• Journal of the Korea Concrete Institute
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• 제17권4호
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• pp.513-520
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• 2005

The uniform truss mechanism is widely accepted as a shear transfer mechanism in reinforced concrete members. However, the uniform truss action cannot be expected when the bond stress distribution is not constant along longitudinal bars. A test method in which only the truss action takes place is developed and conducted to investigate the truss actions under various bond contributions. Based on the experimental results and analysis, the following findings can be obtained: 1) The bond stress distribution depends on the axial compression force, the amount of shear reinforcement and loading conditions. 2) The analysis using the combined truss model consisting of uniform and fan-shape trusses can predict the experimental results

• Transactions of the Korean Society of Mechanical Engineers
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• 제11권6호
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• pp.975-981
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• 1987

Employing a speical yield function for porous metals, a set of special constitutive equations is formulated to predict elastic-plastic responses of porous metals under triaxial compression. The proposed contitutive equations are compared with experimental data for porous tungsten under hydrostatic compression and uniaxial strain compression.

• Journal of Korean Society of Steel Construction
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• 제10권2호통권35호
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• pp.153-160
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• 1998

The sectional dimensions and initial crookedness of the RHS(rectangular hollow section, ${\boxe}-75{\times}75{\times}3.2,\;{\boxe}-100{\times}100{\times}4.2,\;{\boxe}-125{\times}125{\times}6.0$) were measured. The axial compressive strength tests for columns with slenderness $46{\sim}84$ were performed as well as stub tests and tensile tests. FEM analysis was also used. The measurement shows that the errors of sectional dimensions are negligible. For the column length corresponding to ${\lambda}=100$, the initial crookedness with the 2.5% probability estimated from the measured results is 1/490, 1/1121 1/1395 for each section respectively. The yield strengths obtained from tensile test are higher than the specified minimum value by more than 30%. The column test shows that the maximum axial resistances are almost same as, or a little higher than the FEM results and the specified strength curves of AISC Specification and Eurocode, when the maximum strengths from the stub tests are used as the yield strength of the steel. But the test results show much higher column strength than those specified in the Standard and Code, when the specified minimum yield strength of the steel is used.

• Journal of the Society of Naval Architects of Korea
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• 제33권3호
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• pp.8-21
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• 1996

The aim of this study is to derive an empirical formula for predicting ultimate strength of plates and stiffened plates subjected to uniaxial compression. The test data of ultimate compressive strength for unstiffened and stiffened plates previously obtained by others have been collected. Many test data are necessary so that the derived formula will be available in wide range of plate dimensions. Additional collapse tests for a plate specimen with one flat bar stiffener, varying dimensions of plate and stiffener were performed in this study. On the basis of the present and previous experimental data, a more useful empirical formula than the existing ones was derived by applying the least square method.

• Journal of Internet Computing and Services
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• 제21권4호
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• pp.43-49
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• 2020

This paper proposes a lossless image compression method based on arithmetic coding using block-adaptive Context Tree Weighting. The CTW method predicts and compresses the input data bit by bit. Also, it can achieve a desirable coding distribution for tree sources with an unknown model and unknown parameters. This paper suggests the method to enhance the compression rate about image data, especially aerial and satellite images that require lossless compression. The value of aerial and satellite images is significant. Also, the size of their images is huger than common images. But, existed methods have difficulties to compress these data. For these reasons, this paper shows the experiment to prove a higher compression rate when using the CTW method with divided images than when using the same method with non-divided images. The experimental results indicate that the proposed method is more effective when compressing the divided images.

• Journal of the Korea Concrete Institute
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• 제22권2호
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• pp.263-271
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• 2010

The purposes of this study is to verify the fracture characteristic of steel which is manufactured in Korea, subjected to cyclic loading. This investigation deals with the low cycle fatigue behavior of longitudinal reinforcement in reinforced concrete bridge substructure (piles and columns of piers). Eighty-one specimens of longitudinal reinforcement were tested under axial strain controlled reversed cyclic tests with strain amplitudes. The selected test variables are ratio of tension strain to compression strain, yield stress of longitudinal reinforcement, ratio of diameter of longitudinal steel to clear length of longitudinal steel, size of longitudinal steel and strain amplitudes. Low cycle fatigue behavior and low-cycle fatigue life are investigated and discussed in this paper.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.403-408
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• 2008

