• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.249-250
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• 2016

본 논문에서는 3병렬 풍력발전 시스템의 직류단 전류 리플을 저감하기 위한 인터리빙 기법을 제안한다. 병렬 구조의 풍력발전 시스템은 각 발전기 측 컨버터의 전류 고조파로 인해 직류단에 전류 리플이 발생한다. 이러한 전류 고조파들의 합과 관련된 전류 리플은 직류단 커패시터의 수명 단축 및 전체 시스템의 손실을 유발한다. 이를 방지하기 위해 3병렬 풍력발전 시스템에서의 전류 고조파를 분석하고, 전류 리플을 최소화하기 위한 최적의 인터리빙 각을 구하여 전류 리플을 저감하는 기법을 제안한다. 제안하는 기법의 타당성을 PSIM 시뮬레이션을 통해 확인한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.339-342
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• 2003

배치는 칩의 성능 및 레이아웃에 결정적인 영향을 주는 요인으로써 크게 광역배치와 상세배치 두단계를 거쳐 이루어지며 수년 동안 다양한 기법들이 개발되어 왔다. 본 논문에서는 표준 셀 배치를 개선하기 위한 동적 프로그래밍 기법을 이용한 최적 인터리빙 알고리즘을 확장하여 선을 동일 행 내에서만 움직이던 한계점을 극복하여 서로 다른 행 사이에서도 움직일 수 있도록 하였다. 즉, 셀들은 주어진 배치 내에서 임의의 위치로 움직일 수 있어 배치가 더욱 효율적으로 최적화 될 수 있도록 하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.92-104
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• 2006

The proposed method for a force directed global placement algorithm exploits and extends techniques from two leading placers, Kraftwerk (& KraftwerkNC) and Mongrel. It combines the strengths of KraftwerkNC, force directed global placer, and Mongrel's ripple move technique which resolves cell overlaps effectively The proposed technique uses the force spreading technique used in Kraftwerk to optimize the ripple movement. While it is resolving the cell overlap and optimizing wire length physical net constraints are considered for timing. The experimental results obtained by the proposed approach shows significant improvement on wire length as well as on timing.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.967-969
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• 2004

본 논문에서는 표준 셀 배치기 Mongrel을 소개하고 두 가지 분할 기법(FM, hMETIS)을 통해 효율적인 초기 배치를 얻음으로써 Mongrel의 성능을 개선한다. Mongrel은 middle-down 방법론을 채택한 전역 배치와 상세 배치의 2단계 표준 셀 배치기이며 전역 배치 단계에서는 RBLS(Relaxation-Based Local Search)를, 그리고 상세 배치 단계에서는 최적 인터리빙(optimal interleaving) 기법을 통해 최적화 알고리즘을 수행한다. MCNC 벤치마크 회로를 이용한 실험을 통해 Mongrel의 성능을 평가하고 효율적인 초기배치가 최종 결과에 미치는 영향을 분석한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.4
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• pp.405-414
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• 2011

Recently, the development of several hundreds of kW scale PCS for fuel cell generation is required as commercialization process of distributed generation systems using high temperature fuel cells such as MCFC begins. This paper proposes and optimized topology suitable for MCFC fuel cell generation system and LCL filter design method considering voltage quality of local loads such as MBOP. An interleaving technique is applied to step-up DC-DC converter, optimized number of phases is determined considering efficiency and volume. Also, a LCL filter design method is proposed considering quality of current injected to the grid as well as that of voltage across the local load. The proposed PCS system is validated through reduced 1kW prototype.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.263-264
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• 2020

고전압 응용에서 효율을 높이기 위해서는 소프트 스위칭 또는 스위칭 손실이 작은 소자를 사용해야 한다. 스위치는 일반적으로 전압이 높아 질수록 특성이 안 좋아 지는 경향이 있어서, 3레벨 형태로 스위치의 전압 정격을 낮추면 특성이 좋은 스위치를 사용 할 수 있다. 대용량 응용으로 확장 시, 모듈화 및 인터리빙 기법은 전류 정격을 낮춰 시스템의 경제성 및 유지 보수성이 증가하는 장점이 있다. 본 논문에서는 3레벨 인터리브드 양방향 벅-부스트 컨버터의 구조 분석을 통해 고전압, 대용량 응용에 적합한 최적 구조를 제안한다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.595-602
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• 2003

This Paper presents an efficient hybrid techniques for a standard cell placement. The prototype tool adopts a middle-down methodology in which an n${\times}$m grid is imposed over the layout area and cells are assigned to bins forming a global placement. The optimization technique applied in this phase is based on the Relaxation-Based Local Search (RBLS) framework [12］in which a combinatorial search mechanism is driven by an analytical engine. This enables a more global view of the problem and results in complex modifications of the placement in a single search“move.”Details of this approach including a novel placement legalization procedure are presented. When a global placement converges, a detailed placement is formed and further optimized by the optimal interleaving technique[13］. Experimental results on MCNC benchmarking circuits are presented and compared with the Feng Shui's results in［14］. Solution Qualifies are almost the same as the Feng Shui's results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.279-285
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• 2011

The next generation wireless communication systems are required high BER performance better than present performance. Double binary Turbo code have error floor at high SNR, so it cannot be used in next generation wireless communication system. Therefore, many methods are proposed for overcome error floor at DVB-RCS NG(next generation). In this paper, we analysis structure of third-dimension Turbo code(3D-turbo code). 3D-Turbo code overcomes error flow by additive post-encoder in conventional DVB-RCS Turbo code. Performance of 3D-Turbo code is changed by post-encoder form, interleaving method, value of ${\lambda}$. So we are simulated by those parameter and proposed optimal form. By a result, performance of 3D-Turbo is better than conventional DVB-RCS Turbo code and it overcome error floor of conventional DVB-RCS Turbo code.

• The KIPS Transactions:PartA
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• v.18A no.4
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• pp.135-142
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• 2011

This research is to design an effective buffer structure and its management for flash memory based high performance SSDs (Solid State Disks). Specifically conventional SSDs tend to show asymmetrical performance in read and /write operations, in addition to a limited number of erase operations. To minimize the number of erase operations and write latency, the degree of interleaving levels over multiple flash memory chips should be maximized. Thus, to increase the interleaving effect, an effective buffer structure is proposed for the SSD with a hybrid address mapping scheme and super-block management. The proposed buffer operation is designed to provide performance improvement and enhanced flash memory life cycle. Also its management is based on a new selection scheme to determine random and sequential accesses, depending on execution characteristics, and a method to enhance the size of sequential access unit by aggressive merging. Experiments show that a newly developed mapping table under the MBA is more efficient than the basic simple management in terms of maintenance and performance. The overall performance is increased by around 35% in comparison with the basic simple management.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.788-791
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• 2005

In this paper, We propose performance of improvement method for eHDR-WPAN system using Interleaver. Burst error pattern caused by fading in indoor wireless channel. for the reason, using of Interleave method (make burst error to random error) can be enhance to error-rate in system. This paper is used Convolutional, Block, Random Interleaver. We make use of 9 and 27 for symbol spacing. Block-Interleaver is show that performance about 0.6dB of E$_b$/N$_o$ at $10^{-4}$. In result, the suitable Interleaver for eHDR-WPAN system is Block Interleaver of 9 symbol spacing.