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iterative algorithmS FOR NONEXPANSIVE MAPPINGS ON HADAMARD MANIFOLDS

TAIWANESE JOURNAL OF MATHEMATICS 2010年第2期14卷 541-559页

作者： Li, Chong Lopez, Genaro Martin-Marquez, Victoria Zhejiang Univ Dept Math Hangzhou 310027 Peoples R China King Saud Univ Dept Math Coll Sci Riyadh 11451 Saudi Arabia Univ Seville Dept Anlisis Matemat E-41080 Seville Spain

Two iterative algorithms for nonexpansive mappings on Hadamard manifolds, which are extensions of the well-known Halpern's and Mann's algorithms in Euclidean spaces, are proposed and proved to be convergent to... 详细信息

关键词： Hadamard manifold Nonexpansive mapping Fixed point iterative algorithm

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Optimal Offline Packet Scheduling on an Energy Harvesting Broadcast Link

Optimal Offline Packet Scheduling on an Energy Harvesting Br...

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IEEE International Symposium on Information Theory (ISIT)

作者： Ozcelik, F. Mehmet Erkal, Hakan Uysal-Biyikoglu, Elif Middle E Tech Univ Dept Elect & Elect Eng TR-06531 Ankara Turkey

ISBN: (纸本)9781457705953

We consider the minimization of packet transmission duration on an energy harvesting broadcast channel ( BC). Energy and data arrivals are assumed to occur at arbitrary but known instants. An achievable rate region with structural properties satisfied by the two-user AWGN BC capacity region is assumed. Structural properties of power and rate allocation in an optimal policy are established, as well as the uniqueness of the optimal policy under the condition that all the data of the "weaker" user are available at the beginning. An iterative algorithm, DuOpt, based on block coordinate descent that achieves the same structural properties as the optimal is described.

关键词： AWGN AWGN channels Energy harvesting Optimal scheduling Optimized production technology Resource management Schedules Transmitters block coordinate descent broadcast channels data arrivals energy arrivals energy harvesting energy harvesting broadcast channel energy harvesting broadcast link iterative algorithm iterative methods optimal offline packet scheduling packet transmission minimization power allocation rate allocation scheduling two-user AWGN BC capacity region

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Optimal Control for Quality Indices of Heat Furnace

Optimal Control for Quality Indices of Heat Furnace

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2nd International Conference on Manufacturing Science and Engineering

作者： Chen, Youwen Chai, Tianyou Northeast Univ Ctr Automat Res Northeastern Univ Shenyang Peoples R China

ISBN: (纸本)9783037850398

Heat furnace is one of the most important parts in iron and steel industry which is one of the basic industries. The control of furnace quality indices has a direct impact on iron and steel qualities and energy consumptions in an iron and steel manufacturing process. Due to dramatic changes of exhaust gas in combustion, this multi-variable process becomes time-varying, and also has inherent nonlinearities, couplings among the variables, large inertias and time delays. Therefore, manual operations are still being widely used in quality indices control. In this paper, an optimization control method is proposed for the control of furnace quality indices. The optimization consists of a materials temperature calculation model, an optimization objective, an ideal materials heating model and a furnace heating model. Optimization algorithm consists of the maximum principle, the simulated annealing algorithm, the iterative algorithm and sensitive analysis. Finally, quality indices were controlled by lower layer loop control on-line. The proposed optimization control method has been successfully applied to some steel plants. The industrial applications show the effectiveness of the proposed method.

关键词： Heat Furnace Maximum Principle Simulated Annealing algorithm iterative algorithm Sensitive Analysis

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Linear Precoding Designs for Amplify-and-Forward Multiuser Two-Way Relay Systems

Linear Precoding Designs for Amplify-and-Forward Multiuser T...

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54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Wang, Rui Tao, Meixia Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China

ISBN: (纸本)9781424492688

We investigate the linear precoding designs for multiuser two-way relay system (MU-TWRS) where a multi-antenna base-station (BS) communicates with multiple single-antenna mobile stations (MSs) via a multi-antenna relay station (RS). The amplify-and-forward (AF) relay protocol is employed. The design goal is to optimize the precodings at BS, RS or both so as to minimize the total mean-square error (MSE) of the uplink messages while maintaining the individual signal-to-interference-plus-noise ratio (SINR) requirement for each downlink signal. We show that the BS precoding design problem can be converted to a standard second order cone programming (SOCP), while the RS precoding is non-convex for which a local optimal solution is obtained using an iterative algorithm. A joint BS-RS precoding is also obtained by alternating optimization of BS precoding and RS precoding with guaranteed convergence. Numerical results show that RS-precoding is superior to BS-precoding. Furthermore, the joint BS-RS precoding can significantly outperform the two individual precoding schemes. The implementation issues including complexity and feedback overhead are also discussed.

