• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.342-345
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• 2004

An efficient hybrid ARQ scheme based on the rate compatible block turbo codes has been proposed, and its performance has been analyzed. System efficiency is improved by means of adaptive rate code transmission using channel information, trading off bit rate for channel codes, with resulting energy saving. The rate adaptation scheme improves power efficiency while keeping packet delay minimized. On the other hand, power dependant strategies reduce power consumption. Simulation results show that the benefits obtained are very encouraging. The modified hybrid ARQ schemes with the channel information and efficient retransmission structures highly improve the throughput performance in the satellite communication system. Therefore, proposed schemes could be used in future communication systems.

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.10-13
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• 2016

The wet-air oxidation in gravity pressure reactor is effective for organic waste treatment with energy saving under high pressure and high temperature. But its oxidation control is difficulty because its multi-phase flow characteristics is very complicated. The flow characteristics of an oxidizer feed section in the gravity pressure reactor were investigated using numerical method which are verified by comparison with experimental results. In this study, the results showed that the flow rate of oxidizer have an effect on the generation of bubble around feed section.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.695-698
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• 2002

Induction heating process is one of the most efficient heating process in terms of temperature control accuracy and heating time saving. In the past study, fabrication process of cellular 6061 alloys by powder metallurgical route and induction heating process was studied. To supplement the framing conditions that studied in past study, effect of induction heating capacity and holding time at foaming temperature were investigated. Under the achieved framing conditions, teamed 6061 alloys were fabricated for variation of foaming temperature, and porosities(%)-foaming temperature curves were obtained by try-error experimental method. Uniaxial compression tests were performed to investigate the relationship between porosities(%) and stress-strain curves of framed 6061 alloy. Also, energy absorption capacity and efficiency were calculated from stress-strain curves to investigated. Moreover, dependence of plateau stress on strain rate was investigated in case of cellular 6061 alloy with low porosities(%)

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.650-651
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• 2011

공용 컴퓨팅 자원은 전력 자원 소모가 지속적으로 발생하는 컴퓨팅 자원 중 하나이다. 하지만, 공용 컴퓨팅 자원은 그 활용 특성상 소유 의식 및 비용 문제로부터 사용자의 책임성이 떨어지므로 전력자원의 지속적 낭비가 이루어지는 대표적인 전력 소모처이다. 따라서 본 연구에서는 공용 컴퓨팅 시설에서 운용되는 컴퓨터 시스템에 대한 다양한 상태에서의 전력 사용량을 측정 분석하였으며, 이를 통해 시스템 차원에서 제공하는 전력 절약 기능에서도 유휴 상태와 유사한 전력 소모가 있음을 밝히고 있다. 이에 본 논문에서는 공용 컴퓨팅 자원 (컴퓨터 시스템) 및 사용자의 활용성 측정에 기반을 둔 공용 컴퓨팅 자원 제어 시스템을 제안한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.31-34
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• 2001

Changing to a 24-hour urbanistic life style, a night time activities constituted for a major portion. Important of a beautiful exterior lighting as well as safety, and security concerns become increasingly. However, the removal or control of the excessive lighting is considered more important then increasing the brightness of the lamps to achieve bother safety and security. Representing a cheerful and leisure environment from the exterior lighting can also harmonize two aspects of energy saving and sustaining green environment. Designing of exterior lighting at the ＯＯ Agricultural & Fishery Circulation center symbolizes the suitability, convenience and production. It's design and analysis represent the optimum urban night time environment.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1150_1151
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• 2009

전기 에너지는 우리 생활에서 가장 사용하기 쉽고 가까이 있는 에너지이다. 그러나 전기 에너지를 생산하는 화석연료가 점점 고갈되어 가고 기후변화협약에 의해 에너지 절감이 필수인 시대이다. 그래서 본 논문에서는 건축물에서 사용하는 전기 에너지 중에서 많은 부분을 차지하고 있는 조명용 전기 에너지를 줄이기 위한 방안으로서 천연 에너지인 태양광을 이용하여 전기 에너지 사용을 줄이면서도 실내 조도를 기준조도 이상으로 유지할 수 있는 조명제어 알고리즘을 제안하다. 제안된 조명제어 알고리즘은 외부에서 실내로 유입되는 태양광을 최대한 활용하여 조명등 사용을 줄이고, 이를 통해 전기 에너지를 줄일 수 있게 해준다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1956-1957
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• 2006

도로조명의 가로등은 에너지 절약을 위하여 격등제어 방식을 사용하고 있으나 등주 사이의 조도 분포가 균일하지 않아 조도가 낮은 곳에서 운전자가 불안감을 느끼고 피로가 급격히 증가하여 사고로 이어지는 등의 문제점에 대해서 각 가로등에 디밍제어 시스템을 구현하여 안정적인 조도를 유지하고 에너지 절감효과를 증가시킬 수 있는 방안을 제시하였다. 또한 가로등과 배전반 사이에 전력선통신 네트워크를 구성하여 시공과 관리에 소요되는 비용을 대폭 절감하고 신뢰성과 호환성이 높은 $L_{ON}W_{ORKS}$ 전력선통신방식을 사용하여 유지보수의 효율을 높일 수 있도록 구성하였다. 배전반과 관리자 사이에는 다양한 통신방식의 지원으로 관리자가 언제 어디서나 가로등 네트워크에 접근하여 관제가 가능할 수 있도록 가로등의 U-네트워크를 구축하여 에너지 절약형 가로등 디밍제어 시스템 을 제시하였다.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.1005-1008
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• 1999

HMC has developed the lean burn system with alpha 4-valve into domestic market in the end of 1997. In a viewpoint of saving energy and prevention of global warming (CO2 reduction), the lean burn system has recently attracted a considerable attentions in gasoline engines. There has been, however, difficulty in extending LML(Lean Misfire Limit) enough to meet the emission regulations and satisfaction of driveability. In this paper some descriptions will be given upon the new technology of lean bum engine which will be installed in Accent, especially the improvement of the combustion, the development of engine management system such as intake system and wide range air fuel control strategy, and the result of vehicle test.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2556-2558
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• 1999

We present voltage-source inverter for variable speed of washing machine. In the case of previous washing machines only on/off contol of motor was satisfied but these days the desire of customers moves to more silent and energy saving machine. Therefore many white goods manufacturers consider variable driving methods of motor. Nowadays variable speed Induction motors powered by inverters are becoming more and more popular. In this paper the principles of constant V/F control of Induction motor used in washing machine and space vector PWM technique are reviewd. Implementation issues such as command voltage generation, switching pattern determination, speed and power measurement are also presented. Experimental results are included in the end of the paper.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.191-196
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• 2001

In the systems with largely pipe head loss, variable speed pumps are generally used because substantial energy saving can be expected from such systems by controlling pump speed and also they offer simpler maintenance and operational ease even in conditions where abrupt changes In flow rate and head can occur. The invertor or the fluid coupling system are mainly adopted to control the rotating speed. In this paper, operating conditions at Migum pressing pump station(5 stage), where the fluid coupling system was the first installed for KOWACO, are investigated and analysed so that information thus gained can be usefully employed in the efficient operation of variable speed pump in new installations of in-line booster pumping station.