• Title/Summary/Keyword: legendre polynomials

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Structural Behavior Analysis of Skew RC Slabs by p-Version Nonlinear Finite Element Model (p-Version 비선형 유한요소 모델에 의한 철근 콘크리트 경사 슬래브의 역학적 거동 해석)

  • Cho, Jin-Goo;Park, Jin-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.5
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    • pp.17-26
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    • 2005
  • The objectives of this study are to determine the behavior of simply supported skew RC slabs subjected to a point load. The p-version nonlinear skew RC FE model has been used. Integrals of Legendre polynomials are used for shape functions with p-level varying from 1 to 10. In the nonlinear formulation of this model, the material model is based on the Kupfer's yield criterion, hardening rule, and crushing condition and layered model is used through the thickness. The cracking behavior is modeled by a smeared crack model and the fixed crack approach is adopted as the crack model. It is shown that the proposed model is able to adequately predict the deflection and ultimate load of nonlinear skew RC slabs with respect to steel arrangements and steel ratios.

Least square simulation and hierarchical optimal control of distributed parameter systems

  • Ahn, Doo-Soo;Lee, Myung-Kyu;OH, Min-Hwan;Bae, Jong-Il;Shim, Jae-Sun
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10b
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    • pp.1066-1070
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    • 1990
  • This paper presents a method for the optimal control of the distributed parameter systems (DPSs) by a hierarehical computational procedure. Approximate lumped parameter systems (LPSs) are derived by using the Galerkin method employing the Legendre polynomials as the basis functions. The DPSs however, are transformed into the large scale LPSs. And thus, the hierarchical control scheme is introduced to determine the optimal control inputs for the obtained LPSs. In addition, an approach to block pulse functions is applied to solve the optimal control problems of the obtained LPSs. The proposed method is simple and efficient in computation for the optimal control of DPSs.

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Thermal radiation model for rocket plume base heating using the finite-volume method (유한체적법에 의한 로켓플룸 저부가열의 열복사 모델)

  • Kim, Man-Yeong;Baek, Seung-Uk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.11
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    • pp.3598-3606
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    • 1996
  • The finite volume method for radiation is applied to investigate a radiative heating of rocket base plane due to searchlight and plume emissions. Exhaust plume is assumed to absorb, emit and scatter the radiant energy isotropically as well as anisotropically, while the medium between plume boundary and base plane is cold and nonparticipating. Scattering phase function is modelled by a finite series of Legendre polynomials. After validating benchmark solution by comparison with that of previous works obtained by the Monte-Carlo method, further investigations have been done by changing such various parameters as plume cone angle, scattering albedo, scattering phase function, optical radius and nozzle exit temperature. The results show that the base plane is predominantly heated by the plume emission rather than the searchlight emission when the nozzle exit temperature is the same as that of plume.

Estimation of Genetic and Phenotypic Covariance Functions for Body Weight as Longitudinal Data of SD-II Swine Line

  • Liu, Wenzhong;Cao, Guoqing;Zhou, Zhongxiao;Zhang, Guixian
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.5
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    • pp.622-626
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    • 2002
  • Growth records over six generations of 686 pigs in SD-II Swine Line were used to estimate the genetic and phenotypic covariance functions for body weight as longitudinal data. A random regression model with Legendre polynomials of age as independent variables was used to estimate the (co)variances among the regression coefficients, thus the coefficients of genetic and permanent environmental covariance functions by restricted maximum likelihood employing the average information algorithm. The results showed that, using litter effect as additional random effect, a reduced order of fit did not describe the data adequately. For all five orders of fit, however, the change trends of genetic and phenotypic (co)variances were very similar from ${\kappa}$=3 onwards.

DEVELOPMENT OF IMPLICIT DISCONTINUOUS GALERKIN METHOD ON UNSTRUCTURED MESHES (비정렬 격자계에서 내재적 불연속 갤러킨 기법의 개발)

  • Lee, H.D.;Kwon, O.J.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.04a
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    • pp.30-40
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    • 2007
  • The implicit discontinuous Galerkin method for the two-dimensional Euler equations was developed on unstructured triangular meshes, which can achieve higher-order accuracy by wing hierachical basis functions based on Legendre polynomials. Numerical tests were conducted to estimate the convergence order of numerical solutions to the Ringleb flow and the supersonic vortex flow for which analytic solutions are available. And, the flows around a circle and a NACA0012 airfoil was also numerically simulated. Numerical results show that the implicit discontinuous Galerkin methods with higher-order representation of curved solid boundaries can be an efficient higher-order method to obtain very accurate numerical solutions on unstructured meshes.

