• 방송공학회논문지
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• 제18권6호
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• pp.884-894
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• 2013

최근 지구 온난화에 따른 이산화탄소 배출량 감소 및 에너지 절약을 위하여 방송통신 기술 역시 에너지를 절약을 위한 연구가 시작되고 있다. 특히 방송통신 시스템의 전체 소비 에너지는 기지국에서 87.5%이상 차지하고 있지만 물리계층에서 에너지 효율성에 관한 연구는 전송용량을 총 전력 단일 상수로 나누어 분석하기 때문에 실제적인 에너지 특성을 분석하는데 문제점이 많다. 본 논문은 이와 같은 문제점을 해결하기 위하여 실제 증폭기에 사용되는 트랜지스터의 특성과 신호 모델에 관하여 간략히 소개한다. 이는 에너지 효율적인 방송통신 시스템을 설계하는데 이용 가능한 비선형 증폭기의 신호모델 그리고 증폭기의 특성을 고려한 기지국의 총 전력 사용량까지 포함하여 효율적인 에너지 효율을 계산하는 데 중요한 이해를 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1982-1985
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• 2003

Future cellular networks will mainly be driven by, high quality channels, high band with utilization, low power consumption and efficient network management. For a given channel allocation, the capacity and quality of communication of cellular radio systems using CDMA(Code Division Multiple Access) can be increased by using a transmitter power control scheme to combat the near-far problem. Centralized power control schemes or distributed ones to maximize the minimum signal-to-interference in each user of CDMA wireless network have been investigated. This paper has proposed a distributed power control algorithm, which employs an adaptive search scheme, in order to solve quickly the linear systems of equations for power update in CDMA cellular radio systems. The simulation results show that the proposed scheme has faster convergence rate than the typical bang-bang type of distributed power control algorithm, which has been much used as a reference algorithm in IS-95A and W-CDMA communication network.

• 한국정보기술학회 영문논문지
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• 제9권1호
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• pp.39-46
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• 2019

This paper proposes an efficient tag identification scheme for ISO/IEC18000-7 standard by dividing the tags into smaller groups. Tag grouping is based on the reader's transmission power. This can reduce the responding tags in the collection round. If the small number of tags exists, we can anticipate the collision probability will decrease. And it makes the identification speed high. A collection round initiated by the reader's collection command. It also proceeds with increasing the power of the reader until all tags are identified. The results showed that 25% of the performance improved.

• 전력전자학회논문지
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• 제7권2호
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• pp.121-128
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• 2002

새로운 에너지 회수 방식을 채용한 고효율 PDP 구동회로가 제안된다. 제안된 에너지 회수 회로는 PDP의 등가캐패시터에 저장된 에너지를 회수하기 위해서 종래의 에너지 회수 회로에서 부가되었던 별도의 보조 회로 없이 2개의 인덕터 만을 사용하므로 그 구조가 매우 간단하고 시스템 부피가 작으며 적은 수의 전력 소자만으로도 구현이 가능하므로 제작단가 절감효과를 얻을 수 있으며 높은 효율 등의 장점을 가지고 있다. 뿐만 아니라 PDP 화면에서 방사되는 광의 파형이 균일하고 안정적이므로 고화질을 보장하기도 한다. 제안된 회로의 유효성 검증을 위해 전 구간회로를 모두 갖춘 42인치 PDP를 스위칭 주파수 200kHz로 구동한 실험 결과를 제시하며, 본 논문에서 제안된 회로는 차세대 벽걸이형 컬러 TV에 매우 적합하게 적용될 수 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.373-375
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• 2008

Studying for environmentally-friendly and efficient energy source is now actively under way on because problems like environmental pollution and exhaust of natural resources are in issue. Pure Cell which is an alternative energy source has low voltage and high current characteristic, therefore boost up voltage converter and DC-AC converter is required to use as a common power source. In this paper, DC-DC converter which has high efficient and high power density is proposed and verified by experimental result.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1185-1192
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• 2004

Recently heavy traffic is getting worse because increasing population of transportation in urban area. In order to solve this problem. subway is realized with high speed, high density, highly efficiency. When fire accident happened in Dae-Gu subway in February 2003, there happened loss of people and lots of damage because of not being able to control even though fire alarm which was set up in the station rang. This thesis has constructed a simulation integrating operation system using a Database construction, operating program analysis in order to build up the most efficient train operation system. The result of simulation integrating operation system with emergency virtual situation like station and train fire, train failure, power line failure, all trains running on the rail were secured safety by train operation control system. With integrating operation of each train control system, train system, power system, machine facility system, the most efficient integrating operation system should have been constructed at the time the subway fire and power failure broke out.

• Journal of Computing Science and Engineering
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• 제6권4호
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• pp.310-319
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• 2012

Next generation wireless receivers demand low computational complexity algorithms with high computing power in order to perform fast signal detections and error estimations. Several signal detection and estimation algorithms have been proposed for next generation wireless receivers which are primarily designed to provide reasonable performance in terms of signal to noise ratio (SNR) and bit error rate (BER). However, none of them have been chosen for direct implementation as they offer high computational complexity with relatively lower computing power. This paper presents a low-complexity power-efficient algorithm that improves the computing power and provides relatively faster signal detection for next generation wireless multiuser receivers. Measurement results of the proposed algorithm are provided and the overall system performance is indicated by BER and the computational complexity. Finally, in order to verify the low-complexity of the proposed algorithm we also present a formal mathematical proof.

• 전력전자학회논문지
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• 제6권2호
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• pp.217-221
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• 2001

본 논문에서는 통신기기와 같은 저용량 부하를 위한 APLC를 설계하였다. APLC는 부하와 병렬로 위치하여 부하에 필요한 무효전력 성분만을 공급함으로 운전 효율을 향상시켰으며 히스테리스 제어기를 마이크로 프로세서와 아날로그 회로를 이용하여 구현하여 저가형 제어기를 구현하였다. 컴퓨터 시뮬레이션을 통해서 보상 시스템의 특성을 해석하였으며 또한 실험에 의해 제안된 APLC제어기가 고조파 저감 및 역률 개선을 수행하고 있음을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.79-86
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• 2009

This paper presents a flyback technology in power conversion aimed at increasing efficiency and power density, reducing cost and using minimum components in AC-DC conversion. The proposed converter provides these features for square waveforms and constant frequency PWM. It is designed to operate in a wide input voltage range of 75-265VAC RMS with two output voltages of 5V and 20V respectively and full load output power of 5W. The proposed converter is suitable for high efficiency and high power density application such as LCDs, TV power modules, AC adapters, motor control, appliance control, telecom and networking products.

• 공학기술논문지
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• 제10권2호
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• pp.203-208
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• 2017

Due to global climate change issues, there is a growing demand for systems throughout the industry. In the case of power conversion, studies have been actively conducted to change the structure of the power conversion circuit and to apply new power devices. In particular, the WBG (Wide Band Gap), which is newly emerged device in the market for developing semiconductor technology, has demonstrated advantages in applying for various aspects in comparison to the existing Si (Silicon) Semiconductor. Recent research centers in the railway industry are focusing on developing technologies suitable for railway vehicles by utilizing these new developments in railway countries such as Japan and Europe. This paper researches the WBG device that is applicable to the auxiliary power supplies (APS) in railway system, and analyzes the downsizing effects to APS in high-speed railway by conducting a theoretical analysis and simulation.