• 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.

• The Mathematical Education
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• v.20 no.1
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• pp.19-22
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• 1981

• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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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.

• 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.

• 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.

• 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.

• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.109-117
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• 2021

In this paper, the meta-model based approximate optimization was carried out for the structure design of an ocean automatic salt collector in order to minimize the structure weight. The structural analysis was performed by using the finite element method to evaluate the strength performance of the ocean automatic salt collector in its initial design. In the structural analysis, it was evaluated the strength performance of the design load conditions. The optimum design problem was formulated so that design variables of main structure thickness would be determined by minimizing the structure weight subject to strength performance constraints. The meta-models used in the approximate optimization were the response surface method, Kriging model, and Chebyshev orthogonal polynomials. Regarding to the numerical characteristics, the solution results from approximate optimization techniques were compared to the results of non-approximate optimization. The Chebyshev orthogonal polynomials among the meta-models used in the approximate optimization showed the most appropriate optimum design results for the structure design of the ocean automatic salt collector.

• 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.

• 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.