• 제목/요약/키워드: Symmetric Transformation

검색결과 58건 처리시간 0.024초

대역분할과 BW 변환을 이용한 무손실 영상압축 (Lossless image compression using subband decomposition and BW transform)

  • 윤정오;박영호;황찬식
    • 한국산업정보학회논문지
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    • 제5권1호
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    • pp.102-107
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    • 2000
  • 일반적으로 문자와 영상이 갖는 특성이 서로 다르기 때문에 문자 압축 기법들을 영상 압축에 직접 사용하지 않는다. 최근 문자 압축에 뛰어난 결과를 얻을 수 있는 블록 정렬 알고리즘인 BW 변환이 소개되었으나 BW 변환을 직접 영상에 적용하면 만족할 만한 결과를 얻을 수가 없다. 따라서 BW 변환을 영상에 적용할 때 무손실 압축성능 개선을 위한 새로운 방법을 제안한다. 제안한 방법의 구성은 3단계로 나누어지며 SSKF 필터에 의한 10개 영역으로 계층적 대역 분할을 하고 BW 변환에 의한 블록 정렬 알고리즘을 수행하여 적응적 산술 부호화에 의한 중복성를 제거한다. 실험 결과 제안한 방법이 무손실 JPEG 표준안과 LZ계열의 PKZIP 보다 뛰어난 압축 성능을 가졌다.

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Wide Air-gap Control for Multi-module Permanent Magnet Linear Synchronous Motors without Magnetic Levitation Windings

  • Bang, Deok-Je;Hwang, Seon-Hwan
    • Journal of Power Electronics
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    • 제16권5호
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    • pp.1773-1780
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    • 2016
  • This paper proposes a wide air-gap control method for the multi-module permanent magnet linear synchronous motor (MM-PMLSM) based on independent vector control. In particular, the MM-PMLSM consists of symmetrical multi-module and multi-phase structures, which are basically three-phase configurations without a neutral point, unlike conventional three-phase machines. In addition, there are no additional magnetic levitation windings to control the normal force of the air-gap between each stator and mover. Hence, in this paper, a dq-axis current control applying a d-q transformation and an independent vector control are proposed for the air-gap control between the two symmetric stators and mover of the MM-PMLSM. The characteristics and control performance of the MM-PMLSM are analyzed under the concept of vector control. As a result, the proposed method is easily implemented without additional windings to control the air-gap and the mover position. The effectiveness of the proposed independent vector control algorithm is verified through experimental results.

2차원 양자 역학적 해석에 의한 고속 통신용 $Al_{x}Gal{-x}As/Ga_{x}In1$_{-x}$As/GaAs HEMT 소자의 전자 농도 및 전위분포 계산 (Calculation of Electron concentration and Electrostatic potential profile for $Al_{x}Gal{-x}As/Ga_{x}In1$_{-x}$As/GaAs HEMT device by 2-Dimensional Quantum Mechanical analysis))

  • 송영진;황호정
    • 전자공학회논문지A
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    • 제30A권3호
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    • pp.76-87
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    • 1993
  • We present a self-consistent, 2-dimensional solution of the Poisson and Sch rodinger equation based on the finite difference method with a nonuniform mesh size for a AlGaAs/GaInAs/GaAs HEMT devide. During the interative self-consistent calculation, however, we calculate Schrodinger equation only a some region of device, not a fully region in order to save the moemory and the speed-up of computation, and then use the approximated data for the other region using by a interpolation method with a given values. Also we adopt the proper matrix transformation method that allows preservation of the symmetric, form of the discretized Schrodinger equation, even with the use of a nonumiform mesh size, therefor, can reduce the computation time. We calculate the wavefunction, eigenstates and the electron concentration uat channel layer nder the thermal equilibrium and the biased conditions, respectively. Also,these parameters are used to solve 2-dimensional tdistribution of potential in he entire region of device. It is proved that the method is very efficient in finding eigenstages extending over relatively large spatial area without loss of accuracy. So, it can be used rather easily in any sarbitrary modulation doped utucture.

