• 제목/요약/키워드: Hwang Jong-Ha

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In-vacuum undulator 손상원인 분석 및 수리

  • Hong, Man-Su;Ha, Tae-Gyun;Gwon, Hyeok-Chae;Han, Hong-Sik;Hwang, Il-Mun;Lee, Tae-Yeon;Park, Jong-Do
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.105-105
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    • 2015

  • 포항가속기연구소 PLS-II 저장링에 설치 운용중인 In-vacuum undulator (이하, IVU) 내부 Cu/Ni foil에 발생한 국부적 손상에 대하여, 원인을 분석하고 수리 및 정상 운용을 위한 절차들이 진행 되었다. 해체된 IVU의 손상부위를 세밀하게 조사하고 손상 원인에 대하여 다각도로 분석하였다. 손상된 Cu/Ni foil은 개선된 신규 제품으로 교체하고, 손상 원인이 될 수 있는 부품들을 제거토록 하였다. IVU 내부 관측을 위한 장치를 추가 설치하고 안정적인 온도 데이터 획득을 위한 노력도 함께 검토 되었다. 본 발표는 IVU 손상에 대한 원인분석 내용과 함께 해체, 수리, 재설치 과정 등에 대한 종합적인 내용으로 한다.

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Hybrid Re-Adhesion Control Method for Traction System of High-Speed Railways with Parallel Induction Motor Control (유도전동기 병렬 제어형 고속전철 추진시스템의 혼합형 재점착 제어기법)

  • Hwang, Don-Ha;Kim, Mun-Seop;Ryu, Hong-Je;Park, Do-Yeong;Kim, Jong-Su
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.1
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    • pp.40-47
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    • 2002

  • This paper describes a re-adhesion control method for the Korean High-Speed Train (KHST) with parallel induction motor drive. To keep a traction efficiency and to improve vehicle maintenance, the adhesion characteristics between wheel and rail are analyzed. Also the re-adhesion controller is designed as the subsystem of induction motor vector control. In order to verify performance of the proposed control techniques, the simulation is executed by train model and a downscaled re-adhesion control simulator is utilized. Both simulation and running test results show that good re-adhesion characteristics are obtained.

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Leadframe Feeder Heat Rail Design and Verification (Leadframe Feeder Heat Rail의 설계와 검증)

  • Kim, Won-Jong;Hwang, Eun-Ha
    • Journal of the Korean Society of Industry Convergence
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    • v.15 no.1
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    • pp.37-42
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    • 2012

  • Trends in semiconductor equipment industry are to reduce the cost of producing semiconductor, semiconductor process development, facility development, and the minimum investment in terms of cost and quality. Semiconductor equipments are being considered to review and development is proceeding at the same time. In the first part of the semiconductor assembly process, in which the importance of die bonding process is emerging, a wide leadframe type die bonding machine is demanded for productivity. Die bonding machine was designed through experiments and by trial and error. It costs a lot of time and financial burden. The purpose of this study is to solve these problems by using the CAE tool 3G. By using finite element method, thermal analysis of die bonding machine to the various widths leadframe die bonder machine rail is performed for design.

  • https://doi.org/10.21289/KSIC.2012.15.1.037 인용 PDF

Sparse Multinomial Kernel Logistic Regression

  • Shim, Joo-Yong;Bae, Jong-Sig;Hwang, Chang-Ha
    • Communications for Statistical Applications and Methods
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    • v.15 no.1
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    • pp.43-50
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    • 2008

  • Multinomial logistic regression is a well known multiclass classification method in the field of statistical learning. More recently, the development of sparse multinomial logistic regression model has found application in microarray classification, where explicit identification of the most informative observations is of value. In this paper, we propose a sparse multinomial kernel logistic regression model, in which the sparsity arises from the use of a Laplacian prior and a fast exact algorithm is derived by employing a bound optimization approach. Experimental results are then presented to indicate the performance of the proposed procedure.

  • https://doi.org/10.5351/CKSS.2008.15.1.043 인용 PDF KSCI