检索结果-内蒙古大学图书馆

Optimal Power Encoding of OFDM Signals in All-Digital Transmitters

学校读者我要写书评

暂无评论

Optimal Power Encoding of OFDM Signals in All-Digital Transm...

IEEE Global Communications Conference

作者： Omer Tanovic Rui Ma Philip Orlik Alexandre Megretski Mitsubishi Electric Research Laboratories Cambridge MA USA Department of Electrical Engineering and Computer Science Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA USA

ISBN: (数字)9781728109626

ISBN: (纸本)9781728109633

In this paper, we propose a power encoding method for converting a high-resolution OFDM baseband signal into a signal that assumes only a finite number of values. This is achieved by the series interconnection of, optimally (co) designed, delta-sigma (ΔΣM) and digital pulse-width modulators (DPWM). Given an input signal class with a known amplitude distribution (e.g., OFDM), parameters of the multilevel DPWM are designed such that the mean squared error of the inherent DPWM quantization noise is minimized. Parameters of the ΔΣM are then chosen with respect to the designed DPWM, so to optimally shape the inherent quantization noise out of the spectral band of interest. The superior performance of the proposed novel power encoding scheme is demonstrated by Matlab simulations on several standardized LTE test signals.

关键词： Quantization (signal) Encoding Harmonic analysis Baseband OFDM Pulse width modulation

A two-sided iterative framework for model reduction of linear systems with quadratic output

学校读者我要写书评

暂无评论

A two-sided iterative framework for model reduction of linea...

IEEE Conference on Decision and Control

作者： Ion Victor Gosea Athanasios C. Antoulas Data-Driven Reduction and Identification Group Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany Department of Electrical and Computer Engineering Rice University Houston USA

ISBN: (数字)9781728113982

ISBN: (纸本)9781728113999

We propose a model reduction procedure for approximating large-scale linear systems with quadratic output by means of lower dimensional systems with the same structure. The framework is based on an iteration that, at each step, computes left and right projections matrices (hence two-sided). This is done by means of solving two linear Sylvester equations.

关键词： Linear systems Mathematical model Computational modeling Observability Symmetric matrices Kernel Numerical models

Surface plasmon assisted control of hot-electron relaxation time

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Memarzadeh, Sarvenaz Kim, Jongbum Aytac, Yigit Murphy, Thomas E. Munday, Jeremy N. Department of Electrical and Computer Engineering Institute for Research in Electronics and Applied Physics University of Maryland College ParkMD20742 United States Department of Electrical and Computer Engineering University of California DavisCA95616 United States Science Systems and Applications Inc. LanhamMD20706 United States

Surface plasmon mediated hot carrier generation is widely utilized for the manipulation of the electron-photon interactions in many types of optoelectronic devices including solar cells, photodiodes, and optical modulators. A diversity of plasmonic systems such as nanoparticles, resonators, and waveguides have been introduced to enhance hot carrier generation;however, the impact of the propagating surface plasmons on hot carrier lifetime has not been clearly demonstrated. Here, we systematically study the hot carrier relaxation in thin film gold (Au) samples under surface plasmon coupling with the Kretschmann configuration. We observe that the locally confined electric field at the surface of the metal significantly affects the hot carrier distribution and electron temperature, which results in a slowing of the hot electrons relaxation time, regardless of the average value of the absorbed power in the Au thin film. This result could be extended to other plasmonic nanostructures, enabling the control of hot carrier lifetimes throughout the optical frequency range. Copyright © 2019, The Authors. All rights reserved.

关键词： Hot electrons

Decoding Flash Memory with Progressive Reads and Independent vs. Joint Encoding of Bits in a Cell

学校读者我要写书评

暂无评论

Decoding Flash Memory with Progressive Reads and Independent...

IEEE Global Communications Conference

作者： Nathan Wong Ethan Liang Haobo Wang Sudarsan V. S. Ranganathan Richard D. Wesel Physical Optics Corporation Torrance CA Department of Electrical and Computer Engineering University of California Los Angeles Los Angeles CA Institute for Data Systems and Society Massachusetts Institute of Technology Cambridge MA

ISBN: (数字)9781728109626

ISBN: (纸本)9781728109633

This paper develops a paradigm for optimizing progressive reads for flash memory cells that maximize the conditional mutual information (MI) given previous reads and shows that some progressive reads provide substantially more MI than others. We study two flash storage techniques: 1) the common practice of independently encoding each bit of a cell into a separate codeword and 2) jointly encoding all the bits in the cell into the same codeword. We quantify the MI gap between joint and independent encoding and show that this gap becomes negligible when progressive reads are available. The paper provides LDPC simulations that confirm the MI analysis.

