• Title/Summary/Keyword: Ring system

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Computing the DFT in a Ring of Algebraic Integers (대수적 정수 환에 의한 이산 푸릴에 변환의 계산)

  • 강병희;최시연;김진우;김덕현;백상열
    • Proceedings of the IEEK Conference
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    • 2001.09a
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    • pp.107-110
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    • 2001
  • In this paper, we propose a multiplication-free DFT kernel computation technique, whose input sequences are approximated into a ring of Algebraic Integers. This paper also gives computational examples for DFT and IDFT. And we proposes an architecture of the DFT using barrel shifts and adds. When the radix is greater than 4, the proposed method has a high Precision property without scaling errors due to twiddle factor multiplication. A possibility of higher radix system assumes that higher performance can be achievable for reducing the DFT stages in FFT.

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A characterization of the algebraic multiplicity as a map of grothendieck groups

  • Park, Chan-Bong
    • Journal of the Korean Mathematical Society
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    • v.31 no.4
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    • pp.619-628
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    • 1994
  • The multiplicity theory initiated by C. Chevalley was the one with respect to ideals generated by a system of parameters of a local ring containing a field [3] and [4]. Samuel generalized the definition to primary ideals belonging the maximal ideal of a local ring which contains a field by a device which used the Hilbert characteristic function [9]. Furthermore Samuel defined multiplicity also in local rings which contain no field [10].

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Vibration Analysis of Turbocharger Rotor-Bearing System (과급기 축계의 진동 해석)

  • Suk, Ho-Il;Yang, Bo-Suk;Song, Jin-Dea
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.400.2-400
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    • 2002
  • Recently rotating machines have became high speed and high Power and light weight. Bearings are one of the main components which influence power loss and stability of rotating machines. Appropriate bearing should be selected with considering characteristics of rotating machine. Floating ring journal bearing(FIB) consists of an inner film and outer film, and possess high damping and stability. FJB has been for adopted into turbocharger for the high stability at high operating speed. (omitted)

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An adaptive controller for ring rolling precesses (환상 압연 공정의 적응 제어)

  • 최형돈;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.534-539
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    • 1986
  • This paper considers the ring rolling process contorl and treats the problem of controlling the pressure roll and conical roll motion which critically affects final quality of the rolled products. Since the process dynamics reveals nonlinear characteristics and parameter uncertainty, an adaptive control scheme was applied. The results show that this proposed adaptive control scheme can produce rolled rings of closer dimensional tolerances as compared with nonadaptive control system.

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새로운 Pimarane Diterpene의 합성 및 구조-활성 관계

  • 서영거;조윤상;전라옥;최남송;박현주;김영호;이정준;황방연
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1993.04a
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    • pp.43-43
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    • 1993
  • Robinson annotation과 입체선택적 alkylation으로 새로운 pimarane diterpene 의 A,B-ring system을 합성한 후 cyclohexane의 allylation과 Claisen 전위를 이용하여 4급탄소 unit를 얻고 Mcurry coupling 반응으로 C-ring을 도입함으로써 새로운 pimarane diterpene을 전합성하였다. 전합성 중에 개발된 방법들을 이용하여 기본 골격들을 합성한 후 효능 검색하여 구조-활성관계를 확립하고 lead compound를 유도해 내었다.

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Studies on the Strained Ring Compound System (II) The Formation of Tetrahedrane in the Pyrolysis of 2-Butenedial Ditosylhydrazone (小員環 化合物에 關한 硏究 (II) 2-Butenedial Ditosylhydrazone 熱分解에 있어서의 Tetrahedrane 生成에 關하여)

  • Hak-Ki Lee
    • Journal of the Korean Chemical Society
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    • v.13 no.4
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    • pp.347-353
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    • 1969
  • trans-1, 4-Dideutero-2-butenedial ditosylhydrazone has been synthesized to investigate the path of the acetylene formation in the pyrolysis of the dry lithium salt. Mass spectra showed that three isotope isomers of acetylene which might come from the strained ring compound, tricyclo[1, 1, 0, ] butane, were formed.

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Studies on the Strained Ring Compound System (I) The Base-Induced Pyrolysis of 2-Butenedial Distosylhydrazone (小員環 化合物에 關한 硏究 (I) 2-Butenedial Ditosylhydrazone의 熱分解에 關하여)

  • Hak-Ki Lee
    • Journal of the Korean Chemical Society
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    • v.13 no.4
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    • pp.341-346
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    • 1969
  • The synthesis and pyrolysis of trans-2-butenedial ditosylhydrazone with sodium methoxide in aprotic solvents have been studied to investigate the products of pyrolysis. The pyrolysis of dry lithium salt of tosylhydrazone also has been made, one of its products was acetylene which might come from a certain strained ring compound.

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Halogenation of Cannabinoids (Cannabinoid의 할로겐화)

  • Baek Seung-Hwa;Park No-Yeun
    • Journal of the Korean Chemical Society
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    • v.35 no.1
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    • pp.59-63
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    • 1991
  • Several types of cannabinoids have been halogenated in the aromatic ring in good yields with metal halide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. This reagent system effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

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A Comprehensive Development of Urban Greenery Morphs - The Analysis of Greenery Construction of the Middle Ring Line (Puxi section) of Shanghai-

  • Zhongzhai Wang;Wei Zhuang
    • Journal of the Korean Institute of Landscape Architecture International Edition
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    • no.2
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    • pp.140-146
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    • 2004
  • All-round development of urban greenery network morphology is an integrated part of urban space system. The greenbelt construction of the Middle Ring Line is capable of changing linear planning and merging the peripheral greenery construction with 3-D space design to jointly form a broad open space.

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Halogenation of Resorcinol Derivatives

  • Baek Seung-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.9 no.1
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    • pp.13-15
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    • 1988
  • Several types of resocinols have been monobrominated in the ring in good yields with sodium bromide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. Monoiodination takes place with 2'-(1-methylcyclohexen-3-yl)-5-(1,1-dimethylheptyl )-resocinol when sodium iodide is employed. This new reagent system, MX/18-crown-6/m-CPBA (M =$K^+, Na^+, X = Br^-, I^-X$ ), effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.