• Journal of the Korean Vacuum Society
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• v.4 no.4
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• pp.343-349
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• 1995

게데형 분자드래그펌프의 배기특성을 강구(hard sphere)분자모델과 NTC(No Time Counter)충돌 scheme을 이용한 직접모사 법의 하나인 DSMC(direct simulation Monte Carlo)방법을 이용하여 해석하였다. 해석에 사용된 모델은 높이가 일정하고, 길이가 높이의 1~3000배 사이인 이차원 채널이다. 자유분자영역으로부터 연속체 영역까지의 영역에서 최대압축비와 배기속도를 계산하였다. 계산결과 기존의 최대압축비 이론 결과는 채널내의 압력변화가 클 때는 큰 오차를 유발하는 것을 알 수 있었고, 유동방향의 기체분자의 통과확률은 채널 길이와 출구압력에 관계없이 거의 일정한 값을 갖는다는 것을 발견하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.839-842
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• 2008

The ACI 318-05 code requires the maximum amount of shear reinforcement in reinforced concrete (RC) beams to prevent possible sudden shear failure due to over reinforcement. The design equations of the maximum amount of shear reinforcement provided by the current four design codes, ACI 318-05, CSA-04, EC2-02, and JCI-99, differ substantially from one another. The ACI 318-05, CSA-04, and EC2-02 codes provide an expression for the maximum amount of shear reinforcement ratio as a function of the concrete compressive strength, but Japanese code does not take into account the influence of the concrete compressive strength. For high strength concrete, the maximum amount of shear reinforcement calculated by the EC2-02 and CSA-04 is much greater than that calculated by the ACI 318-05. This paper presents the effects of shear reinforcement ratio and compressive strength of concrete on the maximum shear reinforcement in reinforced concrete beams. Ten RC beams having various shear reinforcement ratio were tested. Although the test beams were designed to have much more amount of shear reinforcement than that required in the ACI 318-05 code, all beams failed due to web concrete crushing after the stirrups reached the yield strain.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.23-30
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• 2010

Compression techniques can be applied to large-scale fingerprint systems to store or transmit fingerprint data efficiently. In this paper, we investigate the effects of FBI WSQ fingerprint image compression on the performance of a fingerprint verification system using multiple linear regressions. We propose a maximum compression using fingerprint image quality score. Based on the experiments, we can confirm that the proposed approach can compress the fingerprint images up to 3 times more than the fixed compression ratio without significant degradation of the verification accuracy.

• Journal of Korean Society of Steel Construction
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• v.13 no.3
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• pp.223-232
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• 2001

Column tests subjected to compressive loading were carried out for the estimation of compression buckling strength of steel plate SM570 in beam-column member under high axial load. It was found that the maximum strength of column member was determined by local buckling when satisfied with a limit of width-to-thickness ratio in current steel structure design specifications, but decreased suddenly by local buckling before the maximum strength in case of not satisfying with that ratio. Also, the compression buckling strength of SM570 plate was higher than the design specification value of 4$4.1tonf/cm^2$.

• Journal of Korea Game Society
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• v.14 no.6
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• pp.59-68
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• 2014

Memory bandwidth requirements of UHD (Ultra High Definition $4096{\times}2160$) game scenes have been much more increasing. This paper presents a lossless DPCM-GR based compression algorithm using CUDA for solving the memory bandwidth problem without sacrificing image quality, which is modified from DDPCM-GR [4] to support bit parallel pipelining. The memory bandwidth efficiency increases because of using the shared memory of CUDA. Various asynchronous transfer configurations which can overlap the kernel execution and data transfer between host and CUDA are implemented with the page-locked host memory. Experimental results show that the maximum 31.3 speedup is obtained according to CPU time. The maximum 30.3% decreases in the computation time among various configurations.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.229-236
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• 2011

This study was conducted to understand the characteristics of the compression behavior of steel plate-concrete(SC) structures with a width-to-thickness ratio under axial loading. SC structures are structural systems where concrete is poured into steel plates to which headed stud bolts had been attached inside. The specimens were classified according to the two width-to-thickness (W/T) ratios of 1.60 and 3.56. Through these experiments, the following conclusions could be arrived at. The fracture pattern of the specimens showed that steel plate buckling occurred between the stud lines, and that a crack occurred at the concrete spalling from the sides of the concrete before the system reached the maximum compressive strength. The maximum compressive strength of the specimens was larger than that of the existing equations (AISC 2005, ACI 318-05, and KBC 2005). With the increased W/T ratio of the specimens, the strength of the concrete core was decreased to account for the confinement effects from the steel plates.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.46-46
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• 1999

