• 제목/요약/키워드: quadratic form

검색결과 273건 처리시간 0.041초

웨이블릿 변환영역에서 이차방정식 삽입 방법을 이용한 디지털 워터마킹 (Digital Watermarking using a Quadratic Equation Embedding Method in Wavelet Transform Domain)

  • 신용달
    • 한국멀티미디어학회논문지
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    • 제6권5호
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    • pp.870-875
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    • 2003
  • 본 논문에서는 웨이블릿 변환영역에서 비가시성을 개선하기 위하여 이차방정식 삽입방법을 이용한 디지털 워터마킹을 제안하였다. 기존의 디지털 워터마킹 방법에서 워터마크를 삽입하는 방법은 일차 방정식의 형태로 사용하였으나, 제안한 방법에서는 이차 방정식 형태로 확장하였다. 제안한 방법과 기존의 방법에 대한 성능을 평가하기 위해서 LENA, GOLDHILL, BARBARA, 및 MAN 영상을 사용하여 컴퓨터 모의실험을 행하였다. 모의실험 결과 정규화 된 유사도가 100%일 때 원 영상과 워터마크가 삽입된 영상과의 PSNR을 비교한 결과 제안한 방법이 기존의 방법들 보다 모든 영상에서 비가시성이 매우 우수함을 확인할 수 있었다.

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EXPLICIT ERROR BOUND FOR QUADRATIC SPLINE APPROXIMATION OF CUBIC SPLINE

  • Kim, Yeon-Soo;Ahn, Young-Joon
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제13권4호
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    • pp.257-265
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    • 2009
  • In this paper we find an explicit form of upper bound of Hausdorff distance between given cubic spline curve and its quadratic spline approximation. As an application the approximation of offset curve of cubic spline curve is presented using our explicit error analysis. The offset curve of quadratic spline curve is exact rational spline curve of degree six, which is also an approximation of the offset curve of cubic spline curve.

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EVALUATIONS OF SOME QUADRATIC EULER SUMS

  • Si, Xin;Xu, Ce
    • 대한수학회보
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    • 제57권2호
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    • pp.489-508
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    • 2020
  • This paper develops an approach to the evaluation of quadratic Euler sums that involve harmonic numbers. The approach is based on simple integral computations of polylogarithms. By using the approach, we establish some relations between quadratic Euler sums and linear sums. Furthermore, we obtain some closed form representations of quadratic sums in terms of zeta values and linear sums. The given representations are new.

SMALL AMPLITUDE WAVE IN SHALLOW WATER OVER LINEAR AND QUADRATIC SLOPING BEDS

  • Bhatta, Dambaru D.;Debnath, Lokenath
    • Journal of applied mathematics & informatics
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    • 제13권1_2호
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    • pp.53-65
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    • 2003
  • Here we present a study of small-amplitude, shallow water waves on sloping beds. The beds considered in this analysis are linear and quadratic in nature. First we start with stating the relevant governing equations and boundary conditions for the theory of water waves. Once the complete prescription of the water-wave problem is available based on some assumptions (like inviscid, irrotational flow), we normalize it by introducing a suitable set of non-dimensional variables and then we scale the variables with respect to the amplitude parameter. This helps us to characterize the various types of approximation. In the process, a summary of equations that represent different approximations of the water-wave problem is stated. All the relevant equations are presented in rectangular Cartesian coordinates. Then we derive the equations and boundary conditions for small-amplitude and shallow water waves. Two specific types of bed are considered for our calculations. One is a bed with constant slope and the other bed has a quadratic form of surface. These are solved by using separation of variables method.

MOMENTS OF VARIOGRAM ESTIMATOR FOR A GENERALIZED SKEW t DISTRIBUTION

  • KIM HYOUNG-MOON
    • Journal of the Korean Statistical Society
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    • 제34권2호
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    • pp.109-123
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    • 2005
  • Variogram estimation is an important step of spatial statistics since it determines the kriging weights. Matheron's variogram estimator can be written as a quadratic form of the observed data. In this paper, we extend a skew t distribution to a generalized skew t distribution and moments of the variogram estimator for a generalized skew t distribution are derived in closed forms. After calculating the correlation structure of the variogram estimator, variogram fitting by generalized least squares is discussed.

DESIGN OF A DYNAMIC OUTPUT FEEDBACK CONTROLLER FOR POWER SUSTEM GENERATORS

  • Danjyo, Mitsuaki;Tanaka, Yukihiko;Kominato, Yoshihito;Sagara, Setsuo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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    • pp.871-876
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    • 1989
  • We propose a new algorithm to obtain the output feedback controller, which contains one dynamic element, for power system generators. The performance criterion of this controller is the integral of quadratic form of output differences between reference model and controlled system. with this criterion, we can easily compute the output feedback gains using Astrom's algorithm for the integral calculation of quadratic form.

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Design of an output-feedback controller for power system generator

  • Danjyo, Mitsuaki;Tanaka, Yukihiko;Sagara, Setsuo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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    • pp.837-842
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    • 1988
  • We propose a new algorithm to obtain the output feedback controller for power system generators. The performance criterion of this controller is the integral of quadratic form of output differences between reference model and controlled system. With this criterion, we can easily compute the output feedback gains using Astrom's algorithm for the integral calculation of quadratic form. Simulations on a one machine infinite bus system shows the effectiveness of this approach.

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The General Mornent of Non-central Wishart Distribution

  • Chul Kang;Kim, Byung-Chun
    • Journal of the Korean Statistical Society
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    • 제25권3호
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    • pp.393-406
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    • 1996
  • We obtain the general moment of non-central Wishart distribu-tion, using the J-th moment of a matrix quadratic form and the 2J-th moment of the matrix normal distribution. As an example, the second moment and kurtosis of non-central Wishart distribution are also investigated.

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