• Title, Summary, Keyword: 직교다항식

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Shape form Shading Using Surface Approximation by Orthogonal Polynomials (직교다항식에 의한 표면 근사화를 이요한 Shape form shading)

  • 김방환;박래홍
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.10
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    • pp.1880-1893
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    • 1994
  • In this paper, we propose a new shape from shading algorithm which reconstructs object shapes from a single image. In the proposed intative algorithm, given 3D surfaces are approximated by orthogonal polynomials and the relationships between the given surface and its derivatives are constructed ad matrix forms in terms of polynomial coefficients, Also the relative depth and its derivatives are obtained by updating them iteratively. Performance of the propose shape from shading algorithm is evaluated in terms of brightness error, orientation error, and height error, and the performance comparison of the proposed and conventional algorithms is shown.

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Structural Optimization of Variable Swash Plate for Automotive Compressor Using Orthogonal Polynomials (직교다항식을 이용한 자동차 압축기용 가변 사판의 구조최적설계)

  • Baek, Seok-Heum;Kim, Hyun-Sung;Han, Dong-Seop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.10
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    • pp.1273-1279
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    • 2011
  • The variable-swash-plate compressor has recently been adopted as a vehicle compressor to improve fuel efficiency. The rotation torque in the variable-swash-plate compressor and the pressure-affected piston have a great influence on the swash-plate design and deformation. This paper suggests the optimal configuration design by using Chebyshev orthogonal polynomial and optimization techniques. The orthogonal array (OA) and analysis of variance (ANOVA) techniques and response surface optimization, are employed to determine the main effects and their optimal design variables. According to the optimal design, we confirm an effective design variable in swash plate and explain the optimal solution, the usefulness for satisfying the constraints of maximum stress and deformation.

A Comparative Study on Surrogate Models and Sensitivity Analysis for Structure Design of Automatic Salt Collector Using Orthogonal Array Experiment (직교배열실험을 이용한 자동채염기 구조설계의 민감도해석과 대리모델 비교 연구)

  • Song, Chang Yong;Lee, Dong-Jun
    • Journal of Convergence for Information Technology
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    • v.10 no.7
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    • pp.138-146
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    • 2020
  • The paper deals with comparative study of characteristics of surrogate models and sensitivity evaluation using design of experiments in order to enhance and analysis the structure design of an automatic salt collector under various design load conditions. Orthogonal array design based on numerical analysis was used for the design of experiments. The thickness sizing variables of main structure member were considered the design factors, and the output responses were selected from the strength performances as well as the weight. The quantitative effects on responses for each design factor were evaluated from the orthogonal array experiment. Optimum design case was also identified to improve the strength performances with weight minimization. Using the orthogonal array experiment. various surrogate models such as response surface model, Kriging model, and Chebyshev orthogonal polynomial were generated. The orthogonal array experiment results were validated by the surrogate modeling results. The most suitable surrogate model was the response surface model for the exploration of design space of the automatic salt collector.

Free Vibration of EllllIipticall and Circular Plates (타원형 및 원형 평판의 자유 진동)

  • 김찬수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1485-1492
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    • 1992
  • While the vibration of circular plates were considered by many researchers, rather less attention is given to elliptical plates. In the present paper, the Rayleigh-Ritz mothod is used to obtain an eigenvalue equation for the free flexural vibration of thin elliptical plates having the classical free, simply suported or clmped boundary condition. Circular plates are included as a special case of the elliptical plates. Products of simple polynomials are used as the admissible functions and a recurrence relationship facilitates the evaluation of the necessary integrals. The analysis is developed for rectilinear orthotropic plates but the numerical results are given for isotropic plates with various aspect ratios.

Multiuser Interference Cancellation Scheme using Orthogonal Polynomial Approximation for Multiuser Signal Detection in CDMA Systems (직교 다항식의 근사화를 적용한 다중 사용자 간섭 제거기법)

  • 노재호;최수용;이미숙;신기수;홍대식;강창언
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.7B
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    • pp.928-936
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    • 2001
  • 본 논문은 CDMA 시스템을 근간으로 향후 서비스 될 3세대 이동통신 시스템에 선택적으로 적용될 수 있는 다중 사용자 간섭 제거 기법을 제안한다. 제안 방식은 다단계 간섭 제거기의 각 단계에 직교 다항식의 근사화 기법을 적용하여 제거될 간섭 신호의 양을 결정하고, 이를 상호 보완적으로 제거한다. 사용자 용량의 포화도에 따른 최적해로의 수렴성을 각 방식의 스펙트럼 반경의 분석을 통해 비교하였으며, 제안한 방식이 병렬 간섭 제거 기법(Parallel Interference Cancellation, PIC)을 사용한 방식과 비교하여 2배 이상의 적은 단계를 사용했음에도 거의 같은 정도의 오차 성능을 보였으며, 실험을 통해 비트 오율이 $10^{-5}$을 기준으로 약 30% 정도의 사용자 수용 능력이 증대되었다. 또한 전력 제어의 적용 여부에 대한 시스템의 비트 오율 측면의 성능 비교, 원근 효과의 관점에서 성능을 비교하여 제안된 간섭 제거 기법이 비적응형 가중치를 적용한 병렬 간섭 제거 기법보다 우수함을 보였다.

