检索结果-内蒙古大学图书馆

IEEE International Symposium on Antennas and Propagation

作者： R. Bhattacharya S. Saha T. K. Bhattacharyya Dept. of Electronics & Electrical Communication Engineering Indian Institute of Technology Kharagpur Kharagpur West Bengal India

ISBN: (纸本)9781467304610

This paper presents a novel technique of synthesizing uniformly-excited (UE) thinned time-modulated linear array (T-TMLA) using an improved invasive weed optimization (IWO) algorithm. A novel thinning-boundary-condition (T-BC) is introduced to achieve thinning of UE T-TMLA. Fitness based roulette wheel assisted IWO (FRW-IWO) is proposed to improve upon classical IWO. FRW-IWO (with T-BC) is used to synthesize a 73.33% illuminated 30-element UE T-TMLA, where sidelobe level of -20 dB and maximum sideband level of -30 dB are achieved.

关键词： linear arrays UNITED ELECTRIC Invasive Weeds synthesis optimization algorithms singling Thinning dubnium decibel ROULETTE

来源：评论

学校读者我要写书评

暂无评论

REWIRE: An optimization-based Framework for Unstructured Data Center Network Design

REWIRE: An Optimization-based Framework for Unstructured Dat...

引用

IEEE INFOCOM

作者： Andrew R. Curtis Tommy Carpenter Mustafa Elsheikh Alejandro Lopez-Ortiz S. Keshav Cheriton School of Computer Science University of Waterloo

ISBN: (纸本)9781467307734;9781467307758

Despite the many proposals for data center network (DCN) architectures, designing a DCN remains challenging. DCN design is especially difficult when expanding an existing network, because traditional DCN design places strict constraints on the topology (e.g., a fat-tree). Recent advances in routing protocols allow data center servers to fully utilize arbitrary networks, so there is no need to require restricted, regular topologies in the data center. Therefore, we propose a data center network design framework, that we call REWIRE, to design networks using an optimization algorithm. Our algorithm finds a network with maximal bisection bandwidth and minimal end-to-end latency while meeting user-defined constraints and accurately modeling the predicted cost of the network. We evaluate REWIRE on a wide range of inputs and find that it significantly outperforms previous solutions--its network designs have up to 100-500percent more bisection bandwidth and less end-to-end network latency than equivalent-cost DCNs built with best practices.

关键词： Network design unstructured data data center optimization algorithms Network Routing protocols Best Practices end-to-end

来源：评论

学校读者我要写书评

暂无评论

Post optimization of a Clock Tree for Power Supply Noise Reduction

Post Optimization of a Clock Tree for Power Supply Noise Red...

引用

IEEE Convention of Electrical and Electronics Engineers in Israel

作者： Yakov Kaplan Shmuel Wimer Faculty of Engineering Bar-Ilan University

ISBN: (纸本)9781467346825

The voltage drop incurred in the power supply in today's VLSI chips to is a major concern known as power-supply noise. In sub one-volt supply voltage, noise of very few hundreds millivolts causes circuit malfunction. The reason for power supply noise is the fast and simultaneous transistor switching. While the logic signal switching is spread across the entire clock cycle, the switching of the clock tree and the sequential circuits are occurring simultaneously, causing high local current peaks. The clock related transistor switching is the primary contributor to power supply noise. This paper proposes to spread the switching of clock tree drivers in an attempt to reduce the peak-current, while maintaining the clock signal quality and low skew at the far end tree's leaves where the sequential circuits are connected. A methodology of cell switching characterization was developed for fast computation of peak-current and other signals parameters. This computation is embedded in a branch and bound tree traversal. We propose a novel optimization algorithm based on clock tree delay-invariant branch transformation, replacing low-threshold by high-threshold and smaller size drivers. The algorithm was implemented in 40 nanometers design. We achieved a reduction of 50% of clock-tree peak-current.

关键词： Electric Power Source Timing devices sequential circuits voltage sags Circuit faults optimization algorithms switching transistor Trees clock cycle Noise branches

来源：评论

学校读者我要写书评

暂无评论

Beamforming optimization for Generalized MIMO Y Channels with Both Multiplexing and Diversity

Beamforming Optimization for Generalized MIMO Y Channels wit...

引用

IEEE Vehicular Technology Conference

作者： Zhendong Zhou Branka Vucetic School of Electrical and Information Engineering The University of Sydney NSW 2006 Australia

ISBN: (纸本)9781467309899

We consider a K-user multiple-input multipleoutput (MIMO) relay channel, where each user sends independent messages to the other K ? 1 users via a common relay in two time slots. All users and the relay are equipped with multiple antennas. In contrast to existing work, we consider systems with both multiplexing and diversity, where each user message contains multiple data streams and there are extra degrees of freedom to optimize the transmit beamforming matrices. We propose a novel iterative beamforming optimization algorithm based on orthogonal projection optimization with the signal subspace alignment. An optimal power allocation is also considered to maximize the system sum rate. The sum rate performance of the proposed scheme in various channel configurations is verified by simulations, which shows that the proposed scheme produces significant improvement over existing one.

