Log in

Relevant bibliographies by topics / Diffusion Model / Journal articles

Journal articles on the topic 'Diffusion Model'

To see the other types of publications on this topic, follow the link: Diffusion Model.

Author: Grafiati

Published: 4 June 2021

Last updated: 25 May 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Diffusion Model.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Jaichuang, Atit, and Wirawan Chinviriyasit. "Numerical Modelling of Influenza Model with Diffusion." International Journal of Applied Physics and Mathematics 4, no. 1 (2014): 15–21. http://dx.doi.org/10.7763/ijapm.2014.v4.247.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Lin, C. C., C. L. Tsai, P. K. Wu, and H. J. Lee. "Advancing Diffusion Model for Diffusion in a Cube of Medium." Journal of Mechanics 28, no. 2 (May 8, 2012): 345–54. http://dx.doi.org/10.1017/jmech.2012.38.

Full text

Abstract:

AbstractA solution based on an advancing model for the content of diffusion material in a cube of medium is derived. The cube is assumed to be surrounded by diffusion material, and the diffusion material penetrates through all six surfaces and diffuses toward the center of the cube. The model accounts for the interaction between the diffusions in the three principle coordinates of the Cartesian coordinate system. For the first time, an exact solution of the content of the diffusion material based on the advancing model is derived in a clean form for a three-dimensional case.

APA, Harvard, Vancouver, ISO, and other styles

3

Doremus, R. H. "Diffusion of water in crystalline and glassy oxides: Diffusion–reaction model." Journal of Materials Research 14, no. 9 (September 1999): 3754–58. http://dx.doi.org/10.1557/jmr.1999.0508.

Full text

Abstract:

Diffusion of water in oxides is modeled as resulting from the solution and diffusion of molecular water in the oxide. This dissolved water can react and exchange with the oxide network to form immobile OH groups and different hydrogen and oxygen isotopes in the oxide. The model agrees with many experiments on water diffusion in oxides. The activation energy for diffusion of water in oxides correlates with the structural openness of the oxide, suggesting that molecular water is the diffusing species.

APA, Harvard, Vancouver, ISO, and other styles

4

Bengtsson, Lisa, Sander Tijm, Filip Váňa, and Gunilla Svensson. "Impact of Flow-Dependent Horizontal Diffusion on Resolved Convection in AROME." Journal of Applied Meteorology and Climatology 51, no. 1 (January 2012): 54–67. http://dx.doi.org/10.1175/jamc-d-11-032.1.

Full text

Abstract:

AbstractHorizontal diffusion in numerical weather prediction models is, in general, applied to reduce numerical noise at the smallest atmospheric scales. In convection-permitting models, with horizontal grid spacing on the order of 1–3 km, horizontal diffusion can improve the model skill of physical parameters such as convective precipitation. For instance, studies using the convection-permitting Applications of Research to Operations at Mesoscale model (AROME) have shown an improvement in forecasts of large precipitation amounts when horizontal diffusion is applied to falling hydrometeors. The nonphysical nature of such a procedure is undesirable, however. Within the current AROME, horizontal diffusion is imposed using linear spectral horizontal diffusion on dynamical model fields. This spectral diffusion is complemented by nonlinear, flow-dependent, horizontal diffusion applied on turbulent kinetic energy, cloud water, cloud ice, rain, snow, and graupel. In this study, nonlinear flow-dependent diffusion is applied to the dynamical model fields rather than diffusing the already predicted falling hydrometeors. In particular, the characteristics of deep convection are investigated. Results indicate that, for the same amount of diffusive damping, the maximum convective updrafts remain strong for both the current and proposed methods of horizontal diffusion. Diffusing the falling hydrometeors is necessary to see a reduction in rain intensity, but a more physically justified solution can be obtained by increasing the amount of damping on the smallest atmospheric scales using the nonlinear, flow-dependent, diffusion scheme. In doing so, a reduction in vertical velocity was found, resulting in a reduction in maximum rain intensity.

APA, Harvard, Vancouver, ISO, and other styles

5

Dhar, Joydip, Mani Tyagi, and Poonam Sinha. "Three simultaneous innovations interrelationships: An adopter dynamics model." International Journal of Modeling, Simulation, and Scientific Computing 06, no. 03 (September 2015): 1550031. http://dx.doi.org/10.1142/s1793962315500312.

