• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.592-598
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• 2000

The locality of data references at the distributed shared memory systems affects the performance significantly. Data allocation methods by considering the locality of data references can improve the performance of DSM systems. This paper evaluates the performance for the dynamic limited directory scheme which data allocation methods can apply very effectively. The information of the data allocation is used by the dynamic limited directory scheme to set the presence bit effectively. And the proper use of the presence bit improves the performance by reducing memory overhead and using directory pool efficiently. Simulations are conducted using three application programs which have various data sharing. The results show that the optimal data allocation method improves the performance up to 3.6 times in the proposed scheme.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.28-29
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• 2017

기존의 위상천이 풀 브리지 DC/DC 컨버터의 경우 변압기의 누설 인덕턴스와 2차 측 정류 다이오드의 기생 출력 커패시턴스 사이의 공진으로 인하여 정류 다이오드 양단에 큰 공진 전압이 발생하며, 이는 소자의 신뢰성 저하 및 시스템의 전력 변환 효율을 감소시킨다. 반면 LLC 공진형 컨버터는 2차 측에서 발생되는 공진 에너지가 출력 커패시터로 흡수되지만 경 부하시에 높은 스위칭 주파수로 인하여 효율이 저감되며, 출력 전압을 제어하기 위해 추가적인 부하저항이 요구된다. 따라서 최근에는 LLC 공진형 컨버터로 동작시키면서도 PWM 제어를 통해 출력전압을 제어하는 방법이 연구되고 있으나, 새로운 게이트 구동 방식을 위해 DSP 제어를 사용하고 있다. 따라서 본 논문에서는 산업에서 많이 사용되고 있는 아날로그 IC를 통해 동일한 동작 및 성능을 구현시킬 수 있는 방법에 대하여 제안한다. 본 논문에서는 제안된 방식의 타당성을 검증하기 위하여 이론적으로 분석하며, 6.6kW급 시작품을 제작하여 제안방식의 타당성을 검증하였다.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.70-75
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• 2002

This paper proposes new single stage power factor correction (PFC) full bridge converter. The proposed converter is combined previous ZVS full bridge DC/DC converter with two inductors, two diodes, two magnetic coupling transformer for PFC. This process of power is isolated from the source and also regulate stable DC output voltage in a category. In this topology, the voltage stress of main switches is reduced by zero voltage switching. Moreover, the proposed converter doesn't need active PFC switch and auxiliarly circuits, like control and gating board, so it could decrease the size and cost and increase the efficiency.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.2
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• pp.50-55
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• 2001

In this paper, a 8bit parity checker/generator is designed using a new gate which is proposed to implement the exclusive or(XOR) and exclusive-nor(XNOR) functions for low power consumption on transistor level. Conventional XOR/XNOR gate such as CPL, DPL and CCPL designed to reduce the power consumption has an inverter to get the full swing output signals. But this inverter consumes the major part of power and causes the time delay on CMOS circuits. Thus a new technique was adopted not utilizing inverter in the circuits. The results of simulation by Hspice shows 33% of power reduction compared with CCPL gate when A 8 bit parity checker was made with the proposed new gate using $0.8{\mu}mCMOS$ technology.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.19-21
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• 2019

본 논문에서는 용접 전문의 전력단 스위치로 MOSEFT을 사용하는 ZVS-PWM 스위칭 방식의 풀브리지 회로에 대한 연구결과를 발표한다. 제안된 ZVS-PWM 풀브리지 컨버터는 스위칭 주파수를 60kHz로 사용하고 변압기를 병렬로 적용해 고전력밀도를 갖도록 설계되었다. 변압기 병렬 구동 시 발생하는 전력 불균형 현상은 공통모드 결합 인덕터(CMCI; Common Mode Coupled Inductor) 부착을 통해 개선되었다. 본 논문은 제안된 회로의 연구를 실험을 통해 검증하고 이에 대한 실험 결과 및 분석을 나타내고 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.56-61
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• 2005

The induction heating is widely used not only in the industrial fields but also in the home appliances. But the conventional induction heating systems have shortcoming that it use only magnetic utensil, in this paper, heating of Aluminum sheet by full-bridge series resonant high-frequency inverter is proposed. Also, the principle of induction heating and operations of full-bridge inverter equivalent circuit are explained. The proposed inverter controls the output voltage using phase-shift irrespective of the switching frequency using phase-shift. As a result the proposed induction heating system by full-bridge resonant inverter shows the possibility that make up for the shortcoming of the conventional existing induction heating systems.

