We present a local as well as a semilocal convergence analysis for some iterative algorithms in order to approximate a locally unique solution of a nonlinear equation in a Banach space setting. In the application part...
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The paper is devoted to the development of a methodology for evaluating the scalability of compute-intensive iterative algorithms used in simulating complex physical processes on supercomputer systems. The proposed me...
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ISBN:
(纸本)9781538673867
The paper is devoted to the development of a methodology for evaluating the scalability of compute-intensive iterative algorithms used in simulating complex physical processes on supercomputer systems. The proposed methodology is based on the BSF (Bulk Synchronous Farm) parallel computation model, which makes it possible to predict the upper scalability bound of an iterative algorithm in early phases of its design. The BSF model assumes the representation of the algorithm in the form of operations on lists using high-order functions. Two classes of representations are considered: BSF-M (Map BSF) and BSF-MR (Map-Reduce BSF). The proposed methodology is described by the example of the solution of the system of linear equations by the Jacobi method. For the Jacobi method, two iterative algorithms are constructed: Jacobi-M based on the BSF-M representation and Jacobi-MR based on the BSF-MR representation. Analytical estimations of the speedup, parallel efficiency and upper scalability bound are constructed for these algorithms using the BSF cost metrics on multiprocessor computing systems with distributed memory. An information about the implementation of these algorithms in C++ language using the BSF program skeleton and MPI parallel programming library are given. The results of large-scale computational experiments, performed on a cluster computing system, are demonstrated. Based on the experimental results, an analysis of the adequacy of estimations, obtained analytically by using the cost metrics of the BSF model, is made.
In this paper, we design an iterative channel estimation and data detection algorithm in delay-Doppler domain for orthogonal time frequency space (OTFS) system by taking advantage of the sparse nature of the channel i...
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ISBN:
(纸本)9781665405409
In this paper, we design an iterative channel estimation and data detection algorithm in delay-Doppler domain for orthogonal time frequency space (OTFS) system by taking advantage of the sparse nature of the channel in this domain. The proposed algorithm iterates between message-passing-aided data detection and data-aided channel estimation. This sparse channel estimation is reformulated as a specific marginalization of maximum a posteriori (MAP) problem. To deal with the intractability of this problem, we provide a Bayesian approach based on the variational mean-field approximation via the variational Bayesian expectation maximization (VB-EM) algorithm. Finally, we compare the complexity and performance in term of Bit Error Rate (BER) and Normalized Mean Square Error (NMSE) of the proposed solution to a reference solution in the literature (SP-I).
It has been shown that approximate message passing algorithm is effective in reconstruction problems for compressed sensing. To evaluate dynamics of such an algorithm, the state evolution (SE) has been proposed. If an...
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ISBN:
(纸本)9781457705953
It has been shown that approximate message passing algorithm is effective in reconstruction problems for compressed sensing. To evaluate dynamics of such an algorithm, the state evolution (SE) has been proposed. If an algorithm can cancel the correlation between the present messages and their past values, SE can accurately tract its dynamics via a simple one-dimensional map. In this paper, we focus on dynamics of algorithms which cannot cancel the correlation and evaluate it by the generating functional analysis (GFA), which allows us to study the dynamics by an exact way in the large system limit.
Massive multiple-input multiple-output (MMIMO) can significantly enhance the spectrum efficiency of cellular networks by deploying hundreds of active elements at the base stations and is envisaged to become the key te...
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ISBN:
(纸本)9781509021369
Massive multiple-input multiple-output (MMIMO) can significantly enhance the spectrum efficiency of cellular networks by deploying hundreds of active elements at the base stations and is envisaged to become the key technology in 5th generation (5G) cellular networks. However, the large number of antennas required brings about tremendous challenges for practical implementation, especially for separation of the multiplexed data. iterative approaches, such as Jacobi, Richardson, Gauss-Seidel (GS), successive overrelaxation (SOR), and symmetric successive overrelaxation (SSOR) have received great attention recently due to their low-complexity and high performance for signal detection. In this work, we provide a comprehensive review of recent progress in iterative based signal detection for massive MIMO systems. The system model of an iterative method based minimum mean square error (MMSE) signal detection is provided. The convergence behavior and complexity of the iterative approach based detectors are analyzed. Numerical results show that the iterative algorithm-based detectors can achieve a performance close to the classical MMSE detector with significantly less computational complexity.
