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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
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Proceedings ArticleDOI
01 Jan 1999
TL;DR: A new estimation scheme for the time and amplitude of arrival of a code division multiple access signal transmitted over a single-path Rayleigh fading channel for location finding applications and a new noise and fading bias equalization technique is presented.
Abstract: Wireless location finding is gaining considerable attention in the field of wireless communications. This is due to a recent USA government mandate for wireless service providers to locate users in emergency situations within a high precision. In this paper, we introduce a new estimation scheme for the time and amplitude of arrival of a code division multiple access signal transmitted over a single-path Rayleigh fading channel for location finding applications. Optimum choices of the estimation scheme parameters are derived. The paper also presents a new noise and fading bias equalization technique for amplitude of arrival estimation that enhances its estimation precision significantly. The paper gives simulation and field trial results that show significant robustness of the proposed scheme to high noise levels and fast channel fading.

12 citations

Proceedings ArticleDOI
01 Jan 2015
TL;DR: An adaptive regularized diffusion strategy using Gaussian kernel regularization is proposed to enable the agents to learn about the objectives of their neighbors and to ignore misleading information to meet their objectives more accurately and improve the performance of the network.
Abstract: The focus of this paper is on multitask learning over adaptive networks where different clusters of nodes have different objectives. We propose an adaptive regularized diffusion strategy using Gaussian kernel regularization to enable the agents to learn about the objectives of their neighbors and to ignore misleading information. In this way, the nodes will be able to meet their objectives more accurately and improve the performance of the network. Simulation results are provided to illustrate the performance of the proposed adaptive regularization procedure in comparison with other implementations.

12 citations

Proceedings ArticleDOI
26 Aug 2007
TL;DR: In this article, a robust and low complexity scheme to estimate and track carrier frequency from the received signals at the Earth end is proposed, which employs a hierarchical arrangement of convex linear prediction cells that is dynamically adapted to respond to channel conditions.
Abstract: In the Mars rover missions the signals transmitted back to Earth travel under low SNR conditions in highly non-stationary channels [1, 2]. During the entry, descent and landing phase (EDL), the spacecraft high dynamics yields severe Doppler effects. We propose a robust and low complexity scheme to estimate and track carrier frequency from the received signals at the Earth end. The method employs a hierarchical arrangement of convex linear prediction cells that is dynamically adapted to respond to the channel conditions. The adaptive combination is able to outperform the best individual estimator in the set, leading to a universal scheme for frequency estimation and tracking. In order to compensate the lag error effect, we explore an efficient forward and backward aggregation scheme that improves considerably the frequency RMS error as compared to the original method [3].

12 citations

Proceedings ArticleDOI
15 Oct 1995
TL;DR: A time-domain feedback analysis of the FxLMS algorithm is presented, which has been receiving increasing attention in the literature due to its potential application in the active control of noise and it is shown that the algorithm can in fact be regarded as a member of the class of filtered-error variants.
Abstract: We present a time-domain feedback analysis of the FxLMS algorithm, which has been receiving increasing attention in the literature due to its potential application in the active control of noise. In particular, we introduce a generalized FxLMS variant and derive conditions for its l/sub 2/-stability. We also show that the algorithm can in fact be regarded as a member of the class of filtered-error variants. A special case of the generalized algorithm is the so-called MFxLMS recursion, which refers to a recent modification of the standard FxLMS update. While this modification significantly improves the convergence behaviour of FxLMS, it requires of the order of 3M elementary computations per time step. This is in contrast to the 2M operations required by the standard FxLMS. We suggest two new modifications that keep the computational load at the 2M level, and which present improved convergence over the FxLMS algorithm. Simulation results are included to demonstrate the points raised in the paper.

12 citations

Proceedings ArticleDOI
25 Apr 2007
TL;DR: This paper presents a distributed sampling and estimation framework based on innovations diffusion, within which the sensor selection and estimation are accomplished through local computation and communications between sensor nodes.
Abstract: This paper considers an estimation network of many distributed sensors with a certain correlation structure. Due to limited communication resources, the network selects only a subset of sensor measurements for estimation as long as the resulting fidelity is tolerable. We present a distributed sampling and estimation framework based on innovations diffusion, within which the sensor selection and estimation are accomplished through local computation and communications between sensor nodes. In order to achieve energy efficiency, the proposed algorithm uses a greedy heuristics to select a nearly minimum number of active sensors in order to ensure the desired fidelity for each estimation period. Extensive simulations illustrate the effectiveness of the proposed sampling scheme.

12 citations


Cited by
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Journal ArticleDOI

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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