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Design of halfband filters for orthonormal wavelets using ripple-pinning

IET SIGNAL PROCESSING 2011年第1期5卷 40-48页

作者： Tay, D. B. H. La Trobe Univ Dept Elect Engn Bundoora Vic 3086 Australia

The design of halfband filters for orthonormal wavelet with a prescribed number of vanishing moment and prescribed ripple amplitudes is described. The technique is an extension of the zero-pinning (ZP) technique and is called ripple-pinning (RP). In ZP, the positions of stopband minima (of a Bernstein polynomial) are specified explicitly and the stopband maxima (position and amplitude) depend implicitly on the minima. In RP, the amplitude of the ripples is explicitly specified and this leads to a set of non-linear (polynomial) equations with the position of both the minima and maxima as unknowns. An iterative algorithm is proposed to solve the equations and design examples will be presented. Two variations of the RP technique, which allow for the transition band sharpness to be explicitly specified, are also presented.

关键词： iterative methods Filtering methods in signal processing Interpolation and function approximation (numerical analysis) stopband minima iterative algorithm halfband filter design nonlinear equation zero-pinning technique orthonormal wavelet wavelet transforms Nonlinear and functional equations (numerical analysis) Filters and other networks ripple-pinning nonlinear equations Signal processing theory stopband maxima band-stop filters

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Image segmentation by iterative optimization of multiphase multiple piecewise constant model and Four-Color relabeling

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PATTERN RECOGNITION 2011年第12期44卷 2819-2833页

作者： Liu, Liman Tao, Wenbing Huazhong Univ Sci & Technol Sch Comp Sci & Technol Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Inst Pattern Recognit & Artificial Intellegence Wuhan 430074 Peoples R China

In the paper an iteratively unsupervised image segmentation algorithm is developed, which is based on our proposed multiphase multiple piecewise constant (MMPC) model and its graph cuts optimization. The MMPC model use multiple constants to model each phase instead of one single constant used in Chan and Vese (CV) model and cartoon limit so that heterogeneous image object segmentation can be effectively dealt with. We show that the multiphase optimization problem based on our proposed model can be approximately solved by graph cuts methods. Four-Color theorem is used to relabel the regions of image after every iteration, which makes it possible to represent and segment an arbitrary number of regions in image with only four phases. Therefore, the computational cost and memory usage are greatly reduced. The comparison with some typical unsupervised image segmentation methods using a large number of images from the Berkeley Segmentation Dataset demonstrates the proposed algorithm can effectively segment natural images with a good performance and acceptable computational time. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Unsupervised image segmentation Multiphase optimization Four-Color relabeling iterative algorithm Mean shift

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Projection algorithms for the system of mixed variational inequalities in Banach spaces

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MATHEMATICAL AND COMPUTER MODELLING 2011年第9-10期53卷 1692-1699页

作者： Zhang, Qing-bang Deng, Ruliang Liu, Liu SW Univ Finance & Econ Coll Econ Math Chengdu 610074 Sichuan Peoples R China Sichuan Univ Arts & Sci Dept Math Dazhou 635000 Sichuan Peoples R China

In this paper, the system of mixed variational inequalities is introduced and considered in Banach spaces, which includes some known systems of variational inequalities and the classical variational inequalities as special cases. Using the projection operator technique, we suggest some iterative algorithms for solving the system of mixed variational inequalities and prove the convergence of the proposed iterative methods under suitable conditions. Our theorems generalize some known results shown recently. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： System of mixed variational inequalities Projection operator iterative algorithm Convergence

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Group consensus algorithms based on preference relations

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INFORMATION SCIENCES 2011年第1期181卷 150-162页

作者： Xu, Zeshui Cai, Xiaoqiang Southeast Univ Sch Econ & Management Nanjing 210096 Jiangsu Peoples R China Chinese Univ Hong Kong Dept Syst Engn & Engn Management Shatin Hong Kong Peoples R China

In many group decision-making situations, decision makers' preferences for alternatives are expressed in preference relations (including fuzzy preference relations and multiplicative preference relations). An important step in the process of aggregating preference relations, is to determine the importance weight of each preference relation. In this paper, we develop a number of goal programming models and quadratic programming models based on the idea of maximizing group consensus. Our models can be used to derive the importance weights of fuzzy preference relations and multiplicative preference relations. We further develop iterative algorithms for reaching acceptable levels of consensus in group decision making based on fuzzy preference relations or multiplicative preference relations. Finally, we include an illustrative example. (C) 2010 Published by Elsevier Inc.

