• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.95-96
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• 2016

This paper presents a voltage and frequency droop control for accurate power sharing of parallel distributed generation (DG) inverters in low voltage microgrid. In practice, line impedances between inverters and the point of common coupling of a microgrid are not always equal. This inequality in line impedances often results in reactive power sharing mismatch among inverters. To address this problem, intensive researches have been conducting. Although these methods can solve the unbalanced reactive power sharing, there are still problems remain unresolved, such as complicated structure or circulating current. To overcome such problems, a new droop control scheme is proposed, which not only guarantees accurate reactive power sharing but also has simple structure so that it can be easily implemented in existing systems without any hardware modification. The simulation is performed using Matlab/Simulinks to validate the proposed scheme.

• 한국전자거래학회지
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• 제3권2호
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• pp.113-124
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• 1998

The architectural design requires collaboration among various participants, such as architects, clients and engineers in the stages of the design process. Rapid development of information technology enables effective and prompt exchange and sharing of digital architectural information, otherwise should have been exchanged and managed by traditional ways. However, the core technology for supporting this demands has not been fully investigated so far. This paper aims to show the possibility of adopting network based architectural design information sharing system through surveying and analyzing the state-of-the-art network technology and its uses in architectural information exchange among various design actors. To realize these aims, this paper 1) investigates and analyzes the current status of network technology in the architectural and construction practice, 2) suggests systematic information exchange and sharing mechanism for architectural products and drawings data, and 3) demonstrates network based prototypical architectural information system.

• 전자통신동향분석
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• 제36권5호
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• pp.51-61
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• 2021

To reduce mobile network deployment costs and expand service coverage, mobile infrastructure sharing is becoming increasingly important. This paper introduces the concept and potential benefits of mobile infrastructure sharing as documented in the existing literature. Then, the current status of significant cases of mobile infrastructure sharing in major overseas countries is examined. Finally, sharing 5G infrastructure in rural areas in Korea is introduced. The Korean case is expected to complete national 5G coverage successfully without involving negative competition.

• 정보처리학회논문지C
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• 제11C권6호
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• pp.739-746
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• 2004

라이선스 메커니즘은 DRM(Digital Rights Management) 시스템의 핵심 요소 중의 하나이다. 라이선스 메커니즘은 DRM 시스템의 자원(resources), 자원의 사용 주체(principals), 자원에 대한 사용 규칙(usage rules) 등을 명확하게 식별하고 강제하기 위한 핵심적인 기능을 담당하도록 설계된다. 하지만 기존의 라이선스 메커니즘들은 가정이나 회사의 어떤 부서와 같은 그룹 내의 멤버들이 어떤 컨텐츠론 공유하고자 할 때 공유에 관련된 융통성이 부족하다. 본 논문은 그룹에 등록된 여러 명의 멤버들이 DRM 기술로 보호된 디지털 컨텐츠를 안전하고 융통성 있게 공유할 수 있도록 하는 새로운 라이선스 메커니즘을 제안한다. 본 논문이 제안하는 멤버/그룹 라이선스 메커니즘은 그룹 라이선스, 멤버 라이선스, 허가들(grants)간의 파생 관계 등의 개념들을 도입하여 기존의 라이선스 메커니즘을 확장한다.

• 전력전자학회논문지
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• 제9권4호
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• pp.341-349
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• 2004

본 논문에서는 전체 시스템의 용량 증대와 부하 중요도에 따른 신뢰성 향상을 위해 사용되는 UPS 병렬 운전시 발생하는 문제점을 해석하고, 이를 해결하기 위해 기존에 연구되어온 다양한 제어기법들을 조사하였다. 또한 기존의 연구방법에서 적용할 수 없었던 다른 정격의 병력 운전 적용시 L, C 출력필터에 의한 문제점을 해결하기 위해 주종 제어를 이용한 3상 UPS의 전류 분달 제어기법이 연구되었다. 제안된 제어 알고리즘의 타당성을 검증하기 위해 시뮬레이션 및 실험을 수행하였다.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.161-165
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• 2023

This paper designed a voltage feedback driving circuit to compensate for the characteristic deviation of the Active Matrix Organic Light Emitting Diode driving Thin Film Transistor. This paper describes a stable and fast circuit by applying charge sharing and polar stabilization methods. A 12-inch Organic Light Emitting Diode with a Double Wide Ultra eXtended Graphics Array resolution creates a screen distortion problem for line parasitism, and charge sharing and polar stabilization structures were applied to solve the problem. By applying Charge Sharing, all data lines are shorted at the same time and quickly positioned as the average voltage to advance the compensated change time of the gate voltage in the next operation period. A buffer circuit and a current pass circuit were added to lower the Amplifier resistance connected to the line as a polar stabilization method. The advantage of suppressing the Ringing of the driving Thin Film Transistor can be obtained by increasing the stability. As a result, a circuit was designed to supply a stable current to the Organic Light Emitting Diode even if the characteristic deviation of the driving Thin Film Transistor occurs.