Full text

Abstract:

In this paper, we develop a conceptual framework of a innovation diffusion dynamics model in which multiple parallel innovations are effecting each other during the diffusion process. A mathematical model is proposed to explore the interaction and diffusion of three innovations simultaneously available in market. The stability analysis is carried out for various types of diffusions on such system both analytically and numerically. It is observed that the association between innovations in product market could be complementary, substitute, independent or competitive. The co-existence and extinction of innovation depends on the level of diffusion between the innovations and it may or may not be sensitive to initial distribution of innovations.

APA, Harvard, Vancouver, ISO, and other styles

6

Wolschin, G. "Relativistic diffusion model." European Physical Journal A 5, no. 1 (May 1999): 85–90. http://dx.doi.org/10.1007/s100500050260.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Zheng, Yingchun, and Yunfeng Yang. "Wealth optimization models on jump-diffusion model." Journal of Interdisciplinary Mathematics 21, no. 1 (January 2, 2018): 201–12. http://dx.doi.org/10.1080/09720502.2017.1406629.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Nowok, J. W. "A model of diffusion/viscous mass transport in silicates during liquid-phase sintering." Journal of Materials Research 10, no. 2 (February 1995): 401–4. http://dx.doi.org/10.1557/jmr.1995.0401.

Full text

Abstract:

The model of capillary transport of liquid metals driven by shear stress resulting from the displacement of menisci [J.W. Nowok, Scripta Metal]. Mater. 29, 931 (1993); Acta Metall. Mater. 42, 4025 (1994)] is applicable to liquid-phase sintering of silicate/aluminosilicate glasses. The movement of a liquid phase between adjacent particles is compared with that in capillaries. It appears that the transport property of intergranular melt may be expressed by the viscosity (η) and volume diffusion (D) parameters if mean displacement of menisci is compared with the mean diffusive jump lengths of atoms/molecules (L). This leads to the following relation: (γ/η)Lα = Dcap, where α and Dcap are a specific permeability and volume diffusion coefficient. The use of this model requires the assumption that the diffusing species are also the viscous flow units, and they can be either atoms or structural units. This assumption seems to be applicable for depolymerized silicate melts if the dominant mass transport is initiated by the diffusion of both nonbridging oxygen and silicon atoms.

APA, Harvard, Vancouver, ISO, and other styles

9

Xie, Wenhao, Gongqian Liang, Wei Wang, and Yanhong She. "A spatial SIS model with Holling II incidence rate." International Journal of Biomathematics 12, no. 08 (November 2019): 1950092. http://dx.doi.org/10.1142/s179352451950092x.

Full text

Abstract:

A diffusive SIS epidemic model with Holling II incidence rate is studied in this paper. We introduce the basic reproduction number [Formula: see text] first. Then the existence of endemic equilibrium (EE) can be determined by the sizes of [Formula: see text] as well as the diffusion rates of susceptible and infected individuals. We also investigate the effect of diffusion rates on asymptotic profile of EE. Our results conclude that the infected population will die out if the diffusion rate of susceptible individuals is small and the total population [Formula: see text] is below a certain level; while the two populations persist eventually if at least one of the diffusion rates of the susceptible and infected individuals is large.

APA, Harvard, Vancouver, ISO, and other styles

10

TIAN, CHU-SHUN, SAI-KIT CHEUNG, and ZHAO-QING ZHANG. "CAN DIFFUSION MODEL LOCALIZATION IN OPEN MEDIA?" International Journal of Modern Physics: Conference Series 11 (January 2012): 96–101. http://dx.doi.org/10.1142/s201019451200596x.

Full text

Abstract:

We employed a first-principles theory – the supersymmetric field theory – formulated for wave transport in very general open media to study static transport of waves in quasi-one-dimensional localized samples. We predicted analytically and confirmed numerically that in these systems, localized waves display an unconventional diffusive phenomenon. Different from the prevailing self-consistent local diffusion model, our theory is capable of capturing all disorder-induced resonant transmissions, which give rise to significant enhancement of local diffusion inside a localized sample. Our theory should be able to be generalized to two- and three-dimensional open media, and open a new direction in the study of Anderson localization in open media.

