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Wyszukujesz frazę "Fractal" wg kryterium: Temat


Tytuł:
On the relationship between fractal geometry of space and time in which a system of interacting cells exists and dynamics of gene expression.
Autorzy:
Waliszewski, Przemysław
Molski, Marcin
Konarski, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/1044188.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
complexity
neoplasia
fractal
differentiation
fractal dimension
Opis:
We report that both space and time, in which a system of interacting cells exists, possess fractal structure. Each single cell of the system can restore the hierarchical organization and dynamic features of the entire tumor. There is a relationship between dynamics of gene expression and connectivity (i.e., interconnectedness which denotes the existence of complex, dynamic relationships in a population of cells leading to the emergence of global features in the system that would never appear in a single cell existing out of the system). Fractal structure emerges owing to non-bijectivity of dynamic cellular network of genes and their regulatory elements. It disappears during tumor progression. This latter state is characterized by damped dynamics of gene expression, loss of connectivity, loss of collectivity (i.e., capability of the interconnected cells to interact in a common mode), and metastatic phenotype. Fractal structure of both space and time is necessary for a cellular system to self-organize. Our findings indicate that results of molecular studies on gene expression should be interpreted in terms of space-time geometry of the cellular system. In particular, the dynamics of gene expression in cancer cells existing in a malignant tumor is not identical with the dynamics of gene expression in the same cells cultured in the monolayer system.
Źródło:
Acta Biochimica Polonica; 2001, 48, 1; 209-220
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ubiquitiform in applied mechanics
Autorzy:
Ou, Z.-C.
Li, G.-Y.
Duan, Z.-P.
Huang, F-L.
Powiązania:
https://bibliotekanauki.pl/articles/279395.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ubiquitiform
fractal
Hausdorff dimension
Opis:
We demonstrate that a physical object in nature should not be described as a fractal, despite an ideal mathematical object, rather a ubiquitiform (a terminology coined here for a finite order self-similar or self-affine structure). It is shown mathematically that a ubiquitiform must be of integral dimension, and that the Hausdorff dimension of the initial element of a fractal changes abruptly at the point at infinity, which results in divergence of the integral dimensional measure of the fractal and makes the fractal approximation to a ubiquitiform unreasonable. Therefore, instead of the existing fractal theory in applied mechanics, a new type of ubiquitiformal one is needed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 1; 37-46
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractal analysis of sandstone pore space geometry
Autorzy:
Figiel, M.
Lewandowska-Śmierzchalska, J.
Powiązania:
https://bibliotekanauki.pl/articles/298840.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
pore space
fractal structure
fractal dimension
lacunarity
thin-section
computer image analysis
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.
Źródło:
AGH Drilling, Oil, Gas; 2018, 35, 2; 377-389
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seismo Magnetic Moment Fractal Dimension for Characterizing Shajara Reservoirs of the Permo-Carboniferous Shajara Formation, Saudi Arabia
Autorzy:
Alkhidir, Khalid Elyas Mohamed Elameen
Powiązania:
https://bibliotekanauki.pl/articles/1030683.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Capillary pressure fractal dimension
Seismo magnetic moment fractal dimension
Shajara Formation
Shajara Reservoirs
Opis:
The quality and assessment of a reservoir can be documented in details by the application of seismo magnetic moment. This research aims to calculate fractal dimension from the relationship among seismo magnetic moment, maximum seismo magnetic moment and wetting phase saturation and to approve it by the fractal dimension derived from the relationship among capillary pressure and wetting phase saturation. Two equations for calculating the fractal dimensions have been employed. The first one describes the functional relationship between wetting phase saturation, seismo magnetic moment, maximum seismo magnetic moment and fractal dimension. The second equation implies to the wetting phase saturation as a function of capillary pressure and the fractal dimension. Two procedures for obtaining the fractal dimension have been utilized. The first procedure was done by plotting the logarithm of the ratio between seismo magnetic moment and maximum seismo magnetic moment versus logarithm wetting phase saturation. The slope of the first procedure = 3- Df (fractal dimension). The second procedure for obtaining the fractal dimension was determined by plotting the logarithm of capillary pressure versus the logarithm of wetting phase saturation. The slope of the second procedure = Df -3. On the basis of the obtained results of the fabricated stratigraphic column and the attained values of the fractal dimension, the sandstones of the Shajara reservoirs of the Shajara Formation were divided here into three units.
Źródło:
World Scientific News; 2020, 139, 2; 186-200
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractal Format for Bitmap Images
Autorzy:
Siwocha, A.
