Samuel T. Alexander

Works (24)

Updated: July 5th, 2023 15:47

1996 patent

Apparatus and method for echo characterization of a communication channel

Washington, DC: U.S. Patent and Trademark Office.

By: K. Townsend, H. Punjabi, A. Duel-Hallen  & S. Alexander

Source: NC State University Libraries
Added: August 6, 2018

1993 article

A Method for Recursive Least Squares Filtering Based Upon an Inverse QR Decomposition

Alexander, S. T., & Ghimikar, A. L. (1993, January 1). IEEE Transactions on Signal Processing.

By: S. Alexander n & A. Ghimikar

topics (OpenAlex): Image and Signal Denoising Methods; Advanced Adaptive Filtering Techniques; Blind Source Separation Techniques
TL;DR: A new computationally efficient algorithm for re- cursive least squares filtering is derived, which is based upon an inverse QR decomposition, which solves directly for the time-recursive least squares filter vector, while avoiding the highly serial backsubstitution step required in previously direct QR approaches. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1993 article

Fast adaptive polynomial root tracking using a homotopy continuation method

Alexander, S. T., & Stonick, V. L. (1993, January 1). IEEE International Conference on Acoustics Speech and Signal Processing.

By: S. Alexander n & V. Stonick*

topics (OpenAlex): Digital Filter Design and Implementation; Advanced Adaptive Filtering Techniques; Advanced Vision and Imaging
TL;DR: A fast adaptive method for tracking the roots of a time-varying complex domain polynomial is derived using the method of homotopy continuation and is efficient from both mathematical and implementation standpoints. (via Semantic Scholar)
Source: NC State University Libraries
Added: August 6, 2018

1992 article

A parallel implementation of the inverse QR adaptive filter

Ghirnikar, A. L., Alexander, S. T., & Plemmons, R. J. (1992, May 1). Computers & Electrical Engineering.

By: A. Ghirnikar, S. Alexander n & R. Plemmons *

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Blind Source Separation Techniques; Advanced Wireless Communication Techniques
TL;DR: The individual processing elements contained in the inverse QR algorithm are outlined, after which it is demonstrated how these processing elements may be connected to implement the overall inverse QR array. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1992 article

Globally optimal rational approximation using homotopy continuation methods

Stonick, V. L., & Alexander, S. T. (1992, January 1). IEEE Transactions on Signal Processing.

By: V. Stonick n & S. Alexander n

topics (OpenAlex): Iterative Methods for Nonlinear Equations; Advanced Optimization Algorithms Research; Model Reduction and Neural Networks
TL;DR: A homotopy function is constructed which guarantees that the globally optimum rational approximation solution may be determined by finding all the solutions of the desired nonlinear problem. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1991 journal article

A novel approach for stabilizing recursive least squares filters

IEEE Transactions on Signal Processing, 39(8), 1770–1779.

By: G. Bottomley n  & S. Alexander n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Image and Signal Denoising Methods; Digital Filter Design and Implementation
TL;DR: A novel approach for stabilizing recursive least squares (RLS) filters is presented, which relies on a detailed fixed point analysis that reveals a bias in the error propagation mechanism, providing an analytical basis for instability problems. (via Semantic Scholar)
Sources: Web Of Science, Crossref, NC State University Libraries
Added: August 6, 2018

1991 article

A relationship between the recursive least squares update and homotopy continuation methods

Stonick, V. L., & Alexander, S. T. (1991, January 1). IEEE Transactions on Signal Processing.

By: V. Stonick n & S. Alexander n

topics (OpenAlex): Numerical Methods and Algorithms; Model Reduction and Neural Networks; Neural Networks and Applications
TL;DR: The authors present an alternative derivation of the general recursive least squares (RLS) algorithm using homotopy approaches, and the equivalence between the iterative update for following the path defined by this Homotopy function and the general RLS update is derived. (via Semantic Scholar)
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Source: Web Of Science
Added: August 6, 2018

1991 article

Statistical analysis of initialization methods for RLS adaptive filters

Hubing, N. E., & Alexander, S. T. (1991, January 1). IEEE Transactions on Signal Processing.

By: N. Hubing* & S. Alexander n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Speech and Audio Processing; Blind Source Separation Techniques
TL;DR: Theoretical analysis is used to evaluate the mean and second-moment properties of recursive least squares algorithms incorporating the fast exact initialization and soft constrained initialization methods during the initialization period, and theoretical results are derived that show that the weight vector mean and covariance are finite. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1990 article

Inverse invariant distributions

Hubing, N. E., & Alexander, S. T. (1990, June 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: N. Hubing* & S. Alexander n

topics (OpenAlex): Markov Chains and Monte Carlo Methods; Bayesian Methods and Mixture Models; Matrix Theory and Algorithms
TL;DR: An intuitive method of finding inverse-invariant density functions is presented, with examples and notes on where these distributions arise. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1988 article

Analysis of a recursive least squares hyperbolic rotation algorithm for signal processing

Alexander, S. T., Pan, C.-T., & Plemmons, R. J. (1988, January 1). Linear Algebra and Its Applications.

By: S. Alexander n, C. Pan  n & R. Plemmons  n

topics (OpenAlex): Numerical Methods and Algorithms; Digital Filter Design and Implementation; Advanced Numerical Methods in Computational Mathematics
TL;DR: The hyperbolic rotation algorithm is shown to be forward (weakly) stable and, in fact, comparable to an orthogonal downdating method showing to be backward stable by Stewart, and how the method's accuracy depends upon the conditioning is shown. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1987 journal article

Analytical finite precision results for Burg?s algorithm and the autocorrelation method of linear prediction

IEEE Transactions on Acoustics, Speech, and Signal Processing, 35, 626–635.