• The Mathematical Education
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• v.58 no.1
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• pp.79-99
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• 2019

This study is a study to collect information about 'Limitations of functions' related learning. Especially, this study was conducted on three students who can find answers by algebraic procedure in the process of extreme problem solving. Students have had the experience of converting from their algebraic procedures to graphical expressions. This shows how they reflect on their algebraic procedures. This study is a study that observes these parts. To accomplish this, twelfth were teaching experiment in three high school students. And we analyzed the contents related to the research topic of this study. Through this, students showed the difference of expressions in the method of finding limits by using algebraic interpretation methods and graphs. In addition, we examined the connectivity of the limitations of functions problem solving process of functions using algebraic procedures and graphs in the process of converting algebraic expressions to graph expressions. This study is a study of how students construct limit concepts. As in this study, it is meaningful to accumulate practical information about students' limit conceptual composition. We hope that this study will help students to study limit concept development process for students who have no limit learning experience in the future.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.481-487
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• 2005

Proposed induction-heated system is innovative system which applied special high-frequency power circuit technique for thermal converse technique and IH(Induction-Heating) magnetic induction heating generated from induction-heated metallic package that is for distillation unit. In this occurs not burning, so that the working environment can be improved. This electromagnetic induction heating technique is used high frequency inverter, By using high frequency inverter high frequency alternative current in the range of [kHz] can be made with conventional alternative current. In this contribution IGBT module is used for high frequency inverter. This paper proposes new fluid heating method. Which is operated as follows. Working coil, which is wrapped outside of pipeline, makes the eddy current. Inside of heating vessel in isolated pipeline the specially designed stainless metallic package is inserted, which can be heated by eddy current losses. And then In this paper are discussed action analysis and characteristics analysis of 5[kW] class full-bridge resonant inverter system and resonant metallic package. In addition, by using this system, how high-efficiency heater is developed and application of system are also discussed.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.73-78
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• 2002

In WATM networks, in order to perform dynamic slot allocation required slots of mobile terminals are estimated based on DP (Dynamic Parameter) reflecting characteristics of traffic. In VBR (Variable Bit Rate) traffic, slot allocation is done at MT considering both time-dependent characteristics and QoS (Quality of Service) requirements. In this paper, DPs-buffer state information and buffer state change-are transmitted through in-band signaling. BS (Base Station) performs dynamic slot allocation considering traffic characteristics of each MT (Mobile Terminal), in other words, buffer state information informs the potentiality of 'buffer full state'to BS if MT buffer is over the specific threshold value and buffer state change notifies change in buffer state of incoming cells to MT. If buffer state information is equal to 'low (more than threshold)' and 'abrupt increase' it generates 'buffer full' state cell transmission delay or cell loss might occur. At this time BS should assign additional slots to MT, and then MT consumes cells in its buffer. In simulation, the proposed scheme shows better performance in cell delay and loss than EPSA (Estimation-Prorated Slot Assignment) in-band scheme.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.691-695
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• 2004

본 논문에서는 2대의 다이오드 정류기에 풀브리지 컨버터를 이용하여 전류의 파형을 능동적으로 만들어 정현파의 입력전류를 얻는 새로운 통신용 정류기 시스템을 제안한다. 본 방식으로 낮은 직류전압(48V)을 직접 출력하며 전압의 조정도 가능하다. 또한 역률개선을 위한 부가적인 회로와 그에 따르는 제어가 필요하지 않고 연속 도통모드로 동작하여 비교적 높은 전력에 적용이 가능하다. 제안한 방식의 동작원리와 제어 및 설계방법을 기술하고 1.7KW 축소 모형으로부터의 실험결과를 제시한다.