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Hydrophobicity classification of polymeric materials based on fractal dimension

THOMAZINI, Daniel; GELFUSO, Maria Virginia; ALTAFIM, Ruy Alberto Corrêa
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.93317%
This study proposes a new method to obtain hydrophobicity classification (HC) in high voltage polymer insulators. In the method mentioned, the HC was analyzed by fractal dimension (fd) and its processing time was evaluated having as a goal the application in mobile devices. Texture images were created from spraying solutions produced of mixtures of isopropyl alcohol and distilled water in proportions, which ranged from 0 to 100% volume of alcohol (%AIA). Based on these solutions, the contact angles of the drops were measured and the textures were used as patterns for fractal dimension calculations.

Fractal dimension applied to plant identification

BRUNO, Odemir Martinez; PLOTZE, Rodrigo de Oliveira; FALVO, Mauricio; CASTRO, Mario de
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.0751%
This article discusses methods to identify plants by analysing leaf complexity based on estimating their fractal dimension. Leaves were analyzed according to the complexity of their internal and external shapes. A computational program was developed to process, analyze and extract the features of leaf images, thereby allowing for automatic plant identification. Results are presented from two experiments, the first to identify plant species from the Brazilian Atlantic forest and Brazilian Cerrado scrublands, using fifty leaf samples from ten different species, and the second to identify four different species from genus Passiflora, using twenty leaf samples for each class. A comparison is made of two methods to estimate fractal dimension (box-counting and multiscale Minkowski). The results are discussed to determine the best approach to analyze shape complexity based on the performance of the technique, when estimating fractal dimension and identifying plants. (C) 2008 Elsevier Inc. All rights reserved.

An estimate on the fractal dimension of attractors of gradient-like dynamical systems

Bortolan, M. C.; Caraballo, T.; Carvalho, A. N.; Langa, J. A.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.20922%
This paper is dedicated to estimate the fractal dimension of exponential global attractors of some generalized gradient-like semigroups in a general Banach space in terms of the maximum of the dimension of the local unstable manifolds of the isolated invariant sets, Lipschitz properties of the semigroup and the rate of exponential attraction. We also generalize this result for some special evolution processes, introducing a concept of Morse decomposition with pullback attractivity. Under suitable assumptions, if (A, A*) is an attractor-repeller pair for the attractor A of a semigroup {T(t) : t >= 0}, then the fractal dimension of A can be estimated in terms of the fractal dimension of the local unstable manifold of A*, the fractal dimension of A, the Lipschitz properties of the semigroup and the rate of the exponential attraction. The ingredients of the proof are the notion of generalized gradient-like semigroups and their regular attractors, Morse decomposition and a fine analysis of the structure of the attractors. As we said previously, we generalize this result for some evolution processes using the same basic ideas. (C) 2012 Elsevier Ltd. All rights reserved.; FAPESP [2010/50690-5]; CAPES/DGU [267/2008]; BEX, Brazil [6221/10-6]; FEDER; Ministerio de Ciencia e Innovacion [MTM2011-22411...

A comparative study on multiscale fractal dimension descriptors

Florindo, J. B.; Backes, A. R.; de Castro, M.; Bruno, Odemir Martinez
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.07788%
Fractal theory presents a large number of applications to image and signal analysis. Although the fractal dimension can be used as an image object descriptor, a multiscale approach, such as multiscale fractal dimension (MFD), increases the amount of information extracted from an object. MFD provides a curve which describes object complexity along the scale. However, this curve presents much redundant information, which could be discarded without loss in performance. Thus, it is necessary the use of a descriptor technique to analyze this curve and also to reduce the dimensionality of these data by selecting its meaningful descriptors. This paper shows a comparative study among different techniques for MFD descriptors generation. It compares the use of well-known and state-of-the-art descriptors, such as Fourier, Wavelet, Polynomial Approximation (PA), Functional Data Analysis (FDA), Principal Component Analysis (PCA), Symbolic Aggregate Approximation (SAX), kernel PCA, Independent Component Analysis (ICA), geometrical and statistical features. The descriptors are evaluated in a classification experiment using Linear Discriminant Analysis over the descriptors computed from MFD curves from two data sets: generic shapes and rotated fish contours. Results indicate that PCA...

