• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.875-888
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• 2013

The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.91-100
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• 2004

This study presents the development of a new aluminum seat frame for the commercial bus. Back moment and seat belt anchorage analysis of the conventional steel seat frame was conducted as a base model. Effective aluminum section dimensions for aluminum pipe were calculated from equivalent stiffness and equivalent weight study. Back moment and seat belt anchorage strength with the developed aluminum seat frame were compared to those of the base model. Additionally, to pass the fatigue test, shape modification of side frame assembly was conducted. From this study we could reduce the weight of seat frame more than 5 kg. And the current analysis model and procedure can provide useful informations in designing a new commercial car seat and can reduce the overall design cost and time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.1-5
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• 2009

In this research, structural analysis was conducted by applying ANSYS commercial code in order to evaluate deflection quantitatively when each weight of tension controllers was centered and weights and moments on a controller controlling tension amounts was varied in a machinery manufacturing flexible flat cable. Based on the numerical structure analysis, stress, strain and amounts of maximum deformation were obtained and investigated structural validity and was reflected on design of the controller.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.450-460
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• 2005

Today, multimedia information is used on the internet and various social areas by rapid development of computer and communication technology. Therefor, the usage is growing dramatically. Multimedia information analysis system is basically based on text. So, there are many difficult problems like expressing ambiguity of multimedia information, excessive burden of works in appending notes and a lack of objectivity. In this study, we suggest a method which uses color and shape information of multimedia image partitions efficiently analyze a large amount of multimedia information. Partitions use field growth and union method. To extract color information, we use distinctive information which matches with a representative color from converting process from RGB(Red Green Blue) to HSI(Hue Saturation Intensity). Also, we use IMI(Improved Moment Invariants) which target to only outline pixels of an object and execute computing as shape information.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.357-365
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• 2011

The current trends in steel construction intend to use tapered sections to minimize as much as possible the use of excess material. This can be done by choosing the cross-sections to be as economical as possible, leaving the classical approach of using prismatic members. In addition, it is important to predict the buckling behavior of tapered member with large depth-to-thickness ratio in order to prevent the collapse of PEB system subjected to overloads. An experimental investigation of buckling behavior of tapered beam was presented. The primary test parameter was depth-to-thickness ratio and taper ratio. Using initial stiffness and load-carrying capacity proposed by current provision, the simple plastic hinge method using modified Yoda's model and finite element analysis, the prediction of a moment-rotation curve of linearly tapered member was presented. Moreover, comparisons between analytical and experimental data for moment-rotation curves were accomplished.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.41-51
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• 2010

In the research for driver assistance systems, traffic sign information to the driver must be a very important information. Therefore, the detection system of traffic signs located on the road should be able to handel real-time. To detect the traffic signs, color and shape of traffic signs is to use the information after images obtained using the CCD camera. In the road environment, however, using color information to detect traffic sings will cause many problems due to changes of weather and environmental factors. In this paper, to solve it, the candidate traffic sign regions are detected from road images obtained in a variety of the illumination changes using the HSI eign-color model. And then, using the invariant moment-based SVM classifier to detect traffic signs are proposed. Experimental results show that, traffic sign detection rate is 91%, and the processing time per frame is 0.38sec. Proposed method is useful for real-time intelligent traffic guidance systems can be applied.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.123-128
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• 2018

Girder bridges and slab bridges are equipped with a system consisting of a flexible joint unit, support, inverted T shaped abutment, and a separate connecting slab structure. These systems have problems such as an increase in cost due to frequent breakage of the expansion joints and a decrease in durability due to a structure with low moment redistribution. To improve these problems, propose Inegral and Semi-Integral Hybrid Slab Bridge and examine the safety through structural analysis. As a result of the review, Inegral and Semi-Integral Hybrid Slab Bridge was the section stiffness is small. but it is confirmed that the structural safety, ductility and flexibility are higher than existing bridges because the moment redistribution and the force transmission are surely performed.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.225-237
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• 2006

Based on the study conducted by Kim et al. (205a, b), an improved stability design method for evaluating the effective buckling lengths of beam-column members is proposed herein, using system elastic/inelastic buckling analysis and second-order elastic analysis. For this purpose, the stress-strain relationship of a column is inversely formulated from the reference load-carrying capacity proposed in design codes, so as to derive the tangent modulus of a column as a function of the slenderness ratio. The tangent stiffness matrix of a beam-column element is formulated using the so-called "stability functions," and elastic/inelastic buckling analysis Effective buckling lengths are then evaluated by extending the basic concept of a single simply-supported column to the individual members as one component of a whole frame structure. Through numerical examples of several structural systems and loading conditions, the possibilities of enhancement in stability design for frame structures are addressed by comparing their numerical results obtained when the present design method is used with those obtained when conventional stability design methods are used.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.71-80
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• 2018

In this study, the seismic response of cut-and-cover box tunnels is evaluated from pseudo-static analyses and the fragility curves are derived. A series of site profiles were used to evaluate the effect of soil conditions. A total of 20 ground motions were used. The fragility curves were developed as functions of peak ground acceleration for three damage states, which are minor, moderate, and extensive states. The damage indices, defined as the ratio of the elastic moment to the yield moment, correlated to three damage states, were used. The curves are shown to greatly depend on the site profile. The curves are further compared to those derived in previous studies. The widely used empirically derived curves are shown not to account for the site effects, and therefore underestimate the response for soft sites.

• Journal of Korean Society of Steel Construction
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• v.22 no.2
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• pp.121-128
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• 2010

The current trends in steel construction involve the use of tapered sections to minimize the use of excess materials to the extent possible, by choosing cross-sections that are as economical as possible abandoning the classical approach of using prismatic members. In addition, snug-tightened connections, especially the end-plate type, have the advantage of fetching less construction costs and shorter assembly times as opposed to fully tightened joints. Although they have many merits, however, snug-tightened bolted end plates are extremely complex in their structural behavior. In this study, an experimental investigation of the snug-tightened flush end-plate connections of tapered beams were conducted. The primary test parameters were the torque for the clamping bolt, the loading pattern, the bolt type and the connection failure type. Using initial stiffness and load-carrying capacity as proposed by Silva et al. and AISC (2003), the moment-rotation curve of a linearly tapered member with a snug-tightened flush end-plate connection was predicted. Moreover, numerical and experimental data for moment-rotation curves were compared.