• 정보학연구
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• 제8권2호
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• pp.77-84
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• 2005

In this paper, electromagnetic scattering problems by a resistive strip grating with tapered resistivity on a grounded dielectric plane according to strip width and spacing, relative permittivity and thickness of dielectric layers, and incident angles of a electric wave are analyzed by applying the Fourier-Galerkin Moment Method known as a numerical procedure. The boundary conditions are applied to obtain the unknown field coefficients and the resistive boundary condition is used for the relationship between the tangential electric field and the electric current density on the strip. The resistivity of resistive strips in this paper varies from zeroes at one edge to infinite at the other edge, then the induced surface current density on the resistive strip is expanded in a series of Jacobi polynomials of the order ${\alpha}=0.2,\;{\beta}=-0.2$ as a orthogonal polynomials. The numerical results of the geometrically normalized reflected power in this paper are compared with those for the existing perfectly conducting strip. The numerical results of the normalized reflected power for conductive strips case with zero resistivity in this paper show in good agreement with those of existing papers.

• East Asian mathematical journal
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• 제22권2호
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• pp.249-257
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• 2006

Let n be a 2-step nilpotent Lie algebra which has an inner product <,> and has an orthogonal decomposition $n=\delta{\oplus}\varsigma$ for its center $\delta$ and the orthogonal complement $\varsigma\;of\;\delta$. Then Each element Z of $\delta$ defines a skew symmetric linear map $J_Z:\varsigma{\rightarrow}\varsigma$ given by $=$ for all $X,\;Y{\in}\varsigma$. Let $\gamma$ be a unit speed geodesic in a 2-step nilpotent Lie group H(2, 1) with its Lie algebra n(2, 1) and let its initial velocity ${\gamma}$(0) be given by ${\gamma}(0)=Z_0+X_0{\in}\delta{\oplus}\varsigma=n(2,\;1)$ with its center component $Z_0$ nonzero. Then we showed that $\gamma(0)$ is conjugate to $\gamma(\frac{2n{\pi}}{\theta})$, where n is a nonzero intger and $-{\theta}^2$ is a nonzero eigenvalue of $J^2_{Z_0}$, along $\gamma$ if and only if either $X_0$ is an eigenvector of $J^2_{Z_0}$ or $adX_0:\varsigma{\rightarrow}\delta$ is not surjective.

• 대한전자공학회논문지TE
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• 제42권3호
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• pp.25-30
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• 2005

대부분의 경우, 비선형 최적 제어 문제는 헤밀톤-야코비 방정식(Hamilton-Jacobi equations)을 풀어야하는데, HJEs는 해석적으로 답을 구하기가 매우 어렵다. 그래서 이러한 어려움은 비선형 시스템에 피드백 선형화를 적용하여, 선형화된 시스템을 얻고, 선형화된 선형 시스템에 대한 최적 제어 문제를 고려하게 되었다. 본 논문에서는 간단한 비선형 시스템의 예에 최적 제어 설계 기법과 피드백 선형화 제어기, 선형 제어기를 적용하여, 최적 성능을 평가함으로서, 피드백 선형화 최적 제어가 적용되는 비선형 시스템의 조건을 제시한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.299-306
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• 2006

Using a level set method and topological derivatives, a topological shape optimization method that is independent of an initial design is developed for linearly elastic structures. In the level set method, the initial domain is kept fixed and its boundary is represented by an implicit moving boundary embedded in the level set function, which facilitates to handle complicated topological shape changes. The 'Hamilton-Jacobi (H-J)' equation and computationally robust numerical technique of 'up-wind scheme' lead the initial implicit boundary to an optimal one according to the normal velocity field while minimizing the objective function of compliance and satisfying the constraint of allowable volume. Based on the asymptotic regularization concept, the topological derivative is considered as the limit of shape derivative as the radius of hole approaches to zero. The required velocity field to update the H -J equation is determined from the descent direction of Lagrangian derived from optimality conditions. It turns out that the initial holes is not required to get the optimal result since the developed method can create holes whenever and wherever necessary using indicators obtained from the topological derivatives. It is demonstrated that the proper choice of control parameters for nucleation is crucial for efficient optimization process.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.364-377
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• 2008

Due to the difficulty in solving the Hamilton-Jacobi-Isaacs equation, the nonlinear optimal control approach is not very practical in general. To overcome this problem, Ezal et al. (2000) first solved a linear optimal control problem for the linearized model of a nonlinear system given in the strict-feedback form. Then, using the backstepping procedure, a nonlinear feedback controller was designed where the linear part is same as the linear feedback obtained from the linear optimal control design. However, their construction is based on the cancellation of the high order nonlinearity, which limits the application to the smooth ($C^{\infty}$) vector fields. In this paper, we develop an alternative method for backstepping procedure, so that the vector field can be just $C^1$, which allows this approach to be applicable to much larger class of nonlinear systems.

• 대한수학회보
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• 제29권2호
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• pp.265-275
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• 1992

The characteristic free representation theory of the general linear group has found a wide range of applications, ranging from the theory of free resolutions to the symmetric function theory. Representation theory is used to facilitate the calculation of explicit free resolutions of large classes of ideals (and modules). Recently, K. Akin and D. A. Buchsbaum [2] realized the Jacobi-Trudi identity for a Schur function as a resolution of GL$_{n}$-modules. Over a field of characteristic zero, it was observed by A. Lascoux [6]. T.Jozefiak and J.Weyman [5] used the Koszul complex to realize a formula of D.E. Littlewood as a resolution of schur modules. This leads us to further study resolutions of Schur modules of a particular form. In this article we will describe some new classes of finite free resolutions associated to the Pieri type skew Young diagrams. As a special case of these finite free resolutions we obtain the generalized Koszul complex constructed in [1]. In section 2 we review some of the basic difinitions and properties of Schur modules that we shall use. In section 3 we describe certain exact complexes associated to the Pieri type skew partitions. Throughout this article, unless otherwise specified, R is a commutative ring with an identity element and a mudule F is a finitely generated free R-module.e.