Quantification of fractal dimension and Shannon’s entropy in histological diagnosis of prostate cancer

Arruda, Pedro Francisco Ferraz de; Gatti, Márcio ; Facio Junior, Fernando Nestor; Arruda, José Germano Ferraz de; Moreira, Roberto Douglas ; Murta Junior, Luiz Otavio; Arruda, Laísa Ferraz de; Godoy, Moacir Fernandes de
Fonte: London Publicador: London
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.93317%
Background: Prostate cancer is a serious public health problem that affects quality of life and has a significant mortality rate. The aim of the present study was to quantify the fractal dimension and Shannon’s entropy in the histological diagnosis of prostate cancer. Methods: Thirty-four patients with prostate cancer aged 50 to 75 years having been submitted to radical prostatectomy participated in the study. Histological slides of normal (N), hyperplastic (H) and tumor (T) areas of the prostate were digitally photographed with three different magnifications (40x, 100x and 400x) and analyzed. The fractal dimension (FD), Shannon’s entropy (SE) and number of cell nuclei (NCN) in these areas were compared. Results: FD analysis demonstrated the following significant differences between groups: T vs. N and H vs. N groups (p < 0.05) at a magnification of 40x; T vs. N (p < 0.01) at 100x and H vs. N (p < 0.01) at 400x. SE analysis revealed the following significant differences groups: T vs. H and T vs. N (p < 0.05) at 100x; and T vs. H and T vs. N (p < 0.001) at 400x. NCN analysis demonstrated the following significant differences between groups: T vs. H and T vs. N (p < 0.05) at 40x; T vs. H and T vs. N (p < 0.0001) at 100x; and T vs. H and T vs. N (p < 0.01) at 400x. Conclusions: The quantification of the FD and SE...

Texture analysis using volume-radius fractal dimension

Backes, André R.; Bruno, Odemir Martinez
Fonte: Elsevier; Philadelphia Publicador: Elsevier; Philadelphia
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.723657%
Texture plays an important role in computer vision. It is one of the most important visual attributes used in image analysis, once it provides information about pixel organization at different regions of the image. This paper presents a novel approach for texture characterization, based on complexity analysis. The proposed approach expands the idea of the Mass-radius fractal dimension, a method originally developed for shape analysis, to a set of coordinates in 3D-space that represents the texture under analysis in a signature able to characterize efficiently different texture classes in terms of complexity. An experiment using images from the Brodatz album illustrates the method performance.; CNPq (306628/2007-4, 484474/2007-3)

Implementação e comparação de métodos de estimativa da dimensão fractal e sua aplicação à análise e processamento de imagens; Implementation and comparison of fractal dimension estimative methods and their use on analysis and image processing.

Backes, Andre Ricardo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/03/2006 PT
Relevância na Pesquisa
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A Dimensão Fractal pode ser utilizada para medir algumas características ligadas a complexidade da imagem, permitindo seu uso em análise de formas e texturas e reconhecimento de padrões. Neste trabalho é apresentado um estudo comparativo entre alguns dos principais métodos de estimativa da Dimensão Fractal. Foi realizada uma análise experimental e um estudo de casos para cada uma das técnicas, levando em consideração aspectos de implementação, precisão, variação de resultados segundo ajuste de parâmetros e tolerância a ruídos. Neste trabalho também foi desenvolvido um estudo sobre a Dimensão Fractal Multiescala, visando seu emprego como metodologia de assinatura de complexidade. Na literatura a técnica de multiescala é limitada ao método de Bouligand-Minkowski, sendo aqui ela estendida para outras metodologias de estimativa de Dimensão Fractal. Por meio de análise experimental as metodologias propostas foram comparadas e os resultados discutidos, enfatizando as vantagens e desvantagens destas técnicas.; Fractal Dimension can be used to measure some characteristics related to the image complexity, allowing its use on shape and texture analysis and pattern recognition. In this work is presented a comparative study among some of the most important methods to estimate Fractal Dimension. It was performed a experimental analysis and a case study for each one of the techniques...