By: S. Alexander & S. Ardalan

Source: NC State University Libraries
Added: August 6, 2018

1987 patent

Echo canceller using parametric methods

Washington, DC: U.S. Patent and Trademark Office.

By: S. Ardalan & S. Alexander

Source: NC State University Libraries
Added: August 6, 2018

1987 article

Fixed-point roundoff error analysis of the exponentially windowed RLS algorithm for time-varying systems

Ardalan, S., & Alexander, S. (1987, June 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Ardalan n & S. Alexander n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Blind Source Separation Techniques; Speech and Audio Processing
TL;DR: A fixed-point roundoff error analysis of the exponentially windowed RLS algorithm is presented and it is shown that a tradeoff exists in the choice of the forgetting factor λ in order to reduce the sensitivity of the algorithm to additive noise. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1987 article

Transient weight misadjustment properties for the finite precision LMS algorithm

Alexander, S. (1987, September 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Alexander n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Structural Health Monitoring Techniques; Image and Signal Denoising Methods
TL;DR: A new and more accurate analytical result is derived for the expected misadjustment in the LMS weight vector due to FP effects which is applicable to both the transient adaptation period and steady state. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1986 article

Adaptive Signal Processing

Alexander, S. T. (1986, January 1).

By: S. Alexander n

topics (OpenAlex): Neural Networks and Applications; Advanced Computational Techniques and Applications
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Source: NC State University Libraries
Added: August 6, 2018

1986 article

An SIMD Multiprocessor Ring Architecture for the LMS Adaptive Algorithm

Miller, T., Alexander, S., & Faber, L. (1986, January 1). IEEE Transactions on Communications.

By: T. Miller  n, S. Alexander n & L. Faber n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Speech and Audio Processing; Blind Source Separation Techniques
TL;DR: A new architecture for a single instruction stream, multiple data stream (SIMD) implementation of the LMS adaptive algorithm is investigated, denoted as a ring architecture, and it effectively solves the latency problem often associated with prediction error feedback in adaptive filters. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1986 article

Fast adaptive filters: A geometrical approach

Alexander, S. (1986, October 1). IEEE ASSP Magazine.

By: S. Alexander n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Speech and Audio Processing; Image and Signal Denoising Methods
TL;DR: The geometrical vector space concepts in this article are applied to deriving the very important fast RLS structure known as the fast transversal filter (FTF), which is used in speech coding and linear prediction. (via Semantic Scholar)
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Source: NC State University Libraries
Added: August 6, 2018

1985 article

A simple noniterative speech excitation algorithm using the LPC residual

Alexander, S. (1985, April 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Alexander n

topics (OpenAlex): Speech and Audio Processing; Advanced Adaptive Filtering Techniques; Blind Source Separation Techniques
TL;DR: An analytical derivation of a simple noniterative technique for extracting a multiple impulse excitation model for synthesized speech directly from the LPC residual sequence, which is very applicable for speech enhancement where processor capability is limited. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1985 chapter

Adaptive Compression of Teleconference Sequences Using the LMS Algorithm

In Ramamohan Rao & R. Srinivasan (Eds.), Teleconferencing. New York: Van Rostrand Reinhold, Inc.

By: S. Alexander & S. Rajala

Ed(s): . Ramamohan Rao & R. Srinivasan

Source: NC State University Libraries
Added: August 6, 2018

1985 article

Image compression results using the LMS adaptive algorithm

Alexander, S., & Rajala, S. (1985, June 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Alexander n & S. Rajala n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Image and Signal Denoising Methods; Advanced Data Compression Techniques
TL;DR: Results are presented which show LMS may provide almost 2 bits per symbol reduction in transmitted bit rate compared to DPCM when distortion levels are approximately the same for both methods. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1984 article

A derivation of the complex fast Kalman algorithm

Alexander, S. (1984, December 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Alexander n

topics (OpenAlex): Advanced Scientific and Engineering Studies; Geophysics and Sensor Technology; Neural Networks and Applications
TL;DR: The derivation of a complex-domain recursive linear prediction algorithm with a reduced number of computations is presented, seen to be very similar to real domain fast Kalman, when complex conjugation is considered in formulating the error measure. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

1984 article

Optimal gain derivation for the LMS algorithm using a visual fidelity criterion

Alexander, S., & Rajala, S. (1984, April 1). IEEE Transactions on Acoustics Speech and Signal Processing.

By: S. Alexander n & S. Rajala n

topics (OpenAlex): Advanced Adaptive Filtering Techniques; Speech and Audio Processing; Image and Signal Denoising Methods
Source: NC State University Libraries
Added: August 6, 2018

1983 patent

Gravimeter

Washington, DC: U.S. Patent and Trademark Office.

By: S. Alexander

Source: NC State University Libraries
Added: August 6, 2018

1979 article

Channel Equalization Using Adaptive Lattice Algorithms

Satorius, E., & Alexander, S. (1979, June 1). IRE Transactions on Communications Systems.

By: E. Satorius & S. Alexander*

topics (OpenAlex): Blind Source Separation Techniques; Advanced Adaptive Filtering Techniques; Speech and Audio Processing
TL;DR: The orthogonalization properties of the lattice algorithms make them appear promising for equalizing channels which exhibit heavy amplitude distortion, and the number of operations per update for the adaptive lattice equalizers is linear with respect to thenumber of equalizer taps. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

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