• 한국전자파학회논문지
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• 제25권10호
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• pp.1005-1019
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• 2014

본 논문은 미국 및 유럽을 중심으로 활발하게 진행되고 있는 주파수 공동사용에 대한 정책추진 현황 및 경제성 분석 결과, 이를 통한 주파수 공동사용의 후보 대역 선정 방안에 대해 제안하였다. 이를 위해 현재의 주파수 수요 급증에 대응하기 위해 시행되고 있는 주파수 할당 및 재배치 방법에 대한 추진현황과 문제점을 고찰하였으며, 이에 대한 해결방안으로 선진국을 중심으로 추진되고 있는 주파수 공동사용의 개념 및 국외 정책추진 현황, 사업자 관점에서의 주파수 공동사용에 대한 경제성 분석 결과를 소개하였다. 또한, 조사 및 분석결과를 통하여 주파수 공동사용의 후보 대역 선정을 위한 평가항목 및 선정기준에 대해 제안하였다.

• 전력전자학회논문지
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• 제25권3호
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• pp.188-194
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• 2020

This paper presents a high-efficiency Switch Mode Line Transformer (SMLT) composed of load-shared dual modules, which is based on the AC/AC LLC resonant converter. Given that the conventional adaptor is usually composed of two power stages, namely, the PFC and DC/DC converters, its system size can be increased according to the output power. However, given that the proposed SMLT can separate the PFC converter from the adaptor, the size reduction of the system can be achieved. Meanwhile, the SMLT with a single module has the limit of the size reduction because of a high resonant current. Thus, it can be configured with dual or multiple modules to reduce the resonant current. Then, their load sharing can be guaranteed by only the proposed transformer structure without an extra current controller. The validity of the proposed converter is proven through a 850-W prototype.

• 한국산학기술학회논문지
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• 제12권8호
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• pp.3603-3609
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• 2011

본 논문에서는 CAN(Controller Area Network) 통신을 이용한 균등한 전류 분배를 위한 새로운 부하분담(Load-sharing) 알고리즘(Algorithm)을 제안한다. 기존 아날로그 방식과는 달리 디지털 통신을 이용한 강인한 부하분담특성을 가지며, 모듈마다 독립된 제어기(전압제어기, 전류제어기)가 구성되어 있으며, 마스터(Master)의 지령치 모듈의 지령치에 따라 슬레이브(slave)모듈이 부하분담을 수행한다. 또한 각 모듈 상태를 파악하기 위해 별도의 제어선을 사용하여 모듈의 고장 상태 및 고장난 모듈의 위치를 정확히 파악함으로써, 효율적이고 고속의 부하분담을 구현하였다. 제작된 병렬 시스템은 각 모듈마다 독립된 제어기가 구성되어 있으며, 본 논문에서는 PSIM을 통한 시뮬레이션과 시작품 제작을 통해 제안된 알고리즘의 타당성을 검증하였다.

• 한국식생활문화학회지
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• 제20권6호
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• pp.683-687
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• 2005

This study examined food sharing characteristics revealed in the modern Korean society by both interpreting phenomena and analyzing literature. Diet was said to be the least influenced by western modernization in Korea. Concerning this matter, one of the important explanations to be considered would be a strong influence of 'the first settlement effect' in culture, as reviewed elsewhere. Sharing food means not only sharing food itself but also sharing communal solidarity. The latter was strongly emphasized in Korean food culture due to his own historical grounding. Some examples revealed in current Korea included sometimes too much generous treat when eating out, even saliva allowed food sharing, too much food provision, and too many restaurants. 'Dutch treat' observed in many occasions of food sharing in Korea was also viewed as a product of historical experience, which was related to the degree of traits of feudalism in modern societies as feudalism was based on a sort of a give and take contract. The association of the degree of traits of feudalism and communal solidarity was explored by comparing so called different meal treat manners between Koreans and Japanese, that is, more generous attitude among the former. The concept of communal solidarity was also examined with respect to Koreans' side dish sharing behaviors which sometimes accompanied seemingly insanitary saliva sharing. In addition, provision of too much food was analyzed by relating this manner to a traditional 'hand over dining table' custom. Traditionally, food on a dining table was not supposed to be only for those sitting on the table. Even though the 'hand over dining table' was no longer well preserved at present time, its cultural traits appeared to be well prevailed in the modern Korean society. Finally, an increase of restaurants as well as an increase of eating out occasions were postulated with respect to the notion that restaurants were the places for ascertaining communal solidarity while sharing foods. The above analyses suggest the importance of the influence of sharing originated from his/her own historical grounding for better understanding of modern Korean food culture.