• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2032-2037
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• 2009

The load carrying capacity of bridge structures in public use is generally evaluated without considering their actual behavioral characteristics. This study examined common errors taking place in the evaluation of load carrying capacity of bridge structures. In order to account for their current behavioral characteristics such as the boundary condition, we evaluated the load carrying capacity of a bridge in terms of axial force, which was calculated by applying deflection to the buckling equation for members with initial imperfections, and in terms of bending moment obtained from deflection.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.1-8
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• 2002

Due to the fast development in computer application technologies, a video is now being more widely used than ever in many areas. The current information analyzing systems are basically built to process text-based data. Thus, it has little bits Problems when it needs to correctly represent the ambiguity of a video, when it has to process a large amount of comments. or when it lacks the objectivity that the jobs require. We would like to purpose the method that is capable of analyze a large amount of video efficiently. To extract the color, we translate the color from RGB to HSI and use the information that matches with the representative colors. To extract the shape information, we use improved moment invariants(IMI) so that we can solve many problems of histogram intersection.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.81-88
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• 2017

Residual stress is defined as stress that already exists on a structural member from the effects of welding and plastic deformation before the application of loading. Due to such residual stress, welded H-section compression members under centroidal compression load can undergo buckling and failure for strength values smaller than the predicted buckling load and specified compressive strength. Therefore, this study was carried out to evaluate the effect of residual stress from welding on the determination of the buckling load and specified compressive strength of the H-section compression member according to the column length variation. A three-dimensional nonlinear finite element analysis was performed for the H-section compression member where the welded joint was fillet welded by applying heat inputs of 3.1kJ/mm and 3.6kJ/mm using the SAW welding method.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.439-448
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• 2016

Extended end-plate connections(EEPC) are a type of connection applied in Pre-Engineered Building structures comprising beam-column connections of steel structures or tapered members. Extended end-plate connections(EEPC) show different behavioral characteristics owing to the influence of plate thickness, gauge distance of high strength bolt, diameter of high strength bolt frame, and the number of high strength bolts. In the USA and Europe, extended end-plate connections(EEPC) are applied in beam-column connections of steel structures in various forms; however, these are not widely applied in structures in Korea.This can be attributed to the fact that the proposal of design strength types for extended end-plate connections(EEPC), proposal of connection specifications, evaluation of seismic performance, and are not being performed appropriately. Therefore, the purpose of this study is to provide basic data for the domestic application of Unstiffened extended endplate connections. To realize this, nonlinear finite element analysis was conducted on a 12-mm thick Unstiffened extended endplate connections.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1302-1307
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• 2018

The crystallographic, electrical and magnetic behaviors of magnetite powder in the vicinity of its Verwey transition were investigated in this study. Magnetite was prepared by synthesizing a nanoparticle precursor and then annealing it at $800^{\circ}C$ for 1 h under a dynamic vacuum. Crystallographic and morphology analyses were done by using scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrical and the magnetic properties were examined by using $M{\ddot{o}}ssbauer$ spectroscopy, vibrating sample magnetometer (VSM) and resistivity measurement. Both the magnetic moment and the resistivity showed discontinuous changes at the Verwey transition temperature ($T_V$). The temperature dependence of magnetic anisotropy constant showed a monotonic decrease with increasing temperature, with slight dip near $T_V$. $M{\ddot{o}}ssbauer$ spectra showed the superposition of two sextets, one from the tetrahedral (A) and the other from the octahedral (B) sites. The results revealed that identical charge states existed in the B site at temperatures both above and below $T_V$. A coordination crossover resulted in a transition from an inverse to a normal spinel at or close to $T_V$.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.219-229
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• 2003

The extended tangent stiffness matrices and force-deformation relations of the elastic catenary element were initially derived through the addition of the unstrained length of cables to unknown nodal 'displacements. A beam-column element was then introduced to model the deck and pylon of cable-stayed bridges. The conventional geometric nonlinear analysis, initial force method, and TCUD method were summarized, with an effective method combining two methods presented to determine the initial shapes of cable-stayed bridges with dead loads. In this combined method, TCUD method was applied to eliminate vertical and horizontal displacements at cable-supported points of decks and on top of pylons, respectively. The initial force method was also adopted to eliminate horizontal and vertical displacements of decks and pylons. Finally, the accuracy and validity of the proposed combined method were demonstrated through numerical examples.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.60-68
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• 2017

This study was made to examine the motion characteristics according to the reinforcement of the reinforcement length and stiffener reinforcement for shear reinforcement to the foundation structure reinforced with shear reinforcement steel plate. Experimental study was made after specimen was installed on the ground as the same as in the practical site. Reinforcement lengths of the steel for shear reinforcement are divided into 1,000 mm, 1,200 mm and 1,400 mm in the specimen and as for reinforcement method of the stiffener, 4 stiffeners with interval of 100mm reinforced with the same materials as the shear reinforcement were manufactured for the experiment. Considering result of the experiment, it is expressed that no effect of the stiffener reinforcement was found and regarding the reinforcement length of shear reinforcement material the crossed point of the two converted lines of the value that the shear force is expressed in the bearing power in the expanded dangerous section and the value that the shear capacity receivable by the reinforcement materials in the dangerous section is proposed as effective reinforcement length.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.351-361
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• 2001

The connections are classified as rigid, semi+rigid, or pinned. There are two classification systems, EC3 adn Bjorhovede et al., representatively. The EC3 boundary between rigid and semi-rigid connections is in on the whole restrictive in term of the stiffness as well as the moment capacity of connections. The boundary specified by Bjorhovede et al. may not be sufficient to assure the behavior of rigid frames in some cases. In this study, it is proposed the new classification system for steel connection that depends on the reduction factor(R) of critical buckling load for unbraced semi-rigid frame expressed by the stiffness ratio($\rho$) of beam to column and the stiffness ratio(k) of connection to beam. Finally, it is examined by experimental data that new classification criteria provides a practical boundary compared wit hteh existing classifications.

• Land and Housing Review
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• v.6 no.3
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• pp.129-138
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• 2015

The building structure in Korea is planned to maximize the use of space in recent. The hybrid OCB(Optimized Composite Beam) beam is developed to take advantage of using the space. The OCB beam is composed of the steel H-beam section reinforced by open strands in negative moment zone and the pretensioned PSC concrete section in positive zone. Flexural behavior of typical architectural hybrid OCB beam section was investigated by F.E.M. The 15m, 20m, 30m OCB models were tested on nonlinear material and geometry under static loading system. Following results are obtained from the analysis; 1)The OCB beam develop initial flexural cracking over full service loading. 2)Overall deflections of OCB beam under the service loads are less than those of the allowable limits in KCI Code(2012). 3)The ultimate load capacity get over the nominal strength of the OCB main section. The OCB beam is verified of structural reliability from the finite element analysis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.231-236
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• 2008

A method of moments model for the resistive vee dipole has been established. In order to validate the numerical model, an experimental model is built and reflections from the antenna in the feed line are measured. The measured data and the numerical data agree closely validating the numerical model. Based on the numerical model, efficiency of the antenna and the power dissipated in the resistors are analyzed. The results show that the antenna has low radiation efficiency because of the loading resistors and that the resistors near the drive point of the antenna dissipate more power than do the resisters far from the drive point. The results can be used to determine the amount of power that can be accepted by the resistive vee dipole, to determine the power rating of the loading resistors for a desired application, or to estimate the operation range of the antenna.