• 한국전자파학회논문지
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• 제19권9호
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• pp.968-977
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• 2008

본 논문에서는 Fourier-transform analysis와 Wiener-Hopf technique을 사용하여 병렬 슬릿에 의한 TE파 산란의 완전한 표현식을 유도하고 두 방법의 특징을 비교하고자 한다. Fourier transform analysis는 슬릿의 폭이 좁은 경우에는 빠른 수렴해를 얻을 수 있으며, Wiener-Hopf technique은 슬릿의 폭이 넓을 경우(상호 유도 결합이 적은 경우)에 매우 정확한 근사식 결과를 나타내며, 위의 두 해석 결과는 비교적 일치하는 결과들을 보여준다.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.465-472
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• 2010

The purpose of this article is to introduce a new generalized class of the Wiener-Hopf equations and a new generalized class of the variational inequalities. Using the projection technique, we show that the generalized Wiener-Hopf equations are equivalent to the generalized variational inequalities. We use this alternative equivalence to suggest and analyze an iterative scheme for finding the solution of the generalized Wiener-Hopf equations and the solution of the generalized variational inequalities. The results presented in this paper may be viewed as significant and improvement of the previously known results. In special, our results improve and extend the resent results of M.A. Noor and Z.Y.Huang[M.A. Noor and Z.Y.Huang, Wiener-Hopf equation technique for variational inequalities and nonexpansive mappings, Appl. Math. Comput.(2007), doi:10.1016/j.amc.2007.02.117].

• Journal of applied mathematics & informatics
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• 제7권3호
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• pp.813-831
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• 2000

In recent years, the theory of Wiener-Hopf equations has emerged as a novel and innovative technique for developing efficient and powerful numerical methods for solving variational inequalities and complementarity problems. In this paper, we provide an account of some of the fundamental aspects of the Wiener-Hopf equations with major emphasis on the formulation, computational algorithms, various generalizations and their applications. We also suggest some open problems for further research with sufficient information and references.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권3호
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• pp.102-110
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• 2000

In this paper, Wiener-Hopf design of the two-degree-of-freedom(2DOF) controller configuration is treated for the standard plant model. It is shown that the 2DOF structure makes it possible to treat the design of feedback properties and reference tracking problem separately. Wiener-Hopf factorization technique is used to obtain the optimal controller which minimizes a given quadratic cost index. The class of all stabilizing controllers that yield finite cost index is also characterized. An illustrative example is given for the step reference tracking problem which can not be treated by the conventional H2 controller formula.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.569-572
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• 1999

This paper presents a method for designing an autopilot of the BTT missile using 2DOF Wiener-Hopf control technique to improve tracking performance. Linear controllers are designed based on the linearized models which are obtained from the nonlinear missile dynamic equations at various operating points. The gain scheduling technique is used to implement the final autopilot. A simulation on the flight of missiles is carried out through the use of 6DOF equation program including exact nonlinear equations of the missile and the variations of aerodynamic variables in order to check applicability of the suggested method in real situation.

• 대한기계학회논문집A
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• 제24권6호
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• pp.1557-1564
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• 2000

When the half infinite crack in the orthotropic material strip with a large anisotropic ratio(E11>>E22) propagates with constant velocity, dynamic stress component $\sigma$y occurre d along the $\chi$ axis is derived by using the Fourier transformation and Wiener-Hopf technique, and the dynamic stress intensity factor is derived. The dynamic stress intensity factor depends on a crack velocity, mechanical properties and specimen hight. The normalized dynamic stress intensity factors approach the maximum values when normalized time(=Cs/a) is about 2. They have the constant values when the normalized time is greater than or equal to about 2, and decrease with increasing a/h(h: specimen hight, a: crack length) and the normalized crack propagation velocity( = c/Cs, Cs: shear wave velocity, c: crack propagation velocity).

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.659-668
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• 1998

In this paper we introduce and study a new class of gen-eralized mildly nonlinear complementarity problems for fuzzy map-pings. We use the change of variabes technique to establish the equivalence between the generalized mildly nonlinear complementar-ity problems and the Wiener-Hopf equations. This equivalence is used to suggest and analyze a number of iterative algorithm for solv-ing the generalized mildly nonlinear complemetarity problems.

• 전자공학회논문지S
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• 제36S권6호
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• pp.45-56
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• 1999

본 논문에서는 추종 성능을 향상시키기 위해 표준모델의 2자유도 위너-호프 제어 기법을 이용하여 BTT유도탄의 자동조종장치를 설계하였다. 유도탄의 비선형 방정식으로부터 여러 동작점에 대한 선형화 모델을 구하여 선형 제어기를 설계하였으며 최종 자동조종장치는 설계된 제어기들을 이득 계획 기법을 이용하여 구성하였다. 실제 적용성을 검증하기 위하여 유도탄의 정확한 비선형 방정식과 공력 계수의 변화 등을 포함하는 6 자유도 방정식 프로그램을 이용하여 유도탄의 비행 동작에 대한 모의실험을 수행하였다.

• 대한기계학회논문집A
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• 제21권3호
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• pp.447-456
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• 1997

Stress intensity factor of semi-infinite parallel crack propagation with constant velocity in dissimilar orthotropic strip under out-of-plane clamped desplacement is investigated. Using Fourier integral transforms the boundary value problem is derived by a pair of dual integral equation and finally reduced to a single Wiener-Hopf equation. By applying Wiener-Hopf technique the equation is solved. Applying this result the asymptotic stress fields near the crack tip are determined, from which the stress intensity factor is obtained in closed form. The more the ratio of anisotropy or the ratio of bi-material shear modulus increase in the main material including the crack, the more the stress intensity factor increases. Discontinuity in the stress intensity factor is found as the parallel crack approaches the interface. In special case, the results of isotropic materials agree well with those by the previous researchers.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1863-1870
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• 2000

When an impact stress is applied on the external boundary of double cantilever beam of orthotropic material which crack length is greater than specimen hight and anistropic ratio is very high, dyna mic energy release rate is derived, and the relationship between dynamic energy release rate and crack propagating velocity is studied. Dynamic energy release rate to static energy release rate is decreased with increasment of crack propagating velocity. The relationships between dynamic energy release rate and vertical strain have a similar pattern with those between static energy release rate and vertical strain. When normalized time(Cstla) is greater than or equal to 2, dynamic energy release rate approaches to a constant value.