• 제목/요약/키워드: iterative algorithms

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전처리기를 사용한 반복적 영상복원의 고속화 기법 (Fast iterative image restoration algorithms based on preconditioning)

  • 백준기;문준일;김상구
    • 전자공학회논문지B
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    • 제33B권12호
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    • pp.62-70
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    • 1996
  • Image restoration is the process which estimates the original image form the blurred image observed by the non-ideal imaging system with additivenoise. According to the regularized approach, the resotred image can be obtained by iterative methods or the constrained least square error(CLS) filter. Among those retoratin methods, despite of many advantages, iterative iamge restoration is limited in use because of slow convergence. In the present paper, fast iterative image restoration algorithms based on preconditoning are proposed. The preconditioner can be obtained by using the characteristics finite impulse response (FIR) filter structure.

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도시철도의 DC급전시스템 해석 알고리즘 (Computer Algorithm for the Loadflow of the DC Traction Power Supply System)

  • 정상기;홍재승
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2000년도 춘계학술대회 논문집
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    • pp.78-85
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    • 2000
  • Computer algorithms for the loadflow of the DC traction power supply system are examined. Algorithms to solve the nodal equation are reviewed and the two iterative methods to solve the nonlinear nature of the loadflow are analyzed and tested, which are so called conductance matrix method and current vector iterative mettled. The result of the analysis tells that the current vector iterative method makes faster convergency and needs less computing time, and it is verified by the test running of the programs based on each of the iterative methods.

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Partitioned analysis of nonlinear soil-structure interaction using iterative coupling

  • Jahromi, H. Zolghadr;Izzuddin, B.A.;Zdravkovic, L.
    • Interaction and multiscale mechanics
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    • 제1권1호
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    • pp.33-51
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    • 2008
  • This paper investigates the modelling of coupled soil-structure interaction problems by domain decomposition techniques. It is assumed that the soil-structure system is physically partitioned into soil and structure subdomains, which are independently modelled. Coupling of the separately modelled partitioned subdomains is undertaken with various algorithms based on the sequential iterative Dirichlet-Neumann sub-structuring method, which ensures compatibility and equilibrium at the interface boundaries of the subdomains. A number of mathematical and computational characteristics of the coupling algorithms, including the convergence conditions and choice of algorithmic parameters leading to enhanced convergence of the iterative method, are discussed. Based on the presented coupling algorithms a simulation environment, utilizing discipline-oriented solvers for nonlinear structural and geotechnical analysis, is developed which is used here to demonstrate the performance characteristics and benefits of various algorithms. Finally, the developed tool is used in a case study involving nonlinear soil-structure interaction analysis between a plane frame and soil subjected to ground excavation. This study highlights the relative performance of the various considered coupling algorithms in modelling real soil-structure interaction problems, in which nonlinearity arises in both the structure and the soil, and leads to important conclusions regarding their adequacy for such problems as well as the prospects for further enhancements.

ALGORITHMS FOR NONLINEAR MIXED VARIATIONAL INEQUALITIES

  • Muhammad Aslam Noor;Eisa A. Al-Said
    • Journal of applied mathematics & informatics
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    • 제5권2호
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    • pp.313-328
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    • 1998
  • In this paper we establish the equivalence between the generalized nonlinear mixed variational inequalities and the gener-alized resolvent equations. This equivalence is used to suggest and analyze a number of iterative algorithms for solving generalized vari-ational inequalities. We also discuss the convergence analysis of the propose algorithms. As special cases we obtain various known re-sults from our results.

셀룰러 네트워크상의 간섭정렬을 위한 반복 알고리즘 (Iterative Algorithms for Interference Alignment in Cellular Network)

  • 여정호;조준호
    • 한국통신학회논문지
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    • 제37B권10호
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    • pp.947-955
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    • 2012
  • 본 논문에서는 셀룰러 네트워크상의 간섭정렬을 위한 송수신벡터를 구하는 반복 알고리즘들을 제안한다. 기존의 간섭채널상의 간섭정렬을 위해 고안된 반복 알고리즘을 셀룰러 네트워크에 적용하는 것이 물론 가능하지만, 높은 합용량을 달성하려면 큰 반복횟수가 필요하다. 본 논문에서 제안된 알고리즘의 핵심은 상향링크의 송신벡터 그리고 하향링크의 수신벡터를 갱신할 때 셀내간섭을 고려하지 않는다는 점이다. 모의실험은 간섭정렬을 위해 다중안테나와 단일 반송파가 사용되었을 때, 제안된 알고리즘이 기존의 알고리즘보다 주어진 반복횟수에서 월등히 높은 합용량을 달성함을 보인다. 또한 제안된 알고리즘이 간섭정렬을 위해 단일 안테나와 다중 부반송파가 사용되었을 때도 기존 간섭정렬 알고리즘보다 성능이 우수함을 보인다.

