제를 본 논문에서는 Standard method of Lagrange Multiplier 기법을 적용하여 해석하였으며, 그 결과 저자들은 두 가지 방법이 수학적으로 동일함을 증명하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.201-206
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• 2002

The paper presents the component parts and their models of the Switched Reluctance motor drive system with the angle position-current chopping control and with the fixed angle pulse width modulation control. The calculation of the parameters and the simulated models based on the MATLAB SIMULINK software package are introduced by a four-phase 816 structure prototype with the four-phase asymmetric bridge power converter. The simulation of the prototype in the course of starting is made by the simulated models at the different control strategies and the different given rotor speed.

• 한국콘텐츠학회논문지
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• 제9권7호
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• pp.121-129
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• 2009

전력검침은 전력 사용요금을 부과하기 위하여 전력사용량을 측정하는 행위를 말하며, 이를 자동화한 시스템을 전력원격검침(AMR: Automatic Meter Reading)이라 한다. 전력원격검침은 검침 인력을 시스템으로 대체해 원가를 줄이고 고객 서비스를 강화할 수 있는 시스템으로 부각되고 있다. 본 논문에서는 기존의 전력원격검침 모델의 대안으로 스마트카드 기반의 전력원격검침 프레임워크 SCEMS를 제안하고 구현하였다. 제안된 SCEMS 프레임워크는 자바카드 기반의 다기능 스마트카드를 사용하며, 스마트카드에 수집된 자료와 가구의 전력사용 패턴을 활용하여 다양한 요금제를 지원하는 등의 고객서비스를 제공한다. 제안된 원격검침 모델 연구는 전력산업의 환경변화에서 초래할 다원화, 이질화, 복합화에 대한 해결방안이 될 수 있을 것으로 보인다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1101-1103
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• 1999

Deregulation and restructuring of electric industry change the fundamental nature of electric business which will be coordinated by the evolved market structures such as spot market with pool and bilateral transaction structure, forward market and future market. Introduction of competition can significantly change the system operation in near-terms as well as long-run generation expansion planning Previous centralized planning by monopoly utilities which was guided for the public service purpose will be replaced by decentralized investments plan by individual generation companies in response to commercial incentives. This paper reviews WASP model as a centralized planning tool and presents a methodological analysis of generation expansion planning in deregulated power systems. It stresses how affects the process of planning new generation investments by the introduction of competition and how maintains proper fuel mix and continuously sustains system reliability under deregulated environments.

• Current Photovoltaic Research
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• 제10권2호
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• pp.62-71
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• 2022

The Global RE100 campaign is a one of the voluntary campaign, but it has a lot of influence on domestic companies that have not yet joined the Global RE100. Accordingly, the Korean government introduced the Korean RE100 (K-RE100) system to prepare an institutional mechanism for domestic companies to respond to RE100. However, in Korea, due to the high LCOE of renewable energy and institutional limitations of the power transaction system, there is a limit for companies to implement RE100 in various ways. Therefore, in this study, the implementation cost of RE100 for green tariff, REC purchase, third-party PPA, direct(or corporate) PPA, and self-generation was compared and analyzed to derive the order of implementation with the net present value (NPV) of costs incurred over 20 years. As a result, self-construction was analyzed as the most economical method, but the implementation through the green tariff seemed to be the most realistic implementation method so far. However, considering the gradually falling LCOE, third-party PPA and direct PPA could be secured competitiveness against green tariff in 2025 and 2026. Then it could allow the companies to have various portfolios for implementation of RE100.

• 산업경영시스템학회지
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• 제41권3호
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• pp.21-29
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• 2018

The cooperative relationship between Employer and Contractor in the construction industry is the most important factor to achieve the project success. Employer shall draw the Contractor's cooperative behavior during executing the project. A study on the impact of the Owner's power on the contractor's cooperative behavior is rare in the construction industry in Korea even though the negative impact of the high-power distance between the Employer and the Contractor has been a hot issue in Korea. In this empirical study, it is shown that the Employer's power can address the contractor's cooperative behavior. The respondents were mostly employees in the domestic construction companies who have experienced in the construction projects. The total number of respondents was 317 effectively. The multiple regression analysis using SPSS 21.0 were conducted to verify the hypotheses. In conclusion, the Mediated Power is positively associated with the In-Role Behavior and with the Extra-Role Behavior. Some of Non-Mediated Power is positively associated with the In-Role Behavior and with the Extra-Role Behavior. It seems that the Contract underestimate the Employer's Expert Power. It was known that the cooperative power caused by Non-Mediated Power is good for long term relationship of the business to business transaction. So it is highly recommended that the Employer shall foster its expertise.

• 지능정보연구
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• 제27권1호
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• pp.65-82
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• 2021

주식시장에 참여하는 투자자들은 크게 외국인투자자, 기관투자자, 그리고 개인투자자로 구분된다. 외국인투자자 같은 전문투자자 집단은 개인투자자 집단과 비교하여 정보력과 자금력에서 우위를 보이고 있으며, 그 결과 시장 참여자들 사이에는 외국인투자자들이 좋은 투자 성과를 보이는 것으로 알려져 있다. 외국인 투자자들은 근래에는 인공지능을 이용한 투자를 많이 하고 있다. 본 연구의 목적은 투자자별 거래량 정보와 머신러닝을 결합하는 투자전략을 제안하고, 실제 주가와 투자자별 거래량 데이터를 이용하여 제안 모형의 포트폴리오 투자 성과를 분석하는 것이다. 일별 투자자별 매수 수량과 매도 수량 정보는 한국거래소에서 공개하고 있는 자료를 활용하였으며, 여기에 인공신경망을 결합하여 최적의 포트폴리오 전략을 도출하고자 하였다. 본 연구에서는 자기 조직화 지도 모형 인공신경망을 이용하여 투자자별 거래량 데이터를 그룹화하고 그룹화한 데이터를 변환하여 오류역전파 모형을 학습하였다. 학습 후 검증 데이터 예측결과로 매월 포트폴리오 구성을 하도록 개발하였다. 성과 분석을 위해 포트폴리오의 벤치마크를 지정하였고 시장 수익률 비교를 위해 KOSPI200, KOSPI 지수 수익률도 구하였다. 포트폴리오의 동일배분 수익률, 복리 수익률, 연평균 수익률, MDD, 표준편차, 샤프지수, 벤치마크로 지정한 시가총액 상위 10종목의 Buy and Hold 수익률 등을 사용하여 성과 분석을 진행하였다. 분석 결과 포트폴리오가 벤치마크 대비 2배 수익률을 올렸으며 시장 수익률보다 좋은 성과를 보였다. MDD와 표준편차는 포트폴리오와 벤치마크가 비슷한 결과로 성과 대비 비교한다면 포트폴리오가 좋은 성과라고 할 수 있다. 샤프지수도 포트폴리오가 벤치마크와 시장 결과보다 좋은 성과를 내었다. 이를 통해 머신러닝과 투자자별 거래정보 분석을 활용한 포트폴리오 구성 프로그램 개발의 방향을 제시하였고 실제 주식 투자를 위한 프로그램 개발에 활용할 수 있음을 보였다.