关键词： Group decision making Fuzzy preference relation Multiplicative preference relation Goal programming model Quadratic programming iterative algorithm

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Numerical Inverse Heat Transfer Analysis for Temperature-Sensitive-Paint Measurements in Hypersonic Tunnels

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JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 2011年第1期25卷 59-67页

作者： Cai, Zemin Liu, Tianshu Wang, Bo Rubal, Justin Sullivan, John P. Western Michigan Univ Dept Mech & Aeronaut Engn Kalamazoo MI 49008 USA Shantou Univ Dept Elect Engn Shantou 515063 Peoples R China Purdue Univ Sch Aeronaut & Astronaut W Lafayette IN 47907 USA

This paper describes a numerical inverse method used in temperature-sensitive-paint measurements for quantitative global heat flux diagnostics in hypersonic tunnels. An iterative algorithm is developed to solve the one-dimensional inverse heat transfer problem for unsteady heat flux into a polymer layer (temperature-sensitive paint) on a semi-infinite base, where the temperature dependencies of the thermal properties of materials are taken into account. Surface heat flux distributions on cone models are calculated by using this algorithm from temperature-sensitive-paint images acquired in hypersonic wind tunnel testing.

关键词： Numerical Inverse Heat Transfer Analysis Temperature Sensitive Paint Temperature Fields Polyvinyl Chloride Boundary Layer Transition Inverse Heat Conduction Conduction Equation Hypersonic Wind Tunnels iterative algorithm Charge Coupled Device

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Electromagnetic non-destructive evaluation by vector finite-element neural networks

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 2011年第2期24卷 132-143页

作者： Al Salameh, M. S. H. Taha, S. I. Univ Sci & Technol Dept Elect Engn Irbid 22110 Jordan Arabian Grp Co Ford Co Alsafat 13125 State Kuwait Kuwait

This study proposes neural network-based iterative inverse solutions for non-destructive evaluation (NDE) in which vector finite elements (VFEM) represent the forward model that closely models the physical process. The iterative algorithm can eventually estimate the material parameters. Vector finite element method global matrix is stored in a compact form using its sparsity and symmetry. The stored matrix elements are employed as the neurons weights, and preconditioning techniques are used to accelerate convergence of the neural networks (NN) algorithm. Detailed algorithm describing this new method is given to facilitate implementation. Combining vector finite elements and NNs offers several advantages over each technique alone, such as reducing memory storage requirements and the easily computed fixed weights of the NN. Various examples are solved to show the performance and usefulness of the proposed method, including lossy printed circuit board and lossy inhomogeneous cylindrical problems with ferromagnetic materials. These solutions compare very well with other published data where the maximum relative error was 5%. Copyright (C) 2011 John Wiley & Sons, Ltd.

关键词： vector FEM neural network non-destructive evaluation electromagnetics iterative algorithm

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Strong convergence for a countable family of strict pseudocontractions in q-uniformly smooth Banach spaces

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2011年第2期62卷 787-796页

作者： Cholamjiak, Prasit Suantai, Suthep Chiang Mai Univ Dept Math Fac Sci Chiang Mai 50200 Thailand Univ Phayao Sch Sci Phayao 56000 Thailand

We introduce a new iterative algorithm for finding a common fixed point of a countable family of strict pseudocontractions in q-uniformly smooth and uniformly convex Banach spaces. We then prove that the sequence generated by the proposed algorithm converges strongly to a common fixed point of an infinite family of strict pseudocontractions. Our results mainly improve and extend the results announced by Yao et al. [Y. Yao, Y.-C. Liou, G. Marino, Strong convergence of two iterative algorithms for nonexpansive mappings in Hilbert spaces, Fixed Point Theory Appl. 2009 (2009) 7 pages. doi:10.1155/2009/279058. Art. ID 279058]. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Common fixed points iterative algorithm q-uniformly smooth Banach spaces Strong convergence Strict pseudocontractions

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An iterative method for solving finite element model updating problems

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APPLIED MATHEMATICAL MODELLING 2011年第2期35卷 848-858页

作者： Yuan, Yongxin Liu, Hao Jiangsu Univ Sci & Technol Sch Math & Phys Zhenjiang 212003 Peoples R China Nanjing Univ Aeronaut & Astronaut Dept Math Nanjing 210016 Peoples R China