Random completley generalized nonlinear variational inclusions with non-compact valued random mappings

  • Huang, Nan-Jing;Xiang Long;Cho, Yeol-Je
    • 대한수학회보
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    • 제34권4호
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    • pp.603-615
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    • 1997
  • In this paper, we introduce and study a new class of random completely generalized nonlinear variational inclusions with non-compact valued random mappings and construct some new iterative algorithms. We prove the existence of random solutions for this class of random variational inclusions and the convergence of random iterative sequences generated by the algorithms.

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Approximation Solvability for a System of Nonlinear Variational Type Inclusions in Banach Spaces

  • Salahuddin, Salahuddin
    • Kyungpook Mathematical Journal
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    • 제59권1호
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    • pp.101-123
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    • 2019
  • In this paper, we consider a system of nonlinear variational type inclusions involving ($H,{\varphi},{\eta}$)-monotone operators in real Banach spaces. Further, we define a proximal operator associated with an ($H,{\varphi},{\eta}$)-monotone operator and show that it is single valued and Lipschitz continuous. Using proximal point operator techniques, we prove the existence and uniqueness of a solution and suggest an iterative algorithm for the system of nonlinear variational type inclusions. Furthermore, we discuss the convergence of the iterative sequences generated by the algorithms.

CONVERGENCE OF PARALLEL ITERATIVE ALGORITHMS FOR A SYSTEM OF NONLINEAR VARIATIONAL INEQUALITIES IN BANACH SPACES

  • JEONG, JAE UG
    • Journal of applied mathematics & informatics
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    • 제34권1_2호
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    • pp.61-73
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    • 2016
  • In this paper, we consider the problems of convergence of parallel iterative algorithms for a system of nonlinear variational inequalities and nonexpansive mappings. Strong convergence theorems are established in the frame work of real Banach spaces.

A SYSTEM OF NONLINEAR VARIATIONAL INCLUSIONS IN REAL BANACH SPACES

  • Bai, Chuan-Zhi;Fang, Jin-Xuan
    • 대한수학회보
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    • 제40권3호
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    • pp.385-397
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    • 2003
  • In this paper, we introduce and study a system of nonlinear implicit variational inclusions (SNIVI) in real Banach spaces: determine elements $x^{*},\;y^{*},\;z^{*}\;\in\;E$ such that ${\theta}\;{\in}\;{\alpha}T(y^{*})\;+\;g(x^{*})\;-\;g(y^{*})\;+\;A(g(x^{*}))\;\;\;for\;{\alpha}\;>\;0,\;{\theta}\;{\in}\;{\beta}T(z^{*})\;+\;g(y^{*})\;-\;g(z^{*})\;+\;A(g(y^{*}))\;\;\;for\;{\beta}\;>\;0,\;{\theta}\;{\in}\;{\gamma}T(x^{*})\;+\;g(z^{*})\;-\;g(x^{*})\;+\;A(g(z^{*}))\;\;\;for\;{\gamma}\;>\;0,$ where T, g : $E\;{\rightarrow}\;E,\;{\theta}$ is zero element in Banach space E, and A : $E\;{\rightarrow}\;{2^E}$ be m-accretive mapping. By using resolvent operator technique for n-secretive mapping in real Banach spaces, we construct some new iterative algorithms for solving this system of nonlinear implicit variational inclusions. The convergence of iterative algorithms be proved in q-uniformly smooth Banach spaces and in real Banach spaces, respectively.

ON A SYSTEM OF GENERALIZED NONLINEAR VARIATIONAL INEQUALITIES

  • Li, Jingchang;Guo, Zhenyu;Liu, Zeqing;Kang, Shin-Min
    • 대한수학회논문집
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    • 제22권2호
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    • pp.247-258
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    • 2007
  • In this paper a new class of system of generalized nonlinear variational inequalities involving strongly monotone, relaxed co coercive and relaxed generalized monotone mappings in Hilbert spaces is introduced and studied. Based on the projection method, an equivalence between the system of generalized nonlinear variational inequalities and the fixed point problem is established, which is used to suggest some new iterative algorithms for computing approximate solutions of the system of generalized nonlinear variational inequalities. A few sufficient conditions which ensure the existence and uniqueness of solution of the system of generalized nonlinear variational inequalities are given, and the convergence analysis of iterative sequences generated by the algorithms are also discussed.