نتایج جستجو برای: fractal distribution

تعداد نتایج: 634581  

1992
Hisao Nakanishi Michelle C. Robertson Mark D. Rintoul

We investigate a recent suggestion that the spatial distribution of earthquake hypocenters makes a fractal set with a structure and fractal dimensionality close to those of the backbone of critical percolation clusters, by analyzing four different sets of data for the hypocenter distributions and calculating the dynamical properties of the geometrical distribution such as the spectral dimension...

2008
Martin Hülse

Biological neural systems and the majority of other realworld networks have topologies significant different from fully or randomly connected structures, which are frequently applied for the definition of artificial neural networks (ANN). In this work we introduce a deterministic process generating strongly connected directed graphs of fractal dimension having connectivity structures very disti...

2001
A. M. Brasil T. L. Farias M. G. Carvalho U. O. Koylu

The structures of both cluster}cluster and particle}cluster fractal-like aggregates were investigated in the present study. Statistically signi"cant populations of numerically simulated aggregates having appropriate fractal properties and prescribed number of primary particles per aggregate were generated in order to characterize three-dimensional morphological properties of aggregates, such as...

Journal: :Journal of applied physiology 1996
S A Barman L L McCloud J D Catravas I C Ehrhart

Regional heterogeneity of lung blood flow can be measured by analyzing the relative dispersion (RD) of mass (weight)-flow data. Numerous studies have shown that pulmonary blood flow is fractal in nature, a phenomenon that can be characterized by the fractal dimension and the RD for the smallest realizable volume element (piece size). Although information exists for the applicability of fractal ...

2016
Kyoung Ho Kwak Seong Sik Kim Yong-Il Kim Yong-Deok Kim

OBJECTIVE The purpose of this study was to determine whether the results of fractal analysis can be used as criteria for midpalatal suture maturation evaluation. METHODS The study included 131 subjects aged over 18 years of age (range 18.1-53.4 years) who underwent cone-beam computed tomography. Skeletonized images of the midpalatal suture were obtained via image processing software and used ...

2001
Michinobu Nagao Kenya Murase Takanori Kikuchi Manabu Ikeda Akihiko Nebu Ryuji Fukuhara Yoshifumi Sugawara Hitoshi Miki Junpei Ikezoe

This study describes a method for quantifying cerebral blood flow (CBF) distribution in Alzheimer’s disease (AD) from SPECT images obtained with 99mTc-hexamethylpropyleneamine oxime (HMPAO) by 3-dimensional fractal analysis (3D-FA). Methods: HMPAO SPECT was performed on 68 patients with probable AD and 14 healthy control subjects. We delineated the CBF images using 4 cutoff levels (35%, 40%, 45...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2001
Jyrki T Kuikka

UNLABELLED This study describes a method for quantifying cerebral blood flow (CBF) distribution in Alzheimer's disease (AD) from SPECT images obtained with (99m)Tc-hexamethylpropyleneamine oxime (HMPAO) by 3-dimensional fractal analysis (3D-FA). METHODS HMPAO SPECT was performed on 68 patients with probable AD and 14 healthy control subjects. We delineated the CBF images using 4 cutoff levels...

2013
Jun Zhang Hai Zhao Bo Yang Si-yuan Jia

The coarse-grained renormalization and the fractal analysis of the Internet macroscopic topology can help people better understand the relationship between the part and whole of the Internet, and it is significant for people to understand the essence of the research object through a small amount of information. Aiming at the complexity of Internet IPv6 IP-level topology, we put forward a method...

2013
Biqiang Du Guiji Tang

To process the vibration signal fault diagnosis automatically and effectively, a method to calculate the generalized fractal dimension (Dq) based on the traditional G-P correlation dimension algorithm is presented. First, the vibration signal, a kind of random fractal that meets the statistical self-similarity, is reconstructed according to the phase space reconstruction theory. Second, for var...

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