This paper presents the variance fractal dimension trajectory (VFDT) approach to studying nonstationary transients in power system. Experiments show that multifractal analysis based on the VFDT is efficient for charac...
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This paper presents the variance fractal dimension trajectory (VFDT) approach to studying nonstationary transients in power system. Experiments show that multifractal analysis based on the VFDT is efficient for characterizing most of the transient types found in power system signals and data reduction can be realized by simply changing the window displacement. In addition, analysis of transient signals contaminated by noise shows that the VFDT approach is very immune to noise.
This paper presents a perceptual image compression technique using fractal surface interpolation (FSI). This technique relies on the extraction and reconstruction of self-affine fractal surfaces with a specified Hurst...
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This paper presents a perceptual image compression technique using fractal surface interpolation (FSI). This technique relies on the extraction and reconstruction of self-affine fractal surfaces with a specified Hurst exponent H*. Fractional Brownian motion (fBm) through midpoint displacement (MPD) provides the basis for generating these fractal surfaces between interpolation points. The MPD algorithm is designed to eliminate creasing often associated with MPD in two dimensions. Experimental results show that when applied to 512/spl times/512 8-bit gray-level images, perceptually good results are achieved with a bit rate of 0.35 bpp.
The paper presents a perceptual image representation technique based on fractal surface interpolation (FSI), This technique is motivated from the observation that images taken from the real world contain many textures...
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The paper presents a perceptual image representation technique based on fractal surface interpolation (FSI), This technique is motivated from the observation that images taken from the real world contain many textures that are self similar, or fractal, in nature. The fractal surface interpolation representation is then compressed using a zero tree wavelet compression subsystem with lossless entropy encoding. The fractal surface interpolation technique described relies on the extraction and reconstruction of self affine fractal surfaces with measured Hurst exponents H*. This gives statistically self similar fractal surfaces used to represent textures in a real world image. Fractional Brownian motion (fBm) through a modified midpoint displacement (MPD) algorithm provides the basis for generating these self affine fractal surfaces between interpolation points.
This paper presents the implementation aspects pertinent to the computation of the multifractal singularity spectrum through wavelets, and the methods of overcoming them. Multifractals are mixtures of monofractals, an...
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This paper presents the implementation aspects pertinent to the computation of the multifractal singularity spectrum through wavelets, and the methods of overcoming them. Multifractals are mixtures of monofractals, and monofractals are self-affine objects that hold power law relationships over several scales. Such multifractals can be detected and measured through a singularity spectrum. Many natural and artificial phenomena such as turbulence, diffusion limited aggregates, and electrical discharges exhibit multifractality. Since these phenomena are highly nonlinear and nonstationary, regular analyses such as Fourier decomposition cannot characterize them effectively. In order to characterize, compare and quantify multifractal objects, appropriate measures such as the Renyi fractal dimension spectrum (RS) and Mandelbrot singularity spectrum (MS) are required. There are two major methods for calculating a singularity spectrum; one is through Legendre transform of the RS, and the other is through the wavelet transform modulus maxima (WTMM) method. This paper provides solutions to the difficulties that arise in the computation of the MS through WTMM, for one-dimensional signals and compares them to the existing multifractal literature and software implementations. Appropriate mother wavelets, continuous wavelet implementation, and thresholding of the wavelet coefficients are also discussed
The impact of outliers on signal separation performance of an independent component analysis (ICA) algorithm is an important factor when selecting an ICA algorithm. If an ICA estimator has the property of B-robustness...
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The impact of outliers on signal separation performance of an independent component analysis (ICA) algorithm is an important factor when selecting an ICA algorithm. If an ICA estimator has the property of B-robustness, the influence of an extreme point is bounded, leading to good separation performance in the presence of outliers. Since this property is binary, it does not give the degree of influence an outlier has on the separation performance. To address this issue, a Mamdani-type fuzzy inference, based on the location of a potential outlier and on the skewness of the data set, has been developed. It creates an outlier sensitivity map for an ICA algorithm. The implication of this work is a criterion to switch from one ICA algorithm to another in real time, as determined by the algorithms sensitivity to the data set under consideration. This paper describes estimation of the outlier impact on the separation performance of the non-B-robust FastICA algorithm using a Mamdani-type fuzzy inference. In simulations with data sets contaminated by outliers, the FastICA sensitivity map resembles the separation performance measured by the Amari performance index.