• 한국자동차공학회논문집
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• 제1권3호
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• pp.74-82
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• 1993

Optimal designs of a 3-point and a 4-point engine mount system are presented for reducing the idle shake of a Front Wheel Drive(FWD) vehicle. Design variables used in this study are the locations, the angles and the stiffness of an engine mount system. The goal of the optimization is minimizing the transmitted force without violating the constraints such as static weight sag, resonant frequency and side limits of design variables. The Augmented Lagrange Multiplier(ALM) Method is used for solving the nonlinear constrained optimization. The generalized Jacobi and the impedence method are employed for a free vibration analysis and a forced response analysis. The trend of analysis results well meet that of the experimental results. The optimization results reveal that the 4-point system transmits less torque than the 3-point system. It is also found from the design sensitivity analysis that the vibration characteristics of the 4-point system is less sensitive than those of the 3-point system.

• Animal Systematics, Evolution and Diversity
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• nspc3호
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• pp.45-58
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• 1992

Tetranychoid mites found from Korea until now are 42 species belonging to 12 genera, 2 families as follows: 1 Bryobia japonica Ehara et Yamada, 2. B. praetiosa Koch, 3. B. rubrioculus(Scheuten), 4. Petrobia latens(Muller), 5. Aponychus corpuzae Rimando, 6. A firmianae(Ma et Yuan). 7. Panonychus citri(McGregor), 8. P. ulmi(Koch), 9. Eotetranychus carpini Oudemans, 10. E. hicoriae(McGregor), 11. E. populi(Koch), 12. E. rubiphilus (Reck), 13. E. sexmaculatus (Riley), 14. E. smithi Pritchard et Baker, 15. E. tiliarium (Hermann), 16. E. uchidai Ehara, 17. Schizotetranychus bambusae Reck, 18. S. celarius(Banks), 19. S. leguminosus Ehara, 20. Oligonychus aceris(Shimer), 21. O. clavatus(Ehara), 22. O. hondoensis(Ehara), 23. O. ilicis(McGregor), 24. O. karamatus(Ehara), 25. O. orthius Rimando, 26. O. peridtus Pritchard et Baker, 27. O. shinkajii Ehara, 28. O. pustulosus (Ehara), 29. O. ununguis(Jacobi), 30. O. sp. 31. Tetranychus kanzawai Kishida, 32. T. phaselus Ehara, 33. T. truncatus Ehara, 34. T. urticae Koch, 35. T. vienensis Zacher, 36. Aegyptobia nothus Pritchard et Baker, 37. Pentamerismus taxi (Haller), 38. P. oregonensis McGregor, 39. Brevipalpus californicus(Banks), 40. B. lewisi McGregor, 41. B. obovatus Donnadieu, 42. Tenuipalpus zhizhilashviliae Reck. On the above species, a taxanomic key was made and ecological data including distribution and host plant are presented in this paper.

• 오토저널
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• 제8권2호
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• pp.51-64
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• 1986

There has been considerable interest over the last twenty years in the subject of the elastic properties of the cord-rubber laminate. This has been due to the rather intensive study of the composites materials characteristics brought about by the increased use of rigid composites materials characteristics brought about by the increased use of rigid composites in many structural applications. The object of this study is to obtain the natural frequencies and modes of the simply supported cord-rubber laminate plates prior to the study on the analysis of the dynamic properties of the pneumatic tire. To obtain these natural frequencies and modes, the 12 degrees of freedom orthotropic rectangular plate finite elements are developed. By using classical lamination theory, the stress-strain relations are represented. The governing equation for the finite element is derived by energy method. To find the natural frequencies and modes, he eigenvalues and corresponding eigenvectors are computed by the well known Jacobi power method. In order to verify the capability of this present finite element, the results of the specially orthotropic plate and the angle-ply laminate plate are compared with the analytical solution. The analytical and numberical results are in good agreement. The following problems of the simply supported plate are analyzed by the present finite element. a) the natural frequencies and mode shapes of the cord-rubber laminate plate for various aspect ratio. b) The natural frequencies and mode shapes of the orthotropic plate with the rectangular hole in its center.

• 스마트미디어저널
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• 제3권2호
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• pp.9-13
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• 2014

본 논문은 형광 X선 분석 시스템에서 관찰되는 스펙트럼에서 원하는 원소의 피크값을 검출하는데 쓰이는 마쿼트 알고리즘을 모바일 환경에서 더욱 효과적으로 사용하는 데에 있다. 이러한 마쿼트 알고리즘은 본래 잡음이 섞이기 전의 순수한 데이터가 무엇인지 알아가기 위한 유추해 가는 과정의 방법이다. 이러한 마쿼트 알고리즘에서 매우 중요한 역할을 하는 매개변수가 있는데 이 매개변수에 따라서 구하고자 하는 변수 값을 더욱 빠르게 구할 수도 있고 아닐 수도 있다. 기존의 방법에서 불필요한 계산량을 줄이기 위하여 매우 중요한 역할을 하는 매개변수인 ${\mu}$ 자리에 이 매개변수 대신 다른 매개변수를 도입한다. 또한 하드웨어적 측면을 고려시, 여러개의 정규분포의 모양으로 되어있는 함수를 여러개의 정규분포로 나누어서 생각하면 원하는 값을 구하기 더욱 간단해지지만 신뢰도 문제가 발생할 수 있다. 이러한 문제를 해결할 새로운 시스템을 제시한다.