• Title/Summary/Keyword: Lee Sam

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Research about Chemical-Biological Protection Capability of Selectively Permeable Membrane Materials Based on Polyvinyl Alcohol (폴리비닐알코올 기반 선택투과막 재료의 화생방호성능 연구)

  • Kang, Jae-Sung;Seo, Hyeon-Kwan;Kwon, Tae-Geun;Park, Hyen-Bae;Lee, Hae-Wan
    • Membrane Journal
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    • v.23 no.3
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    • pp.237-244
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    • 2013
  • We fabricated several composite membranes with selectively permeable performance designed to facilitate water vapor transport and resist DMMP vapor permeation. Materials for selective permeable membrane were based on polyvinyl alcohol and functional polymer containing basic functional group. With these materials, we characterized selectively permeable performance to identify next-generation material with chemical-biological protective capability. Results showed that polyvinyl alcohol (PVA)/polyethyleneimine (PEI) materials possessed performance with superior water vapor permeation ($2,200{\sim}2,900g/m^2/day$) and protective capability against DMMP vapor ($47g/m^2/day$).

State space disturbance observer based controller design for self servo writing (셀프 서보 라이팅을 위한 상태공간 외란 관측기 기반의 제어기 설계)

  • Jung, Youn-Sung;Kang, Hyun-Jae;Lee, Choong-Woo;Chung, Chung-Choo;Cho, Kyu-Nam;Suh, Sang-Min;Oh, Dong-Ho
    • Proceedings of the KIEE Conference
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    • 2007.10a
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    • pp.129-130
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    • 2007
  • Self servo track writing(SSTW)은 servo track writer(STW)를 이용하지 않고 hard disk drive의 내부 VCM을 이용하여 servo track을 기록하는 방식이다. SSTW는 이전 servo track을 상대적인 reference로 하여 기록하게 되므로 초기에 발생된 error와 외부의 disturbance의 영향으로 error는 급속하게 증가된다. 이것을 radial error propagation 이라 한다. 본 논문에서는 radial error propagation을 억제하기 위한 correction signal을 설계하고 servo writing 과정에서 발생하는 disturbance의 영향을 제거하기 위하여 disturbance observer(DOB)를 add-on type으로 구성하여 tracking 제어기를 설계하였다. 또한 DOB를 적용한 경우와 유사한 gain margin, phase margin과 sensitivity function을 갖는 제어기를 설계하여 그 성능을 비교하였다. 제안된 방식은 radial error propagation을 억제 하였을 뿐만 아니라 disturbance의 최소화하여 쓰여진 track의 DC track spacing과 AC track Squeeze가 개선된 것을 모의실험을 통하여 검증하였다.

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R-S Decoder Design for Single Error Correction and Erasure Generation (단일오류 정정 및 Erasure 발생을 위한 R-S 복호기 설계)

  • Kim, Yong Serk;Song, Dong Il;Kim, Young Woong;Lee, Kuen Young
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.23 no.5
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    • pp.719-725
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    • 1986
  • Reed-solomon(R-S) code is very effective to coerrect both random and burst errors over a noise communication channel. However, the required hardware is very complex if the B/M algorithm was employed. Moreover, when the error correction system consists of two R-S decoder and de-interleave, the I/O data bns lines becomes 9bits because of an erasure flag bit. Thus, it increases the complexity of hardware. This paper describes the R-S decoder which consisits of a error correction section that uses a direct decoding algorithm and erasure generation section and a erasure generation section which does not use the erasure flag bit. It can be shown that the proposed R-S dicoder is very effective in reducing the size of required hardware for error correction.

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