본 논문은 모바일 그래픽스 응용에 적합한 메쉬 위치정보의 압축 기법을 제시한다. 제시한 기법은 복원 에러를 최소화하기 위한 메쉬 분할 기법과 기존의 방법에서 방생하는 시각적 손상문제를 해결한 지역적 정량화 기법으로 구성된다. 기존 방법에서는 분할된 조각 메쉬들 간의 경계가 벌어지는 시각적 손상문제가 방생하는데, 모든 조각 메쉬의 지역적 양자화 셀이 같은 크기와 정렬된 지역 좌표축을 갖게 하여 이 문제를 해결했다. 제시한 기법은 메쉬를 렌더링할 때 압축된 위치정보를 메모리에서 그래픽스 하드웨어로 전송하여 실시간으로 복원함으로써 모바일 기기의 자원을 절약하는 특징을 갖는다. 압축된 위치정보의 복원을 표준화된 렌더링 파이프라인에 결합이 가능하도록 설계함으로써 조각 메쉬당 한번의 행렬 곱셈으로 복원이 가능하다. 실험에서는 32 비트 부동소수점 수로 표현되는 위치정보를 8 비트 정수로 지역적 정량화하여 70%의 압축률에서 11 비트 전역적 정량화와 대등한 수준의 시각적 품질을 달성했다.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제18권11호
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• pp.1645-1654
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• 1993

Unlike a noise removal recursive temporal filter, this paper presents a temporal filter which improves visual quality and data compression efficiency. In general, for the temporal band-limitation, temporal aliasing should be considered. Since most of a video signal has temporally aliased components, it is desirable to consider them. From a signal processing point of view, it is impossible to realize the filtering not afeced by the aliasings. However, in this paper, efficient filtering with de-aliasing characteristics is proposed. Considering the location of a video signal, temporal filtering can be accomplished by the spatial filtering along the motion vector trajectory (Motion Adaptive Spatial Filter). This filtered result dose not include the aliasings. Besides the efficient band-limitation, temporal noise is also reduced. For the evaluation of the MASF, its realization and filtering characteristics will be discussed in ditail.

• Economic and Environmental Geology
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• 제49권1호
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• pp.23-30
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• 2016

Powder samples of natural lawsonite (Ca-lawsonite, $CaAl_2Si_2O_7(OH)_2{\cdot}H_2O$) was studied structurally up to 8 GPa at room temperature using monochromatic synchrotron X-ray powder diffraction and a diamond anvil cell (DAC) with a methanol : ethanol : water (16 : 3 : 1 by volume) mixture solution as a penetrating pressure transmitting medium (PTM). Upon pressure increase, lawsonite does not show any apparent pressure induced expansion (PIE) or phase transition. Pressure-volume data were fitted to a second-order Birch-Murnaghan equation of state using a fixed pressure derivative of 4 leading to a bulk modulus ($B_0$) of 146(6) GPa. This compression is further characterized to be isotropic with calculated linear compressibilities of ${\beta}^a=0.0022GPa^{-1}$, ${\beta}^b=0.0024GPa^{-1}$, and ${\beta}^c=0.0020GPa^{-1}$.

• Computational Structural Engineering
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• 제8권4호
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• pp.117-127
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• 1995

The objective of this research is to investigate the effectiveness of rotating orthotropic axes model in analyzing reinforced concrete planar members under cyclic as well as monotonic loading. The structural members to be addressed are moderately reinforced beams, columns, beam-column joints, and shear walls, whose failure occurs due to compressive crushing after extensive crack propagation, The rotating orthotropic axes model which is usually used for monotonic loading is developed for cyclic loading. With the existing cyclic material models of reinforcing steel and bond-slip, this material model is used for the finite element analysis. For monotonic loading, the analytical results of the rotating orthotropic axes model are compared with reinforced concrete beams which have brittle failure. For Shear wall members under cyclic loading, the analyses are compared with the experiments for the ultimate load capacity, nonlinear deformation, and pinching effect due to crack opening and closing.