• Title/Summary/Keyword: Method of Moments

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Characteristic modes of a longitudinal slot in the outer conductro of coaxial waveguide for scattering : TE case (외부도체면에 축방향 슬롯이 있는 동축선로 도파관의 산란에 대한 특성모드의 해석 : TE의 경우)

  • 윤리호;조영기
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.7
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    • pp.23-29
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    • 1995
  • A characteristic mode theory for longitudinal slot of arbitrary width in the outer conductor of coaxial waveguide is applied for calculating the characteristic magnetic currents, the characteristic fields, radiation patterns, and the fields evershere(inside and outside the guide, and in the aperture region). Numerical results of the equivalent magnetic currents and the radiation patterns are compared with those obtained by use of the method of moments.

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Antenna Factors of Half-wave Resonance Dipole Antennas above the Ground Plane (접지판 위에 놓여진 반파장 공진다이폴 안테나의 안테나 인자)

  • Ki-Chai Kim
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.2 no.4
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    • pp.3-9
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    • 1991
  • This paper presents the characteristics of antenna factors of half-wave resonance dipole antennas above a ground plane. The current distributions on a horizontal and vertical dipole antennas were analyzed by the Galerkin's method of moments, and these solutions are used for calculating the horizontal and vertical antenna factors above the ground plane. It is shown that accurate antenna factors of the horizontal and vertical dipole above the ground plane are required of the radiated emission test.

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ESTIMATING MOMENTS OF THE SURVIVAL TIME FROM CENSORED OBSERVATIONS

  • Jung, In-Ha;Lee, Kang-Sup
    • The Pure and Applied Mathematics
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    • v.2 no.2
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    • pp.83-89
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    • 1995
  • A Bayes estimator of the survival distribution function due to Susarla and Van Ryzin(1976) is used to estimate the mth moment of a survival time on the basis of censored observations in a random censorship model. Asymptotic normality of the estimator is proved using the functional version of the delta method.

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Likelihood ratio in estimating Chi-square parameter

  • Rahman, Mezbahur
    • Journal of the Korean Data and Information Science Society
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    • v.20 no.3
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    • pp.587-592
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    • 2009
  • The most frequent use of the chi-square distribution is in the area of goodness-of-t of a distribution. The likelihood ratio test is a commonly used test statistic as the maximum likelihood estimate in statistical inferences. The recently revised versions of the likelihood ratio test statistics are used in estimating the parameter in the chi-square distribution. The estimates are compared with the commonly used method of moments and the maximum likelihood estimate.

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Temperature control of a batch PS polymerization reactor using on-line two-step method (온라인 2단계 방법을 이용한 회분식 PS 중합반응기의 온도제어)

  • 이병모;노형준;이현구
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.305-308
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    • 1997
  • The on-line calculation method is developed to obtain the temperature trajectory that brings the reactants to the desired state in batch styrene polymerization reactor. The temperature trajectory is obtained by applying the moments of the polymer concentration to the 2-step calculation method. The computer simulation is also carried out to verify the superiority of the on-line method to the off-line one. When a temperature disturbance of constant size is introduced, the off-line results shows considerable deviation from the target degree of polymerization. The on-line strategy set up a new trajectory to reach the desired state by using the current state of the reactor. Therefore, the on-line strategy deals with the changes of the system more adequately than the off-line strategy.

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A Study on the Analysis of Overload of a Two-Span Continuous Bridige (2경간 연속교의 과재하중 해석방법에 관한 연구)

  • 한상철
    • Journal of the Korean Society of Safety
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    • v.8 no.1
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    • pp.47-53
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    • 1993
  • Residual Deformation Analysis(RDA) is a new method for ratings of the continuous bridges. The RDA makes it possible to expand the inelastic steel girder bridge design method set forth in the American Association of State Highway Officals'(AASHTO) Guide Specifications for Alternate Load Factor Design Procedures for Steel Beam Bridges Using Braced Compact Sections(1986) into an inelastic rating method. It is a method to assess the residual moments and deformations that are set up in a beam that has been loaded into the post-elastic range This method combines classical elastic conjugate beam theory with linear moment-rotation relationships for midspan inelastic positive moment. The limit state is inelastic serviceability limit. which is defined as the ratio of the span to midspan inelastic deflection(C=L/D).

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Characteristics mode analysis for the finite slotted parallel-plate waveguide as a leaky wave antenna structure (유전체로 채워진 유한한 슬롯을 가지는 평행평판 도파관 누설파 안테나 구조에 대한 특성 모드 해석)

  • 윤이호;조영기
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.10
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    • pp.32-38
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    • 1997
  • A characteristic mode analysis of parallel-plate waveguide with finite number of slot as a leaky wav eantenna structure is considered for calculating the characteristics currents, the characteristic patterns, radiatin patterns, and the complex propagation constants. For the cases of 1, 11 and 29 slots, numericl resutls for the equivalent magnetic currents, the radiatin patterns, and thecomplex propagation constants are computed and compared with those obtained by use of the conventional method of moments. Good correspondence between them is observed.

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Statistical Inferences for Bivariare Exponential Distribution in Reliability and Life Testing Problems

  • PARK, BYUNG-GU
    • Journal of Korean Society for Quality Management
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    • v.13 no.1
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    • pp.31-40
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    • 1985
  • In this paper, statistical estimation of the parameters of the bivariate exponential distribution are studied. Bayes estimators of the parameters are obtained and compared with the maximum likelihood estimators which are introduced by Freund. We know that the method of moments estimators coincide with the maximum likelihood estimators and Bayes estimators are more efficient than the maximum likelihood estimators in moderate samples. The asymptotic distributions of the maximum likelihood estimators and the estimator of mean time to system failure are obtained.

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A Study on Optimum Design of Yagi-Uda Antenna (Yagi-Uda 안테나의 최적설계에 관한 연구)

  • Lee, Seon-Mi;Cheon, Chang-Yul
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1207-1209
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    • 1994
  • An optimization technique applicable to the Yagi-Uda antenna was proposed in this paper. An objective function, which is the gain of the antenna in our case, was computed using method of moments. Design variables for the Yagi-Uda antenna were chosen with lengths, positions and diameters of the antenna elements. For the optimization process, the evolution strategy technique was adopted. The results were compared with existing results and showed better performances.

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Antenna factors of short dipole antennas with roberts balun (Roberts밸런을 갖는 단축 다이폴 안테나의 안테나 인자)

  • 김기채
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.3
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    • pp.532-538
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    • 1997
  • Exactly aclculated antenna factors are requeired for determining EMI levels in an actual radiated emission test. In this paper, the antenna factors of short dipole antennas above the ground plane are calculated theoretically for the antenna with Roberts balun specified ANSI C63.5 regulation. Also treated is a half-wavelength dipole antenna with Roberts balun to compare the antenna factors with those of resonant dipole antenna. In formulationof antenna factors the antenna is treated as the boundary value problem of Maxwells equations and is analyzed by the Galerkins method of moments. The balun is treated using circuit theory based on power transmission mismatch.

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