关键词： Encoding Decoding Degradation Parity check codes Analytical models Optimization Computational modeling

Same-cluster querying for overlapping clusters

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Huleihel, Wasim Mazumdar, Arya Médard, Muriel Pal, Soumyabrata Department of Electrical Engineering-Systems Tel-Aviv university Tel-Aviv6997801 Israel Computer Science Department University of Massachusetts Amherst AmherstMA01003 United States Department of Electrical Engineering & Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Computer Science Department University of Massachusetts Amherst AmherstMA01003 United States

Overlapping clusters are common in models of many practical data-segmentation applications. Suppose we are given n elements to be clustered into k possibly overlapping clusters, and an oracle that can interactively answer queries of the form "do elements u and v belong to the same cluster?" The goal is to recover the clusters with minimum number of such queries. This problem has been of recent interest for the case of disjoint clusters. In this paper, we look at the more practical scenario of overlapping clusters, and provide upper bounds (with algorithms) on the sufficient number of queries. We provide algorithmic results under both arbitrary (worst-case) and statistical modeling assumptions. Our algorithms are parameter free, efficient, and work in the presence of random noise. We also derive information-theoretic lower bounds on the number of queries needed, proving that our algorithms are order optimal. Finally, we test our algorithms over both synthetic and real-world data, showing their practicality and effectiveness. Copyright © 2019, The Authors. All rights reserved.

关键词： Query processing

Low frequency non-resonant rectification in spin-diodes

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Tomasello, R. Fang, B. Artemchuk, P. Carpentieri, M. Fasano, L. Giordano, A. Prokopenko, O.V. Zeng, Z.M. Finocchio, G. Institute of Applied and Computational Mathematics FORTH Heraklion-CreteGR-70013 Greece Key Laboratory of Multifunctional Nanomaterials and Smart Systems Suzhou Institute of Nano-Tech and Nano-Bionics CAS Suzhou Jiangsu215123 China Faculty of RadioPhysics Electronics and Computer Systems Taras Shevchenko National University of Kyiv Kyiv01601 Ukraine Department of Physics Oakland University RochesterMI48309 United States Department of Electrical and Information Engineering Politecnico of Bari via Orabona 4 Bari70125 Italy Italy Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina MessinaI-98166 Italy

Spin-diodes are usually resonant in nature (GHz frequency) and tuneable by magnetic field and bias current with performances, in terms of sensitivity and minimum detectable power, overcoming the semiconductor counterpart, i.e. Schottky diodes. Recently, spin diodes characterized by a low frequency detection (MHz frequency) have been proposed. Here, we show a strategy to design low frequency detectors based on magnetic tunnel junctions having the interfacial perpendicular anisotropy of the same order of the demagnetizing field out-of-plane component. Micromagnetic calculations show that to reach this detection regime a threshold input power has to be overcome and the phase shift between the oscillation magnetoresistive signal and the input radiofrequency current plays the key role in determining the value of the rectification voltage. Copyright © 2020, The Authors. All rights reserved.

关键词： Schottky barrier diodes

Neural-learning trajectory tracking control of flexible-joint robot manipulators with unknown dynamics

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Chen, Shuyang Wen, John T. Department of Mechanical Aerospace and Nuclear Engineering Rensselaer Polytechnic Institute 110 8th St TroyNY12180 United States Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute TroyNY12180 United States

