• Title/Summary/Keyword: lanczos algorithm

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Dynamic Analysis of Structures by Superposition of Modified Lanczos Vectors (수정된 Lanczos 벡터의 중첩을 통한 구조물의 동적해석)

  • Kim, Byoung-Wan;Jung, Hyung-Jo;Kim, Woon-Hak;Lee, In-Won
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.04a
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    • pp.11-18
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    • 2003
  • This paper proposes modified Lanczos vector superposition method for efficient dynamic analysis of structures. Proposed method is based on the modified Lanczos algorithm that generates stiffness-orthonormal Lanczos vectors. Proposed method has better computing efficiency than the conventional Lanczos vector superposition method in the analysis of multi-input-loaded structures. The efficiency of proposed method is verified through numerical examples. Comparison with other vector superposition methods is also presented through numerical examples.

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Reducing Decoding Complexity by Improving Motion Field Using Bicubic and Lanczos Interpolation Techniques in Wyner-Ziv Video Coding

  • Widyantara, I Made O.;Wirawan, Wirawan;Hendrantoro, Gamantyo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.9
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    • pp.2351-2369
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    • 2012
  • This paper describes interpolation method of motion field in the Wyner-Ziv video coding (WZVC) based on Expectation-Maximization (EM) algorithm. In the EM algorithm, the estimated motion field distribution is calculated on a block-by-block basis. Each pixel in the block shares similar probability distribution, producing an undesired blocking artefact on the pixel-based motion field. The proposed interpolation techniques are Bicubic and Lanczos which successively use 16 and 32 neighborhood probability distributions of block-based motion field for one pixel in k-by-k block on pixel-based motion field. EM-based WZVC codec updates the estimated probability distribution on block-based motion field, and interpolates it to pixel resolution. This is required to generate higher-quality soft side information (SI) such that the decoding algorithm is able to make syndrome estimation more quickly. Our experiments showed that the proposed interpolation methods have the capability to reduce EM-based WZVC decoding complexity with small increment of bit rate.

Nonlinear Transient Heat Transfer Analysis Based on LANCZOS Coordinates (LANCZOS 알고리즘에 기초한 비선형 트랜지언트 열전달 해석)

  • Im, Chang Kyun;Chang, Sung Pil
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2 s.35
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    • pp.317-326
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    • 1998
  • This paper describes a reduced finite element formulation for nonlinear transient heat transfer analysis based on Lanczos Algorithm. In the proposed reduced formulation all material nonlinearities of irradiation boundary element are included using the pseudo force method and numerical time integration of the reduced formulation is conducted by Galerkin method. The results of numerical examples demonstrate the applicability and the accuracy of the proposed method for the nonlinear transient heat transfer analysis.

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A Study on the Efficient m-step Parallel Generalization

  • Kim, Sun-Kyung
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • 2005.11a
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    • pp.13-16
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    • 2005
  • It would be desirable to have methods for specific problems, which have low communication costs compared to the computation costs, and in specific applications, algorithms need to be developed and mapped onto parallel computer architectures. Main memory access for shared memory system or global communication in message passing system deteriorate the computation speed. In this paper, it is found that the m-step generalization of the block Lanczos method enhances parallel properties by forming m simultaneous search direction vector blocks. QR factorization, which lowers the speed on parallel computers, is not necessary in the m-step block Lanczos method. The m-step method has the minimized synchronization points, which resulted in the minimized global communications compared to the standard methods.

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NUMERICAL IMPLEMENTATION OF THE QMR ALGORITHM BY USING DISCRETE STOCHASTIC ARITHMETIC

  • TOUTOUNIAN FAEZEH;KHOJASTEH SALKUYEH DAVOD;ASADI BAHRAM
    • Journal of applied mathematics & informatics
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    • v.17 no.1_2_3
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    • pp.457-473
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    • 2005
  • In each step of the quasi-minimal residual (QMR) method which uses a look-ahead variant of the nonsymmetric Lanczos process to generate basis vectors for the Krylov subspaces induced by A, it is necessary to decide whether to construct the Lanczos vectors $v_{n+l}\;and\;w{n+l}$ as regular or inner vectors. For a regular step it is necessary that $D_k\;=\;W^{T}_{k}V_{k}$ is nonsingular. Therefore, in the floating-point arithmetic, the smallest singular value of matrix $D_k$, ${\sigma}_min(D_k)$, is computed and an inner step is performed if $\sigma_{min}(D_k)<{\epsilon}$, where $\epsilon$ is a suitably chosen tolerance. In practice it is absolutely impossible to choose correctly the value of the tolerance $\epsilon$. The subject of this paper is to show how discrete stochastic arithmetic remedies the problem of this tolerance, as well as the problem of the other tolerances which are needed in the other checks of the QMR method with the estimation of the accuracy of some intermediate results. Numerical examples are used to show the good numerical properties.