Estimação da dimensão fractal de imagens de SPM; Estimating fractal dimension of SPM images

Pinto, Silvia Cristina Dias
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/10/2001 PT
Relevância na Pesquisa
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Este trabalho utiliza o método da Salsicha de Minkowski usando dilatação exata para estimação da dimensão fractal em imagens de superfícies de SPM (Microscópio de Varredura por Ponta de prova). Descrevemos uma rotina que permite o cálculo de uma série de dilatações da superfície original em relação a vários raios. O método de dilatação exata considera todas as possíveis salsichas envolvendo um pré-cálculo das distâncias (raios) numa grade ortogonal, que são armazenadas em uma lista junto com suas coordenadas relativas. A partir daí, realizamos um estudo multiescala sobre a curva log-log do volume dilatado em termos dos raios a fim de obter o valor da dimensão fractal para a superfície analisada. Para isso aplicamos dois métodos numéricos exatos, os quais são baseados em: diferenciação da curva por diferenças finitas e, por diferenciação usando uma propriedade da Transformada de Fourier. Os valores da derivada do sinal obtido permitem caracterizar a evolução da dimensão fractal da superfície ao longo de várias escalas espaciais, isto é, a dimensão fractal apresenta um comportamento dinâmico em termos de escalas espaciais definida pelos raios.; This work uses the Minkowski Sausage method using exact dilation for estimating fractal dimension to SPM (Scanning Probe Microscopy) surface images. We describe a routine that permits the calculation of a series of dilations of the original surface...

Análise de dados funcionais aplicada à geração de descritores de assinaturas de dimensão fractal multiescala; Functional Data Analysis Applied to Descriptors Generation of Multiscale Fractal Dimension Signatures.

Florindo, João Batista
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/01/2009 PT
Relevância na Pesquisa
68.03829%
Esta dissertação faz um estudo da aplicação da técnica estatística denominada Análise de Dados Funcionais (ADF) à geração de descritores usados em reconhecimento de padrões, mais especificamente, no reconhecimento de objetos de interesse em imagens. Estes objetos podem ser representados por vetores de características, também chamados de assinaturas, obtidos por uma técnica chamada de Dimensão Fractal Multiescala (DFM). Ocorre que estes vetores apresentam alta dimensionalidade (número de elementos), fazendo-se assim necessário o uso de uma abordagem que reduza este número de valores, sem que haja uma grande perda da informação transmitida pela assinatura. Neste contexto, diversas técnicas de extração de um reduzido conjunto de descritores da assinatura são apresentadas pela literatura. Entre estas, as mais populares são Fourier e \emph, ambas relativamente simples de se apresentar e com resultados satisfatórios. A proposta aqui apresentada é de se utilizar ADF em combinação com DFM na geração de descritores de padrões. Os resultados obtidos com o uso desta abordagem na geração de descritores demostraram que a técnica possibilita bons resultados, mesmo em situações em que não é possível o uso de muitos descritores. Os experimentos demostraram que ADF apresenta um bom potencial para aplicação neste tipo de problema...

Atratores para sistemas dinâmicos discretos: dimensão fractal e continuidade da estrutura por perturbações; Discrete dynamical systems attractors: fractal dimension and continuity of the structure under perturbations

Bortolan, Matheus Cheque
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/05/2009 PT
Relevância na Pesquisa
68.159673%
Neste trabalho, estudamos uma generalização dos semigrupos gradientes, os semigrupos gradiente-like, algumas de suas propriedades e a sua invariância por pequenas perturbações; isto é, pequenas perturbações de sistemas gradiente-like continuam sendo gradiente-like. Como consequência da caracterização dos atratores para este tipo de sistema, estudamos a atração exponencial de atratores. Por fim, estudamos o concetio de dimensão de Hausdorff e dimensão fractal de atratores e apresentamos alguns resultados sobre este assunto, e estudamos a construção de uma nova classe de atratores, os atratores exponenciais fractais; In this work, we study a generalization of gradient discrete semigroups, the gradientlike semigroups, some of its properties and its invariance under small perturbations; that is, small perturbations of gradient-like semigroups are still gradient-like semigroups. As a consequence of the characterization of the attractors for this sort of semigroups, we study the exponential attraction of attractors. Finally, we study some concepts of Hausdorff dimension and fractal dimension and present some results about this subject, and we studied the construction of a new class of attractors, the exponential fractal attractors

Structure of attractors and estimates of their fractal dimension; Estrutura de atratores e estimativas de suas dimensões fractais

