• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.345-354
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• 2016

In the present study, hybrid moment connections of welding and bar reinforcement for composite beam-column connections were proposed. Concrete-filled octagonal tube and U-section were used for the column and beam, respectively. In the beam-column connection, the top flange and web of the beam U-section were connected to the column plate by welding. However, to reduce stress concentration at the weld joints, the bottom flange of the beam was not welded to the column plate. Instead, to transfer the tension force of the beam flange, reinforcing bars passing through the column plate were used. Four exterior connections with conventional welded and hybrid moment connections were tested under cyclic loading and their cyclic behaviors were investigated. The test results showed that the hybrid moment connections successfully transferred the beam moment to the column. The strength and ductility of the hybrid moment connections were comparable to the conventional welded moment connection with exterior diaphragm; however, the connection performance was significantly affected by the details of the hybrid moment connection.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.175-185
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• 2013

Currently in precast concrete construction, precast concrete and cast-in-place concrete with different concrete strengths are used. However, current design codes do not provide shear design methods for PC-CIP hybrid members using dual concrete strengths. In the present study, the shear strengths of beams using dual concrete compressive strengths (24 MPa, 60 MPa) were tested. The test variables were the area ratio of the two concretes, longitudinal bar ratio, and shear span-to-depth ratio. The shear strengths of test specimens were evaluated by current design methods, using an effective concrete strength (considering the area ratio of the two concrete strengths). The test result showed that when 60 MPa concrete was used in the compressive zone and the longitudinal bar ratio was low, the shear strengths of the test specimens were less than the predictions. On the basis of the results, design recommendations were provided for the shear design of the PC-CIP hybrid beams.

• Composites Research
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• v.34 no.6
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• pp.394-399
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• 2021

Piecewise Integrated Composite (PIC) is a new concept to design composite structures of multiple stacking angles both for in-plane direction and through the thickness direction in order to improve stiffness and strength. In the present study, PIC beam was suggested based on 3D training data instead of 2D data, which did offer a limited behavior of beam characteristics, with enhancing the stiffness accompanied by reduced tip deformation. Generally training data were observed from the designated reference finite elements, and preliminary FE analysis was conducted with respect to regularly distributed reference elements. Also triaxiality values for each element were obtained in order to categorize the loading state, i.e. tensile, compressive or shear. The main FE analysis was conducted to predict the mechanical characteristics of the PIC beam.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.1
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• pp.89-114
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• 2020

This research is a basic study to understand the current state of the complex cultural space in the public library and the programs in operation and to explore ways to activate the programs by complex cultural space based on the understanding of the public libraries that formed the complex cultural space. Thus, a survey was conducted on librarians of public libraries that had complex cultural space within the library and found that there were a number of educational, exhibition, and performance spaces, and in the same vein, there were a lot of related programs being run in the complex cultural space. However, due to the lack of personnel in charge and budget, difficulty in developing programs, low participation in the programs, and lack of cultural facilities and materials, the substantialization of complex cultural space management seems to be lacking. Therefore, it will be required to set the goals and visions for the complex cultural space in libraries and to secure space, manpower, budget, and promotional efforts to reinvigorate the complex cultural space in the future.

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.65-70
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• 1998

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.04a
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• pp.205-208
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• 1999

• 월간 기계설비
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• no.9 s.206
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• pp.97-100
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• 2007

(주)스마트뱅킹이 일용근로자 지급조서 제출업무 등을 자동화 할 수 있는 휴대용 복합금융단말기 시스템을 개발 했다. 일용근로자에 대한 원천징수 영수증 교부와 분기별 임금지급조서 신고가 의무화됨에 따라 건설현장에서 발생하는 불편을 해소할 방법이 될 것으로 보여진다. 2007년부터 달라진 세법과 휴대용 복합금융단말기에 대해 알아본다.

• Composites Research
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• v.12 no.3
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• pp.55-65
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• 1999

In this paper, the thermal buckling and postbuckling behaviour of composite beam with embedded shape memory alloy (SMA) wires are investigated experimentally and analytically. The results of thermal buckling tests on uniformly heated, clamped, composite beam embedded with SMA wire actuators are presented and discussed in consideration of geometric imperfections, slenderness ratio of beam and embedding position of SMA wire actuators. The shape recovery force can reduce the thermal expansion of composite laminated beam, which result in increment of the critical buckling temperature and reduction of the lateral deflection of postbuckling behaviours. It is presented quantitatively on the temperature-load-deflection behaviour records how the shape recovery force affects the thermal buckling. The cross tangential method is suggested to calculate the critical buckling temperature on the temperature-deflection plot. Based on the experimental analysis, the new formula is also proposed to describe the critical buckling temperature of a laminated composite beam with embedded SMA wire actuators.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.51-56
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• 2003

The piezoelectric thin film(PVDF: polyvinylidene fluoride) sensors having good dynamic sensing charachteristics can be used to monitor low vwlocit impact on composite structures. The impact response function for composite sandwich beam was derved. The impact tests at low energy without inducing damage were performed on the instrumented drop weight impact tester. The measured signals of PVDF sensors attached on the surface of the beam agreed well with the simulated signals. And the inverse technique was applied to reconstruct the impact forces from the PVDF sensor signals. Most of reconstructed impact forces showed good agreement with the measured forces. The comparison results showed that the piezoelectric thin film sensor can be used to monitor the low velocity impact on composite sandwich structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.128-137
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• 2012

In high multistory buildings, hybrid coupled shear walls can provide an efficient structural system to resist horizontal force due to wind and seismic loads. Hybrid coupled shear walls are usually built over the whole height of the building and are laid out either as a series of walls coupled by steel beams with openings to accommodate doors, elevator walls, windows and corridors. In this paper, the behavior characteristics of hybrid coupled shear wall system considering connection details is examined through results of an experimental research program where 5 two-thirds scale specimens were tested under cyclic loading. Such connections details are typically employed in hybrid coupling wall system consisting of steel coupling beams and reinforced concrete shear wall. The test variables of this study are embedment length of steel coupling beam and wall thickness of concrete shear wall. The results and discussion presented in this paper provide fundamental data for seismic behavior of hybrid coupled shear wall systems.