scispace - formally typeset
Search or ask a question
Author

Ali H. Sayed

Bio: Ali H. Sayed is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Adaptive filter & Optimization problem. The author has an hindex of 81, co-authored 728 publications receiving 36030 citations. Previous affiliations of Ali H. Sayed include Harbin Engineering University & University of California, Los Angeles.


Papers
More filters
Journal ArticleDOI
TL;DR: The proposed filter can be used to mitigate the dispersion penalty in other fiber optic applications as well and increases the overall achievable signal-to-noise-and-distortion ratio to 52 dB in the presence of linear distortions.
Abstract: Time-stretched analog-to-digital converters (ADCs) have offered revolutionary enhancements in the performance of electronic converters by reducing the signal bandwidth prior to digitization. An inherent limitation of the time-stretched ADC is the frequency-selective response of the optical system that reduces the effective number of bits for ultrawideband signals. This paper proposes a solution based on spatio-temporal digital processing. The digital algorithm exploits the optical phase diversity to create a flat RF frequency response, even when the system's transfer function included deep nulls within the signal spectrum. For a 10times time-stretch factor with a 10-GHz input signal, simulations show that the proposed solution increases the overall achievable signal-to-noise-and-distortion ratio to 52 dB in the presence of linear distortions. The proposed filter can be used to mitigate the dispersion penalty in other fiber optic applications as well.

10 citations

Proceedings ArticleDOI
22 May 2011
TL;DR: The analysis reveals that the adapt-then-combine (ATC) adaptive network algorithm can achieve lower excess-mean-square-error (EMSE) than a centralized solution that is based on either block or incremental LMS strategies with the same convergence rate.
Abstract: In this work we analyze the mean-square performance of different strategies for adaptation over two-node least-mean-squares (LMS) networks. The results highlight some interesting properties for adaptive networks in comparison to centralized solutions. The analysis reveals that the adapt-then-combine (ATC) adaptive network algorithm can achieve lower excess-mean-square-error (EMSE) than a centralized solution that is based on either block or incremental LMS strategies with the same convergence rate.

10 citations

Proceedings ArticleDOI
08 Aug 2000
TL;DR: This work proposes a novel structure for adaptive sigma delta modulation that leads to considerable improvement in the dynamic range of the modulator and can be implemented rather directly by means of analog switches.
Abstract: This work proposes a novel structure for adaptive sigma delta modulation that leads to considerable improvement in the dynamic range of the modulator. The quantizer step-size is adapted based on estimates of the input signal to the quantizer block rather than on estimates of the input signal to the modulator itself, as is common in current schemes. The proposed structure can be implemented rather directly by means of analog switches. Theoretical and simulation results show considerable improvement in SNR performance, especially for small amplitude signals, over existing adaptive sigma delta modulators.

10 citations

Proceedings ArticleDOI
06 Apr 2003
TL;DR: An efficient adaptive receiver for joint equalization and interference cancellation for multi-user space-time block-coded transmissions and exploits the rich code structure to attain RLS performance at LMS complexity.
Abstract: We develop an efficient adaptive receiver for joint equalization and interference cancellation for multi-user space-time block-coded transmissions The receiver exploits the rich code structure and allows multiple user transmissions over frequency-selective fading channels with reduced complexity and lower system overhead The adaptation scheme is based on a recursive least-squares implementation for faster convergence; nevertheless, it exploits the code structure to attain RLS performance at LMS complexity

9 citations

Proceedings ArticleDOI
01 Nov 2012
TL;DR: This work develops and study a procedure by which the entire network can be made to follow one objective or the other through a distributed and collaborative decision process.
Abstract: It is common for biological networks to encounter situations where agents need to decide between multiple options, such as deciding between moving towards one food source or another or between moving towards a new hive or another. In previous works, we developed several powerful diffusion strategies that allow agents to estimate a model of interest in an adaptive and distributed manner through a process of in-network collaboration and learning. In this work, we consider the situation in which the data observed by the agents may arise from two different distributions or models. We develop and study a procedure by which the entire network can be made to follow one objective or the other through a distributed and collaborative decision process.

9 citations


Cited by
More filters
Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: This survey provides an overview of higher-order tensor decompositions, their applications, and available software.
Abstract: This survey provides an overview of higher-order tensor decompositions, their applications, and available software. A tensor is a multidimensional or $N$-way array. Decompositions of higher-order tensors (i.e., $N$-way arrays with $N \geq 3$) have applications in psycho-metrics, chemometrics, signal processing, numerical linear algebra, computer vision, numerical analysis, data mining, neuroscience, graph analysis, and elsewhere. Two particular tensor decompositions can be considered to be higher-order extensions of the matrix singular value decomposition: CANDECOMP/PARAFAC (CP) decomposes a tensor as a sum of rank-one tensors, and the Tucker decomposition is a higher-order form of principal component analysis. There are many other tensor decompositions, including INDSCAL, PARAFAC2, CANDELINC, DEDICOM, and PARATUCK2 as well as nonnegative variants of all of the above. The N-way Toolbox, Tensor Toolbox, and Multilinear Engine are examples of software packages for working with tensors.

9,227 citations

Proceedings ArticleDOI
22 Jan 2006
TL;DR: Some of the major results in random graphs and some of the more challenging open problems are reviewed, including those related to the WWW.
Abstract: We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

7,116 citations

Journal ArticleDOI

6,278 citations

01 Jan 2016
TL;DR: The table of integrals series and products is universally compatible with any devices to read and is available in the book collection an online access to it is set as public so you can get it instantly.
Abstract: Thank you very much for downloading table of integrals series and products. Maybe you have knowledge that, people have look hundreds times for their chosen books like this table of integrals series and products, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. table of integrals series and products is available in our book collection an online access to it is set as public so you can get it instantly. Our book servers saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the table of integrals series and products is universally compatible with any devices to read.

4,085 citations