检索结果-内蒙古大学图书馆

Adaptive nonlinear least bit error-rate detection for symmetrical RBF beamforming

NEURAL NETWORKS 2008年第2-3期21卷 358-367页

作者： Chen, S. Wolfgang, A. Harris, C. J. Hanzo, L. Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England

A powerful symmetrical radial basis function (RBF) aided detector is proposed for nonlinear detection in so-called rank-deficient multiple-antenna assisted beamforming systems. By exploiting the inherent symmetry of the optimal Bayesian detection solution, the proposed RBF detector becomes capable of approaching the optimal Bayesian detection performance using channel-impaired training data. A novel nonlinear least bit error algorithm is derived for adaptive training of the symmetrical RBF detector based on a stochastic approximation to the Parzen window estimation of the detector output's probability density function. The proposed adaptive solution is capable of providing a signal-to-noise ratio gain in excess of 8 dB against the theoretical linear minimum bit error rate benchmark, when supporting four users with the aid of two receive antennas or seven users employing four receive antenna elements. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： radial basis function network symmetry probability density function recursive learning stochastic algorithm multiple-antenna system beamforming

来源：评论

学校读者我要写书评

暂无评论

MCMC methods for restoration of nonlinearly distorted autoregressive signals

引用

SIGNAL PROCESSING 2001年第1期81卷 83-97页

作者： Troughton, PT Godsill, SJ Univ Cambridge Dept Engn Signal Proc Grp Cambridge CB2 1PZ England

We approach the problem of restoring distorted autoregressive (AR) signals by using a cascade model, in which the observed signal is modelled as the output of a nonlinear AR (NAR) process excited by the linear AR signal we are attempting to recover. The Volterra expansion of the NAR model has a very large number of possible terms even when truncated at fairly small maximum polynomial degrees and lags. We address the problem of subset selection and uncertainty in the nonlinear stage and model order uncertainty in the linear stage through a hierarchical Bayesian approach. A Markov chain Monte Carlo (MCMC) approach is used for implementation, with reversible-jump moves for the linear model order and a rapidly mixing Gibbs sampler for subset selection in the nonlinear model stage, exploiting the partially analytic properties of the model. We demonstrate the method using both synthetic AR data and an audio extract, and extend the approach to process a long distorted audio time series, for which the source model cannot be considered to be time invariant. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： stochastic algorithm reversible-jump Markov chain Monte Carlo (MCMC) Gibbs sampler Bayesian model selection subset selection Volterra expansion polynomial autoregressive model cascade modelling

来源：评论

学校读者我要写书评

暂无评论

A MODEL OF INVARIANT CONTROL SYSTEM USING MEAN CURVATURE DRIFT FROM BROWNIAN MOTION UNDER SUBMERSIONS

引用

QUARTERLY OF APPLIED MATHEMATICS 2023年第1期81卷 175-202页

作者： Ching-peng, H. U. A. N. G. Brown Univ Div Appl Math 170 Hope St Providence RI 02912 USA

Given a Riemannian submersion phi : M-+ N, we construct a stochastic process X on M such that the image Y := phi(X) is a (reversed, scaled) mean curvature flow of the fibers of the submersion. The model example is the mapping pi : GL(n)-+ GL(n)/O(n), whose image is equivalent to the space of n-by -n positive definite matrices, S+(n, n), and the said flow has deterministic image. We are able to compute explicitly the mean curvature (and hence the drift term) of the fibers w.r.t. this map, (i) under diagonalization and (ii) in matrix entries, writing mean curvature as the gradient of log volume of orbits. As a consequence, we are able to write down Brownian motions explicitly on several common homogeneous spaces, such as Poincare acute accent 's upper half plane and the Bures-Wasserstein geometry on S+(n, n), on which we can see the eigenvalue processes of Brownian motion reminiscent of Dyson's Brownian *** choosing the background metric via natural GL(n) action, we arrive at an invariant control system on the GL(n)-homogenous space GL(n)/O(n). We investigate the feasibility of developing stochastic algorithms using the mean curvature flow.

关键词： Mean curvature flow gradient flow Brownian motion Riemannian submersion random matrix eigenvalue processes geometry of positive definite matrices stochastic algorithm control theory on homogeneous space

来源：评论

学校读者我要写书评

暂无评论

An adaptive scheme for the approximation of dissipative systems

引用

stochastic PROCESSES AND THEIR APPLICATIONS 2007年第10期117卷 1491-1518页

作者： Lemaire, Vincent Univ Marne la Vallee Lab Anal & Math Appliuees F-77454 Marne La Vallee France

We propose a new scheme for the long time approximation of a diffusion when the drift vector field is not globally Lipschitz. Under this assumption, a regular explicit Euler scheme-with constant or decreasing step - may explode and implicit Euler schemes are CPU-time expensive. The algorithm we introduce is explicit and we prove that any weak limit of the weighted empirical measures of this scheme is a stationary distribution of the stochastic differential equation. Several examples are presented including gradient dissipative systems and Hamiltonian dissipative systems. (C) 2007 Elsevier B.V. All rights reserved.