Fast and precise motion control is important for industrial robots in manufacturing applications. However, some collaborative robots sacrifice precision for safety, particular for high motion speed. The performance degradation is caused by the inability of the joint servo controller to address the uncertain nonlinear dynamics of the robot arm, e.g., due to joint flexibility. We consider two approaches to improve the trajectory tracking performance through feedforward compensation. The first approach uses iterative learning control, with the gradient-based iterative update generated from the robot forward dynamics model. The second approach uses dynamic inversion to directly compensate for the robot forward dynamics. If the forward dynamics is strictly proper or is non-minimum-phase (e.g., due to time delays), its stable inverse would be non-causal. Both approaches require robot dynamical models. This paper presents results of using recurrent neural networks (RNNs) to approximate these dynamical models – forward dynamics in the first case, inverse dynamics (possibly non-causal) in the second case. We use the bi-directional RNN to capture the noncausality. The RNNs are trained based on a collection of commanded trajectories and the actual robot responses. We use a Baxter robot to evaluate the two approaches. The Baxter robot exhibits significant joint flexibility due to the series-elastic joint actuators. Both approaches achieve sizable improvement over the uncompensated robot motion, for both random joint trajectories and Cartesian motion. The inverse dynamics method is particularly attractive as it may be used to more accurately track a user input as in teleoperation. Copyright © 2019, The Authors. All rights reserved.

关键词： Flexible manipulators

Ultrahigh bandwidth applications of microcombs: Neural networks and optical data transmission

学校读者我要写书评

暂无评论

TechRxiv

TechRxiv 2021年

作者： Moss, David J. Tan, M. Xu, X. Corcoran, B. Wu, J. Boes, A. Nguyen, T. Chu, S. Little, B. Morandotti, R. Mitchell, A. Optical Sciences Centre Swinburne University of Technology HawthornVIC3122 Australia Department of Electrical and Computer Systems Engineering Monash University ClaytonVIC3800 Australia School of Engineering RMIT University MelbourneVIC3001 Australia Department of Physics City University of Hong Kong Tat Chee Avenue Hong Kong Xi’an Institute of Optics and Precision Mechanics Precision Mechanics of CAS Xi’an China INRS-Énergie Matériaux et Télécommunications 1650 Boulevard Lionel-Boulet VarennesQCJ3X 1S2 Canada Inst. of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu610054 China

We report ultrahigh bandwidth applications of Kerr microcombs to optical neural networks and to optical data transmission, at data rates from 44 Terabits/s (Tb/s) to approaching 100 Tb/s. Convolutional neural networks (CNNs) are a powerful category of artificial neural networks that can extract the hierarchical features of raw data to greatly reduce the network complexity and enhance the accuracy for machine learning tasks such as computer vision, speech recognition, playing board games and medical diagnosis [1-7]. Optical neural networks can dramatically accelerate the computing speed to overcome the inherent bandwidth bottleneck of electronics. We use a new and powerful class of micro-comb called soliton crystals that exhibit robust operation and stable generation as well as a high intrinsic efficiency with an extremely low spacing of 48.9 GHz. We demonstrate a universal optical vector convolutional accelerator operating at 11 Tera-OPS/s (TOPS) on 250,000 pixel images for 10 kernels simultaneously — enough for facial image recognition. We use the same hardware to sequentially form a deep optical CNN with ten output neurons, achieving successful recognition of full 10 digits with 900 pixel handwritten digit images. We also report world record high data transmission over standard optical fiber from a single optical source, at 44.2 Terabits/s over the C-band, with a spectral efficiency of 10.4 bits/s/Hz, with a coherent data modulation format of 64 QAM. We achieve error free transmission across 75 km of standard optical fiber in the lab and over a field trial with a metropolitan optical fiber network. Our work demonstrates the ability of optical soliton crystal micro-combs to exceed other approaches in performance for the most demanding practical optical communications applications. © 2021, CC0.

关键词： Diagnosis

Communications in Computer and Information Science

学校读者我要写书评

暂无评论

Preface

Communications in computer and Information Science 2025年 2194 CCIS卷 v-vi页

作者： Singh, Mayank Tyagi, Vipin Gupta, P.K. Flusser, Jan Ören, Tuncer Cherif, Amar Ramdane Tomar, Ravi G.L. Bajaj Institute of Technology and Management Uttar Pradesh Greater Noida India Academics and Research Department Jaypee University of Engineering and Technology Madhya Pradesh Raghogarh India School of Computing Department of Data Science and Engineering Mohan Babu University Andhra Pradesh Tirupati India Institute of Information Theory and Automation Prague Czech Republic School of Electrical Engineering and Computer Science OttawaON Canada University of Paris-Saclay Paris France Persistent Systems Uttarakhand Dehradun India