• Title/Summary/Keyword: Choi Dong Hoon

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Instant Messenger System for Group Collaboration and Contents Sharing (그룹 내 협업 및 콘텐츠 공유를 위한 인스턴트 메신저 시스템)

  • Son, Dong-Hwan;Park, Kyoung;Bae, Seong-Jo;Choi, Hoon
    • Proceedings of the Korean Information Science Society Conference
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    • 2010.06d
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    • pp.208-211
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    • 2010

  • 소셜 네트워크 서비스에 대한 관심이 높아지고 있으며 이의 하나로 인스턴트 메신저를 이용한 통합 커뮤니케이션 서비스의 필요성이 커지고 있다. 본 논문은 이러한 요구사항 중 그룹 내 회의를 진행하는 데 필요한 정보의 생성, 전송 및 저장을 위한 기능을 XMPP 기반 인스턴트 메신저 형태로 구현하였다.

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Optical Anisotropy of Polyimide and Polymethacrylate Containing Photocrosslinkable Chalcone Group in the Side Chain under Irradiation of a Linearly Polarized UV Light

  • Choi, Dong-Hoon;Cha, Young-Kwan
    • Bulletin of the Korean Chemical Society
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    • v.23 no.3
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    • pp.469-476
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    • 2002

  • Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy. The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  • https://doi.org/10.5012/bkcs.2002.23.3.469 인용 PDF KSCI