• Environmental Engineering Research
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• v.23 no.1
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• pp.76-83
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• 2018

Spatial moment analysis has been performed on the concentration of the first species in a multispecies solute transport in porous media. Finite difference numerical technique was used in obtaining the solute concentration. A constant continuous source of contaminant was injected at the inlet of the domain. Results suggest that the decaying of solute mass increases as the magnitude of mean fluid velocity increases. The dispersion coefficient is highly time dependent under decaying of solutes with a complex behavior of mixing of solutes. The solute mobility and mixing varies non-linearly with time during its initial period, while the same ceases with higher decay rates of the first species much faster.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.11-14
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• 2000

We present an image retrieval method that improves retrieval rate by using the fusion of histogram and wavelet moment features. The key idea is that images similar to a query image are selected in DB by using the wavelet moment features. Then the result images are retrieved from the selected images by using histogram method. In order to evaluate the performance of the proposed method, we use Brodatz texture database, MPEG-7 T1 database and Corel Draw photo. Experimental result shows that the proposed method is better than each of histogram method and wavelet moment method.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.81-87
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• 2006

This study has been conducted to predict the ultimate moment capacities of double angle connections with various angle thicknesses and bolt gage distances. Considering the results of experimental tests conducted previously, a simplified analytical model is suggested in this research. In addition, some basic data are also provided for structural engineers to design a double angle connection preliminary.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.2
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• pp.78-85
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• 2000

The moment equations of the concentration distribution for the multi-region model are derived using the method of moment. The method originally devised by Aris is to obtain the concentration moments satisfying a given PDE (Partial Differential Equation. The method of moment is used to obtain the first five moments (0th to 4to) that satisfy the model PDE. Each moment of the concentration distribution for the model equation is plotted for the dimensionless time and gave similar results except the skewness and the kurtosis. The results of the analysis show the physical meaning of each moment. The comparisons with the number of regions or the global interaction coefficient give a possibility to determine the parameters of the multi-region model with the analytical concepts.

• Journal of Korean Association for Spatial Structures
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• v.13 no.1
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• pp.69-77
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• 2013

This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete moment frame and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. It also shows the result of the seismic performance improvement which is the ratio of seismic performance appreciation result yield displacement 19%, yield strength ratio 24%, displace ductility ratio the maximum 27% comparing Multi degree of freedom, column member of Reinforced Concrete with the performance improvement column member considering the thickness of the determined Steel Jacket. The developed Algorithm and program are easy to apply seismic design and application to the original Reinforced Concrete building, at the same time, it applicate to display well the design result of Target displacement performance level about nonlinear behavior.

• Journal of Korean Association for Spatial Structures
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• v.17 no.4
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• pp.35-42
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• 2017

This study develops a new hybrid passive energy dissipation device for seismic rehabilitation of an existing structure. The device is composed of a friction damper combined with a steel plate with vertical slits as a hysteretic damper. Analytical model is developed for the device, and the capacity of the hybrid device to satisfy a given target performance is determined based on the ASCE/SEI 7-10 process. The effect of the device is verified by nonlinear dynamic analyses using seven earthquake records. The analysis results show that the dissipated inelastic energy is concentrated on the hybrid damper and the maximum interstory drift of the SMRF with damping system satisfies the requirement of the current code.

• Journal of Korean Association for Spatial Structures
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• v.15 no.1
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• pp.47-55
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• 2015

This paper shows the simplified equation to predict the ultimate moment capacity and corresponding rod stress in reinforced concrete beam with external post-tensioning rods. Because the stress of external post-tensioning rod depends on the beam deflection, the previous analytical model for post-tensioned beams requires a tedious iteration process. Also, the stress equations in ACI code or other researchers' models are suitable only for internal tendons in concrete beams. In this study, given the lack of analytical approaches to predict the nominal stress of the external unbonded rod, a simple and robust equation has been proposed for externally post-tensioned concrete beams. It is concluded that the proposed equation predicted the stress of external steel rods in post-tensioned concrete beams reasonably well.

• Journal of Korean Association for Spatial Structures
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• v.3 no.1 s.7
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• pp.77-85
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• 2003

This paper presents a truss model that can predict the shear behavior of reinforced concrete (RC) beams subjected to the combined actions of shear and flexure. Unlike other truss models, the proposed truss model, TATM, takes into account the effect of the flexural moment on the shear strength of RC beams with different shear span-to-depth ratios. To check the successfulness of the proposed model experimentally obtained stress shear strain curves were compared to the predicted ones using the proposed truss model. Furthermore, the shear strengths of 170 RC test beams with variable shear span-to-depth ratios were compared to the shear strengths as given by the truss model reported in this paper.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.3-15
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• 2004

• Journal of Korean Association for Spatial Structures
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• v.8 no.2
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• pp.85-93
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• 2008

This study summarizes the results of a research project aimed at investigating the inelastic rotation capacity of beam-column joints of reinforced concrete special moment frames. All of the test specimens were classified as special moment frame (SMF), based on the design and detailing requirements of the ACI 318-02 provisions. The acceptance criteria, originally defined for steel moment frame connections in the 1997 edition of the AISC Seismic provisions, were used to evaluate the beam-column joints of the reinforced concrete moment frames. A total of 39 test specimens were examined in detail. Most of the joints that satisfy the design requirements for special moment frame structures were found to be ductile up to a plastic rotation of 3% without any major degradation in strength. This is mainly due to the stringent ACI 318-02 requirements for special moment frame joints. The presence of transverse beams increases confinement and shear resistance of joints, which results in better performance than for joints without transverse beams. All of the SMF connections that satisfy the ACI 318-02 limitations on joint shear stress turned out to meet the acceptance criteria.