A Study on the Dynamic Analysis in the Shaft of Turbo-Blower for Fuel Cell (연료전지용 터보압축기 회전축의 동특성 해석에 관한 연구)

  • 김홍건;나석찬;김성철;강영우;양균의;이희관;최문창
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.1
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    • pp.81-87
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    • 2004
  • A 3-D FEM (Finite Element Method) analysis of the turbo-blower shaft attached to a fuel cell was performed using Lanczos algorithm. The modal analysis was analyzed in order to investigate natural frequency and maximum displacement for 10 times. It was found that the first mode of natural frequency is 109.1Hz with the maximum displacement of 0.16mm while the tenth mode of natural frequency is 2464Hz with the maximum displacement of 0.25mm. Consequently, the results of modal analysis of the turbo-blower for a fuel cell system show good dynamic responses.

Performance Analysis of Face Recognition by Distance according to Image Normalization and Face Recognition Algorithm (영상 정규화 및 얼굴인식 알고리즘에 따른 거리별 얼굴인식 성능 분석)

  • Moon, Hae-Min;Pan, Sung Bum
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.23 no.4
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    • pp.737-742
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    • 2013
  • The surveillance system has been developed to be intelligent which can judge and cope by itself using human recognition technique. The existing face recognition is excellent at a short distance but recognition rate is reduced at a long distance. In this paper, we analyze the performance of face recognition according to interpolation and face recognition algorithm in face recognition using the multiple distance face images to training. we use the nearest neighbor, bilinear, bicubic, Lanczos3 interpolations to interpolate face image and PCA and LDA to face recognition. The experimental results show that LDA-based face recognition with bilinear interpolation provides performance in face recognition.

Study on Principal Sentiment Analysis of Social Data (소셜 데이터의 주된 감성분석에 대한 연구)

  • Jang, Phil-Sik
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.12
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    • pp.49-56
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    • 2014
  • In this paper, we propose a method for identifying hidden principal sentiments among large scale texts from documents, social data, internet and blogs by analyzing standard language, slangs, argots, abbreviations and emoticons in those words. The IRLBA(Implicitly Restarted Lanczos Bidiagonalization Algorithm) is used for principal component analysis with large scale sparse matrix. The proposed system consists of data acquisition, message analysis, sentiment evaluation, sentiment analysis and integration and result visualization modules. The suggested approaches would help to improve the accuracy and expand the application scope of sentiment analysis in social data.

A Versatile Medical Image Enhancement Algorithm Based on Wavelet Transform

  • Sharma, Renu;Jain, Madhu
    • Journal of Information Processing Systems
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    • v.17 no.6
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    • pp.1170-1178
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    • 2021
  • This paper proposed a versatile algorithm based on a dual-tree complex wavelet transform for intensifying the visual aspect of medical images. First, the decomposition of the input image into a high sub-band and low-sub-band image is done. Further, to improve the resolution of the resulting image, the high sub-band image is interpolated using Lanczos interpolation. Also, contrast enhancement is performed by singular value decomposition (SVD). Finally, the image reconstruction is achieved by using an inverse wavelet transform. Then, the Gaussian filter will improve the visual quality of the image. We have collected images from the hospital and the internet for quantitative and qualitative analysis. These images act as a reference image for comparing the effectiveness of the proposed algorithm with the existing state-of-the-art. We have divided the proposed algorithm into several stages: preprocessing, contrast enhancement, resolution enhancement, and visual quality enhancement. Both analyses show the proposed algorithm's effectiveness compared to existing methods.

Comparative study on dynamic analyses of non-classically damped linear systems

  • Greco, Annalisa;Santini, Adolfo
    • Structural Engineering and Mechanics
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    • v.14 no.6
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    • pp.679-698
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    • 2002
  • In this paper some techniques for the dynamic analysis of non-classically damped linear systems are reviewed and compared. All these methods are based on a transformation of the governing equations using a basis of complex or real vectors. Complex and real vector bases are presented and compared. The complex vector basis is represented by the eigenvectors of the complex eigenproblem obtained considering the non-classical damping matrix of the system. The real vector basis is a set of Ritz vectors derived either as the undamped normal modes of vibration of the system, or by the load dependent vector algorithm (Lanczos vectors). In this latter case the vector basis includes the static correction concept. The rate of convergence of these bases, with reference to a parametric structural system subjected to a fixed spatial distribution of forces, is evaluated. To this aim two error norms are considered, the first based on the spatial distribution of the load and the second on the shear force at the base due to impulsive loading. It is shown that both error norms point out that the rate of convergence is strongly influenced by the spatial distribution of the applied forces.