• 대한전자공학회논문지SD
• /
• 제37권11호
• /
• pp.36-42
• /
• 2000

Buried channel waveguides의 필드 분포에 대한 analytic 표현식을 effective index method (EIM), variational method(VM)와 각각의 방향으로의 경계조건을 적용한 variational method (VM_vec)를 사용하여 구한 뒤 angular spectrum 방법을 적용하여 도파로 폭에 따른 단면 반사율을 계산하고 이를 비교 검토하였다. 도파로 폭이 커질수록 buried channel waveguides의 단면 반사율은 slab 도파로의 단면 반사율에 접근하였고 도파로 폭이 작아질수록 slab 도파로의 단면 반사율로부터 quasi-TE 모드의 단면 반사율은 감소하였고 quasi-TM 모드의 단면 반사율은 증가하였다. 도파로 폭에 따른 단면 반사율 변화량은 quasi-TM 모드보다 quasi-TE 모드에 대한 변화량이 크게 나타남을 알 수 있었다. Aspect ratio가 1일 때 VM과 VM_vec으로 구한 quasi-TE 모드와 quasi-TM 모드와 quasi-TM 모드의 반사율은 차이가 크게 나타났다. Quasi-TE 모드의 경우는 VM_vec으로 구한 필드 분포에 angular spectrum 방법을 적용하여 계산한 단면 반사율이 EIM으로 구한 반사율보다 정확한 값임을 알 수 있었고 quasi-TM 모드의 경우는 각 방법으로 구한 반사율이 거의 같음을 볼 수 있었다.

• 한국해안·해양공학회논문집
• /
• 제20권6호
• /
• pp.553-563
• /
• 2008

만일 임의의 지형을 다수의 계단으로 근사하면 이 지형 위를 지나는 선형 파랑의 변형을 계산하기 위해 변분근사법과 고유함수 전개법을 사용할 수 있다. 본 논문에서는 반사율과 투과율을 계산하기 위해 변분근사식과 연계된 산란체법을 제시하였다. 본 기법은 O'Hare and Davies의 변환행렬 축차법보다 간단하고 직접적인 방법임을 보였다. 또한 수 개의 수치실험을 실시하여 기존 결과와 거의 같은 결과를 얻었다.

• Journal of Information Processing Systems
• /
• 제19권3호
• /
• pp.275-288
• /
• 2023

Many image edge details are easily lost in the image denoising process, and the smooth image regions are prone to produce jagged. In this paper, we propose a wavelet-based image global k- singular value decomposition variational method to remove image noise. A layer of wavelet decomposition is applied to the noisy image first. Then, the image global k-singular value decomposition (IGK-SVD) method is used to remove the random noise of low-frequency components. Furthermore, a constructed variational denoising method (VDM) removes the random noise in the high-frequency component. Finally, the denoised image is obtained by wavelet reconstruction. The experimental results show that the proposed method's peak signal-to-noise ratio (PSNR) value is higher than other methods, and its structural similarity (SSIM) value is closer to one, indicating that the proposed method can effectively suppress image noise while retaining more image edge details. The denoised image has better denoising effects.

• Korean Journal of Mathematics
• /
• 제23권3호
• /
• pp.457-478
• /
• 2015

In this paper we propose an iteration hybrid method for approximating a point in the intersection of the solution-sets of pseudomonotone equilibrium and variational inequality problems and the fixed points of a semigroup-nonexpensive mappings in Hilbert spaces. The method is a combination of projection, extragradient-Armijo algorithms and Manns method. We obtain a strong convergence for the sequences generated by the proposed method.

• Advances in aircraft and spacecraft science
• /
• 제1권1호
• /
• pp.93-123
• /
• 2014

A variational asymptotic composite beam model has been developed for thermoelastic analysis. Composite beams, including sandwich structure and laminates, under different boundary conditions are examined. Previously developed beam model, which is based on variational-asymptotic method, is extended to incorporate temperature-dependent materials experiencing large temperature changes. The recovery relations have been derived so that the temperatures, heat fluxes, stresses, and strains can be recovered over the cross-section. The present theory is implemented into the computer program VABS (Variational Asymptotic Beam Sectional analysis). Numerical results are compared with the 3D analysis for the purpose of demonstrating advantages of the present theory and use of VABS.

• Journal of applied mathematics & informatics
• /
• 제24권1_2호
• /
• pp.179-190
• /
• 2007

In this paper, we consider the general variational inequality GVI(F, g, C), where F and g are mappings from a Hilbert space into itself and C is the fixed point set of a nonexpansive mapping. We suggest and analyze a new modified hybrid steepest-descent method of type method $u_{n+l}=(1-{\alpha}+{\theta}_{n+1})Tu_n+{\alpha}u_n-{\theta}_{n+1g}(Tu_n)-{\lambda}_{n+1}{\mu}F(Tu_n),\;n{\geq}0$. for solving the general variational inequalities. The sequence $\{x_n}\$ is shown to converge in norm to the solutions of the general variational inequality GVI(F, g, C) under some mild conditions. Application to constrained generalized pseudo-inverse is included. Results proved in the paper can be viewed as an refinement and improvement of previously known results.

• 한국기계가공학회지
• /
• 제7권1호
• /
• pp.38-46
• /
• 2008

Design technology and speciality production technology to manufacture high quality valve are insufficient in Korea. In order to design the experiments using Taguchi method and Variational Technology Also, from verification of the response model with optimized results was confirmed that usefulness and reliance of application Taguchi method and Variational Technology to structural's optimum design using Taguchi method and Variational Technology.

• Nonlinear Functional Analysis and Applications
• /
• 제26권2호
• /
• pp.347-371
• /
• 2021

A plethora of applications from mathematical programmings, such as minimax, mathematical programming, penalization and fixed point problems can be framed as variational inequality problems. Most of the methods that used to solve such problems involve iterative methods, that is why, in this paper, we introduce a new extragradient-like method to solve pseudomonotone variational inequalities in a real Hilbert space. The proposed method has the advantage of a variable step size rule that is updated for each iteration based on previous iterations. The main advantage of this method is that it operates without the previous knowledge of the Lipschitz constants of an operator. A strong convergence theorem for the proposed method is proved by letting the mild conditions on an operator 𝒢. Numerical experiments have been studied in order to validate the numerical performance of the proposed method and to compare it with existing methods.

• Korean Journal of Mathematics
• /
• 제21권3호
• /
• pp.213-222
• /
• 2013

In this paper, we introduce and consider a new system of generalized variational inequalities involving five different operators. Using the sunny nonexpansive retraction technique we suggest and analyze some new explicit iterative methods for this system of variational inequalities. We also study the convergence analysis of the new iterative method under certain mild conditions. Our results can be viewed as a refinement and improvement of the previously known results for variational inequalities.

• East Asian mathematical journal
• /
• 제31권3호
• /
• pp.383-391
• /
• 2015

We considered a new system of generalized nonlinear mixed variational inclusions in Hilbert spaces and define an iterative method for finding the approximate solutions of this class of system of generalized nonlinear mixed variational inclusions. We also established that the approximate solutions obtained by our algorithm converges to the exact solutions of a new system of generalized nonlinear mixed variational inclusions.