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Simultaneous Extrapolations Using Bessel and Chebyshev Functions (Bessel와 Chebyshev 함수를 이용한 동시 추정에 관한 기법)

  • 강석진;차정근;윤호태;고진환
    • Proceedings of the Korean Information Science Society Conference
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    • pp.70-72
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    • 2003
  • 전자계 산란의 시간영역 신호는 대응하는 주파수 영역 응답에 대해서도 동시에 효율적인 방법으로 나타낼 수 있는 이유는 다항식의 직교하는 성질 때문이다. 직교 다항식을 이용함으로써, 이른 시간과 낮은 주파수 영역을 동시에 추정할 수 있다 그 접근법은 CGM(Conjugate Gradient Method)방법과 간단한 DFT(Discrete Fourier transform)에 의거한다. 본 논문에서는 Bessel-Chebyshev 함수를 이용한 이른 시간과 낮은 주파수영역 응답을 동시에 추정하기 위한 접근의 방법을 제시하고, 구현하였다. 오직 이른 시간과 낮은 주파수 정보를 필요로 하기 때문에 이 방법으로 계산시 반복계산의 수렴속도가 무척 빠르다는 이점이 있어, 신속한 정보를 얻을 수 있다.

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Optimization of Laser Process Parameters for Realizing Optimal Via Holes for MEMS Devices (MEMS 소자의 비아 홀에 대한 레이저 공정변수의 최적화)

  • Park, Si-Beom;Lee, Chul-Jae;Kwon, Hui-June;Jun, Chan-Bong;Kang, Jung-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.11
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    • pp.1765-1771
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    • 2010
  • In the case of micro.electro-mechanical system (MEMS) devices, the quality of punched via hole is one of the most important factors governing the performance of the device. The common features that affect the laser micromachining of via holes drilled by using Nd:$YVO_4$ laser are described, and efficient optimization methods to measure them are presented. The analysis methods involving an orthogonal array, analysis of variance (ANOVA), and response surface optimization are employed to determine the main effects and to determine the optimal laser process parameters. The significant laser process parameters were identified and their effects on the quality of via holes were studied. Finally, an experiment in which the optimal levels of the laser process parameters were used was carried out to demonstrate the effectiveness of the optimization method.

Dynamic Analysis of the Multi-Span Beam on Elastic Foundation Part one : Natural Frequencies (탄성지반 위에 놓여있는 다지지 보의 동적해석 제1보 : 고유진동수)

  • Y.C. Kim;K.J. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.1
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    • pp.83-91
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    • 1991
  • In this paper the dynamic analysis of the multi-span beam on elastic foundation, which include discrete transnational and rotational springs, was performed. Furthermore, the effects of the intermediate supports were investigated. As a solution method, first the orthogonal polynomial functions which satisfy both the geometric and dynamic boundary conditions are obtained by imposing the orthogonality conditions. Then, the Galerkin's method is used to obtain the natural frequencies of the system. From numerical tests for various constraint and boundary conditions, it was found that the higher order orthogonal polynomial functions obtained by the present method can be used to get the accurate solution.

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Three-Dimensional Vibration Analysis of Rectangular Laminated Composite Plates with Combination of Clamped and Free Boundary Conditions (고정과 자유경계조건의 조합을 고려한 직사각형 복합적층판의 3차원 진동해석)

  • Kim, Joo woo
    • Journal of Korean Society of Steel Construction
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    • v.18 no.2
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    • pp.161-171
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    • 2006
  • paper presents the results of a three-dimensional study of the natural vibration of laminated composite rectangular plates with various combinations of clamped and free boundaries. The Ritz method was used to obtain the stationary values of the associated Lagrangian, with displacements approximated using mathematicaly complete, characteristic orthogonal polynomials. The correctness of the three-dimensional model was established through a convergence study of the non-dimensional frequencies, followed by a comparison of the analytical findings in the existing literature. The wide scope of additional three-dimensional frequency results explains the influence of a number of geometrical and material parameters for angle-ply and cross-ply laminated plates, namely aspect ratio (${\mathcal{a/b}}$), thickness ratio (${\mathcal{a/h}}$), orthotropy of material, number of plies (${\mathcal{N}}$), fiber orientation angle (${\theta}$), and stacking sequence.