关键词： diffusion process dissipative system invariant measure stochastic algorithm Euler method simulation

来源：评论

学校读者我要写书评

暂无评论

An exact and efficient first passage time algorithm for reaction diffusion processes on a 2D-lattice

引用

JOURNAL OF COMPUTATIONAL PHYSICS 2014年 256卷 183-197页

作者： Bezzola, Andri Bales, Benjamin B. Alkire, Richard C. Petzold, Linda R. Univ Calif Santa Barbara Dept Mech Engn Santa Barbara CA 93106 USA Univ Illinois Dept Chem Engn Urbana IL 61801 USA Univ Calif Santa Barbara Dept Comp Sci Santa Barbara CA 93106 USA

We present an exact and efficient algorithm for reaction-diffusion-nucleation processes on a 2D-lattice. The algorithm makes use of first passage time (FPT) to replace the computationally intensive simulation of diffusion hops in KMC by larger jumps when particles are far away from step-edges or other particles. Our approach computes exact probability distributions of jump times and target locations in a closed-form formula, based on the eigenvectors and eigenvalues of the corresponding 1D transition matrix, maintaining atomic-scale resolution of resulting shapes of deposit islands. We have applied our method to three different test cases of electrodeposition: pure diffusional aggregation for large ranges of diffusivity rates and for simulation domain sizes of up to 4096 x 4096 sites, the effect of diffusivity on island shapes and sizes in combination with a KMC edge diffusion, and the calculation of an exclusion zone in front of a step-edge, confirming statistical equivalence to standard KMC simulations. The algorithm achieves significant speedup compared to standard KMC for cases where particles diffuse over long distances before nucleating with other particles or being captured by larger islands. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Reaction-diffusion stochastic algorithm First passage time Nucleation and growth Electrodeposition Discrete Laplacian

来源：评论

学校读者我要写书评

暂无评论

Finding multiple roots of a box-constrained system of nonlinear equations with a biased random-key genetic algorithm

引用

JOURNAL OF GLOBAL OPTIMIZATION 2014年第2期60卷 289-306页

作者： Silva, Ricardo M. A. Resende, Mauricio G. C. Pardalos, Panos M. Univ Fed Pernambuco Ctr Informat BR-50740560 Recife PE Brazil AT&T Labs Res Algorithms & Optimizat Res Dept Florham Pk NJ 07932 USA Univ Florida Dept Ind & Syst Engn Gainesville FL 32611 USA

Several numerical methods for solving nonlinear systems of equations assume that derivative information is available. Furthermore, these approaches usually do not consider the problem of finding all solutions to a nonlinear system. Rather, most methods output a single solution. In this paper, we address the problem of finding all roots of a system of equations. Our method makes use of a biased random-key genetic algorithm (BRKGA). Given a nonlinear system, we construct a corresponding optimization problem, which we solve multiple times, making use of a BRKGA, with areas of repulsion around roots that have already been found. The heuristic makes no use of derivative information. We illustrate the approach on seven nonlinear equations systems with multiple roots from the literature.

关键词： Nonlinear systems of equations Global optimization Continuous optimization Heuristic stochastic algorithm Nonlinear programming BRKGA

来源：评论

学校读者我要写书评

暂无评论

Non-convex multiobjective optimization under uncertainty: a descent algorithm. Application to sandwich plate design and reliability

引用

ENGINEERING OPTIMIZATION 2019年第5期51卷 733-752页

作者： Mercier, Q. Poirion, F. Desideri, J. A. Off Natl Etud & Rech Aerosp Chatillon France INRIA Nice France

In this paper a novel algorithm for solving multiobjective design optimization problems with non-smooth objective functions and uncertain parameters is presented. The algorithm is based on the existence of a common descent vector for each sample of the random objective functions and on an extension of the stochastic gradient algorithm. The proposed algorithm is applied to the optimal design of sandwich material. Comparisons with the genetic algorithm NSGA-II and the DMS solver are given and show that it is numerically more efficient due to the fact that it does not necessitate the objective function expectation evaluation. It can moreover be entirely parallelizable. Another simple illustration highlights its potential for solving general reliability problems, replacing each probability constraint by a new objective written in terms of an expectation. Moreover, for this last application, the proposed algorithm does not necessitate the computation of the (small) probability of failure.