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INJECTIVE PARTIAL TRANSFORMATIONS WITH INFINITE DEFECTS

  • Singha, Boorapa;Sanwong, Jintana;Sullivan, Robert Patrick
    • 대한수학회보
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    • 제49권1호
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    • pp.109-126
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    • 2012
  • In 2003, Marques-Smith and Sullivan described the join ${\Omega}$ of the 'natural order' $\leq$ and the 'containment order' $\subseteq$ on P(X), the semigroup under composition of all partial transformations of a set X. And, in 2004, Pinto and Sullivan described all automorphisms of PS(q), the partial Baer-Levi semigroup consisting of all injective ${\alpha}{\in}P(X)$ such that ${\mid}X{\backslash}X{\alpha}\mid=q$, where $N_0{\leq}q{\leq}{\mid}X{\mid}$. In this paper, we describe the group of automorphisms of R(q), the largest regular subsemigroup of PS(q). In 2010, we studied some properties of $\leq$ and $\subseteq$ on PS(q). Here, we characterize the meet and join under those orders for elements of R(q) and PS(q). In addition, since $\leq$ does not equal ${\Omega}$ on I(X), the symmetric inverse semigroup on X, we formulate an algebraic version of ${\Omega}$ on arbitrary inverse semigroups and discuss some of its properties in an algebraic setting.

MRI에 있어서 체동 아티팩트의 제거 (Cancellation of Motion Artifact in MRI)

  • 김응규
    • 대한전자공학회논문지SP
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    • 제37권3호
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    • pp.70-78
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    • 2000
  • 본 연구에서는 촬상단면내의 평행이동에 기인한 MRI 아티팩트를 제거하는 새로운 방법을 제안한다 임상 진단에 있어서 종종 문제가 되고 있는 호흡에 따른 두뇌부분의 상하이동을 고려해서 위상 엔코드 축인 y 방향만의 강체의 평행이동을 취급한다 종래의 발견적인 반복위상탐색 처리법과는 달리, MRI 촬상과정과 화장 특성의 해석에 근거한 MRI 신호내의 체동성분과 화상성분을 단순한 대수연산에 의해 분리할 수 있는 새로운 구속조건을 도출한다 MRI 신호에 대해서 x 방향의 1차원 푸리에 변환을 행한 후의 y 방향 스펙트럼 위상값은 화상자신의 성분과 체동성분의 합이 되고 있다 한편 두뇌부위 등의 단층상에 있어서 주위의 피하지방 부분의 밀도는 거의 균일하다고 알려져 있어, 이 부위상에 있는 y 방향의 한 라인의 말도분포는 대칭모양으로 간주할 수 있다 밀도함수가 대칭인 경우 스펙트럼의 위상은 그 위치에 대하여 선형적으로 변화한다 따라서 이 선형함수로부터 벗어난 성분을 체동으로 분리할 수 있다. 이러한 구속조건에 기초를 둔 새로운 아티팩트의 제거방법이 본 연구에서 제안된다 최종적으로 phantom 화상을 사용한 시뮬레이션을 통해 본 방 법의 유효성을 나타낸다.

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Stochastic optimal control analysis of a piezoelectric shell subjected to stochastic boundary perturbations

  • Ying, Z.G.;Feng, J.;Zhu, W.Q.;Ni, Y.Q.
    • Smart Structures and Systems
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    • 제9권3호
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    • pp.231-251
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    • 2012
  • The stochastic optimal control for a piezoelectric spherically symmetric shell subjected to stochastic boundary perturbations is constructed, analyzed and evaluated. The stochastic optimal control problem on the boundary stress output reduction of the piezoelectric shell subjected to stochastic boundary displacement perturbations is presented. The electric potential integral as a function of displacement is obtained to convert the differential equations for the piezoelectric shell with electrical and mechanical coupling into the equation only for displacement. The displacement transformation is constructed to convert the stochastic boundary conditions into homogeneous ones, and the transformed displacement is expanded in space to convert further the partial differential equation for displacement into ordinary differential equations by using the Galerkin method. Then the stochastic optimal control problem of the piezoelectric shell in partial differential equations is transformed into that of the multi-degree-of-freedom system. The optimal control law for electric potential is determined according to the stochastic dynamical programming principle. The frequency-response function matrix, power spectral density matrix and correlation function matrix of the controlled system response are derived based on the theory of random vibration. The expressions of mean-square stress, displacement and electric potential of the controlled piezoelectric shell are finally obtained to evaluate the control effectiveness. Numerical results are given to illustrate the high relative reduction in the root-mean-square boundary stress of the piezoelectric shell subjected to stochastic boundary displacement perturbations by the optimal electric potential control.