Bortolan, Matheus Cheque
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/03/2013 EN
Relevância na Pesquisa
68.43933%
This work is dedicated to the study of the structure of attractors of dynamical systems with the objective of estimating their fractal dimension. First we study the case of exponential global attractors of some generalized gradient-like semigroups in a general Banach space, and estimate their fractal dimension in terms of themaximumof the dimension of the local unstablemanifolds of the isolated invariant sets, Lipschitz properties of the semigroup and rate of exponential attraction. We also generalize this result for some special evolution processes, introducing a concept of Morse decomposition with pullback attractivity. Under suitable assumptions, if (A, 'A POT. ') is an attractor-repeller pair for the attractor A of a semigroup {T (t ) : t 0}, then the fractal dimension of A can be estimated in terms of the fractal dimension of the local unstable manifold of 'A POT. ', the fractal dimension of A, the Lipschitz properties of the semigroup and the rate of the exponential attraction. The ingredients of the proof are the notion of generalized gradient-like semigroups and their regular attractors, Morse decomposition and a fine analysis of the structure of the attractors. Also, making use of the skew product semiflow and its Morse decomposition...

Descritores fractais aplicados à análise de texturas; Fractal descriptors applied to texture analysis

Florindo, João Batista
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/02/2013 PT
Relevância na Pesquisa
58.463438%
Este projeto descreve o desenvolvimento, estudo e aplicação de descritores fractais em análise de texturas. Nos últimos anos, a literatura vem apresentando a geometria fractal como uma ferramenta poderosa para a análise de imagens, com aplicações em variados campos da ciência. A maior parte destes trabalhos faz uso direto da dimensão fractal como um descritor do objeto representado na imagem. Entretanto, em função da complexidade de muitos problemas nesta área, algumas soluções foram propostas para melhorar essa análise, usando não apenas o valor da dimensão fractal, mas um conjunto de medidas que pudessem ser extraídas pela geometria fractal e que descrevessem as texturas com maior riqueza e precisão. Entre essas técnicas, destacam-se a metodologia de multifractais, de dimensão fractal multiescala e, mais recentemente, os descritores fractais. Esta última técnica tem se mostrado eficiente na solução de problemas relacionados à discriminação de imagens de texturas e formas, uma vez que os descritores gerados fornecem uma representação direta do padrão de complexidade (distribuição dos detalhes ao longo das escalas de observação) da imagem. Assim, essa solução permite que se tenha uma descrição rica da imagem estudada pela análise da distribuição espacial e/ou espectral dos pixels e intensidade de cores/tons de cinza...

Flocs vs granules : differentiation by fractal dimension

Bellouti, M.; Alves, M. M.; Novais, J. M.; Mota, M.
Fonte: Elsevier Science Publicador: Elsevier Science
Tipo: Artigo de Revista Científica
Publicado em //1997 ENG
Relevância na Pesquisa
68.223486%
High rate anaerobic wastewater treatment systems usually give rise to biomass structured in different types of aggregates, depending on prevalent environmental conditions. Although highly dependent on wastewater characteristics, granules are generally formed and found in UASB reactors, whereas flocs are mainly found in fixed bed reactors. Different structures usually have different shapes and surface roughness. The aim of this work is to provide a contribution to the differentiation of those kinds of aggregates. A numerical parameter, the fractal dimension, was used to quantify the surface roughness. The fractal dimension, of two families of particles, was measured by two methods: (i) a box counting method; (ii) a method based on an area-size relationship. In both cases, the differences were highly statistically significant. Using the box counting method, for each of the 54 particles of each family, the average fractal dimension was 1.90 ± 0.02 for flocs and 1.95 ± 0.01 for granules (±99% confidence interval). The log-log plot of area vs longest size was linear and the calculated fractal dimensions from this plot were 1.84 ± 0.13 and 2.14 ± 0.08 (±99% confidence interval) for flocs and granules, respectively. Fractal dimension was proven to be a suitable parameter to quantify and differentiate surface roughness of different microbial aggregates present in high rate anaerobic digesters.; União Europeia. Comissão - Human Capital and Mobility programme.

Can the fractal dimension be applied for the early diagnosis of non-proliferative diabetic retinopathy?

Kunicki,A.C.B.; Oliveira,A.J.; Mendonça,M.B.M.; Barbosa,C.T.F.; Nogueira,R.A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2009 EN
Relevância na Pesquisa
68.259395%
The fractal dimension has been employed as a useful parameter in the diagnosis of retinal disease. Avakian et al. (Curr Eye Res 2002; 24: 274-280), comparing the vascular pattern of normal patients with mild to moderate non-proliferative diabetic retinopathy (NPDR), found a significant difference between them only in the macular region. This significant difference in the box-counting fractal dimension of the macular region between normal and mild NPDR patients has been proposed as a method of precocious diagnosis of NPDR. The aim of the present study was to determine if fractal dimensions can really be used as a parameter for the early diagnosis of NPDR. Box-counting and information fractal dimensions were used to parameterize the vascular pattern of the human retina. The two methods were applied to the whole retina and to nine anatomical regions of the retina in 5 individuals with mild NPDR and in 28 diabetic but opthalmically normal individuals (controls), with age between 31 and 86 years. All images of retina were obtained from the Digital Retinal Images for Vessel Extraction (DRIVE) database. The results showed that the fractal dimension parameter was not sensitive enough to be of use for an early diagnosis of NPDR.