Cader, A.
Kolibabka, M.
Krupski, M.
Powiązania:
https://bibliotekanauki.pl/articles/108680.pdf
Data publikacji:
2012
Wydawca:
Społeczna Akademia Nauk w Łodzi
Tematy:
fractal interpolation method
image recording formats
fractal dimension
multifractal analysis
non-local characteristics
Opis:
The conception of proposed recording format is the example of the theoretical and practical application of the FBS method, which was precisely described in thesis [18,19,20]. The foundation of the presented recording format is the use of a new method of fractal basis splines (FB-splines), which allows the reconstruction of complex geometric structures with the properties of fractals. Fractral basis splines method is based on the use of non-local characteristics to describe the interpolation nodes. With that the one-parameter family of fractal curves is used as the basic approximating elements.
Źródło:
Journal of Applied Computer Science Methods; 2012, 4 No. 2; 41-54
1689-9636
Pojawia się w:
Journal of Applied Computer Science Methods
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Psychoacoustic Annoyance on EEG Signals of Tractor Drivers
Autorzy:
Lashgari, Majid
Arab, Mohammad Reza
Nadjafi, Mohsen
Rafiee, Mojtaba
Powiązania:
https://bibliotekanauki.pl/articles/31339953.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
EEG
Higuchi
fractal
tractor
sound.
Opis:
The purpose of this study was to evaluate the psychoacoustic annoyance (PA) that the tractor drivers are exposed to, and investigate its effects on their brain signals during their work activities. To this aim, the sound of a garden tractor was recorded. Each driver’s electroencephalogram (EEG) was then recorded at five different engine speeds. The Higuchi method was used to calculate the fractal dimension of the brain signals. To evaluate the amount of acoustic annoyance that the tractor drivers were exposed to, a psychoacoustic annoyance (PA) model was used. The results showed that as the engine speed increased, the values of PA increased as well. The results also indicated that an increase in the Higuchi’s fractal dimension (HFD) of alpha and beta bands was due to the increase of the engine speed. The regression results also revealed that there was a high correlation between the HFD of fast wave activities and PA, in that, the coefficients of determination were 0.92 and 0.91 for alpha and beta bands, respectively. Hence, a good correlation between the EEG signals and PA can be used to develop a mathematical model which quantifies the human brain response to the external stimuli.
Źródło:
Archives of Acoustics; 2022, 47, 4; 469-477
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A stereological ubiquitiformal softening model for concrete
Autorzy:
Ou, Zhuo-Cheng
Li, Guan-Ying
Duan, Zhuo-Ping
Huang, Feng-Lei
Powiązania:
https://bibliotekanauki.pl/articles/281602.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ubiquitiform
fractal
concrete
softening curve
Opis:
A stereological ubiquitiformal softening model for describing the softening behavior of concrete under quasi-static uniaxial tensile loadings is presented in this paper. In the model, both the damage evaluation process of fracture cross-sections and their distribution along the specimens axis are taken into account. The numerical results of a certain kind of full grade concrete made of crushed coarse aggregate are found to be in good agreement with the experimental data. Moreover, an experiental relation between the lower bound to the scale invariance of concrete and its tensile strength is also obtained by data fitting of the experimental data, which provides an effective approach to determine the lower bound to scale invariance of concrete.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 1; 27-35
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The mind and brain in time: implications for modern neuropsychology
Autorzy:
Brown, Jason W
Powiązania:
https://bibliotekanauki.pl/articles/2137697.pdf
Data publikacji:
2018-03-28
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
organism
fractal theory
human mentality
Opis:
In this paper, I wish to describe the categorical nature of the mind/brain state from its origins in drive to the refinements of human cognition. Categories are concepts with a broader scope. The virtual quality of category members corresponds to the relation of whole and part. A successive individuation of categories is the foundational operation of the mind/brain state. There is a similarity to fractal theory and the mereology of wholes and parts, though categories are not sums or containers, members are virtual and the whole/part specification is qualitative, unlike the self-similar replications of fractal theory. The discussion takes up the problem of causal transmission between the mind and brain and within and across mental states, concluding that an assimilation model has more explanatory power than a strictly causal one, in keeping with the distinction of potential/actual from cause/effect. The idea that mind-brain interaction is causal introduces the possibility of subjectivity independent of a material substrate. This leads to speculation on a world soul animating the brain as part of nature, and conversely, the effort to extract all vestiges of spirit to leave a purely material organism and universe. There is no bifurcation of the mental and physical; rather a graded series of stages with properties of material and subjective entities that eventuate in human mentality. This conforms to a neutral monism. Duration is inherent in nature and evolves in company with organisms of increasing complexity.