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Decentralized Optimal Control of Distributed Parameter Systems (분포정수계의 분산형 최적제어에 관한 연구)

  • 안두수;이명규
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.10
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    • pp.1075-1085
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    • 1990
  • This paper presents a new method for the optimal control of the distributed parameter systems by a decentralized computational procedure. Approximate lumped parameter models are derived by using the Galerkin method employing the Legendre polynomials as the basis functions. The distributed parameter systems, however, are transformed into the large scale lumped parameter models. And thus, the decentralized control scheme is introduced to determine the optimal control inputs for the obtained lumped parameter models. In addition, an approach to block pulse functions is applied to solve the optimal control problems of the obtained lumped parameter models. The proposed method is simple and efficient in computation for the optimal control of distributed paramter systems. Illustrative examples given to demonstrate the validity of the presently proposed method.

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p-Version Finite Element Analysis of Stiffened Plates Including Transverse Shear Deformation (전단 변형을 고려한 보강판의 p-Version 유한요소 해석)

  • 홍종현;우광성;신영식
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1995.10a
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    • pp.145-152
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    • 1995
  • A general stiffener element which includes transverse shear deformation(TSD) is formulated using the p-version of finite element method. Hierarchic C"-shape functions, derived from Integrals of Legendre polynomials, are used to define the assembled stiffness matrix of the stiffener and plate on the basis of 5 D.0.F displacement fields. The stiffness matrix for the stiffener with respect to the local reference frame is transformed to the plate reference system by applying the appropriate transformation matrices in order to insure compatibility of displacements at the junction of the stiffener and plate. The transformation matrices which account for the orientation and the eccentricity effects of the stiffener with respect to the plate reference axes are used to find local behavior at the junction of the stiffener and the relative contributions of the plate and stiffener to the strength of the composite system. The results obtained by the p-version of the finite element method are compared with the results in literatures, especially those by the h-version software, MICROFEAP-II.P-II.

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Phase Equilibria in Multicomponent Mixtures using Continuous Thermodynamics (연속열역학을 이용한 다성분 혼합물의 상평형)

  • Yong, Pyeong-Soon;Kim, Ki-Chang;Kwon, Yong Jung
    • Journal of Industrial Technology
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    • v.18
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    • pp.267-275
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    • 1998
  • Continuous thermodynamics has been applied for modeling of phase equilibria in multicomponent mixtures, to avoid disadvantages of the pseudo-component and key-component method. In this paper continuous thermodynamic relations formulated by using the Pate-Teja equation of state were adopted for calculations of phase equilibria in natural gas mixtures, crude oil mixtures and mixtures extracted by supercritical $CO_2$ fluids. Calculations of phase equilibria were performed by two procedures ; a moment method coupled with the beta distribution function and a quadrature method combined with Gaussian-Legendre polynomials. Calculated results were compared with experimental data. It was showed that continuous thermodynamic frameworks considered in this paper were well-matched to experimental data.

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Development of Analytical Two Dimensional Infinite Elements for Soil-Structure Interaction Analysis (지반-구조물의 상호작용 해석을 위한 해석적 2차원 무한요소)

  • 윤정방;김두기
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.04a
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    • pp.19-26
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    • 1997
  • In this paper, two dimensional analytical infinite elements which can include multiple wave components to model a underlying half-space are developed. Since these elements are expressed clearly and simply using Legendre polynomials of frequencies in frequency domain, these are very economical and efficient in computing the responses of strip foundations in frequency domain and are easily transformed for SSI analysis in time domain. To prove the behavior of the proposed two dimensional analytical infinite elements, vertical, horizontal, and rocking compliances of a rigid strip foundation in layered soils are analyzed and compared with those of Tzong ' Penzie $n^{(17)}$ and with those which calculated by numerical infinite elemen $t^{(1)}$ in frequency domain, and good agreements are noticed between them. As an application for a further study, a new scheme for SSI analysis in time domain are proposed and verified by comparing the displacement responses of the soil with a underlying rock due to a rectangular impulse loading with those of a soil modeled extended FE meshes.soil modeled extended FE meshes.

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Truncation Parameter Selection in Binary Choice Models (이항 선택 모형에서의 절단 모수 선택)

  • Kim, Kwang-Rae;Cho, Kyu-Dong;Koo, Ja-Yong
    • Communications for Statistical Applications and Methods
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    • v.17 no.6
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    • pp.811-827
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    • 2010
  • This paper deals with a density estimation method in binary choice models that can be regarded as a statistical inverse problem. We use an orthogonal basis to estimate density function and consider the choice of an appropriate truncation parameter to reflect the model complexity and the prediction accuracy. We propose a data-dependent rule to choose the truncation parameter in the context of binary choice models. A numerical simulation is provided to illustrate the performance of the proposed method.