• 한국산업정보학회논문지
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• 제22권2호
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• pp.79-89
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• 2017

본 연구에서는 적응형혼합유전알고리즘(Adaptive Hybrid Genetic Algorithm: AHGA) 접근법을 이용한 폐쇄루프 공급망(Closed-Loop Supply Chain: CLSC) 모델 최적화를 다루고 있다. CLSC 모델 구축을 위해 공급업체(Part Supplier), 제품제조업체(Product Manufacturer)등으로 구성된 전방향물류(Forward Logistics)와 수집업체(Collection Center), 회복센터(Recovery Center)등으로 구성된 역물류(Reverse Logistics)를 함께 고려하고 있다. 제안된 CLSC 모델은 수리모형(Mathematical Model)으로 표현되며, AHGA접근법을 이용해 이행되어 그 최적해를 구하게 된다. 수치실험에서는 기존연구에서 제안된 몇몇 접근법과 AHGA 접근법을 함께 사용하여 그 수행도를 비교분석하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.118-118
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• 2003

전력반도체 소자로 사용되는 p$^{-}$-n$^{-}$ 접합 다이오드의 스위칭 속도를 향상시키고 그에 따른 에너지 손실을 감소시키기 위해 전자 조사를 실시하였다. Reverse recovery time이 현저히 감소한 반면, 전자 조사에 의한 누설전류와 on-state 전압 강하와 같은 그 외의 전기적 특성 저하는 무시할 수 있는 정도였다. 그밖에 시료의 deep level transient spectroscpy(DLTS) 분석 결과와 secondary ion mass spectrometry(SIMS) depth profile을 근거로 결함 분포와 전자조사 유도결함의 유형을 논하였다.

• Journal of Power Electronics
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• 제14권2호
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• pp.265-270
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• 2014

In terms of power loss, a MOSFET has two advantages over an IGBT with an antiparallel diode: purely resistive without an offset voltage in conduction and no tail current at turn-off. However, the reverse recovery characteristic of the body diode is so poor that MOSFETs have not yet been available for high-voltage power converters with bidirectional power flow legs. This paper introduces how MOSFETs can be fully applied to high-voltage power converters with bidirectional power flow legs in order to achieve high efficiency. With a bidirectional DC-DC converter with one leg as the simplest example, the basic circuit topology and operating principle are described in detail. The high efficiency and stable operation of the proposed converter are validated through experiments with a 1.5 kW prototype.

• 전기전자학회논문지
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• 제24권2호
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• pp.586-591
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• 2020

본 논문에서는 인터리브된 전류 주입형 고승압 DC-DC 컨버터가 제안된다. 높은 전압 이득 외에도 인터리빙 방식을 채택하여 낮은 리플 입력 전류가 달성된다. 또한 제안 된 컨버터의 소프트 스위칭 특성은 전력 스위치의 스위칭 손실을 줄이고 변환 효율을 높인다. 변압기의 누설 인덕턴스를 활용하여 다이오드의 전류 변화율을 제어함으로써 출력 정류기의 역 회복 문제도 완화된다. 200W 프로토 타입에서 얻은 실험 결과에 대해 설명한다.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1438-1448
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• 2019

We present a new technique, called VED (very effective debugging), for detecting and correcting division by zero errors for all types of .NET application. We use applications written in C# because C# applications are distributed through the internet and its executable format is used extensively. A tool called Immunity Debugger is used to reverse engineer executable code to get binaries of source code. With this technique, we demonstrate integer division by zero errors, the location of the error causing assembly language code, as well as error recovery done according to user preference. This technique can be extended to work for other programming languages in addition to C#. VED can work on different platforms such as Linux. This technique is simple to implement and economical because all the software used here are open source. Our aims are to simplify the maintenance process and to reduce the cost of the software development life cycle.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.373-376
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• 2004

전력전자 회로의 고속화에 따라 정류기의 역할은 점차 중요해지고 있다. 전원장치의 compact화 및 초소형화에 따라 스위칭 주파수는 높아지고 있다. 최근 전원장치의 on-line 뿐만 아니라 off-line에서의 효율을 향상시키려면 도통손실 및 스위칭 손실을 최소화를 요구받고 있다. 스위칭 주파수가 증가함에 따라 power rectifier는 도전 및 스위칭 손실의 최소화를 위해서는 스위칭 손실의 주된 원인인 역회복 특성을 잘 파악해야 한다. 이를 위해 본 고에서는 최근 제작된 SiC SBD의 역회복 특성을 분석을 위한 $t_{rr}$, 측정을 위한 $t_{rr}$ Tester를 MIL-STD-750-4031.4에 참고하여 제작하였으며, 제작된 $t_{rr}$ Tester를 이용하여 SiC SBD의 $t_{rr}$의 측정결과에 대해 기술하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.746-748
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• 1993

To overcome the problem of the diode reverse recovery in high switching frequency inverter, a new gate drive scheme is proposed for IGBT in this paper. Using this circuit, the reverse recovery current can be controlled and faster switching time can be achieved for hard switching inverter. The over-current protection method, which is suitable for the proposed gate driver, is also presented. The operation of the proposed circuit is investigated and its usefulness is verified through the experimental results.

• 한국전기전자재료학회논문지
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• 제17권12호
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• pp.1308-1313
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• 2004

Proton irradiation technology was used for the improvement of power diode switching characteristics. Proton irradiation was carried out at the energies of 2.32 MeV, 2.55 MeV, 2.97 MeV so that the projection range of irradiated proton would be at the metallurgical junction, depletion region and neutral region of pn diode, respectively. Dose conditions were varied into three conditions of 1${\times}$10$^{11}$ cm$^{-2}$ , 1${\times}$10$^{12}$ cm$^{-2}$ , 1${\times}$10$^{13}$ cm$^{-2}$ at each condition of energies. Characterization of the device was performed by I-V(current-voltage), C-V(capacitance-voltage) and trr(reverse recovery time) measurement. At the optimum condition of irradiation, the reverse recovery time of device has been reduced about 1/5 compared to that of original un-irradiated device.

• Journal of Power Electronics
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• 제19권3호
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• pp.645-654
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• 2019

In this paper, a new high step up DC/DC converter with a modified super-lift technique is presented. The coupled inductor technique is combined with the super-lift technique to provide a tenfold or more voltage gain with a proper duty cycle and a low turn ratio. Due to a high conversion ratio, the voltage stress on the semiconductor devices is reduced. As a result, low voltage ultra-fast recovery diodes and low on resistance MOSFET can be used, which improves the reverse recovery problems and conduction losses. This converter employs a passive clamp circuit to recycle the energy stored in the leakage inductance. The proposed convertor features a high conversion ratio with a low turn ratio, low voltage stress, low reverse recovery losses, omission of the inrush currents of the switch capacitor loops, high efficiency, small volume and reduced cost. This converter is suitable for renewable energy applications. The operational principle and a steady-state analysis of the proposed converter are presented in details. A 200W, 30V input, 380V output laboratory prototype circuit is implemented to confirm the theoretical analysis.

• 경영과학
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• 제21권2호
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• pp.1-14
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• 2004

This paper presents a review on the operations research modeis for environmental management including water, land, and air poliution in the environmental chain and including waste treatment, reverse logistics, and product recovery in the supply chain for last 30 years. The integrated and globalized environmental issues have given OR professionals a lot of natural opportunities for an effective environmental management with mathematical programming and computer simulation tool.