Źródło:
Acta Neuropsychologica; 2018, 16(1); 99-116
1730-7503
2084-4298
Pojawia się w:
Acta Neuropsychologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ubiquitiformal fracture energy
Autorzy:
Ou, Z.-C.
Yang, M.
Li, G.-Y.
Duan, Z.-P.
Huang, F-L.
Powiązania:
https://bibliotekanauki.pl/articles/280189.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fractal
ubiquitiform
fracture energy
size effect
Opis:
The ubiquitiformal fracture energy is proposed in the paper and its explicit expression is obtained. Moreover, the numerical results for concrete are found to be in good agreement with those for the critical strain energy release rate. The discrepancy between the numerical results of the traditional fracture energy and the critical strain energy release rate can be explained reasonably, which implies that the ubiquitiformal fracture energy should be taken as an available fracture parameter of materials. Finally, it is numerically found for some concrete that there is not size effect for the ubiquitiformal fracture energy.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 1101-1108
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft Computing and Fractal Theory for Intelligent Manufacturing
Autorzy:
Castillo, O.
Melin, P.
Powiązania:
https://bibliotekanauki.pl/articles/384470.pdf
Data publikacji:
2007
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
fuzzy logic
fractal theory
neural network
Opis:
We describe in this paper the combination of soft computing techniques and fractal theory for achieving intelligent manufacturing. Soft computing techniques can be used to develop hybrid intelligent systems. Fractal theory can be used to analyze the geometrical complexity of natural and artificial objects. The careful combination of soft computing and fractal theory can provide us with a good mix of intelligent techniques and fractal mathematical tools, which can help in achieving automation of manufacturing processes. We consider in this paper several manufacturing and automation problems that are efficiently solved with the proposed approach.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2007, 1, 1; 41-47
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of fractal compression of 3d images using a genetic algorithm
Autorzy:
Khanmirza, Z
Ramezani, F
Motameni, H
Powiązania:
https://bibliotekanauki.pl/articles/102068.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
stereo system
fractal compression
genetic algorithm
Opis:
3D image technologies are widely recognized as the next generation of visual presentation considering the achievement of more natural experiences. To produce such images, two cameras are placed in a bit different position. When we seek to compress such images, we need a procedure to compress two images synchronously. In this paper, a procedure is presented for a suitable compression based on fractal compression which shows that we obtain high compression rate with an appropriate image quality; however, since the proposed procedure has a low search speed, we used genetic algorithm to remove the case.
Źródło:
Advances in Science and Technology. Research Journal; 2015, 9, 26; 124-128
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of CEC using fractal parameters by artificial neural networks
Autorzy:
Bayat, H.
Davatgar, N.
Jalali, M.
Powiązania:
https://bibliotekanauki.pl/articles/25675.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
cation exchange capacity
prediction
fractal structure
fractal theory
particle size distribution
artificial neural network
pedotransfer function
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.
Źródło:
International Agrophysics; 2014, 28, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invariant measures whose supports possess the strong open set property
Autorzy:
Goodman, G. S.
Powiązania:
https://bibliotekanauki.pl/articles/1397779.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
core
fractal
fractal measure
invariant measure
scaling function
scaling operator
strong open set condition
zero-one law
Opis:
Let X be a complete metric space, and S the union of a finite number of strict contractions on it. If P is a probability distribution on the maps, and K is the fractal determined by S, there is a unique Borel probability measure $ \mu_P$ on X which is invariant under the associated Markov operator, and its support is K. The Open Set Condition (OSC) requires that a non-empty, subinvariant, bounded open set $ V \subset X$ exists whose images under the maps are disjoint; it is strong if $ K \cup V \ne 0 $.In that case, the core of $ V, \check{V} = \bigcap_{n=0}^\infty $ is non-empty and dense in K. Moreover, when X is separable, $\check{V}$ has full $\mu_p$-measure for every P. We show that the strong condition holds for V satisfying the OSC iff $\mu_P(\delta V) = 0 $, and we prove a zero-one law for it. We characterize the complement of V relative to K, and we establish that the values taken by invariant measures on cylinder sets defined by K, or by the closure of V, form multiplicative cascades.
Źródło:
Opuscula Mathematica; 2008, 28, 4; 471-480
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł

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