Interference alignment(IA) with symbol extensions in the K-user multiple-input multiple-output (MIMO) interference channel(IC) is considered in this paper. Symbol extensions produce the channels of special structure. ...
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ISBN:
(纸本)9781467358293;9781467358309
Interference alignment(IA) with symbol extensions in the K-user multiple-input multiple-output (MIMO) interference channel(IC) is considered in this paper. Symbol extensions produce the channels of special structure. Most of existing approaches are limited in cases where the channels have some special structure, because they align the interference without preserving the dimensionality of the desired signal. For that reason, two novel iterative algorithms for IA with symbol extensions are proposed. The first algorithm designs transceivers for IA based on minimizing the maximum per-user mean square error(MSE) while preserving the dimensionality of the desired signal. Utilizing channel reciprocity, the second algorithm is proposed which is the constrained optimization problem. It maximizes each receiver's SINR while preserving the dimensionality of the desired signal. The simulation results show that the proposed algorithms not only achieve good performance in terms of BER performance but also achieve good performance on maximizing sum rate of the system.
In this paper, we introduce two iterative algorithms for the split feasibility problem in real Hilbert spaces by reformulating it as a fixed point equation. Under suitable conditions, weak and strong convergence theor...
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In this paper, we introduce two iterative algorithms for the split feasibility problem in real Hilbert spaces by reformulating it as a fixed point equation. Under suitable conditions, weak and strong convergence theorems are established. As a consequence, we obtain weak and strong convergence iterative sequences for the split equality problem introduced by Moudafi. The efficiency of the proposed algorithms is illustrated by numerical experiments. Our results improve and extend the corresponding results announced by many others.
In this paper, we study the iterative algorithm and convergence theorems for F-implicit generalized variational inequalities problem (F-IGVIP). By employing our earlier works ([6], Theorem 2.2), we establish several i...
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In this paper, we study the iterative algorithm and convergence theorems for F-implicit generalized variational inequalities problem (F-IGVIP). By employing our earlier works ([6], Theorem 2.2), we establish several iterative convergence results for F-IGVIP. The algorithm and convergence results are new for solving the strong solution of F-IGVIP. Furthermore, new algorithms and convergence theorems for F-implicit generalized complementarity problem (F-IGCP) are also discussed.
This paper documents a novel fast method, named the iterative Minimum Zone algorithm (IMZA), for the evaluation of cylindricity deviation on a large number of measurement points, which plays a crucial role in the qual...
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This paper documents a novel fast method, named the iterative Minimum Zone algorithm (IMZA), for the evaluation of cylindricity deviation on a large number of measurement points, which plays a crucial role in the quality control of high-value products and components when a measurement is undertaken by a modern instrument, such as roundness tester, 3D laser/CT scanner. Firstly, the cylindricity deviation model and the minimum zone's theoretical basis are presented. Secondly, the Six-point-subset (SPS) and the replacement strategy are introduced, together with the detailed algorithm. The method strictly adheres to the latest ISO definition. A comparison between the proposed method and the typical approaches is carried out on both simulated data and measured data. The results show that IMZA can fast and accurately evaluate the cylindricity deviation with a large number of measurement points.
This paper proposes a relaxation algorithm for an inverse filter that is adaptive to environmental change in a multichannel sound reproduction system. For a conventional multichannel sound reproduction system, a desig...
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This paper proposes a relaxation algorithm for an inverse filter that is adaptive to environmental change in a multichannel sound reproduction system. For a conventional multichannel sound reproduction system, a design method has been proposed for an inverse filter by means of the Moore-Penrose-type generalized inverse matrix. However, in the inverse filter in the conventional method, background noise and line noise may be enhanced when the room transfer characteristics vary. In order to resolve this problem, an adaptive relaxation method based on the truncated singular value decomposition (TSVD) has been introduced. In the present paper, a microphone for monitoring the noise is placed at a location far from both ears of the listener. Relaxation of the inverse filter is carried out by using the reproduced sound observed by this microphone. From the results of computer simulation, it is found that the proposed method prevents amplification of the noise. Also, as a result of a subjective evaluation experiment on sound reproduction in a real acoustic environment, the sound quality was found to be improved significantly without damaging the sound localization of position. (C) 2004 Wiley Periodicals, Inc.
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