APA, Harvard, Vancouver, ISO, and other styles

11

Zhang, Hongtao, and Jingfu Zhao. "Stationary Patterns of a Cross-Diffusion Prey-Predator Model with Holling Type II Functional Response." Journal of Mathematics 2023 (October 3, 2023): 1–9. http://dx.doi.org/10.1155/2023/2588998.

Full text

Abstract:

In this paper, we consider positive steady-state solutions of a cross-diffusions prey-predator model with Holling type II functional response. We investigate sufficient conditions for the existence and the nonexistence of nonconstant positive steady state solutions. It is observed that nonconstant positive steady states do not exist with small cross-diffusion coefficients, and the constant positive steady state is global asymptotically stable without cross-diffusion. Furthermore, we show that if natural diffusion coefficient or cross-diffusion coefficient of the predator is large enough and other diffusion coefficients are fixed, then under some conditions, at least one nonconstant positive steady state exists.

APA, Harvard, Vancouver, ISO, and other styles

12

Kim, Yong-Jung, and Hyowon Seo. "Model for Heterogeneous Diffusion." SIAM Journal on Applied Mathematics 81, no. 2 (January 2021): 335–54. http://dx.doi.org/10.1137/19m130087x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Joo, Young-Jin. "Network Based Diffusion Model." Korean Management Science Review 32, no. 3 (September 30, 2015): 29–36. http://dx.doi.org/10.7737/kmsr.2015.32.3.029.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Lieck, Robert, Fabian C. Moss, and Martin Rohrmeier. "The Tonal Diffusion Model." Transactions of the International Society for Music Information Retrieval 3, no. 1 (October 16, 2020): 153. http://dx.doi.org/10.5334/tismir.46.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Beiruti, Ahmad A. R., and Hazim K. Al-Omishy. "Traffic atmospheric diffusion model." Atmospheric Environment (1967) 19, no. 9 (January 1985): 1519–24. http://dx.doi.org/10.1016/0004-6981(85)90289-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Wen, Lingfeng, Xuan Tang, Mingjie Ouyang, Xiangxiang Shen, Jian Yang, Daxin Zhu, Mingsong Chen, and Xian Wei. "Hyperbolic Graph Diffusion Model." Proceedings of the AAAI Conference on Artificial Intelligence 38, no. 14 (March 24, 2024): 15823–31. http://dx.doi.org/10.1609/aaai.v38i14.29512.

Full text

Abstract:

Diffusion generative models (DMs) have achieved promising results in image and graph generation. However, real-world graphs, such as social networks, molecular graphs, and traffic graphs, generally share non-Euclidean topologies and hidden hierarchies. For example, the degree distributions of graphs are mostly power-law distributions. The current latent diffusion model embeds the hierarchical data in a Euclidean space, which leads to distortions and interferes with modeling the distribution. Instead, hyperbolic space has been found to be more suitable for capturing complex hierarchical structures due to its exponential growth property. In order to simultaneously utilize the data generation capabilities of diffusion models and the ability of hyperbolic embeddings to extract latent hierarchical distributions, we propose a novel graph generation method called, Hyperbolic Graph Diffusion Model (HGDM), which consists of an auto-encoder to encode nodes into successive hyperbolic embeddings, and a DM that operates in the hyperbolic latent space. HGDM captures the crucial graph structure distributions by constructing a hyperbolic potential node space that incorporates edge information. Extensive experiments show that HGDM achieves better performance in generic graph and molecule generation benchmarks, with a 48% improvement in the quality of graph generation with highly hierarchical structures.