터보분자펌프(turbomolecular pump, TMP)는 각종 연구장비, 반도체 제조장치, 가속기, 핵융합 실험 장치 등 여러 분야에서 가장 널리 쓰이는 고진공 펌프로서 자리잡고 있다. 이런 TMP의 광범위한 사용에도 불구하고 성능평가에 관한 통일된 규격이 마련되어 있지 않다. 국제 규격협회(ISO)의 터보분자펌프 성능평가방법 시안을 토대로 제정중인 KS 규격은 아직 실험적인 근거를 자체적으로 가지고 있지 못하므로 앞으로 각 항목들에 대한 많은 실험이 수행되어야 한다. TMP의 성능을 나타내 주는 항목들 중 배기속도(pumping speed)와 압축비(compression ratio)는 가장 중요한 것들로서 다른 고진공 펌프 및 TMP 상호간의 성능을 비교할 수 있는 기본 항목이라 할 수 있다. 본 실험에서는 종래의 단순 TMP와 큰 기체유량에서도 안정된 배기속도를 유지하는 복합터보분자펌프(compound molecular pump, CMP)의 배기속도와 압축비 및 임계배압(critical backing pressure)을 KS 규격안대로 시험 평가하여 안의 평가방법과 기준의 타당성을 검토하고, 두 가지 다른 방식의 펌프에 적용할 수 있는지를 검토하였다. TMP 및 CMP 흡기구에 표준용기를 부착하고 수소 및 질소 기체를 사용하여 흡기구 압력을 변화시키면서 배기속도 및 압축비를 측정하고 배기구 압력을 변호시키면서 최대압축비 및 임계배압을 측정하였다. 흡기구의 압력측정에는 인출형 전리진공계(EG)를 사용하였고, 배기구의 압력측정은 전기용량의 격막진공계(CDG)와 피라니 진공계로 측정하였다. 진공계는 모두 회전식 점성진공계(SRG)로 교정한 후 사용하였다.

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.167-178
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• 1998

횡방향철근에 의하여 적절히 구속된 콘크리트 기둥은 강도증가 및 연성의 확보면에서 유리하다. 본 연구의 목적은 횡방향철근에 의하여 구속된 코아콘크리트의 크기,횡방향철근의 간격비 및 체적철근비 등의 변화에 따른 콘크리트 기둥의 극한강도를 포함한 최대하중 이전의 거동 및 최대하중 이후의 거동을 실험적, 해석적으로 고찰함으로써 콘크리트 기둥의 구속효과정도를 규명하려는데 있다. 본 연구에서는 횡구속된 콘크리트 기둥모형의 압축재하실험을 수행하였으며, 최대하중 이전의 거동에 대하여 연속체적 파괴와 소성을 고려한 3차원 모델링을 통한유한요소해석을 실시하였다. 또한 횡구속된 콘크리트 기둥의 변형률국소화 모델에 의한 파괴해석을 통하여 구속된 콘크리트 기둥의 최대하중 이후의 거동을 재현하였다. 해석결과는 압축재하실험의 결과와 비교, 분석되었으며, 이에 따른 구속효과를 규명하였다.

• Journal of the Korean Geotechnical Society
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• v.35 no.8
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• pp.43-56
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• 2019

This research has been conducted to suggest an estimation equation of compression index to be practically applied to the southeastern areas by finding out physical and mechanical characteristics of 229 points on the southeastern coast areas (Busan area: 78 points, Gimhae area: 103 points, Geoje area: 18 points, Changwon area: 30 points) through indoor tests and analyzing its relation to the compression index. From the results, we could not only find out correlation between natural water content, liquid limit and initial void ratio versus compression index for soft ground on each of the southeastern coast areas, but also an integrated correlation equation of the southeastern coast areas. In addition, we have performed a comparative analysis of the existing estimated equation of compression index and that found in this paper. As a result, the existing estimated equation suggested by foreign researchers has shown considerable error to be applied to the soft ground on the southeastern coast areas in Korea. The estimated equation of compression index with the water content out of the existing estimated equations has shown minimum 10.8% to maximum 48.1% of error rate, minimum 13.4% to maximum 288.5% of error rate with liquid limit or minimum 9.4% to maximum 211.4% of error rate with initial void ratio. On the other hand, error rates calculated with the estimated equations of compression index from this research have shown minimum 10.5% to maximum 13.4% with water content, minimum 11.6% to maximum 21.3 with liquid limit or minimum 7.1% to maximum 11.7% with initial void ratio, for better results than those with existing estimated equations. In addition, relation between compression index and expansion index has shown Cs = (1/5 ~ 1/12)Cc similar to the existing relation of Cs = (1/5 ~ 1/10)Cc.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.613-616
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• 2010

본 논문에서는 라인파이프 강관의 압축-휨 좌굴 성능 평가 기법을 개발하기 위해 비선형 유한요소해석을 사용하였다. 고강도 강재의 연성거동을 모사하기 위해 범용 유한요소해석 프로그램인 ABAQUS의 사용자 재료모델을 사용하여 GTN(Gurson-Tvergaad-Needleman) 모델을 작성하였다. 실험결과와의 비교를 통해 재료모델상수를 결정하였으며 압축-휨 좌굴 실험의 모사에 사용하였다. 압축-휨 좌굴 성능 평가는 비선형 유한요소해석의 결과로부터 얻어진 한계압축변형률과 최대휨모멘트를 기준으로 수행될 수 있다. 개발된 성능 평가 기법은 고강도 강재를 이용한 라인파이프의 설계 시 대변형 거동 분석에 유용하게 사용될 수 있다.