Fractal coding based on image local fractal dimension

Conci,Aura; Aquino,Felipe R.
Fonte: Sociedade Brasileira de Matemática Aplicada e Computacional Publicador: Sociedade Brasileira de Matemática Aplicada e Computacional
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2005 EN
Relevância na Pesquisa
68.18854%
Fractal codification of images is based on self-similar and self-affine sets. The codification process consists of construction of an operator which will represent the image to be encoded. If a complicated picture can be represented by an operator then it will be transmitted or stored very efficiently. Clearly, this has many applications on data compression. The great disadvantage of the automatic form of fractal compression is its encoding time. Most of the time spent in construction of such operator is due on finding the best match between parts of the image to be encoded. However, since the conception of automatic fractal image compression, researches on improvement of the compression time are widespread. This work aims to provide a new idea for decrease the encoding time: a classification of image parts based on their local fractal dimension. The idea is implemented on two steps. First, a preprocessing analysis of the image identify the complexity of each image block computing its dimension. Then, only parts within the same range of complexity are used for testing the better self-affine pairs, reducing the compression time. The performance of this proposition, is compared with others fractal image compression methods. The points considered are image fidelity...

Hydrophobicity classification of polymeric materials based on fractal dimension

Thomazini,Daniel; Gelfuso,Maria Virginia; Altafim,Ruy Alberto Corrêa
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2008 EN
Relevância na Pesquisa
67.93317%
This study proposes a new method to obtain hydrophobicity classification (HC) in high voltage polymer insulators. In the method mentioned, the HC was analyzed by fractal dimension (fd) and its processing time was evaluated having as a goal the application in mobile devices. Texture images were created from spraying solutions produced of mixtures of isopropyl alcohol and distilled water in proportions, which ranged from 0 to 100% volume of alcohol (%AIA). Based on these solutions, the contact angles of the drops were measured and the textures were used as patterns for fractal dimension calculations.

The use of fractal dimension for texture-based enhancement of aeromagnetic data.

Dhu, Trevor
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
Relevância na Pesquisa
67.723657%
This thesis investigates the potential of fractal dimension (FD) as a tool for enhancing airborne magnetic data. More specifically, this thesis investigates the potential of FD-based texture transform images as tools for aiding in the interpretation of airborne magnetic data. A series of different methods of estimating FD are investigated, specifically: • geometric methods (1D and 2D variation methods and 1D line divider method); • stochastic methods (1D and 2D Hurst methods and 1D and 2D semi-variogram methods), and; • spectral methods (1D and 2D wavelet methods and 1D and 2D Gabor methods). All of these methods are able to differentiate between varying theoretical FD in synthetic profiles. Moreover, these methods are able to differentiate between theoretical FDs when applied to entire profiles or in a moving window along the profile. Generally, the accuracy of the estimated FD improves when window size is increased. Similarly, the standard deviation of estimated FD decreases as window size increases. This result implied that the use of moving window FD estimates will require a trade off between the quality of the FD estimates and the need to use small windows to allow better spatial resolution. Application of the FD estimation methods to synthetic datasets containing simple ramps...