This paper describes a fast multiscale time-domain technique for the analysis of natural speech waveforms in the presence of noise. The technique is based on the variance fractal dimension trajectory algorithm that is...
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ISBN:
(纸本)9781424425389
This paper describes a fast multiscale time-domain technique for the analysis of natural speech waveforms in the presence of noise. The technique is based on the variance fractal dimension trajectory algorithm that is used not only to detect the external boundaries of an utterance, but also its internal pauses representing the unvoiced speech. The algorithm can also identify internal features of phonemes. The features can be amplified so that the speech utterances can be segmented into sentences, words and phonemes. This approach is superior to other energy-based boundary-detection techniques. These observations are based on extensive experimental results on speech utterances digitized at 44.1 kilosamples per second, with 16 bits in each sample.
The goal of this work was to determine if fractal dimensions would be useful in attempting to characterize and extract emergent behaviour from cellular automata. More specifically, we sought to determine if entropy-ba...
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The goal of this work was to determine if fractal dimensions would be useful in attempting to characterize and extract emergent behaviour from cellular automata. More specifically, we sought to determine if entropy-based fractal dimensions might prove more useful in extracting behavioural information than morphological dimensions, such as the Hausdorff dimension. This hypothesis was confirmed over several experiments by calculating the gyration dimension, Hausdorff dimension, and by finding Shannon's entropy of the automata's supporting environment during each system iteration.
This paper addresses the problem of approximation of arbitrary object boundaries that result from image segmentation. We present a new technique to reconstruct the self-similar boundaries with any fractal or multifrac...
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This paper addresses the problem of approximation of arbitrary object boundaries that result from image segmentation. We present a new technique to reconstruct the self-similar boundaries with any fractal or multifractal dimension, using the iterated function system (IFS). The boundaries are assumed to be rough (non-smooth) but crisp (one-pixel wide) and are fractal or multifractal in nature. We show that such boundaries can be regarded as an attractor of a linear IFS having the same multifractal spectrum as the boundaries. We also discuss the hidden variable IFS in order to reconstruct multifractal boundary curvatures, while preserving the original multifractal spectrum of the boundary. Experimental results show that such arbitrary boundaries can be reconstructed more accurately using the IFS as compared to other standard techniques like the midpoint displacement algorithm.
Presents a nonlinear extension of the affine transform as used in the iterated function systems (IFS) to compress signals and data. Compared with Oien and Narstad's orthogonal transform with compression ratio of 6...
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Presents a nonlinear extension of the affine transform as used in the iterated function systems (IFS) to compress signals and data. Compared with Oien and Narstad's orthogonal transform with compression ratio of 6.0:1 for the electrocardiogram (ECG) signal, the nonlinear approach produces higher compression ratios of 10.2:1, and is more flexible in finding the corresponding strange attractor of the ECG signal. It can model the QRS complex of the ECG signal well, which has been a problem for the affine transform in fractal compression.
Current methods of compressing 3D animation for transmission over the Internet tend to be of very low quality. Quality is sacrificed to keep bandwidth low when using lossy compression techniques such as MPEG, Cinepak,...
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Current methods of compressing 3D animation for transmission over the Internet tend to be of very low quality. Quality is sacrificed to keep bandwidth low when using lossy compression techniques such as MPEG, Cinepak, or more recent formats such as Vivo and VDOnet. While these techniques can be effective approaches to all-purpose video compression, it should be possible to achieve better performance with the knowledge that the source consists of 3D animation. A new technique is proposed, which instead of focusing on compressing the rendered frames of the animation sequence, compresses and optimizes the original source scene data for streaming, and renders the 3D scene in real time on the client system.
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