关键词： Beamforming optimization Generalized MIMO Y Channels Both Multiplexing and Diversity MULTIPLEXOR Beamforming Degree of freedom relay multiple input multiple output systems multiple antenna data flow Consumers power splitting optimization algorithms

来源：评论

学校读者我要写书评

暂无评论

Joint Spectrum Sensing and Power Allocation Algorithm for Spectrum Efficiency optimization in Ultra Wideband Cognitive Radio Networks

Joint Spectrum Sensing and Power Allocation Algorithm for Sp...

引用

IEEE Vehicular Technology Conference

作者： Liaoyuan Zeng Sean McGrath Intelligent Visual Information Processing and Communication Lab University of Electronic Science and Technology of China Wireless Access Research Centre University of Limerick

ISBN: (纸本)9781467318808

Ultra Wideband (UWB) system uses extremely low signal power to coexist with other primary users (PUs), which limits the use of the UWB's wide spectrum band. Cognitive Radio (CR) enables UWB systems to efficiently use the overlapped spectrum without causing interference to other wireless systems. In this paper, we focuses on the low-complexity joint optimization algorithm design with respect to transmit power allocation and spectrum sensing time (SST) for maximizing the spectrum efficiency of the Orthogonal Frequency Division Multiplexing based CR-UWB system. The SST optimization algorithm minimizes the spectrum sensing time in order to maximize the time length of applying the power allocation algorithm for data transmission. The proposed group power allocation algorithm adaptively assigns the transmit power to the subcarrier groups according to the effective signal-to-noise ratio (SNR) of each subcarrier group based on greedy algorithm. The proposed joint optimization algorithm can maximize the CR-UWB systems spectrum efficiency at a extremely low primary user SNR regime with low complexity.

关键词： Ultra wideband technologies spectral efficiency Allocation Algorithm power splitting Transmitter power Orthogonal frequency division multiplexing signal to noise ratios optimization algorithms Spectra Cognitive radio Radio networks signal power CARRIER SYSTEM greedy algorithm data transmission

来源：评论

学校读者我要写书评

暂无评论

Stochastic optimization Assisted Joint Channel Estimation and Multi-User Detection for OFDM/SDMA

Stochastic Optimization Assisted Joint Channel Estimation an...

引用

IEEE Vehicular Technology Conference

作者： Jiankang Zhang Sheng Chen Xiaomin Mu Lajos Hanzo School of Information Engineering Zhengzhou University School of ECS University of Southampton

ISBN: (纸本)9781467318808

Stochastic optimization assisted joint Channel Estimation (CE) and Multi-User Detection (MUD) were conceived and compared in the context of multi-user Multiple-Input Multiple-Output (MIMO) aided Orthogonal Frequency-Division Multiplexing/Space Division Multiple Access (OFDM/SDMA) systems. The development of stochastic optimization algorithms, such as Genetic algorithms (GA), Repeated Weighted Boosting Search (RWBS), Particle Swarm optimization (PSO) and Differential Evolution (DE) has stimulated wide interests in the signal processing and communication research community. However, the quantitative performance versus complexity comparison of GA, RWBS, PSO and DE techniques applied to joint CE and MUD is a challenging open issue at the time of writing, which has to consider both the continuous-valued CE optimization problem and the discrete-valued MUD optimization problem. In this study we fill this gap in the open literature. Our simulation results demonstrated that stochastic optimization assisted joint CE and MUD is capable of approaching both the Cramer-Rao Lower Bound (CRLB) and the Bit Error Ratio (BER) performance of the optimal ML-MUD, respectively, despite the fact that its computational complexity is only a fraction of the optimal ML complexity.

关键词： Orthogonal frequency division multiplexing (OFDM) Space division multiple access (SDMA) Channel estimation Multiuser detection Stochastic optimization algorithm channel estimation mud Multiuser detection optimization algorithms signal processing cerium Stochastic Joints Joints

来源：评论

学校读者我要写书评

暂无评论

An Iterative Beamforming optimization Algorithm for Generalized MIMO Y Channels

An Iterative Beamforming Optimization Algorithm for Generali...

引用

IEEE International Conference on Communications

作者： Zhendong Zhou Branka Vucetic School of Electrical and Information Engineering The University of Sydney

ISBN: (纸本)9781457720529

We consider a K-user multiple-input multiple-output (MIMO) relay channel, where each user sends K - 1 independent messages to the other K - 1 users via a common relay. All users and the relay are assumed to have multiple antennas. The communication happens in two time slots, the multiple access (MA) stage and the broadcast (BC) stage. A linear transmit beamforming and receive combining scheme is proposed based on signal subspace alignment and physical layer network coding. The optimization of the beamforming and combining vectors is addressed with an iterative suboptimal algorithm based on orthogonal projection optimization in the signal subspaces. Suboptimal power allocation is also considered to maximize the effective signal-to-noise ratios (SNRs). The bit error rate (BER) performance of the proposed scheme in various channel configurations is verified by simulation, which shows that the proposed scheme produces significant improvement over existing one.

