We have developed a computational framework for iterative cone-beam micro-CT reconstruction. When applied to small animal imaging and other high-resolution applications, iterative algorithms pose significant implement...
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We have developed a computational framework for iterative cone-beam micro-CT reconstruction. When applied to small animal imaging and other high-resolution applications, iterative algorithms pose significant implementation difficulties due to the associated high computational burden. To address this burden, we use threads and message passing (MPI) to facilitate multiprocessor cluster computing. The system matrix can be either precomputed or calculated on-the-fly. Additionally, the system matrix can be based on trilinear interpolation or volumetric intersection methods. In the case of storing the system matrix, we exploit symmetries in the cone-beam geometry to reduce the storage requirements by a factor of nearly eight. We chose simultaneous iterative reconstruction technique (SIRT) to demonstrate the framework, although other algorithms are easily implemented. When precomputing the system matrix, each iteration of SIRT completes several times faster than when using an on-the-fly system matrix computation. The precomputed method remains faster when implementing ordered subsets, but the performance advantage diminishes as the number of subsets increases. We present reconstructions of the three-dimensional (3-D) Shepp-Logan head phantom as well as mouse data acquired by a small animal X-ray CT scanner.
In this paper, we introduce the concept of Phi-contractor couple and study the existence of solutions for a couple of nonlinear equations with fuzzy mappings in fuzzy normed spaces. We construct some new iterative alg...
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In this paper, we introduce the concept of Phi-contractor couple and study the existence of solutions for a couple of nonlinear equations with fuzzy mappings in fuzzy normed spaces. We construct some new iterative algorithms for solving the couple of nonlinear equations with fuzzy mappings and prove the convergence of iterative sequences generated by the algorithms in fuzzy normed spaces. As applications, we obtain some new common fixed point theorems for fuzzy mappings in fuzzy normed spaces. The results presented in this paper improve and generalize corresponding results of Cho et al. (Fuzzy Sets and Systems 110 (2000) 115) and Fang and Song (Fuzzy Sets and Systems 121 (2001) 267). (c) 2004 Elsevier B.V. All rights reserved.
In this paper, three distributed load-balancing algorithms for dynamic networks are investigated. Dynamic networks are networks in which the topology may change dynamically. The definition of a dynamic network is intr...
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In this paper, three distributed load-balancing algorithms for dynamic networks are investigated. Dynamic networks are networks in which the topology may change dynamically. The definition of a dynamic network is introduced and its graph model is presented. The main result of this study consists in proving the convergence toward the uniforrn load distribution of the diffusion algorithm on an arbitrary dynamic network despite communication link failures. We also give two adaptations of this algorithm (the GAE and the relaxed diffusion). Note that the hypotheses of our result are realistic and that for example the network does not have to be maintained connected. To study the behavior of these algorithms, we compare the load evolution by several simulations. (c) 2005 Elsevier Inc. All rights reserved.
作者：
Even, JMoisan, EENSIEG
UMR 5083 Grp Nonlineaire Lab Images & Signaux F-38405 St Martin Dheres France
This paper shows the possibility to blindly separate instantaneous mixtures of sources by means of a criterion exploiting order statistics. Properties of higher order statistics and second-order methods are first unde...
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This paper shows the possibility to blindly separate instantaneous mixtures of sources by means of a criterion exploiting order statistics. Properties of higher order statistics and second-order methods are first underlined. Then a brief description of the order statistics shows that they gather all these properties and a new criterion is proposed. Next an iterative algorithm able to simultaneously extract all the sources is developed. The last part is comparison of this algorithm with well-known methods (JADE and SOBI). The most striking result is the possibility to exploit together independence and correlation through the use of order statistics. (C) 2005 Elsevier B.V. All rights reserved.
The binary GCD algorithm, discovered by Stein, is an alternative to the Euclidean algorithm for computing the greatest common divisor of two integers. In this work, the binary GCD algorithm is applied to Reed-Solomon ...
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The binary GCD algorithm, discovered by Stein, is an alternative to the Euclidean algorithm for computing the greatest common divisor of two integers. In this work, the binary GCD algorithm is applied to Reed-Solomon decoding and a novel iterative algorithm for computing error locator polynomials is proposed. Compared to Euclidean-based algorithms, this algorithm exhibits some speed and area advantages.
The semianalytic finite-element method is used to develop a method for solving problems of creep and continuous fracture of complex spatial bodies. The method allows modeling the variation of the stress-strain state d...
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The semianalytic finite-element method is used to develop a method for solving problems of creep and continuous fracture of complex spatial bodies. The method allows modeling the variation of the stress-strain state during creep, accompanying accumulation of dispersed microdamages, and development of macroscopic effects-continuous fracture process zones. The growth of a continuous fracture process zone is modeled. A criterion is formulated for determination of the applicability limits of continuum damage mechanics. The method is exemplified by the problem of deformation and continuous fracture of a gas turbine blade.
A fuel-minimization and near-miss avoidance control are developed for clustered satellites. A penalty function of class C2 with respect to the distances between satellites is imposed on the fuel-consumption index. It ...
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A fuel-minimization and near-miss avoidance control are developed for clustered satellites. A penalty function of class C2 with respect to the distances between satellites is imposed on the fuel-consumption index. It is found enough to solve just the two-point boundary-value problem even if unspecified multiple near misses occur between satellites. The proposed simulation procedure is to repeat shooting searches and to increase the height of the penalty function.
In this paper, we introduce and study a new system of variational inclusions involving (H, eta)-monotone operators in Hilbert space. Using the resolvent operator associated with (H, eta)monotone operators, we prove th...
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In this paper, we introduce and study a new system of variational inclusions involving (H, eta)-monotone operators in Hilbert space. Using the resolvent operator associated with (H, eta)monotone operators, we prove the existence and uniqueness of solutions for this new system of variational inclusions. We also construct a new algorithm for approximating the solution of this system and discuss the convergence of the sequence of iterates generated by the algorithm. (c) 2005 Elsevier Ltd. All rights reserved.
The structured total least squares estimator, defined via a constrained optimization problem, is a generalization of the total least squares estimator when the data matrix and the applied correction satisfy given stru...
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The structured total least squares estimator, defined via a constrained optimization problem, is a generalization of the total least squares estimator when the data matrix and the applied correction satisfy given structural constraints. In the paper, an affine structure with additional assumptions is considered. In particular, Toeplitz and Hankel structured, noise free and unstructured blocks are allowed simultaneously in the augmented data matrix. An equivalent optimization problem is derived that has as decision variables only the estimated parameters. The cost function of the equivalent problem is used to prove consistency of the structured total least squares estimator. The results for the general affine structured multivariate model are illustrated by examples of special models. Modification of the results for block-Hankel/Toeplitz structures is also given. As a by-product of the analysis of the cost function, an iterative algorithm for the computation of the structured total least squares estimator is proposed. (c) 2004 Elsevier B.V. All rights reserved.
This paper establishes necessary and sufficient conditions for operators to be H-monotone. Based on these conditions, we introduce a new iterative algorithm for solving a class of variational inclusions. Strong conver...
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This paper establishes necessary and sufficient conditions for operators to be H-monotone. Based on these conditions, we introduce a new iterative algorithm for solving a class of variational inclusions. Strong convergence of this algorithm is established under appropriate assumptions on the parameters. Estimate of its convergence rate is also provided. (c) 2005 Elsevier Ltd. All rights reserved.
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