• 제목/요약/키워드: Scalar

검색결과 1,036건 처리시간 0.027초

Constant scalar curvature on open manifolds with finite volume

  • Kim, Seong-Tag
    • 대한수학회논문집
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    • 제12권1호
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    • pp.101-108
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    • 1997
  • We let (M,g) be a noncompact complete Riemannina manifold of dimension $n \geq 3$ with finite volume and positive scalar curvature. We show the existence of a conformal metric with constant positive scalar curvature on (M,g) by gluing solutions of Yamabe equation on each compact subsets $K_i$ with $\cup K_i = M$ .

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CONSTANT NEGATIVE SCALAR CURVATURE ON OPEN MANIFOLDS

  • Kim, Seong-Tag
    • 대한수학회보
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    • 제35권2호
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    • pp.195-201
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    • 1998
  • We let (M,g) be a noncompact complete Riemannian manifold of dimension n $\geq$ 3 with scalar curvatue S, which is close to -1. We show the existence of a conformal metric $\bar{g}$, near to g, whose scalar curvature $\bar{S}$ = -1 by gluing solutions of the corresponding partial differential equation on each bounded subsets $K_i$ with ${\bigcup}K_i$ = M.

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Linear Eddy Model을 이용한 스칼라의 혼합특성 해석 (Analysis for Scalar Mixing Characteristics using Linear Eddy Model)

  • 김후중;김용모;안국영
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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    • pp.133-137
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    • 2004
  • The present study is focused on the small scale turbulent mixing processes in the scalar field. In order to deal with molecular mixing in turbulent flow, the linear eddy model is addressed. In each realization, the molecular mixing term is implemented deterministically, and turbulent stirring is represented by a sequence of instantaneous, statistically independent rearrangement event called by triplet map. The LEM approach is applied with relatively simple conditions. The characteristics of scalar mixing and PDF profiles are addressed in detail.

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질소희석과 압력이 석탄가스 비예혼합 화염구조와 소염 스칼라 소산율에 미치는 영향 해석 (Effects of Fuel-Side dilution and Pressure on Structure and Extinction Scalar Dissipation Rate of Syngas Nonpremixed Flames)

  • 박상운;신영준;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.61-62
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    • 2012
  • The present study has numerically investigated the effects of fuel-side dilution and pressure on flame structure and extinction scalar dissipation rate of turbulent syngas nonpremixedd flames. Numerical results indicate that for highly diluted case, peak temperature is decreased and stoichiometric mixture fraction is increased. By decreasing the pressure and the nitrgen dilution levelcreased, the extinction scalar dissipation rate is increased.

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THREE DIMENSIONAL CRITICAL POINT OF THE TOTAL SCALAR CURVATURE

  • Hwang, Seungsu
    • 대한수학회보
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    • 제50권3호
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    • pp.867-871
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    • 2013
  • It has been conjectured that, on a compact 3-dimensional orientable manifold, a critical point of the total scalar curvature restricted to the space of constant scalar curvature metrics of unit volume is Einstein. In this paper we prove this conjecture under a condition that ker $s^{\prime}^*_g{\neq}0$, which generalizes the previous partial results.

A Study on The Jump Error Smoothing Scheme by Fuzzy Logic

  • Lee, Tae-Gyoo;Kim, Kwang-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.56.3-56
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    • 2001
  • This study describes the jump error smoothing scheme with fuzzy logic based on the scalar adaptive filter. The scalar adaptive filter is an useful algorithm for smoothing abrupt jump errors. However, the performances of scalar adaptive algorithm depend on the variance of real signal. So to design an effective algorithm, many informations of real and jump signal are required. In this paper, the fuzzy rules are designed by the analysis of scalar adaptive filter, and then the improved and simplified scheme is developed for smoothing the jump error. Simulations to INS/GPS integrated system show that the proposed method is effective.

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RICCI AND SCALAR CURVATURES ON SU(3)

  • Kim, Hyun-Woong;Pyo, Yong-Soo;Shin, Hyun-Ju
    • 호남수학학술지
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    • 제34권2호
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    • pp.231-239
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    • 2012
  • In this paper, we obtain the Ricci curvature and the scalar curvature on SU(3) with some left invariant Riemannian metric. And then we get a necessary and sufficient condition for the scalar curvature (resp. the Ricci curvature) on the Riemannian manifold SU(3) to be positive.

TOTAL SCALAR CURVATURE AND EXISTENCE OF STABLE MINIMAL SURFACES

  • Hwang, Seung-Su
    • 호남수학학술지
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    • 제30권4호
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    • pp.677-683
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    • 2008
  • On a compact n-dimensional manifold M, it has been conjectured that a critical point metric of the total scalar curvature, restricted to the space of metrics with constant scalar curvature of volume 1, should be Einstein. The purpose of the present paper is to prove that a 3-dimensional manifold (M,g) is isometric to a standard sphere if ker $s^*_g{{\neq}}0$ and there is a lower Ricci curvature bound. We also study the structure of a compact oriented stable minimal surface in M.

A NOTE ON SCALAR CURVATURE FUNCTIONS OF ALMOST-KÄHLER METRICS

  • Kim, Jongsu
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제20권3호
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    • pp.199-206
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    • 2013
  • We present a 4-dimensional nil-manifold as the first example of a closed non-K$\ddot{a}$hlerian symplectic manifold with the following property: a function is the scalar curvature of some almost K$\ddot{a}$hler metric iff it is negative somewhere. This is motivated by the Kazdan-Warner's work on classifying smooth closed manifolds according to the possible scalar curvature functions.

$H_{\upsilon}$-GROUPS WITH WEAK SCALAR ELEMENTS

  • Choi, Byung-Mun;Chung, Sang-Cho
    • Journal of applied mathematics & informatics
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    • 제9권1호
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    • pp.401-413
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    • 2002
  • In this paper, we consider hyperstructures (H,.) defined on the set H = {e, a, b}. We study the hyperstructure of H when every element is one of a scalar unit, a unit or a weak scalar. On those conditions the $H_{\upsilon}$-quasigroups are classified. And we obtain the 15 minimal $H_{\upsilon}$-groups and 2 non-quasi $H_{\upsilon}$-semigroups For these we use the Mathematica 3.0 computer programs.