APA, Harvard, Vancouver, ISO, and other styles

17

Borina, Maria Yur'evna, and A. A. Polezhaev. "Diffusion instability in a threevariable reaction-diffusion model." Computer Research and Modeling 3, no. 2 (June 2011): 135–46. http://dx.doi.org/10.20537/2076-7633-2011-3-2-135-146.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Li, Hua, Yu-Hang Chen, and Bin-Ze Tang. "A revised jump-diffusion and rotation-diffusion model." Chinese Physics B 28, no. 5 (May 2019): 056105. http://dx.doi.org/10.1088/1674-1056/28/5/056105.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Kubota, Kiyoshi, and Takashi Ishizaki. "A diffusion-diffusion model for percutaneous drug absorption." Journal of Pharmacokinetics and Biopharmaceutics 14, no. 4 (August 1986): 409–39. http://dx.doi.org/10.1007/bf01059200.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Doremus, Robert H. "Diffusion of hydrogen in silicon: Diffusion-reaction model." Materials Research Innovations 4, no. 1 (November 2000): 49–59. http://dx.doi.org/10.1007/s100190000068.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Ma, Man-jun, Jia-jia Hu, Jun-jie Zhang, and Ji-cheng Tao. "A reaction-diffusion model with nonlinearity driven diffusion." Applied Mathematics-A Journal of Chinese Universities 28, no. 3 (August 30, 2013): 290–302. http://dx.doi.org/10.1007/s11766-013-2966-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Simal, S., M. C. Garau, A. Femenia, and C. Rosselló. "A Diffusional Model with a Moisture-Dependent Diffusion Coefficient." Drying Technology 24, no. 11 (November 2006): 1365–72. http://dx.doi.org/10.1080/07373930600952404.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Łach, Łukasz, and Dmytro Svyetlichnyy. "3D Model of Carbon Diffusion during Diffusional Phase Transformations." Materials 17, no. 3 (January 30, 2024): 674. http://dx.doi.org/10.3390/ma17030674.

Full text

Abstract:

The microstructure plays a crucial role in determining the properties of metallic materials, in terms of both their strength and functionality in various conditions. In the context of the formation of microstructure, phase transformations that occur in materials are highly significant. These are processes during which the structure of a material undergoes changes, most commonly as a result of variations in temperature, pressure, or chemical composition. The study of phase transformations is a broad and rapidly evolving research area that encompasses both experimental investigations and modeling studies. A foundational understanding of carbon diffusion and phase transformations in materials science is essential for comprehending the behavior of materials under different conditions. This understanding forms the basis for the development and optimization of materials with desired properties. The aim of this paper is to create a three-dimensional model for carbon diffusion in the context of modeling diffusional phase transformations occurring in carbon steels. The proposed model relies on the utilization of the LBM (Lattice Boltzmann Method) and CUDA architecture. The resultant carbon diffusion model is intricately linked with a microstructure evolution model grounded in FCA (Frontal Cellular Automata). This manuscript provides a concise overview of the LBM and the FCA method. It outlines the structure of the developed three-dimensional model for carbon diffusion, details its correlation with the microstructure evolution model, and presents the developed algorithm for simulating carbon diffusion. Demonstrative examples of simulation results, illustrating the growth of the emerging phase and affected by various model parameters within particular planes of the 3D calculation domain, are also presented.

APA, Harvard, Vancouver, ISO, and other styles

24

Jung, Minseop, Minseong Kim, and Jibum Kim. "Generating 3D CAD Models using a Transformer Autoencoders and a Diffusion Model." Journal of the Institute of Electronics and Information Engineers 60, no. 12 (December 31, 2023): 25–28. http://dx.doi.org/10.5573/ieie.2023.60.12.25.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Wu, Xiao, and Mingkang Ni. "Dynamics in diffusive Leslie–Gower prey–predator model with weak diffusion." Nonlinear Analysis: Modelling and Control 27, no. 6 (October 19, 2022): 1168–88. http://dx.doi.org/10.15388/namc.2022.27.29535.

Full text

Abstract:

This paper is concerned with the diffusive Leslie–Gower prey–predator model with weak diffusion. Assuming that the diffusion rates of prey and predator are sufficiently small and the natural growth rate of prey is much greater than that of predators, the diffusive Leslie–Gower prey–predator model is a singularly perturbed problem. Using travelling wave transformation, we firstly transform our problem into a multiscale slow-fast system with two small parameters. We prove the existence of heteroclinic orbit, canard explosion phenomenon and relaxation oscillation cycle for the slow-fast system by applying the geometric singular perturbation theory. Thus, we get the existence of travelling waves and periodic solutions of the original reaction–diffusion model. Furthermore, we also give some numerical examples to illustrate our theoretical results.

