• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.167-169
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• 2005

The occurrence of a single bit error in transmission bitstream leads to serious temporal and spatial errors. Because moving picture coding as MPEG-2 based on block coding algorithm uses variable length coding and motion compensation coding algorithm. In this paper, we propose algorithm to conceal occurred error of I-frames in transmission channel using data of the neighboring blocks in decoder. We divide a damaged macroblock of I-frame into four sub blocks and compose new macroblock using the neighboring blocks for each sub block. We estimate the block with minimum difference value through block matching with previous frame for new macroblocks and replace each estimated block with damaged sub block in the same position. Through simulation results, the proposed algorithm will be applied to a characteristic of moving with effect and shows better performance than conventional error concealment algorithms from visual and PSNR of view.

• 한국산학기술학회논문지
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• 제20권11호
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• pp.479-486
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• 2019

캡스기초공법은 조립골재층의 아칭효과를 이용하여 건물의 하중을 경감시키는 기초공법이지만, 아직까지 이에 대한 검증은 부족한 실정이다. 본 논문에서는 캡스기초공법 적용에 따른 하중의 경감효과를 정량적으로 입증하기 위해 캡스기초블록을 이용한 실내모형시험을 수행하였다. 실내모형시험은 캡스기초블록의 크기와 하중 재하판의 면적에 따라 모두 6가지 조건으로 실시하였으며, 모형 토조 내 3곳에서 재하 하중의 크기에 따른 토압의 변화를 관찰하였다. 시험 결과 캡스기초블록의 크기와 하중 재하판의 면적에 관계없이 하중 재하 지점과 가장 가까운 위치에서 토압이 가장 크게 나타났으며, 하중 재하 위치에서 멀어질수록 토압은 작게 나타났다. 토압이 가장 크게 나타난 위치에서 재하판의 면적이 30 cm × 30 cm 일 때 축소블록에 의한 토압은 블록이 없는 경우의 토압에 비해 평균 35.4 %, 표준블록은 평균 39.7 % 경감되었다. 또한, 재하판의 면적이 60 cm×60 cm 일 때 축소블록의 토압은 블록이 없는 경우의 토압에 비해 평균 33.9%, 표준블록은 평균 42.7 % 경감되었다. 따라서 조립골재의 아칭효과를 이용한 캡스기초공법을 적용한다면 축소블록의 경우 33 %, 표준블록의 경우 39 % 이상 하중경감효과가 있을 것으로 판단된다.

• 한국환경과학회지
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• 제22권6호
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• pp.687-694
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• 2013

To investigate organoclay, high styrene resin masterbatch (HSR), high impact polystyrene (HIPS), and polystyrene (PS) as reinforcing materials for the improvement of the abrasion resistance of poly(styrene-block-butadiene-block-styrene) (SBS), SBS/organoclay nanocomposites, SBS/HSR, SBS/HIPS, and SBS/PS blends were prepared. The effect of organoclay and blends on the abrasion resistance and mechanical properties of SBS was investigated. Even though intercalations of organoclay are observed for SBS/Cloisite 20A nanocomposites and not for SBS/Cloisite 30B composites, the abrasion resistance of SBS/Cloisite 20A nanocomposites is worse than that of SBS/Cloisite 30B composites. When SBS was blended with HSR, HIPS and PS, the abrasion resistance of the blends increases with increasing of HSR, HIPS and PS content from 0 to 20 wt%.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.863-864
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• 2005

In recent years, we use overdriving scheme to improve the response time of the liquid crystal. Since conventional overdriving scheme uses memory to perform ideal processing, it is desired to reduce system cost by decreasing the data stored in these SDRAMs. As a general compression method, quantization, sub-sampling and Block Truncation Coding ( BTC ) are used, which process data in block base and cause block effect. So we proposed new data compression method by color space conversion. Because this method compresses luminance and chrominance signal by different ratio, it can efficiently reduce error of block effect in decompression image.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 봄 학술발표회 논문집
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• pp.84-90
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• 1991

Underground structures usually consist of rock masses or concretes which can be cracked or have cracks. This study aims to develop an analysis program which can deal with the effect of discontinuous behavior due to those cracks using the block theory. It is assumed that rock masses form blocks along the discontinuity lines, and deformation within the block is relatively small. The behavior of discontinuity plane of the structures is divided into sliding along the discontinuity plane. separation of discontinuity by tensile force, and degradation of asperity angle of discontinuity plane by external force with sliding of rock Basses. These behaviors are implemented using constitutive relation and relevent load-displacement relation defined through normal and shear stiffnesses. Time varying displacements and block velocities are calculated by explicit time stepping algorithm. The effect of rock supports including rockbolts is also considered, and the tending effects which occurs in relatively thin lining is also considered.