Updating finite element models using measured data is a challenging problem in the area of structural dynamics. The model updating process requires that the updated model can reproduce a given set of measured data by replacing the corresponding ones from the original model, and preserves the symmetry of the original model. The finite element model updating problems can be mathematically formulated as following two problems. Problem 1: Given M(a) is an element of R(nxn), Lambda = diag{lambda 1,..., lambda(p)} is an element of C(pxp), X = [x(1),...,x(p)] is an element of C(nxp), where p < n and both Lambda and X are closed under complex conjugation in the sense that lambda(2j) = <(lambda)over bar>(2j-1) is an element of C, x(2j) = (x) over bar (2j-1) is an element of C(n) for j = 1,...,l, and lambda(k) is an element of R, x(k) is an element of R(n) for k = 2l + 1,...,p, find real-valued symmetric matrices D and K such that M(0)X Lambda(2) + DX Lambda + KX = 0. Problem 2: Given real-valued symmetric matrices D(a), K(a) is an element of R(nxn), find ((D) over cap, (K) over cap) is an element of S(E) such that parallel to(D) over cap - D(a)parallel to(2) + parallel to(K) over cap - K(a)parallel to = min((D,K)is an element of SE) (parallel to D - D(a)parallel to + parallel to K - K(a)parallel to(2)), where S(E) is the solution set of Problem 1 and parallel to . parallel to is the Frobenius norm. This paper presents an iterative method to solve Problems 1 and 2. By the method, a symmetric solution pair can be obtained within finite iteration steps in the absence of round errors, and the minimum Frobenius norm symmetric solution pair can be obtained by choosing a special kind of initial matrix pair. Moreover, the optimal approximation solution ((D) over cap, (K) over cap) of Problem 2 can be obtained by finding the minimum Frobenius norm symmetric solution pair of a changed Problem 1. Numerical examples show that the introduced iterative algorithm is quite efficient. (C) 20

关键词： Model updating iterative algorithm Damped structural system Partially prescribed spectral data Optimal approximation

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Rate Distortion Theory for Causal Video Coding: Characterization, Computation algorithm, and Comparison

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IEEE TRANSACTIONS ON INFORMATION THEORY 2011年第8期57卷 5258-5280页

作者： Yang, En-Hui Zheng, Lin He, Da-Ke Zhang, Zhen Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada Res Mot SlipStream Waterloo ON N2L 5Z5 Canada Univ Calif Los Angeles Dept Elect Engn Syst Los Angeles CA 90095 USA

Causal video coding is considered from an information theoretic point of view, where video source frames X-1, X-2, ..., X-N are encoded in a frame by frame manner, the encoder for each frame X-k can use all previous frames and all previous encoded frames while the corresponding decoder can use only all previous encoded frames, and each frame X-k itself is modeled as a source X-k = {X-k(i)}(i=1)(infinity). A novel computation approach is proposed to analytically characterize, numerically compute, and compare the minimum total rate of causal video coding R-c*(D-1, ..., D-N) required to achieve a given distortion (quality) level D-1, ..., D-N > 0. Among many other things, the computation approach includes an iterative algorithm with global convergence for computing R-c*(D-1, ..., D-N). The global convergence of the algorithm further enables us to demonstrate a somewhat surprising result (dubbed the more and less coding theorem)-under some conditions on source frames and distortion, the more frames need to be encoded and transmitted, the less amount of data after encoding has to be actually sent. With the help of the algorithm, it is also shown by example that R-c*(D-1, ..., D-N) is in general much smaller than the total rate offered by the traditional greedy coding method. As a by-product, an extended Markov lemma is established for correlated ergodic sources.

关键词： Causal video coding extended Markov lemma iterative algorithm multi-user information theory predictive video coding rate distortion characterization and computation rate distortion theory stationary ergodic sources

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A system of generalized variational inclusions involving generalized H(.,.)-accretive mapping in real q-uniformly smooth Banach spaces

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APPLIED MATHEMATICS AND COMPUTATION 2011年第23期217卷 9679-9688页

作者： Kazmi, K. R. Khan, F. A. Shahzad, Mohammad Aligarh Muslim Univ Dept Math Aligarh 202002 Uttar Pradesh India Tabuk Univ Fac Sci Dept Math Tabuk 71491 Saudi Arabia Aligarh Muslim Univ Dept Appl Math Aligarh 202002 Uttar Pradesh India

In this paper, we consider a class of accretive mappings called generalized H(.,.)-accretive mappings in Banach spaces. We prove that the proximal-point mapping of the generalized H(.,.)-accretive mapping is single-valued and Lipschitz continuous. Further, we consider a system of generalized variational inclusions involving generalized H(.,.)-accretive mappings in real q-uniformly smooth Banach spaces. Using proximal-point mapping method, we prove the existence and uniqueness of solution and suggest an iterative algorithm for the system of generalized variational inclusions. Furthermore, we discuss the convergence criteria of the iterative algorithm under some suitable conditions. Our results can be viewed as a refinement and improvement of some known results in the literature. (C) 2011 Elsevier Inc. All rights reserved.

关键词： System of generalized variational inclusions Generalized H(.,.)-accretive mapping Proximal-point mapping method iterative algorithm Convergence criteria

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