APA, Harvard, Vancouver, ISO, and other styles

26

Wirbeleit, Frank. "Non-Gaussian Local Density Diffusion (LDD-) Model for Boron Diffusion in Si- and Si_xGe_1-x Ultra-Shallow Junction Post-Implant and Advanced Rapid-Thermal-Anneals." Defect and Diffusion Forum 305-306 (October 2010): 71–84. http://dx.doi.org/10.4028/www.scientific.net/ddf.305-306.71.

Full text

Abstract:

Boron diffusion after implant and anneal has been studied extensively in the past, without de-convoluting the Boron diffusion behavior by the initial post implant Boron concentration profile, which is done in this work first time. To support the de-convolution approach, the local density diffusion (LDD) model is selected, because this model is based on just one single arbitrary diffusion parameter per atomic species and host lattice combination. The LDD model is used for Phosphorus and Arsenic diffusion so far and an extension to simulate Boron diffusion in presence of Boron clusters is presented here. As the result, maximum Boron penetration depth post different rapid thermal anneals and the quantification of diffusing and clustering (non-diffusing) Boron in silicon and silicon-germanium host lattice systems are given.

APA, Harvard, Vancouver, ISO, and other styles

27

Kang, Woo-Kyu. "Exploring the Possibilities and Implications of Teaching Classical Literature Using Diffusion Model." Studies of Korean Literature 78 (April 30, 2023): 133–62. http://dx.doi.org/10.20864/skl.2023.4.78.133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Chen, Meijun, Shengmao Fu, and Xiaoli Yang. "Global Behavior of Solutions in a Predator-Prey Cross-Diffusion Model with Cannibalism." Complexity 2020 (May 22, 2020): 1–19. http://dx.doi.org/10.1155/2020/1265798.

Full text

Abstract:

The global asymptotic behavior of solutions in a cross-diffusive predator-prey model with cannibalism is studied in this paper. Firstly, the local stability of nonnegative equilibria for the weakly coupled reaction-diffusion model and strongly coupled cross-diffusion model is discussed. It is shown that the equilibria have the same stability properties for the corresponding ODE model and semilinear reaction-diffusion model, but under suitable conditions on reaction coefficients, cross-diffusion-driven Turing instability occurs. Secondly, the uniform boundedness and the global existence of solutions for the model with SKT-type cross-diffusion are investigated when the space dimension is one. Finally, the global stability of the positive equilibrium is established by constructing a Lyapunov function. The result indicates that, under certain conditions on reaction coefficients, the model has no nonconstant positive steady state if the diffusion matrix is positive definite and the self-diffusion coefficients are large enough.

APA, Harvard, Vancouver, ISO, and other styles

29

Ramanuj, S. "CONTINUOUS DIFFUSION OF AUSTRIAN MODEL GERMAN FRONT VOWELS: A SOCIOLINGUISTIC ANALYSIS." CURRENT RESEARCH JOURNAL OF PHILOLOGICAL SCIENCES 02, no. 05 (May 30, 2021): 18–19. http://dx.doi.org/10.37547/philological-crjps-02-05-05.

Full text

Abstract:

In Austrian Model German ASG , the vowels in the words Beeren and Bärenare ordinarily respected to be consolidated. Some acoustic investigations on ASG additionally recommend a consolidation between the vowels as in Maitland Mitteand even between the BEEREN/BÄREN consolidation and the MIETE vowel. This paper re-examines these consolidations from a sociolinguistic perspective and shows that more established speakers will in general union the vowels more than more youthful speakers. This focuses towards a continuous scattering or 'unmerger' and we contend that this is an aftereffect of convenience toward Model German as it is articulated in Germany.

