Temat: fractal structure - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Geometry of the quantum universe
Autorzy:: Jurkiewicz, Jerzy
Gőrlich, Andrzej
Ambjørn, J.
Loll, R.
Opis:: A quantum universe with the global shape of a (Euclidean) de Sitter spacetime appears as dynamically generated background geometry in the causal dynamical triangulation (CDT) regularisation of quantum gravity. We investigate the micro- and macro-geometry of this universe, using geodesic shell decompositions of spacetime. More specifically, we focus on evidence of fractality and global anisotropy, and on how they depend on the bare coupling constants of the theory.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 2.

Tytuł:: Fractal analysis of sandstone pore space geometry
Autorzy:: Figiel, M.
Lewandowska-Śmierzchalska, J.
Tematy:: pore space
fractal structure
fractal dimension
lacunarity
thin-section
computer image analysis; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/298840.pdf Link otwiera się w nowym oknie
Opis:: Fractal analysis is currently one of the fastest evolving branches of science. Numerous objects in nature exhibit a fractal structure. Additionally, the vast majority of rocks – especially reservoir rocks – take the form of a fractal. Computer image analysis based on thin-section images has been used for examining the fractal structure of pore spaces, directly applying the definition of the fractal box-counting dimension. For the examined sandstone sample, thin sections were made and photographed, and the corresponding values of the fractal dimension and lacunarity were calculated. Each of the photos was encompassed by porosity that was calculated based on the number of pixels. Furthermore, the volatility of the fractal dimension and lacunarity were studied as well as their relationships with the porosity. A correlation analysis between the fractal parameters and the porosity was carried out. The results were compared with the data obtained from a mercury porosimetry of the same sample of sandstone.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Scale cutoffs and the limits of fractal soil structure
Autorzy:: Millan, H.
Tematy:: organic matter
bulk density
soil structure
fractal structure
porosity
soil system; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/26376.pdf Link otwiera się w nowym oknie
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Prediction of CEC using fractal parameters by artificial neural networks
Autorzy:: Bayat, H.
Davatgar, N.
Jalali, M.
Tematy:: cation exchange capacity
prediction
fractal structure
fractal theory
particle size distribution
artificial neural network
pedotransfer function; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/25675.pdf Link otwiera się w nowym oknie
Opis:: The prediction of cation exchange capacity from readily available soil properties remains a challenge. In this study, firstly, we extended the entire particle size distribution curve from limited soil texture data and, at the second step, calculated the fractal parameters from the particle size distribution curve. Three pedotransfer functions were developed based on soil properties, parameters of particle size distribution curve model and fractal parameters of particle size distribution curve fractal model using the artificial neural networks technique. 1 662 soil samples were collected and separated into eight groups. Particle size distribution curve model parameters were estimated from limited soil texture data by the Skaggs method and fractal parameters were calculated by Bird model. Using particle size distribution curve model parameters and fractal parameters in the pedotransfer functions resulted in improvements of cation exchange capacity predictions. The pedotransfer functions that used fractal parameters as predictors performed better than the those which used particle size distribution curve model parameters. This can be related to the non-linear relationship between cation exchange capacity and fractal parameters. Partitioning the soil samples significantly increased the accuracy and reliability of the pedotransfer functions. Substantial improvement was achieved by utilising fractal parameters in the clusters.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Delivery-flow routing and scheduling subject to constraints imposed by vehicle flows in fractal-like networks
Autorzy:: Bocewicz, G.
Banaszak, Z.
Nielsen, I.
Tematy:: transport network
fractal structure
declarative modeling
multimodal processes
delivery flow
vehicles flow; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/229533.pdf Link otwiera się w nowym oknie
Opis:: The problems of designing supply networks and traffic flow routing and scheduling are the subject of intensive research. The problems encompass the management of the supply of a variety of goods using multi-modal transportation. This research also takes into account the various constraints related to route topology, the parameters of the available fleet of vehicles, order values, delivery due dates, etc. Assuming that the structure of a supply network, constrained by a transport network topology that determines its behavior, we develop a declarative model which would enable the analysis of the relationships between the structure of a supply network and its potential behavior resulting in a set of desired delivery-flows. The problem in question can be reduced to determining sufficient conditions that ensure smooth flow in a transport network with a fractal structure. The proposed approach, which assumes a recursive, fractal network structure, enables the assessment of alternative delivery routes and associated schedules in polynomial time. An illustrative example showing the quantitative and qualitative relationships between the morphological characteristics of the investigated supply networks and the functional parameters of the assumed delivery-flows is provided.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Multifractal approach in pattern recognition of an announcer’s voice
Multifraktalnyjj podkhod v zadachakh raspoznavanija golosa diktora
Autorzy:: Solovyov, V.
Byelozorova, Y.
