Papers by Keyword: Multifractal Analysis

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Authors: Da Hui Li, Ming Diao
Abstract: In the paper, the first introduced multifractal features of image, and defined some measures; then described procedures of the edge extraction algorithm; the final analyses the results of experiment and selection criteria commonly used in multifractal, proposing a different multiple fractal image, the algorithm has excellent effect on edge extraction, highlights the detail information of the main edge.
Authors: Da Hui Li, Ming Diao
Abstract: This paper utilizes the multiple fractal theories to define the box dimension and the multiple fractal dimensions, and realizes the feature of voice signal. Then it designs an extraction algorithm for voice signal feature. The result shows, the multifractal method is better than sole fractal method and it may be the characteristic parameter of the voice recognition.
Authors: Yong Kui Sun, Zhi Bin Yu
Abstract: Analog circuits fault diagnosis using multifractal analysis is presented in this paper. The faulty response of circuit under test is analyzed by multifratal formalism, and the fault feature consists of multifractal spectrum parameters. Support vector machine is used to identify the faults. Experimental results prove the proposed method is effective and the diagnosis accuracy reaches 98%.
Authors: V.V. Lepov, Anastassia Ivanova, Valentina Achikasova, Kiounna Lepova
Abstract: In this paper, an attempt is made to describe the structural-statistical aspects of the damage accumulation and fracture of structural steel by means of experimental and numerical micromacromodeling. The new approach of multiscale modeling of structure element fracture based on evolution of microstructure levels is proposed. The lifetime is considered as an ultimate state in a local volume of material, or a critical value of the local damage approaching.
Authors: Zhi Li, Chun Yu Ma, Qing Yu Zhang
Abstract: HfO2 films were sputter deposited under varying substrate temperatures (Ts) and their structural and morphological characteristics, optical properties were systematically studied by means of X-ray diffraction (XRD), atomic force microscope (AFM), and UV/VIS spectrophotometry. A statistical analysis based on multifractal formalism shows the uniformity of the height distribution increases as Ts is increased and the widths Δα of multifractal spetra are related to the average grain size D (-111) as Δα ∼ [D(-111)]-0.83. The monoclinic HfO2 is highly oriented along (-111) direction with increasing Ts. The Lattice expansion increases with diminishing HfO2 crystalline size below 7 nm while maximum lattice expansion occurs with highly oriented monoclinic HfO2 of crystalline size about 14.8 nm. The film growth process at Ts ≥ 200°C with surface diffusion energy of ∼ 0.29 eV is evident from the structural analysis of HfO2 films.
Authors: Mikhail Lebyodkin, Ivan V. Shashkov, Tatiana Lebedkina, Vladimir S. Gornakov
Abstract: Recent studies of plastic deformation using high-resolution experimental techniques bear witness that deformation processes are often characterized by collective effects emerging on an intermediate scale between the scales describing the dynamics of individual crystal defects or the macroscopic plastic flow. In particular, the acoustic emission (AE) reveals intermittency of plastic deformation in various experimental conditions, which is manifested by the property of scale invariance, a characteristic feature of self-organized phenomena. Some materials, e.g., Al or Mg alloys, display a macroscopic discontinuity of plastic flow due to the Portevin-Le Chatelier effect or twinning. These materials are therefore of special interest for the study of collective effects in plasticity. The present work reviews the results of a multiscale investigation of AE accompanying plastic deformation of such model alloys. The AE is analyzed by methods borrowed from the theory of nonlinear dynamical systems, including statistical and multifractal analyses.
Authors: Stanislav Jurečka, Hikaru Kobayashi, Masao Takahashi, Róbert Brunner, Mohammad Madani, Emil Pinčík
Abstract: The microroughness of the semiconductor/oxide interface substantially influence properties of the whole structure. In our work Si/SiO2/SiOx structures were prepared by using low temperature nitric acid oxidation technique and by the electron gun technique and then the whole structure was passivated by the HCN technique. In the present study we investigate the surface morphology evolution during the creation of the SiO2/SiOx double-layer and after the passivation steps. Surface roughness properties are studied by the fractal geometry methods. The complexity of analysed surface is sensitive to the oxidation and passivation steps and the proposed fractal complexity measure values enable quantifying of the fine surface changes.
Authors: Sebastian Stach, Stanisław Roskosz, Jerzy Cybo, Jan Cwajna
Abstract: A quantitative description of overlaps on fractures in sialon ceramics, is presented in the paper. A conventional analysis, aiming at the determination of the percentage share of overlaps on the basis of quantitative fractography, was preceded by stereometric/fractal analyses. They enabled the selection of representative sections of samples and then, the production of transverse microsections in those places for an analysis of the fractures’ profiles using the light microscopy method and fractographic image analysis. Based on the compared results from both methods, a successful verification was made of the research methodology developed earlier for sintered carbides and proven for a chromium-molybdenum steel.
Authors: Yun Ping Chen, Yan Chen, Ling Tong
Abstract: Synthetic Aperture Radar (SAR) images are corrupted by multiplicative speckle noise, which is due to random interference of electromagnetic waves. The noise degrades the quality of images and makes them hard to be interpreted, analyzed and classified. It appears sensible to reduce speckle in SAR images, while the structural features and textural information are not lost. This paper applies the framework of multifractal and regularity analysis to SAR image enhancement and denoising. The method does not make explicit assumptions about the model of the noise, but rather supposes that image denoising is equivalent to increasing the Hölder exponent at each point. The image is characterized via its multifractal spectrum, which mode yields the most frequent Hölder exponent. This manipulation leads to a smooth image while preserving the useful information in the signal. In order to evaluate the restoration result, Equivalent Number of Look (ENL) and edge save index (ESI) are used as criterion. Better result is obtained when regularity increase equal 0.5 (δ=0.5).
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