• 대한임베디드공학회논문지
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• 제12권3호
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• pp.121-130
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• 2017

NAND flash memory has advantages of non-volatility, little power consumption and fast access time. However, it suffers from inability that does not provide to update-in-place and the erase cycle is limited. Moreover, the unit of read/write operation is a page and the unit of erase operation is a block. Therefore, erase operation is slower than other operations. The AGC, the proposed garbage collection policy focuses on not only garbage collection time reduction for real-time guarantee but also wear-leveling for a flash memory lifetime. In order to achieve above goals, we define three garbage collection operating modes: Fast Mode, Smart Mode, and Wear-leveling Mode. The proposed policy decides the garbage collection mode depending on system CPU usage rate. Fast Mode selects the dirtiest block as victim block to minimize the erase operation time. However, Smart Mode selects the victim block by reflecting the invalid page number and block erase count to minimizing the erase operation time and deviation of block erase count. Wear-leveling Mode operates similar to Smart Mode and it makes groups and relocates the pages which has the similar update time. We implemented the proposed policy and measured the performance compare with the existing policies. Simulation results show that the proposed policy performs better than Cost-benefit policy with the 55% reduction in the operation time. Also, it performs better than Greedy policy with the 87% reduction in the deviation of erase count. Most of all, the proposed policy works adaptively according to the CPU usage rate, and guarantees the real-time performance of the system.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.162-167
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• 1999

In Auxiliary block of High speed train Power factor correction and Harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. but the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increases switching frequency. In this paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.123-126
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• 2001

Block filter implementation technique for uniform filter banks is uniform in this paper. By applying block filter into decimation and interpolation filters, it is shown that down and up samplers are cancelled out in respective liters. Furthermore by applying block filters into uniform filter banks, significant reduction for computational complexity is achieved since prototype filter can be shared in each channel implementation. Also, it is shown that proposed implementation is a reconfigurable structure in terms of order variation.

• 대한가정학회지
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• 제42권8호
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• pp.203-218
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• 2004

Recently, knitted materials are used more often than ever before in fashion. Therefore it is necessary to study their application into garment patterns. The purpose of this study was to develop a system by which the tensile property of knitted fabrics can be applied. In this study, 5 different distribution methods of tensile property were tested on 2 sample fabrics which have a lower and higher tensile property than moderate-stretch. The subjects were five women within an age range from 18 to 24 who showed average body figures. The major findings derived from this investigation were as follows; The 4th method was regarded as the most valid. The 4th method was fixed proportional alteration based on the reduction amount of bust girth, i.e. front (back) width and shoulder width reduced by 60％ of the bust girth reduction and neck point reduced by 28％ of the bust girth reduction. When the reduction was based on the proportion of the actual measurements, the alteration was too severe, so that the armhole curve was changed into a very uncomfortable curve.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2018년도 하계학술대회
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• pp.175-177
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• 2018

This paper proposes an algorithm to speed up block structure partition of quad tree plus binary tree (QTBT) in Joint Exploration Test Model (JEM) encoder. The proposed fast encoding of QTBT block partition employs three spatially neighbor coded blocks, such as left, top-left, and top of current block, to early terminate QTBT block structure pruning. The propose algorithm is organized based on statistical similarity of those spatially neighboring blocks, such as block depths and coded block types, which are coded with overlapped block motion compensation (OBMC) and adaptive multi transform (AMT). The experimental results demonstrate about 30% encoding time reduction with 1.3% BD-rate loss on average compared to the anchor JEM-7.1 software under random access configuration.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권4호
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• pp.1389-1408
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• 2021

Proof-of-Work (PoW) is the first and still most common consensus protocol in blockchain. But it is costly and energy intensive, aiming at addressing these problems, we propose a consensus algorithm named Proof-of-Work-and-Block-Compression (PoW-BC). PoW-BC is an improvement of PoW to compress blocks and adjust consensus parameters. The algorithm is designed to encourage the reduction of block size, which improves transmission efficiency and reduces disk space for storing blocks. The transaction optimization model and block compression model are proposed to compress block data with a smaller compression ratio and less compression/ decompression duration. Block compression ratio is used to adjust mining difficulty and transaction count of PoW-BC consensus protocol according to the consensus parameters adjustment model. Through experiment and analysis, it shows that PoW-BC improves transaction throughput, and reduces block interval and energy consumption.

