• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.99-100
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• 2013

기존 용접 컨버터는 풀 브릿지 컨버터는 하드스위칭을 하게 되는데, 이는 스위칭 소자로 사용되는 IGBT의 턴 오프 손실을 증가시키는 단점을 가지고 있다. 본 논문에서는 스위치의 손실을 줄이고자 기존의 풀 브릿지 컨버터에 ZVS(zero voltage switching) 턴 오프 방식를 적용한 회로와 하드 스위칭 방법에 대하여 손실을 PSIM 모의해석을 통하여 비교 분석하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.56-61
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• 1999

The fine blanking is a process of pressworking which makes possible to produce thick sheet metal parts of finished sheared surface and close dimensional accuracy over whole material thickness in single blanki ng operation. Fine blanked parts in general are characterized by their cleanly sheared surface over the whole sock thickness and accurate size for the specific functions. The fine blanking technology is urgently needed to remove secondary operations which are necessary in conventional blanking operation and cost reduction. In this study, the effect of material texture and vee-ring on parts for automobile is investigated by experimental observation and analysis.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.37-42
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• 1999

A compact imaging system, the Multi-spectral Earth Imaging System (MEIS) was developed and operated on an engineering test satellite, KITSAT-3 at the orbital altitude of 720 km. The MEIS takes multi-spectral images of the earth's surface with the swath width of 48 km and the ground sampling distance of 13.8 m in three spectral bands. A brief technical description of the KITSAT-3 MEIS and the result from its initial operation since early June, 1999 are presented. The quality of images produced by the KITSAT-3 MEIS was found comparable to that of images from existing commercial earth observation satellites from its preliminary assessment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.481-490
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• 2007

WASP which is used to plan generation expansion has disadvantages that can't manage environmental factors and regional supply-demand planning. But with the effectuation of the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol, it is expected that reducing greenhouse gases affects power system in its long-term generation expansion planning. Therefore national countermeasures is needed. This paper formulates a mathematical model considering CO2 emission constraints and Emission Trading that will be enforced. This model is based on the MEFISET (Model for Economic Feasibility of Interstate Electrical Ties) which was made by Korea Energy Economics Institute and Hong-ik university and manages generation expansion planning. And this mathematical model is verified by studying a case system.

• Environmental Engineering Research
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• v.17 no.3
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• pp.151-156
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• 2012

This research described the magnetic method for the rapid removal of green algae in water. We modified the pH, cation concentration, and magnetic powder concentration to discover the best removal performance. In order to rapidly remove green algae from water, we added magnetic powder and chitosan into algae water to make a magnetic substance and this was extracted by a strong neodymium magnet. The optimized conditions were pH of 6.5-7.5, chitosan concentration of 10 mg/L, and magnetite powder concentration of less than 0.05%. A higher removing rate was observed when a higher amount of magnetite or chitosan was used, but the total amounts of phosphorus or nitrogen were not decreased.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.120-123
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• 2011

모바일 디바이스와 플랫폼이 다양해지면서 개발 및 유지보수 비용이 증가하고 있다. 특히, 비즈니스 기능적인 요구사항을 충촉시킬 수 있는 사용자화면 개발방법이 중요해 지고, 높은 복잡도를 요구하는 모바일 어플리케이션의 문제점을 해결하고자 모바일 웹 어플리케이션이 등장하였다. 하지만 웹 기술요소만으로 사용자 화면을 개발하다 보니 서비스 성능이 저하됨 알 수 있었다. 이런 문제를 해결하기 위해서 하이브리드형 모바일 어플리케이tus 아키텍처를 제안만한다. 이는 웹 요소기술만을 사용하지 않고, 비즈니스 기능적인 요구사항을 충족시켜주기 위해서 UIFrame이라는 개념을 제안한다. 제안한 UIFrame 모델은 UI 표현능력, 서비스 성능향상과 디자이너의 영역과 개발자의 영역을 분리 함으로서 다양한 플랫폼에 대한 독립적이며 이식성이 우수하다. 또한 개발 효율성 및 유지보수가 용이함을 보인다.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.148-154
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• 1982

The effects of the various ligands on the oscillator strengths of the hypersensitive transitions of Nd(III) and Ho(III) have been studied in aqueous solution. The ligands used in the study are furoate, anthranilate, and squarate. The covalent character of the metal-ligand bond in the complex is discussed on the basis of the correlation diagram between pKa of the ligands and the oscillator strengths of the complexes previously reported.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.389-390
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• 2013

본 논문에서는 블록 놀이의 질적 향상을 위한다. 일반 블록 완구의 해결하지 못한 문제점인 조립과 완성으로 즐거움이 끝나고 분리시의 지루함을 해결하기위한 블록 자동분리 시스템에 관한 것으로, 좀 더 구체적으로는 블록을 이용하여 물체를 완성시키는 것에서 더 나아가 자동분리 블록의 외부에 부착된 마커를 스마트 폰을 이용하여 인식하고, 인식된 마커에 해당하는 영상을 스마트 폰을 통해 보며 미션을 수행하여 흥미를 유발시키고, 미션 완료 후 블록을 자동 분리 시키기 위한 블록 자동분리 시스템에 관한 것이다. 특히, 블록에 분리장치를 구성함으로써 스마트 폰과의 통신에 의해 분리장치가 동작하여 블록을 자동으로 분리 가능하도록 하여 물체를 완성 후 분리 시에 느끼는 지루함을 최소화하고, 흥미를 극대화시킬 수 있도록 한다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1543-1546
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• 2008

Modified pulse waveforms were applied to an AC plasma display panel with an auxiliary electrode in order to improve the operation voltage margin. Reciprocal sustain pulse waveforms and modified auxiliary pulse waveforms were applied to the sustain and auxiliary electrode, respectively. During the sustain period, the influence of the address electrode on the luminous efficacy of long-coplanar gap discharges was mitigated by application of reciprocal sustain pulse waveforms. Modified auxiliary pulse waveforms maintained the high efficacy obtained from the AC PDP with an auxiliary electrode. The proposed reciprocal sustain and modified auxiliary pulses waveforms can induce stable discharges in long-coplanar gap discharges and can control wall charges with a wider auxiliary pulse voltage margin, thereby enhancing the luminous efficacy of the AC PDP with an auxiliary electrode.

• Journal of electromagnetic engineering and science
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• v.7 no.3
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• pp.109-115
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• 2007

The performances of M-ary PSK(MPSK) systems using L-branch maximum ratio combining(MRC) diversity reception in frequency-nonselective slow Rician fading channels are derived theoretically. Especially we investigate the effect of number of symbols on the difference between the approximation to bit error probability and the exact bit error rate(BER) in evaluating the performance of MPSK signals through numerical analyses. On the other hand, when M-ary DPSK(MDPSK) signals experience the Rician fading channels, the general formula for evaluating BER of MDPSK signals in the independent branch diversity system is presented using the integral-form expressions.