关键词： BS-precoding Downlink Interference Joints Optimization RS-precoding Relays Signal to noise ratio Vectors amplify and forward communication amplify and forward protocol concave programming cone programming interference suppression iterative algorithm iterative methods linear codes linear precoding design mean square error method mean square error methods mobile stations multi-antenna base station multi-antenna relay station multifrequency antennas multiuser channels multiuser two-way relay system nonconvex programming optimization precoding protocols signal to interference plus noise ratio uplink messages

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Resource Allocation for Secure OFDMA Networks with Imperfect CSIT

Resource Allocation for Secure OFDMA Networks with Imperfect...

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54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Ng, Derrick Wing Kwan Lo, Ernest S. Schober, Robert Univ British Columbia Dept Elect & Comp Engn Vancouver BC V5Z 1M9 Canada CTTC Catalunya Spain

ISBN: (纸本)9781424492688

In this paper, we formulate an optimization problem for resource allocation and scheduling in orthogonal frequency division multiple access (OFDMA) networks. Our problem formulation takes into account artificial noise generation to combat a passive multiple antenna eavesdropper and the effects of imperfect channel state information at the transmitter (CSIT) in slow fading. The optimization problem is solved by dual decomposition which results in an iterative resource allocation algorithm with a fast speed of convergence. The packet data rate, secrecy data rate, power, and subcarrier allocation policies are optimized to maximize the average secrecy outage capacity (bit/s/Hz securely and successfully delivered to the users). Simulation results illustrate that our proposed iterative algorithm converges to the optimal solution in a small number of iterations and guarantees a non-zero secrecy data rate for given target secrecy outage and channel outage probability requirements.

关键词： Channel capacity Fading Noise OFDM modulation OFDMA networks Optimization Resource management Throughput Vectors artificial noise generation channel outage probability requirements channel state information frequency division multiple access imperfect CSIT iterative algorithm optimisation optimization problem orthogonal frequency division multiple access networks probability resource allocation resource allocation scheduling

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Linear Precoding for MIMO Multiple Access Channels with Discrete-Constellation Inputs

Linear Precoding for MIMO Multiple Access Channels with Disc...

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54th Annual IEEE Global Telecommunications Conference (GLOBECOM)

作者： Wang, Mingxi Zeng, Weiliang Xiao, Chengshan Missouri Univ Sci & Technol Dept Elect & Comp Engn Rolla MO 65401 USA Tsinghua Univ Dept Elect Engn Beijing Peoples R China

ISBN: (纸本)9781424492688

In this paper, we study linear precoding for multiple-input multiple-output (MIMO) multiple access channels (MAC) with discrete-constellation inputs. We derive the constellation-constrained capacity region for the MIMO MAC with an arbitrary number of users. Due to the non-concavity of the objective function, we obtain the necessary conditions for the weighted sum rate (WSR) maximization problem through Karush-Kuhn-Tucker (KKT) analysis. To find the optimal precoding matrices, we propose an iterative algorithm utilizing alternating optimization strategy and gradient descent update. Numerical results show that when inputs are digital modulated signals and the signal-to-noise ratio (SNR) is in the medium range, our proposed algorithm offers significantly higher sum rate than non-precoding and the traditional method which maximizes Gaussian-input sum capacity. Furthermore, the bit error rate (BER) results of a low-density parity-check (LDPC) coded system also indicate that the system with the proposed linear precoder achieves significant gains over other methods.

关键词： BER Bit error rate Covariance matrix Gaussian-input sum capacity KKT analysis Karush-Kuhn-Tucker analysis LDPC coded system MIMO MIMO MAC MIMO communication Parity check codes Phase shift keying SNR Signal to noise ratio Vectors WSR maximization problem bit error rate channel coding constellation-constrained capacity region digital modulated signals discrete-constellation inputs error statistics gradient descent update gradient methods iterative algorithm iterative methods linear codes linear precoding low-density parity-check coded system multiple-input multiple-output multiple access channels optimal precoding matrices optimisation parity check codes signal-to-noise ratio weighted sum rate maximization problem wireless channels

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An efficient algorithm for solving extended Sylvester-conjugate transpose matrix equations

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Arab Journal of Mathematical Sciences 2011年第2期17卷 115-134页

作者： Song, Caiqin Chen, Guoliang Department of Mathematics East China Normal University Shanghai 200241 China

This note studies the iterative solutions to the extended Sylvester-conjugate transpose matrix equations with a unique solution. By using the hierarchical identification principle, an iterative algorithm is presented for solving this class of extended matrix equations. It is proved that the iterative solution consistently converges to the exact solution for any initial values. Meanwhile, by means of a real representation of a complex matrix, sufficient conditions are derived to guarantee that the iterative solutions given by the proposed algorithm converge to the exact solution for any initial matrices. Finally, a numerical example is given to illustrate the efficiency of the proposed approach. © 2011

关键词： Convergence Extended Sylvester-conjugate transpose matrix equation iterative algorithm Real representation Spectral norm

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Robust Training Sequence Design for Spatially Correlated MIMO Channels and Arbitrary Colored Disturbance

Robust Training Sequence Design for Spatially Correlated MIM...

