• Title/Summary/Keyword: projective

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Power Analysis Attacks and Countermeasures on ${\eta}_T$ Pairing over Binary Fields

  • Kim, Tae-Hyun;Takagi, Tsuyoshi;Han, Dong-Guk;Kim, Ho-Won;Lim, Jong-In
    • ETRI Journal
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    • v.30 no.1
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    • pp.68-80
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    • 2008
  • Since many efficient algorithms for implementing pairings have been proposed such as ${\eta}_T$ pairing and the Ate pairing, pairings could be used in constraint devices such as smart cards. However, the secure implementation of pairings has not been thoroughly investigated. In this paper, we investigate the security of ${\eta}_T$ pairing over binary fields in the context of side-channel attacks. We propose efficient and secure ${\eta}_T$ pairing algorithms using randomized projective coordinate systems for computing the pairing.

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A Calibration Algorithm Using Known Angle (각도 정보를 이용한 카메라 보정 알고리듬)

  • 권인소;하종은
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.5
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    • pp.415-420
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    • 2004
  • We present a new algorithm for the calibration of a camera and the recovery of 3D scene structure up to a scale from image sequences using known angles between lines in the scene. Traditional method for calibration using scene constraints requires various scene constraints due to the stratified approach. Proposed method requires only one type of scene constraint of known angle and also it directly recovers metric structure up to an unknown scale from projective structure. Specifically, we recover the matrix that is the homography between the projective structure and the Euclidean structure using angles. Since this matrix is a unique one in the given set of image sequences, we can easily deal with the problem of varying intrinsic parameters of the camera. Experimental results on the synthetic and real images demonstrate the feasibility of the proposed algorithm.

DEFORMATION SPACES OF CONVEX REAL-PROJECTIVE STRUCTURES AND HYPERBOLIC AFFINE STRUCTURES

  • Darvishzadeh, Mehdi-Reza;William M.Goldman
    • Journal of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.625-639
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    • 1996
  • A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

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HOLOMORPHIC EMBEDDINGS OF STEIN SPACES IN INFINITE-DIMENSIONAL PROJECTIVE SPACES

  • BALLICO E.
    • Journal of the Korean Mathematical Society
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    • v.42 no.1
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    • pp.129-134
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    • 2005
  • Lpt X be a reduced Stein space and L a holomorphic line bundle on X. L is spanned by its global sections and the associated holomorphic map $h_L\;:\;X{\to}P(H^0(X, L)^{\ast})$ is an embedding. Choose any locally convex vector topology ${\tau}\;on\;H^0(X, L)^{\ast}$ stronger than the weak-topology. Here we prove that $h_L(X)$ is sequentially closed in $P(H^0(X, L)^{\ast})$ and arithmetically Cohen -Macaulay. i.e. for all integers $k{\ge}1$ the restriction map ${\rho}_k\;:\;H^0(P(H^0(X, L)^{\ast}),\;O_{P(H^0(X, L)^{\ast})}(k)){\to}H^0(h_L(X),O_{hL_(X)}(k)){\cong}H^0(X, L^{\otimes{k}})$ is surjective.

CHARACTERIZATIONS OF SOME ISOMETRIC IMMERSIONS IN TERMS OF CERTAIN FRENET CURVES

  • Choi, Jin-Ho;Kim, Young-Ho;Tanabe, Hiromasa
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.6
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    • pp.1285-1296
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    • 2010
  • We give criterions for a submanifold to be an extrinsic sphere and to be a totally geodesic submanifold by observing some Frenet curves of order 2 on the submanifold. We also characterize constant isotropic immersions into arbitrary Riemannian manifolds in terms of Frenet curves of proper order 2 on submanifolds. As an application we obtain a characterization of Veronese embeddings of complex projective spaces into complex projective spaces.