Wireless sensor networks (WSNs) have attracted considerable attention in recent years and motivate a host of new challenges for distributed signalprocessing. The problem of distributed or decentralized estimation has...
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Wireless sensor networks (WSNs) have attracted considerable attention in recent years and motivate a host of new challenges for distributed signalprocessing. The problem of distributed or decentralized estimation has often been considered in the context of parametric models. However, the success of parametric methods is limited by the appropriateness of the strong statistical assumptions made by the models. In this paper, a more flexible nonparametric model for distributed regression is considered that is applicable in a variety of WSN applications including field estimation. Here, starting with the standard regularized kernel least-squares estimator, a message-passing algorithm for distributed estimation in WSNs is derived. The algorithm can be viewed as an instantiation of the successive orthogonal projection (SOP) algorithm. Various practical aspects of the algorithm are discussed and several numerical simulations validate the potential of the approach.
In this paper we describe aspects of an ongoing program of work aimed at the practical realization of systolic array structures to implement digital adaptive beam-forming algorithms.
ISBN:
(纸本)0819406945
In this paper we describe aspects of an ongoing program of work aimed at the practical realization of systolic array structures to implement digital adaptive beam-forming algorithms.
We use the Wigner distribution to study pulse propagation in a dispersive media and we show that it leads naturally to a particle view. Using the results obtained we develop a simple approximation method that evolves ...
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ISBN:
(纸本)0819441880
We use the Wigner distribution to study pulse propagation in a dispersive media and we show that it leads naturally to a particle view. Using the results obtained we develop a simple approximation method that evolves a pulse in time.
For an assessment of the power quality in power distribution systems, classical Fourier series-based power quality indices are normally employed. The classical Fourier series-based power quality indices assume the per...
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For an assessment of the power quality in power distribution systems, classical Fourier series-based power quality indices are normally employed. The classical Fourier series-based power quality indices assume the periodicity of the disturbance so that the applications are limited to the harmonics. Hence, it is necessary for us to redefine power quality indices for the "transient" disturbances. In this paper, development of time-frequency based power quality indices are discussed for an assessment of transient power quality. The time and frequency localized information of the transient disturbance signals will be utilized for a new definition of the transient power quality indices. As an example of time-frequency based power quality indices, new definition of transient telephone interference factor has been carefully derived and verified in comparison with traditional telephone interference factor has been carefully derived and verified in comparison with traditional telephone interference factor. Time-frequency based power quality indices allow one to quantify the effects of transient disturbances by time and frequency localized information.
When the short-time Fourier transform (STFT) of an audio signal is arbitrarily modified, it no longer truly represents a time-domain signal. Classically, the accepted solution to obtain a time-domain signal from a mod...
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When the short-time Fourier transform (STFT) of an audio signal is arbitrarily modified, it no longer truly represents a time-domain signal. Classically, the accepted solution to obtain a time-domain signal from a modified STFT (MSTFT) is to invert the MSTFT to a time-domain signal that has an STFT that is closest to the MSTFT in a least squares sense. This is also the approach currently taken by our modulation filtering techniques. However, it was never established that using the original and unmodified STFT phase in this reconstruction is optimal for modulation filtering. In this paper, we compare our signal reconstruction approach to a well-known iterative procedure that approximates a time-domain signal using only the STFT magnitude. We analyze the signal reconstruction of speech signals after filtering them with low-pass, band-pass and high-pass modulation filters. Our study shows that the iterative procedure yields quantitatively and qualitatively comparable signals at significantly higher computational cost. It therefore does not seem a worthwhile alternative to our current reconstruction technique, but it may prove useful for IIR modulation filtering.
A new derivation of the QR-based fast recursive least squares algorithms for Toeplitz matrices is presented. algorithms for computing Q and R in the QR decomposition of the data matrix are proposed. These algorithms c...
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ISBN:
(纸本)0819406945
A new derivation of the QR-based fast recursive least squares algorithms for Toeplitz matrices is presented. algorithms for computing Q and R in the QR decomposition of the data matrix are proposed. These algorithms can be efficiently incorporated with the fast recursive least squares algorithm and can be performed only when they are needed.
We formulate in a simple fashion the concept of invariance for a linear system. We show that one must define what we call an "associated Hermitian operator"' which commutes with the system function. We s...
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ISBN:
(纸本)9780819468451
We formulate in a simple fashion the concept of invariance for a linear system. We show that one must define what we call an "associated Hermitian operator"' which commutes with the system function. We show that it is this Hermitian operator that defines the invariance and also determines the appropriate transform and other connections between input and output relations.
We calculate the instantaneous frequency at a fixed position of a propagating pulse in the asymptotic regime. We also discuss the multimode case and relate it to the concept of instantaneous bandwidth.
ISBN:
(纸本)0819425842
We calculate the instantaneous frequency at a fixed position of a propagating pulse in the asymptotic regime. We also discuss the multimode case and relate it to the concept of instantaneous bandwidth.
This paper presents, Index Mapping, a technique to efficiently map a widely used class of digital signalprocessingalgorithms onto a space/time paradigm with immediate representation as the partitioning and schedulin...
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ISBN:
(纸本)0819425842
This paper presents, Index Mapping, a technique to efficiently map a widely used class of digital signalprocessingalgorithms onto a space/time paradigm with immediate representation as the partitioning and scheduling map of a small, I/O efficient, hardware array. When applied to reconfigurable FPGA based hardware architectures with downstream Sea-of-Gates optimization methods, the resulting systems form a dynamic signalprocessing environment with the best mix of performance and flexibility for wireless applications. Herein, Index Mapping is demonstrated with a mapping of the Fast Fourier Transform (FFT) onto an FPGA computing machine, the ReConfigurable Processor (RCP).
Implementing Jacobi algorithms in parallel VLSI processor arrays is a non-trivial task, in particular when the algorithms are parametrized with respect to size and the architectures are parametrized with respect to sp...
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ISBN:
(纸本)0819412767
Implementing Jacobi algorithms in parallel VLSI processor arrays is a non-trivial task, in particular when the algorithms are parametrized with respect to size and the architectures are parametrized with respect to space-time trade-offs. The paper is concerned with an approach to implement several time-adaptive Jacobi-type algorithms on a parallel processor array, using only Cordic arithmetic and asynchronous communications, such that any degree of parallelism, ranging from single-processor up to full-size array implementation, is supported by a `universal' processing unit. This result is attributed to a gracious interplay between algorithmic and architectural engineering.
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