Tematy:: experimental research
multi-fractal structure
vowel phoneme
pattern recognition
radio announcer
voice
speech
recognition system; Pokaż więcej
Wydawca:: Komisja Motoryzacji i Energetyki Rolnictwa
Powiązania:: https://bibliotekanauki.pl/articles/792602.pdf Link otwiera się w nowym oknie
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Structure fractals and para-quaternionic geometry
Autorzy:: Ławrynowicz, Julian
Vaccaro, Massimo
Tematy:: Fractal
quaternion
para-quaternion
Clifford structure
para-quaternionic structure
bilinear form
quadratic form; Pokaż więcej
Wydawca:: Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Powiązania:: https://bibliotekanauki.pl/articles/747163.pdf Link otwiera się w nowym oknie
Opis:: It is well known that starting with real structure, the Cayley-Dickson process gives complex, quaternionic, and octonionic (Cayley) structures related to the Adolf Hurwitz composition formula for dimensions \(p = 2, 4\) and \(8\), respectively, but the procedure fails for \(p = 16\) in the sense that the composition formula involves no more a triple of quadratic forms of the same dimension; the other two dimensions are \(n = 2^7\). Instead, Ławrynowicz and Suzuki (2001) have considered graded fractal bundles of the flower type related to complex and Pauli structures and, in relation to the iteration process \(p \to p + 2 \to p + 4 \to ...\), they have constructed \(2^4\)-dimensional “bipetals” for \(p = 9\) and \(2^7\)-dimensional “bisepals” for \(p = 13\). The objects constructed appear to have an interesting property of periodicity related to the gradating function on the fractal diagonal interpreted as the “pistil” and a family of pairs of segments parallel to the diagonal and equidistant from it, interpreted as the “stamens”. The first named author, M. Nowak-Kepczyk, and S. Marchiafava (2006, 2009a, b) gave an effective, explicit determination of the periods and expressed them in terms of complex and quaternionic structures, thus showing the quaternionic background of that periodicity. In contrast to earlier results, the fractal bundle flower structure, in particular petals, sepals, pistils, and stamens are not introduced ab initio; they are quoted a posteriori, when they are fully motivated. Physical concepts of dual and conjugate objects as well as of antiparticles led us to extend the periodicity theorem to structure fractals in para-quaternionic formulation, applying some results in this direction by the second named author. The paper is concluded by outlining some applications.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Compact coplanar-fed tree-shaped antenna
Autorzy:: Malinowska, Małgorzata
Kitliński, Marek
Tematy:: broadband antenna
fractal antenna
reflection coefficient,
defected ground structure
coplanar waveguide; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226372.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the concept of a fully planar tree-shaped antenna with quasi-fractal geometry. The shape of the proposed radiator is based on a multi-resonant structure. Developed planar tree has symmetrical branches with different length and is fed by a coplanar waveguide (CPW) with modified edge of the ground plane. The antenna of size 29 mm x25 mm has been designed on Taconic - RF-35 substrate (er = 3.5, tgde= 0.0018, h = 0.762 mm). The paper shows simulated and measured characteristics of return loss, as well as measured radiation patterns. The proposed antenna could be a good candidate for broadband applications (for instance: wideband imaging for medical application and weather monitoring radars in satellite communication etc.)
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Analiza komputerowa struktury nadźwiękowionych kłaczków osadów biologicznych
Computer analysis of the structure of sonicated biological sludge
Autorzy:: Fryźlewicz-Kozak, B.
Drabik, K.
Tematy:: osad czynny
analiza obrazu
wymiar fraktalny
struktura kłaczka
activated sludge
image analysis
fractal dimension
floc structure; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/2071317.pdf Link otwiera się w nowym oknie
Opis:: Analizowany materiał stanowił zdjęcia nadźwiękowionego osadu czynnego, pochodzące z oczyszczalni ścieków w Olkuszu. Do obróbki zdjęć użyto specjalistycznych oprogramowań: Fraclalyse - do analizy fraktalnej oraz programu ImageJ do analizy parametrów geometrycznych. W celu dokładniejszego zilustrowania zmian zachodzących w nadżwiękowionym osadzie, posłużono się dodatkowo parametrami kształtu.
Analyzed materials were images of sonicated activated sludge, from wastewater treatment plants in Olkusz. The image processing specialized software was: Fractalyse - for fractal analysis and ImageJ for the analysis of geometrical parameters. In order to illustrate more accurately the changes in sonicated sediment shape parameters were used.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: On a formula finding fractal dimension
Autorzy:: Kamilov, Kh.
Zaitov, A.
Tulaganov, A.
Tematy:: fractal dimension
cellular concrete
structure
mineral binder
porosity
density
wymiar fraktalny
beton komórkowy
struktura
spoiwo mineralne
porowatość
gęstość; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/1818513.pdf Link otwiera się w nowym oknie
Opis:: Purpose: The article is devoted to the determination of the fractal dimension of cellular concrete, in particular foam concrete, and the further clarification of the relationship between fractal dimension and porosity and average density of cellular concrete. Design/methodology/approach: In the theoretical description of disordered systems, the fundamentals of fractal theory are actively used, which allow obtaining statistical indicators of chaotic natural and artificially disordered systems, which include cellular concrete. The parameters of the pore structure are difficult to quantify by conventional methods because of the complexity and irregularity of the pore structure due to their random distribution. Findings: Formulas for calculating the fractal dimension and average density of highly porous material are calculated and proposed. The formula for calculating the average density takes into account the density of the material between the pore walls. Research limitations/implications: The calculation of the fractal dimension is one of the main factors affecting the practical application of the theory of fractals, a natural problem arises on a theoretical basis to justify these calculations. Practical implications: The formulas proposed in this work for calculating the fractal dimension and density of a highly porous structure improve research on methods for producing substances with a controlled fractal structure, which will help create materials with unusual mechanical properties, density, and porosity. Originality/value: The formula for calculating the fractal dimension obtained in the work improves the well-known Hausdorff-Bezikovich formula. On the other hand, it makes it possible to obtain a highly porous structure with a given density of the material under study.
Dostawca treści:: Biblioteka Nauki

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