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22nd IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Shariati, Nafiseh Bengtsson, Mats KTH Royal Inst Technol Sch Elect Engn ACCESS Linnaeus Ctr Stockholm Sweden

ISBN: (纸本)9781457713484

In this paper, we study the design of optimal robust training sequences for multiple-input multiple-output (MIMO) channel estimation, based on known second order statistics of both the channel and the colored disturbance, but with an uncertainty in the channel covariance matrix. More specifically, the training sequences are designed by taking the least-favorable channel covariance component into account throughout an iterative algorithm. Numerical experiments are carried out to demonstrate the performance gained by employing the proposed design procedure and to compare it with other relevant schemes.

关键词： Channel estimation Covariance matrix Eigenvalues and eigenfunctions MIMO MIMO communication Optimization Robustness Training channel covariance matrix channel estimation channel estimation colored disturbance covariance matrices iterative algorithm iterative methods multiple-input multiple-output channel robust training sequence design second order statistics spatially correlated MIMO channel statistical analysis

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Joint Power Control and Beamforming for Interference MIMO Relay Channel

Joint Power Control and Beamforming for Interference MIMO Re...

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17th Asia-Pacific Conference on Communications (APCC)

作者： Khandaker, Muhammad R. A. Rong, Yue Curtin Univ Dept Elect & Comp Engn Bentley WA 6102 Australia

ISBN: (纸本)9781457703881

In this paper, we consider an interference multiple-input multiple-output (MIMO) relay system where multiple source nodes communicate with their desired destination nodes with the aid of distributed relay nodes. An iterative algorithm is developed to minimize the total source and relay transmit power such that a minimum signal-to-interference-plus-noise ratio (SINR) threshold is maintained at each receiver. The proposed algorithm exploits the network beamforming technique at the relay nodes and the receive beamforming technique at the destination nodes to mitigate the interferences from the unintended sources in conjunction with transmit power control. In particular, we apply the semidefinite relaxation technique to transform the relay transmission power minimization problem into a semidefinite programming (SDP) problem which can be efficiently solved by interior point-based methods. Numerical simulations are performed to demonstrate the effectiveness of the proposed iterative algorithm.

关键词： Array signal processing Interference Joints MIMO communication MIMO relay channel Power control Relays Signal to noise ratio Vectors array signal processing beamforming interior point-based methods iterative algorithm iterative methods multiple-input multiple-output numerical simulations power control semidefinite programming problem signal-to-interference-plus-noise ratio telecommunication control transmit power control

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Simultaneous Investigation of Local and Distributed Functional Brain Connectivity from fMRI Data

Simultaneous Investigation of Local and Distributed Function...

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5th International IEEE Engineering-in-Medicine-and-Biology-Society (EMBS) Conference on Neural Engineering (NER)

作者： Deshpande, Gopikrishna Kerssens, Chantal Huo, Xiaoming Hu, Xiaoping Auburn Univ AU MRI Res Ctr Dept Elect & Comp Engn Auburn AL 36849 USA Emory Univ Dept Anesthesia Atlanta GA 30322 USA Georgia Tech Dept Ind & Syst Engn Atlanta GA 30332 USA Georgia Inst Technol WHC Dept Biomed Engn Atlanta GA 30332 USA

ISBN: (纸本)9781424441419

In this paper we propose a new method for simultaneous assessment of local and distributed functional brain connectivity from functional magnetic resonance imaging (fMRI) data. Our method maps fMRI time series from brain voxels into a high dimensional feature space where in clustering and vector quantization are performed in order to aggregate voxels with similar temporal evolution and segregate those with low temporal correlation. An iterative algorithm is proposed based on the Eigen structure of the geodesic distance matrix of the high dimensional manifold for selecting the number of clusters. The choice is then verified by unfolding the manifold using ISOMAP. A combined connectivity index (CCI) is then defined for every brain region based on the percentage of its voxels connected to each other and to voxels from other regions. The CCI maps local and distributed connectivity on a continuum from 0 to 1. This method was applied to resting state fMRI data obtained from humans in one of the two states: normal awake state and a sedated state induced by propofol anesthesia. Our results demonstrate that propofol anesthesia makes the connectivity in the brain become more local and less distributed as compared to awake state. In addition, our results show that the distributed connectivity between the thalamus and the cortex is greatly impacted by anesthesia, lending support to the thalamo-cortical disconnection hypothesis. However, our results indicate the thalamus was still connected to the cortex via the amygdala, providing a pathway for sensory information to reach the cortex during sedation. In the cortex, the connectivity also tended to become more local than distributed, supporting the cortico-cortical disconnection hypothesis. Therefore, our conclusions reconcile both the hypotheses of anesthetic action and altered states of consciousness, and demonstrate the utility of our approach for addressing important neuroscientific questions.

关键词： Anesthesia Drugs IP networks ISOMAP Magnetic resonance imaging Manifolds Time series analysis Vector quantization amygdala biomedical MRI brain brain voxels clustering combined connectivity index cortex cortico-cortical disconnection data acquisition distributed functional brain connectivity fMRI functional magnetic resonance imaging geodesic distance matrix high dimensional feature space iterative algorithm iterative methods local functional brain connectivity medical image processing neurophysiology pattern clustering propofol anesthesia thalamus time series vector quantisation vector quantization

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