Now showing items 1-20 of 50

  • An Adaptive Optimal-Kernel Time-Frequency Representation 

    Jones, Douglas L.; Baraniuk, Richard G. (1995-10-01)
    Time-frequency representations with fixed windows or kernels figure prominently in many applications, but perform well only for limited classes of signals. Representations with signal- dependent kernels can overcome this ...
  • Adaptive Wavelet Transforms via Lifting 

    Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1999-05-01)
    This paper develops new algorithms for adapted multiscale analysis and signal adaptive wavelet transforms. We construct our adaptive transforms with the <i>lifting scheme</i>, which decomposes the wavelet transform into ...
  • Adaptive Weighted Highpass Filters Using Multiscale Analysis 

    Nowak, Robert David; Baraniuk, Richard G. (1998-07-01)
    In this paper, we propose a general framework for studying a class of weighted highpass filters. Our framework, based on a multiscale signal decomposition, allows us to study a wide class of filters and to assess the ...
  • Conditional and Relative Multifractal Spectra 

    Riedi, Rudolf H.; Scheuring, Istvan (1997-03-01)
    In the study of the involved geometry of singular distributions the use of fractal and multifractal analysis has shown results of outstanding significance. So far, the investigation has focused on structures produced by ...
  • Detecting Periodic Behavior in Nonstationary Signals 

    Venkatachalam, Vidya; Aravena, Jorge.L. (1998-10-20)
    This paper presents results on the multiresolution analysis of nonstationary signals with the objective of detecting underlying periodic phenomena. Wavelet packet analysis with coefficient thresholding is the basis for the ...
  • Detection of Target Speakers in Audio Databases 

    Magrin-Chagnolleau, Ivan; Rosenberg, Aaron; Parthasarathy, S. (1999-01-15)
    The problem of speaker detection in audio databases is addressed in this paper. Gaussian mixture modeling is used to build target speaker and background models. A detection algorithm based on a likelihood ratio calculation ...
  • Effect of Utterance Duration and Phonetic Content on Speaker Identification Usind Second Order Statistical Methods 

    Magrin-Chagnolleau, Ivan; Bonastre, Jean-Francois; Bimbot, Frederic (1995-01-01)
    Second-order statistical methods show very good results for automatic speaker identification in controlled recording conditions. These approaches are generally used on the entire speech material available. In this paper, ...
  • Efficient Methods for Identification of Volterra Filters 

    Nowak, Robert David; Van Veen, Barry D. (1996-02-01)
    A major drawback of the truncated Volterra series or "Volterra filter" for system identification is the large number of parameters required by the standard filter structure. The corresponding estimation problem requires ...
  • Empirical Mode Decomposition Based Frequency Attributes 

    Magrin-Chagnolleau, Ivan; Baraniuk, Richard G. (1999-11-01)
    This paper describes a new technique, called <i>Empirical Mode Decomposition</i> (EMD), which allows the decomposition of one-dimensional signals into intrinsic oscillatory modes. Each component, called <i>Intrinsic Mode ...
  • Equivalence of Generalized Joint Signal Representations of Arbitrary Variables 

    Sayeed, Akbar M.; Jones, Douglas L. (1996-12-20)
    Joint signal representations (JSRs) of arbitrary variables generalize time-frequency representations (TFRs) to a much broader class of nonstationary signal characteristics. Two main distributional approaches to JSRs of ...
  • Exceptions to the Multifractal Formalism for Discontinuous Measures 

    Riedi, Rudolf H.; Mandelbrot, Benoit (1998-01-15)
    In an earlier paper the authors introduced the <i>inverse measure</i> <i>µ</i><sup>â  </sup>(<i>dt</i>) of a given measure <i>µ</i>(<i>dt</i>) on [0,1] and presented the 'inversion formula' <i>f</i><sup>â  </sup>(<i>a</i>) ...
  • Fast, Exact Synthesis of Gaussian and nonGaussian Long-Range-Dependent Processes 

    Crouse, Matthew; Baraniuk, Richard G. (1999-01-15)
    1/<i>f</i> noise and statistically self-similar processes such as fractional Brownian motion (fBm) are vital for modeling numerous real-world phenomena, from network traffic to DNA to the stock market. Although several ...
  • A Further Investigation on AR-Vector Models for Text Independent Speaker Identification 

    Magrin-Chagnolleau, Ivan; Bimbot, Frederic (1996-01-01)
    In this paper, we investigate on the role of dynamic information on the performances of AR-vector models for speaker recognition. To this purpose, we design an experimental protocol that destroys the time structure of ...
  • Hybrid Linear / Bilinear Time-Scale Analysis 

    Pasquier, Martin; Goncalves, Paulo; Baraniuk, Richard G. (1999-01-01)
    We introduce a new method for the time-scale analysis of non-stationary signals. Our work leverages the success of the "time-frequency distribution series / cross-term deleted representations" into the time-scale domain ...
  • Image enhancement by nonlinear wavelet processing 

    Odegard, Jan E. (1994-10-20)
    In this paper we describe how the theory of wavelet thresholding introduced by Donoho and Johnstone can successfully be applied to two distinct problems in image processing where traditional linear filtering techniques are ...
  • An Improved Multifractal Formalism and Self Affine Measures 

    Riedi, Rudolf H. (1993-01-20)
    This document is a six page summary of my Ph.D. thesis in which multifractal formalism based on counting on coarse levels (as opposed to a dimensional approach) is developed. This formalism is then applied to self-affine ...
  • An Improved Multifractal Formalism and Self Similar Measures 

    Riedi, Rudolf H. (1995-01-01)
    To characterize the geometry of a measure, its so-called generalized dimensions D(<i>q</i>) have been introduced recently. The mathematically precise definition given by Falconer turns out to be unsatisfactory for reasons ...
  • Improved Time-Frequency Filtering of Signal-Averaged Electrocardiograms 

    Sayeed, Akbar M.; Jones, Douglas L. (1995-01-15)
    A recently proposed time-frequency filtering technique has shown promising results for the enhancement of signal-averaged electrocardiograms. This method weights the short-time Fourier transform (STFT) of the ensemble-averaged ...
  • Inverse Measures, the Inversion formula, and Discontinuous Multifractals 

    Mandelbrot, Benoit; Riedi, Rudolf H. (1997-01-20)
    The present paper is part I of a series of three closely related papers in which the inverse measure m' of a given measure m on [0,1] is introduced. In the first case discussed in detail, both these measures are multifractal ...
  • Inversion Formula for Continuous Multifractals 

    Riedi, Rudolf H.; Mandelbrot, Benoit (1997-01-20)
    In a previous paper the authors introduced the inverse measure <i>µ</i><sup>â  </sup> of a probability measure <i>µ</i> on [0,1]. It was argued that the respective multifractal spectra are linked by the 'inversion formula' ...