• 제목/요약/키워드: 판 분리

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An Experimental Study of Demountable Bolted Shear Connectors for the Easy Dismantling and Reconstruction of Concrete Slabs of Steel-Concrete Composite Bridges (강합성 교량의 콘크리트 바닥판 해체 및 재시공이 용이한 분리식 볼트접합 전단연결재에 관한 실험적 연구)

  • Jung, Dae Sung;Park, Se-Hyun;Kim, Tae Hyeong;Kim, Chul Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.6
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    • pp.751-762
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    • 2022
  • Welded head studs are mainly used as shear connectors to bond steel girders and concrete slabs in steel-concrete composite bridges. For welded shear connectors, environmental problems include noise and scattering dust which are generated during the removal of damaged or aged slabs. Therefore, it is necessary to develop demountable shear connectors that can easily replace aged concrete slabs for efficient maintenance and thus for better management of environmental problems and life cycle costs. The buried nut method is commonly studied in relation to bolted shear connectors, but this method is not used in civil structures such as bridges due to low rigidity, low shear resistance, and increased initial slip. In this study, in order to mitigate these problems, a demountable bolted shear connector is proposed in which the buried nut is integrated into the stud column and has a tapered shape at the bottom of an enlarged column shank. To verify the performance of the proposed demountable stud bolts in terms of static shear strength and slip displacement, a horizontal shear test was conducted, with the performance outcomes compared to those of conventional welded studs. It was confirmed that the proposed demountable bolted shear connector is capable of excellent shear performance and that it satisfies the slip displacement and ductility design criteria, meaning that it is feasible as a replacement for existing welding studs.

A Study on Recognition of Both of PCA and LAD Using Types of Vehicle Plate (PCA와 LDA을 이용한 차량 번호판 통합 인식에 관한 연구)

  • Lee, Jin-Ki;Kim, Hyun-Yul;Lee, Seung-Kyu;Lee, Geon-Wha;Park, Yung-Rok;An, Ki-Nam;Bae, Cheol-Su;Park, Young-Cheol
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.6 no.1
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    • pp.6-17
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    • 2013
  • Recently, the color of vehicle license plate has been changed from green to white. Thus the vehicle plate recognition system used for parking management systems, speed and signal violation detection systems should be robust to the both colors. This paper presents a vehicle license plate recognition system, which works on both of green and white plate at the same time. In the proposed system, the image of license plate is taken from a captured vehicle image by using morphological information. In the next, each character region in the license plate image is extracted based on the vertical and horizontal projection of plate image and the relative position of individual characters. Finally, for the recognition process of extracted characters, PCA(Principal Component Analysis) and LDA(Linear Discriminant Analysis) are sequentially utilized. In the experiment, vehicle license plates of both green background and white background captured under irregular illumination conditions have been tested, and the relatively high extraction and recognition rates are observed.