关键词： Multiobjective optimization uncertainty stochastic algorithm reliability

来源：评论

学校读者我要写书评

暂无评论

Joint Optimization on Both Routing and Resource Allocation for Millimeter Wave Cellular Networks

引用

IEEE ACCESS 2019年 7卷 93631-93642页

作者： Ji, Pengshuo Jia, Jie Chen, Jian Northeastern Univ Dept Comp Sci & Engn Shenyang 110819 Liaoning Peoples R China Minist Educ Engn Res Ctr Secur Technol Complex Network Syst Shenyang 110819 Liaoning Peoples R China Southeast Univ Key Lab Comp Network & Informat Integrat Minist Educ Nanjing 211189 Jiangsu Peoples R China Liaoning Res Ctr Safety Engn Technol Ind Control Neusoft Grp Res Shenyang 110179 Liaoning Peoples R China

Due to the spectrum scarcity issue in conventional cellular networks, millimeter-wave ( mmWave) technology has been proposed and is expected to be used in small cells to meet the requirements for spectrum resources, especially for those small cells that are densely deployed and form a multi-hop backhaul structure. For this novel architecture, a cross-layer optimization problem aiming at maximizing the energy efficiency while taking into account both the route selection and resource allocation is formulated. To find the optimal solution, we first decouple the original problem into a resource allocation sub-problem at the link-physical layer and a route selection sub-problem at the network layer. Since the resource allocation sub-problem at the link-physical layer is a non-convex problem and NP-hard, we apply stochastic algorithms to search for the optimal solution. Since the network layer sub-problem is simplified as a linear programming problem, an LP solver is applied to optimize energy efficiency. To reflect the interplay between these two problems, we further propose two joint optimization strategies. One uses stochastic algorithms that are composed of four schemes with given routes for resource allocation and linear programming for the route selection based on the given resource allocation. The other uses the linear programming to evaluate the fitness of each individual in the stochastic algorithms. The simulation results reveal the following: 1) our proposed schemes are capable of finding near-optimal solutions and can improve the energy and spectrum efficiency;and 2) properly finding the route without overloading any one of the base stations is capable of improving the throughput of the networks.

关键词： Cross-layer optimization mmWave resource allocation route selection stochastic algorithm

来源：评论

学校读者我要写书评

暂无评论

An equivalent dipole method with novel measurement positioning for modeling electric emissions in space missions

引用

ELECTROMAGNETICS 2017年第7期37卷 439-453页

作者： Baklezos, Anargyros T. Nikolopoulos, Christos D. Capsalis, Christos N. Natl Tech Univ Athens Sch Elect & Comp Engn Div Informat Transmiss Syst & Mat Technol 9 Zografou Athens Greece

Prediction of the electric emissions in space missions is critical due to the sensitivity of their payload. A reliable method to predict such emissions is the accurate electric source identification. In this work, every space component is modeled by a small number of electric dipoles based on the measurement of the magnitude of the electric field at novel set of near-field positions. The location (x(i), y(i), z(i)) and electric moment (p(x i), p(y i), p(z i),) are accurately predicted via stochastic algorithms resulting in the correct reconstruction of the source's electric field both at measurement and extrapolation points.

关键词： Electromagnetic compatibility electric fields measurement modeling stochastic algorithm

来源：评论

学校读者我要写书评

暂无评论

An improved CLMS algorithm for feedback cancellation in hearing aids

引用

APPLIED ACOUSTICS 2018年第Jan.期129卷 417-426页

作者： Anand, Ankita Kar, Asutosh Swamy, M. N. S. Birla Inst Technol & Sci Dept Elect & Elect Engn Pilani Rajasthan India Concordia Univ Dept Elect & Comp Engn Montreal PQ Canada

In LMS algorithm-based feedback estimation, the value of the adaptation step size chosen imposes establishes a compromise between the speed at which the algorithm converges to the feedback-path estimate and the misadjustment between the true and estimated feedback paths at steady state. The combined LMS (CLMS) scheme overcomes this issue, but itself suffers from a sluggish adaptation of the mixture parameter during periods of a rapidly-varying or a stationary feedback path, leading to a degradation in the performance of the feedback canceller. In this work, we propose an acoustic feedback canceller with an improved affine combination of two different-step-size LMS filters, for a bias-less estimation of the acoustic feedback. The new filter-combiner parameter controls the filter combination and ensures at least a minimum adaptation of the mixture parameter for a stationary as well as a varying acoustic environment. We analyse the proposed algorithm for feedback reduction and prove that it performs as well as the element filters or even better in some situations, as compared to the CLMS algorithm. A detailed behaviour analysis of the proposed algorithm is also presented for scenarios of a stationary as well as a time-varying acoustic environment of the user. Simulation results verify the validity of the derived expressions. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： LMS Adaptive filters Convex combination stochastic algorithm Feedback cancellatio

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：