변위법(變位法)에 의한 곡선형교(曲線桁橋)의 정적탄성해석(靜的彈性解析) (An Elastic Static Analysis of Curved Girder Bridges by the Displacement Method)

  • 정진환;장승필
    • 대한토목학회논문집
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    • 제6권2호
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    • pp.121-131
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    • 1986
  • ?(warping)의 효과(効果)가 포함된 원형곡선부재(圓形曲線部材)의 부재강도(部材剛度)매트릭스를 미분방정식(微分方程式)의 해석적(解析的)인 해(解)를 사용(使用)하여 유도(誘導)하고, 원형곡선부재(圓形曲線部材)의 변위법(變位法)에 의(依)한 정적탄성해석방법(靜的彈性解析方法)을 제시(提示)하였다. 예제(例題)를 통하여 얻어진 결과(結果)는 다른 방법(方法)에 의(依)한 해석결과(解析結果)와 잘 일치(一致)하고 있어, 본(本) 논문(論文)의 정당성을 입증하였고 원형곡선부재(圓形曲線部材)로 구성(構成)된 구조물(構造物)을 해석(解析)할 때 곡선좌표계(曲線座標系)를 사용(使用)하므로써, 한 절점에 연결된 양쪽 부재축(部材軸)의 접선(接線)이 일치(一致)한다면, 국부좌표계(局部座標系)로부터 전체좌표계(全體座標系)로의 변환(變換)이 필요(必要)없음을 보였다. 본(本) 논문(論文)에서 유도(誘導)된 이론(理論)은 P.S. 상자형(箱子桁)의 폐단면(閉斷面) 또는 부재평면(部材平面)과 수직(垂直)인 축(軸)에 대하여 대칭인 개단면(開斷面)을 갖는 수평원형곡선부재(水平圓形曲線部材)로 이루어진 구조물(構造物)의 엄밀(嚴密)한 해석(解析)에 적용(適用)할 수 있다.

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A Study on the Characteristics of Knitwear Fashion Design: With a focus on Missoni, Sonia Rykiel, Azzedine Alaia

  • Chun, Hei Jung;Park, Jae Min
    • International Journal of Costume and Fashion
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    • 제13권1호
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    • pp.23-34
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    • 2013
  • The purpose of this study is to better understand the development and characteristics of knitwear fashion design by examining the transformation process of the modern knits. The subjects of the study are Missoni, Sonia Rykiel, and Azzedine Alaia, designers who are world-renowned knit designers, and the expressive techniques in their designs will be evaluated. The study also intends to analyze the aesthetic value of each designer's style through their product's silhouette, colors, and knitting techniques. On the basis of the analysis, we hope to research the factors in the designing process that will allow knits, which were made for practical purposes, to be valued as a luxury fashion item, and with the results, show the potential for knits in expanding its domain in fashion to become a more luxurious, creative fashion item. The characteristic comparison of the designers is as follows: First, in the case of colors, Missoni shows its distinct identity through a balance of splashy colors as well as nature-inspired color composition and balance. And, only with color use, is also able to express perspective, form composition, and rhythm. Sonia Rykiel designs are composed of black backgrounds with strong primary colors that are contrasted with one-point or stripes to express a light, urban image. Alaia emphasizes femininity by the use of black and white colors, which show modernity, in combination with neutral skin-toned colors, such as beige and gray. So, in other words, Missoni and Sonia Rykiel mixed colors for visual interconnectivity, while Alaia expressed femininity through the use of an achromatic color. Second, in the case of knitting techniques, Missoni uses the jacquard technique to make complex patterns that show balance of colors and patterns such as zigzag, stripe, geometries, and titan check, which are geometric, abstract, and symmetric. Sonia Rykiel who uses stripes as her trademark, most often utilizes the intarsia technique, which is expressed through one-point. Alaia combines diverse techniques, such as the Skashi weaving, by using computerized knitting. Third, as for silhouettes, Missoni eliminated exaggerated details in order to emphasize the flashy colors and delicate patterns and weavings of its designs, and this resulted in simplistic and relaxed silhouettes. Sonia Rykiel took advantage of the elasticity that the knit offers to get a tight silhouette, and in turn, emphasized the female sensuality. Alaia used curvilinear cuts that emphasized the womanly curves and gained an image considered soft and feminine.