Fractal dimension and architecture of trabecular bone

Fazzalari, N.; Parkinson, I.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Artigo de Revista Científica
Publicado em //1996 EN
Relevância na Pesquisa
68.36834%
The fractal dimension of trabecular bone was determined for biopsies from the proximal femur of 25 subjects undergoing hip arthroplasty. The average age was 67·7 years. A binary profile of the trabecular bone in the biopsy was obtained from a digitized image. A program written for the Quantimet 520 performed the fractal analysis. The fractal dimension was calculated for each specimen, using boxes whose sides ranged from 65 to 1000 μm in length. The mean fractal dimension for the 25 subjects was 1·195+0·064 and shows that in Euclidean terms the surface extent of trabecular bone is indeterminate. The Quantimet 520 was also used to perform bone histomorphometric measurements. These were bone volume/total volume (BV/TV) (per cent)=11·05+4·38, bone surface/total volume (BS/TV) (mm2/mm3)=1·90+0·51, trabecular thickness (Tb.Th) (mm)=0·12+0·03, trabecular spacing (Tb.Sp) (mm)=1·03+0·36, and trabecular number (Tb.N) (number/mm)=0·95+0·25. Pearsons' correlation coefficients showed a statistically significant relationship between the fractal dimension and all the histomorphometric parameters, with BV/TV (r=0·85,P0·0001), BS/TV (r=0·74,P0·0001), Tb.Th (r=0·50,P0·02), Tb.Sp (r=−0·81,P0·0001), and Tb.N (r=0·76,P0·0001). This method for calculating fractal dimension shows that trabecular bone exhibits fractal properties over a defined box size...

Fractal dimension and Shannon's entropy analyses of the architectural complexity caused by the inflammatory reactions induced by highly crystalline polyvinyl alcohol) microspheres implanted in subcutaneous tissues of the Wistar rats

Silva, Danilo A.; Basso, Glaucia G.; Semenzim, Vinícius L.; Godoy, Moacir F.; Taboga, Sebastião R.; Andrade, Alexandre L.; Luvizotto, Maria Cecília Rui; Braile, Domingo M.; Nery, Jose G.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 326-339
ENG
Relevância na Pesquisa
67.847695%
The results of the histopathological analyses after the implantation of highly crystalline PVA microspheres in subcutaneous tissues of Wistar rats are here in reported. Three different groups of PVA microparticles were systematically studied: highly crystalline, amorphous, and commercial ones. In addition to these experiments, complementary analyses of architectural complexity were performed using fractal dimension (FD), and Shannon's entropy (SE) concepts. The highly crystalline microspheres induced inflammatory reactions similar to the ones observed for the commercial ones, while the inflammatory reactions caused by the amorphous ones were less intense. Statistical analyses of the subcutaneous tissues of Wistar rats implanted with the highly crystalline microspheres resulted in FD and SE values significantly higher than the statistical parameters observed for the amorphous ones. The FD and SE parameters obtained for the subcutaneous tissues of Wistar rats implanted with crystalline and commercial microparticles were statistically similar. Briefly, the results indicated that the new highly crystalline microspheres had biocompatible behavior comparable to the commercial ones. In addition, statistical tools such as FD and SE analyses when combined with histopathological analyses can be useful tools to investigate the architectural complexity tissues caused by complex inflammatory reactions. © 2012 WILEY PERIODICALS...

Análise direcional do crescimento urbano da região metropolitana de São Paulo entre 1905 e 2001, utilizando-se a dimensão fractal; Análisis direccional del crecimiento urbano de la región metropolitana de são paulo entre 1905 y 2001, utilizando la dimensión fractal; Directional analysis of são paulo metropolitan region urban growing (1905-2001), using fractal dimension

Marques, Mara Lúcia
Fonte: Universidade de São Paulo. Faculdade de Arquitetura e Urbanismo Publicador: Universidade de São Paulo. Faculdade de Arquitetura e Urbanismo
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/06/2008 POR
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Este estudo teve como propósito principal compreender o processo de expansão do aglomerado urbano da região metropolitana de São Paulo no período 1905 a 2001. Para tanto, foi empregada uma metodologia baseada em análise fractal, para a identificação dos fatores que influenciaram a forma urbana ao longo do tempo e determinaram a distribuição espacial das estruturas e da densidade de ocupação de áreas urbanizadas. Este estudo foi realizado a partir de mapas temáticos e imagens orbitais relativos ao período 1905-2001. Partindo-se da associação dos métodos de círculos concêntricos e contagem de células, foi realizada a estimativa da dimensão fractal por densidade de preenchimento (Dd). Os resultados mostraram que o aglomerado urbano apresentou, no período analisado, valores médios Dd (1,755) ou tendência de adensamento heterogêneo por área construída, entre os círculos centrais e periféricos do aglomerado urbano. A análise fractal multidirecional de crescimento foi realizada em oito setores radiais de expansão urbana, cujos valores médios do parâmetro Dd para cada setor, no período 1905-2001, são abaixo mencionados: (I) Cantareira =1,829; (II) Zona Leste=1,898; (III) Mauá=1,848; (IV) Ipiranga=1,852; (V) Billings=1...