• Title/Summary/Keyword: partial elimination ideal

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Advanced Block Matching Algorithm for Motion Estimation and Motion Compensation

  • Cho, Hyo-Moon;Cho, Sang-Bock
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.23-25
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    • 2007
  • The partial distortion elimination (PDE) scheme is used to decrease the sum of absolute difference (SAD) computational complexity, since the SAD calculation has been taken much potion of the video compression. In motion estimation (ME) based on PDE, it is ideal that the initial value of SAD in summing performance has large value. The traditional scan order methods have many operation time and high operational complexity because these adopted the division or multiplication. In this paper, we introduce the new scan order and search order by using only adder. We define the average value which is called to rough average value (RAVR). Which is to reduce the computational complexity and increase the operational speed and then we can obtain the improvement of SAD performance. And also this RAVR is used to decide the search order sequence, since the difference RAVR between the current block and candidate block is small then this candidate block has high probability to suitable candidate. Thus, our proposed algorithm combines above two main concepts and suffers the improving SAD performance and the easy hardware implementation methods.

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SOME GEOMETRIC PROPERTIES OF GOTZMANN COEFFICIENTS

  • Jeaman Ahn
    • Journal of the Chungcheong Mathematical Society
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    • v.37 no.2
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    • pp.57-66
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    • 2024
  • In this paper, we study how the Hilbert polynomial, associated with a reduced closed subscheme X of codimension 2 in ℙN, reveals geometric information about X. Although it is known that the Hilbert polynomial can tell us about the scheme's degree and arithmetic genus, we find additional geometric information it can provide for smooth varieties of codimension 2. To do this, we introduce the concept of Gotzmann coefficients, which helps to extract more information from the Hilbert polynomial. These coefficients are based on the binomial expansion of values of the Hilbert function. Our method involves combining techniques from initial ideals and partial elimination ideals in a novel way. We show how these coefficients can determine the degree of certain geometric features, such as the singular locus appearing in a generic projection, for smooth varieties of codimension 2.

PROJECTIONS OF ALGEBRAIC VARIETIES WITH ALMOST LINEAR PRESENTATION I

  • Ahn, Jeaman
    • Journal of the Chungcheong Mathematical Society
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    • v.32 no.1
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    • pp.15-21
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    • 2019
  • Let X be a reduced closed subscheme in ${\mathbb{P}}^n$ and $${\pi}_q:X{\rightarrow}Y={\pi}_q(X){\subset}{\mathbb{P}}^{n-1}$$ be an isomorphic projection from the center $q{\in}{\mathbb{P}}^n{\backslash}X$. Suppose that the minimal free presentation of $I_X$ is of the following form $$R(-3)^{{\beta}2,1}{\oplus}R(-4){\rightarrow}R(-2)^{{\beta}1,1}{\rightarrow}I_X{\rightarrow}0$$. In this paper, we prove that $H^1(I_X(k))=H^1(I_Y(k))$ for all $k{\geq}3$. This implies that Y is k-normal if and only if X is k-normal for $k{\geq}3$. Moreover, we also prove that reg(Y) ${\leq}$ max{reg(X), 4} and that $I_Y$ is generated by homogeneous polynomials of degree ${\leq}4$.

PROJECTIONS OF ALGEBRAIC VARIETIES WITH ALMOST LINEAR PRESENTATION II

  • Ahn, Jeaman
    • Journal of the Chungcheong Mathematical Society
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    • v.34 no.2
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    • pp.181-188
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    • 2021
  • Let X be a nondegenerate reduced closed subscheme in ℙn. Assume that πq : X → Y = πq(X) ⊂ ℙn-1 is a generic projection from the center q ∈ Sec(X) \ X where Sec(X) = ℙn. Let Z be the singular locus of the projection πq(X) ⊂ ℙn-1. Suppose that IX has the almost minimal presentation, which is of the form R(-3)β2,1 ⊕ R(-4) → R(-2)β1,1 → IX → 0. In this paper, we prove the followings: (a) Z is either a linear space or a quadric hypersurface in a linear subspace; (b) $H^1({\mathcal{I}_X(k)})=H^1({\mathcal{I}_Y(k)})$ for all k ∈ ℤ; (c) reg(Y) ≤ max{reg(X), 4}; (d) Y is cut out by at most quartic hypersurfaces.

The Availability of Allogenic Fibular Bone Graft with Autogenous Bone Dust in Anterior Cervical Fusion after Cervical Discectomy (경추 추간판절제술후 전방 골유합시에 자가골분진을 충전시킨 동결건조된 동종비골이식의 유용성)

  • Lee, Sang Dae;Rhee, Dong Youl;Kim, Soo Young;Jeong, Young Gyun;Cho, Bong Soo;Park, Hyuck
    • Journal of Korean Neurosurgical Society
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    • v.29 no.8
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    • pp.1043-1049
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    • 2000
  • Objective : This study was undertaken to evaluate the availability of allogenic fibular bone graft filled with autogenous bone dust in anterior cervical fusion after cervical discectomy. Methods : During a 4-year period(1995-1998), twenty four cases of anterior cervical fusion after discectomy were performed with fibular allograft filled with autogenous bone dust in degenerative cervical disease. We used freeze-dried fibular allograft and autogenous bone dust. Autogenous bone dust obtained from spondylotic spurs, osteophytes, and during foraminotomy. Cervical plating system was done at 8 patients. 5 patients were 1 level and 3 patients were 2 levels. All patients were routinely evaluated after surgery at 2 weeks, 1 month, 3 months, 5 months and 12 months. Mean follow-up period was 21months. Results : Eighty eight percent of the patients were found to have excellent or good clinical results. Radiographic follow-up revealed that 92% of the patients obtained complete or partial union by 5 months after surgery. One patient had graft extrusion immediately after surgery and had the graft reinserted. Two patients had longitudinal graft fractures. There were no graft related complications. Conclusion : Fibular allograft filled with autogenous bone dust for cervical interbody fusion after discectomy is an ideal graft material by showing obvious benefits of good fusion rate and elimination of donor site complications. And also we were able to obtain satisfactory clinical outcome.

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