• 한국통신학회논문지
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• 제35권6C호
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• pp.523-529
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• 2010

본 논문에서는 페이딩 채널의 시간 상관성을 이용한 Lattice Reduction(LR)기반 MIMO 수신기의 계산량을 효과적으로 감소시키는 새로운 기법을 제안한다. 시변 페이딩 채널 환경에서는 채널의 시간 상관 특성으로 인하여 LR을 통해 얻어진 P 행렬이 시간에 따라 크게 바뀌지 않는다. 이러한 특성을 이용하여 제안된 기법에서는 채널이 바뀔 때 마다 LR을 수행하는 것이 아니라 수신단에서 K개의 채널 프레임을 저장하여 K번째 채널, 즉 nK번째 (n=1,2,3..) 채널에서만 LR을 수행하여 P 행렬을 구한 후 (n-1)K번째 P 행렬과 비교한다. 두 개의 P 행렬이 동일한 경우 K-1개의 채널 프레임에서는 LR을 수행하지 않고 K번째 채널 프레임의 P 행렬을 그대로 사용하여 불필요한 계산량을 감소시켰다. 반대로 두 개의 P 행렬이 다른 경우 나머지 K-1개 채널 프레임의 P 행렬을 이전 채널 프레임에서 구한 P 행렬을 초기조건으로 하여 LR을 수행함으로써 계산량을 감소시킨다. 제안된 기법은 기존 LR 기법과 같은 성능을 유지하면서 계산량을 확연히 감소시킨다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.437-440
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• 2000

This paper proposes a method to improve video quality on images that have blocking artifacts at block boundary. Block image transform coding suffers from blocking artifact that is a main cause of degrading video quality because of the quantization error of transform coefficients in quantization process. filtering and DPCM for DC components have been widely used to reduce blocking artifact. Recently, lots of works focus on the technique that minimizes block effects using discontinuity of block boundaries. In this paper, image blurring in decoding stage is improved by adding compensation factor to each transformed blocks so that discontinuity of block boundaries can be decreased. The compensation factor is applied on each block without much loss of edge components.

• 정보통신설비학회논문지
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• 제9권3호
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• pp.80-85
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• 2010

In this paper, we present an algorithm for efficient control of backlight LED in order to reduce the power consumption of LCD TV. In addition, a pragmatic implementation method is presented. In conventional local dimming control, backlight LEDs of LCD TV are divided into $M{\times}N$ blocks. And, the proper luminance for each block is computed according to input image and used for dimming control. But, LED light of each block is diffused and affects the neighboring blocks, so that luminance of each block becomes larger than that of intent. In the proposed algorithm, dimming control values are reduced by the amount of quantity affected by the neighboring blocks using light spread function, resulting in additional reduction of power consumption.

• Journal of Oral Medicine and Pain
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• 제36권1호
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• pp.71-79
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• 2011

공률이 낮은 것으로 알려져 있다. 본 연구의 목적은 이개측두신경을 전달마취하여 수조작할 경우 변위된 관절원판의 정복에 영향이 있는지 여부 및 그 결과에 영향을 미치는 인자들을 조사하는 것이다. 비정복성관절원판변위로 진단된 112명의 환자들에 대해 수조작정복술을 시도하였으며, 그 중 35명의 환자들에서 관절원판 변위가 해소되었다. 관절원판 재위치에 실패한 77명의 환자들 가운데 이개측두신경의 전달마취 시술에 동의하는 49명(평균 연령 $34.3\;{\pm}\; 15.1$, 남자 24명, 여자 25명)에 대해 마취시술 후 수조작 정복술을 다시 시행하였다. 연령, 발병후 경과시간, 술전 능동적개구량을 포함한 요인들과 국소마취 후 수조작 정복 성공률과의 관련성을 분석하였다. 수조작만으로 정복이 되지 않았던 49명 환자 중, 이개측두신경 전달마취 후 19명(38.8%)에서 성공적으로 정복이 되었다. 국소마취 전 49명의 최대 능동적 절치간 개구량은 $25.7\;{\pm}\;6.0$ mm로서 개구가 상당히 제한된 상태였으나, 국소마취 및 수조작 후 관절원판이 성공적으로 재위치된 19명의 개구량은 $46.1\;{\pm}\;4.5$ mm로서 정상범위로 회복되었다. 연령, 발병후 경과시간, 술전 능동적개구량 인자들과 국소마취 후 수조작 정복 성공률과는 유의한 관련성이 없었다. 결론적으로 이개측두신경 전달마취는 수조작정복술과 함께 시행할 경우 비정복성관절원판변위의 정복 성공률을 향상시 키므로, 비정복성관절원판변위의 일차적인 치료 단계에서 적극적으로 활용하는 것이 권장된다.