• 한국도로학회논문집
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• 제14권5호
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• pp.67-74
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• 2012

PURPOSES: In this study the influence factors related to abrasion resistance of interlocking concrete block have been evaluated, and comparisons between various domestic and foreign abrasion test methods was also accomplished. METHODS: The modified rotational cutting method suggested in ASTM C 944 was applied. Surface materials with different types of fine aggregate such as crushed sand, sea sand, and mixture of crushed and sea sand were tested to compare the aggregate effect for abrasion resistance. RESULTS: The different surface mixtures with various W/C ratios, mortar and fly ash ratios have been investigated for functional and economical considerations. CONCLUSIONS: This study had obtained reliable results by changing diamond blade of rotating cutter. Therefore, in order to improve the abrasion resistance of interlocking concrete block for road, a new mix design was proposed.

• 한국주조공학회지
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• 제20권3호
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• pp.181-187
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• 2000

There are two types of vacuum die casting, one is known as the chill block method, and the other is the valve block method. Efficiency of the valve block method is better than the chill block method. However purchasing and maintaining cost of the former one is very high, the latter method is popular in many small and medium die casting shops. Simple evacuation system using chill vent was prepared to investigate the effect of the air pressure, hose length and chill vent type on the pressure change in die cavity in this study. The rate of evacuation was influenced by the evacuation method, chill vent condition and hose length. Evacuation time became longer and vacuum level lower when evacuating cavity via chill vent. It took a longer time to evacuate the cavity when a longer hose was used. Vacuum level in the cavity also decreased with increase in hose length.

• 한국도로학회논문집
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• 제16권2호
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• pp.1-9
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• 2014

PURPOSES : This study aims to evaluate the performance of interlocking block pavement system for low speed highway. METHODS : Through on-site monitoring, environmental impact assessment of interlocking block pavement such as heat island reduction, traffic safety, noise pollution were evaluated as compared with asphalt pavement. Also the pavement condition and roughness were evaluated according to performance period. RESULTS : Surface temperature of interlocking block pavement was about 7 degree lower than asphalt pavement in midsummer. Compared to asphalt pavement, vehicle speed reduction effect of interlocking block pavement was about 2kph. For low speed driving, the noise pollution was measured at a similar level for both asphalt and interlocking block pavement. After 42month service period, the breakage of block was only 0.24% for the whole surveyed area. IRI of interlock block pavement was estimated within the range of 5~8m/km. CONCLUSIONS : Depending on the performance monitoring results such as heat island reduction, providing traffic safety and keeping a good pavement condition for a long service period, it assures that interlocking block pavement was applicable for low speed road.

• 대한한의학회지
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• 제25권1호
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• pp.213-219
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• 2004

1. 경막의 차단술 시행시 경막천자로 인해 두통, 이명, 항부강직감, 현운 등의 후유증이 발생할 수 있다. 2. 경막외 차단술 후유증의 증상들은 간신음허로 변증할 수 있다. 3. 경막외 차단술 후유증 동반한 유추간판탈출증 환자에게 음허변증에 기본하여 한방치료한 결과 후유증으로 인한 두통, 이명, 항부강직감 등이 소실되었고, 요통, 하지인통의 추간판탈출증상도 개선되었다.

• 대한기계학회논문집B
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• 제22권3호
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• pp.294-302
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• 1998

Ignition characteristics of a vertical solid fuel plate with block have been investigated experimentally. For low radiant heat flux, ignition does not occur in a vertical solid fuel plate without block. In the case with the block on a vertical fuel plate, however, ignition can occur by increasing the residence time and the time to absorb the incident radiation flux by fuel vapor in gas phase. The ignition occurs below block and the point varies according to the block location and the block height. As the block height increases, the block locates at higher position, and the hot wall temperature increases, the ignition delay time decreases. Also as the initial temperature of fuel plate rises, the ignition delay time of the solid fuel plate decreases. The temperature distribution of solid fuel plate with block is nearly proportional to the radiant heat flux distribution. Therefore, the effect temperature by natural convection heat transfer is of the same order as that of inhibition of temperature increase by pyrolysis.