关键词： Beamforming multiple input multiple output systems relay power splitting Consumers Iterative hierarchical network optimization algorithms

来源：评论

学校读者我要写书评

暂无评论

Developing Learning algorithms via Optimized Discretization of Continuous Dynamical Systems

引用

IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS 2012年第1期42卷 140-149页

作者： Tao, Qing Sun, Zhengya Kong, Kang Chinese Acad Sci Inst Automat Beijing 100190 Peoples R China New Star Res Inst Appl Technol Hefei 230031 Peoples R China

Most of the existing numerical optimization methods are based upon a discretization of some ordinary differential equations. In order to solve some convex and smooth optimization problems coming from machine learning, in this paper, we develop efficient batch and online algorithms based on a new principle, i.e., the optimized discretization of continuous dynamical systems (ODCDSs). First, a batch learning projected gradient dynamical system with Lyapunov's stability and monotonic property is introduced, and its dynamical behavior guarantees the accuracy of discretization-based optimizer and applicability of line search strategy. Furthermore, under fair assumptions, a new online learning algorithm achieving regret O(root T) or O(logT) is obtained. By using the line search strategy, the proposed batch learning ODCDS exhibits insensitivity to the step sizes and faster decrease. With only a small number of line search steps, the proposed stochastic algorithm shows sufficient stability and approximate optimality. Experimental results demonstrate the correctness of our theoretical analysis and efficiency of our algorithms.

关键词： Dynamical systems line search machine learning online learning optimization algorithms projected subgradient algorithms Regret

来源：评论

学校读者我要写书评

暂无评论

Universal algorithm for the analysis of charge distributions in segmented electrodes of gas detectors

引用

EUROPEAN PHYSICAL JOURNAL A 2012年第5期48卷 60-60页

作者： Carbone, D. Cappuzzello, F. Cavallaro, M. Ist Nazl Fis Nucl Lab Nazl Sud Via S Sofia 62 I-95125 Catania Italy Univ Catania Dipartimento Fis & Astron I-95125 Catania Italy

A general algorithm to extract the center of gravity of charge distributions generated in a patterned electrode is presented. The results obtained analyzing the data produced by the gas focal plane detector of the MAGNEX spectrometer are discussed. The algorithm is characterized by an unprecedented efficiency and accuracy when dealing with data with small signal-to-noise ratio. A clear recovery of the smooth position distribution from the quantized one obtained with standard algorithms is observed. The optimized algorithm is also able to naturally mitigate the cross-talk phenomena that are quite strong in this kind of compact detectors.

关键词： plate detector optimization algorithms Center of gravity Gas detectors algorithms generalized algorithm Electrodes CHARGE DISTRIBUTION analysis of algorithm

来源：评论

学校读者我要写书评

暂无评论

AN OPTIMAL SCALING FRAMEWORK FOR COLLABORATIVE FILTERING RECOMMENDATION SYSTEMS

引用

INTERNATIONAL JOURNAL ON ARTIFICIAL INTELLIGENCE TOOLS 2012年第6期21卷 1250033-1250033页

作者： Vozalis, Manolis G. Markos, Angelos I. Margaritis, Konstantinos G. Univ Macedonia Dept Appl Informat Thessaloniki 54006 Greece Democritus Univ Thrace Dept Primary Educ Alexandroupolis Greece

Collaborative Filtering (CF) is a popular technique employed by Recommender Systems, a term used to describe intelligent methods that generate personalized recommendations. Some of the most efficient approaches to CF are based on latent factor models and nearest neighbor methods, and have received considerable attention in recent literature. Latent factor models can tackle some fundamental challenges of CF, such as data sparsity and scalability. In this work, we present an optimal scaling framework to address these problems using Categorical Principal Component Analysis (CatPCA) for the low-rank approximation of the user-item ratings matrix, followed by a neighborhood formation step. CatPCA is a versatile technique that utilizes an optimal scaling process where original data are transformed so that their overall variance is maximized. We considered both smooth and non-smooth transformations for the observed variables (items), such as numeric, (spline) ordinal, (spline) nominal and multiple nominal. The method was extended to handle missing data and incorporate differential weighting for items. Experiments were executed on three data sets of different sparsity and size, MovieLens 100k, 1M and Jester, aiming to evaluate the aforementioned options in terms of accuracy. A combined approach with a multiple nominal transformation and a "passive" missing data strategy clearly outperformed the other tested options for all three data sets. The results are comparable with those reported for single methods in the CF literature.

关键词： Collaborative filtering recommender systems low-rank approximation optimization algorithms categorical principal component analysis optimal scaling

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：