APA, Harvard, Vancouver, ISO, and other styles

30

Ashokan, Rashini, Gabriel Lopez Zenarosa, and Xiuli He. "Diffusion Model for the Adoption of Smartphone Brands under Competitive Pricing." International Journal of Trade, Economics and Finance 9, no. 3 (June 2018): 96–99. http://dx.doi.org/10.18178/ijtef.2018.9.3.595.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Somjaivang, Dussadee, and Settapat Chinviriyasit. "Numerical Modeling of an Influenza Epidemic Model with Vaccination and Diffusion." International Journal of Applied Physics and Mathematics 4, no. 1 (2014): 68–74. http://dx.doi.org/10.7763/ijapm.2014.v4.257.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Wolpers, H. G., A. Hoeft, H. Korb, P. R. Lichtlen, and G. Hellige. "Transport of inert gases in mammalian myocardium: comparison with a convection-diffusion model." American Journal of Physiology-Heart and Circulatory Physiology 259, no. 1 (July 1, 1990): H167—H173. http://dx.doi.org/10.1152/ajpheart.1990.259.1.h167.

Full text

Abstract:

Because tracer techniques are gaining an increasing importance for imaging flow (and metabolism) in the heart, experimental evidence is needed on the role of convection and diffusion in the transcoronary transport of solutes. In the present work, the transport of four different inert gases through the coronary system is studied in five closed-chest dog experiments and is compared with a digital multicapillary convection-diffusion model. Transport may be defined as flow dependent, as judged by the gross similarity of shape of the time-normalized dilution curves. However, the results show that the transcoronary transport of helium and xenon is more dispersed than that of argon and krypton, probably because of differences in diffusibility and solubility. A comparison of the animal and model experiments emphasizes the importance of diffusive transport of the gases. It is suggested that there is a diffusion shunt that is mainly located within the capillary network itself rather than between conduit vessels. Only for helium (which has the highest diffusivity) was a small arteriovenous shunt fraction seen that is thought to bypass the capillary exchange region. The conclusion is that although there is evidence of diffusional shunting at a capillary level, the inert gas kinetics in the heart are compatible with a basically flow-limited transport.

APA, Harvard, Vancouver, ISO, and other styles

33

Söderström, Torsten, and Susanne Remle. "Parameter Estimation and Model Approximation for Diffusion Models." IFAC Proceedings Volumes 33, no. 15 (June 2000): 965–70. http://dx.doi.org/10.1016/s1474-6670(17)39878-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Dellaportas, Petros, Nial Friel, and Gareth O. Roberts. "Bayesian model selection for partially observed diffusion models." Biometrika 93, no. 4 (December 1, 2006): 809–25. http://dx.doi.org/10.1093/biomet/93.4.809.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Scribano, Carmelo, Danilo Pezzi, Giorgia Franchini, and Marco Prato. "Denoising Diffusion Models on Model-Based Latent Space." Algorithms 16, no. 11 (October 28, 2023): 501. http://dx.doi.org/10.3390/a16110501.

Full text

Abstract:

With the recent advancements in the field of diffusion generative models, it has been shown that defining the generative process in the latent space of a powerful pretrained autoencoder can offer substantial advantages. This approach, by abstracting away imperceptible image details and introducing substantial spatial compression, renders the learning of the generative process more manageable while significantly reducing computational and memory demands. In this work, we propose to replace autoencoder coding with a model-based coding scheme based on traditional lossy image compression techniques; this choice not only further diminishes computational expenses but also allows us to probe the boundaries of latent-space image generation. Our objectives culminate in the proposal of a valuable approximation for training continuous diffusion models within a discrete space, accompanied by enhancements to the generative model for categorical values. Beyond the good results obtained for the problem at hand, we believe that the proposed work holds promise for enhancing the adaptability of generative diffusion models across diverse data types beyond the realm of imagery.

APA, Harvard, Vancouver, ISO, and other styles

36

Alexandrowicz, Rainer W. "The diffusion model visualizer: an interactive tool to understand the diffusion model parameters." Psychological Research 84, no. 4 (October 25, 2018): 1157–65. http://dx.doi.org/10.1007/s00426-018-1112-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

NEC, YANA. "Explicitly solvable eigenvalue problem and bifurcation delay in sub-diffusive Gierer–Meinhardt model." European Journal of Applied Mathematics 27, no. 5 (January 29, 2016): 699–725. http://dx.doi.org/10.1017/s0956792516000012.

Full text

Abstract:

A spike solution is constructed on the infinite line for a sub-diffusive version of the Gierer–Meinhardt reaction – diffusion model. A non-local eigenvalue problem governs the spike's stability and is explicitly solvable for a certain choice of the kinetic parameters. Its solution generalises former results for the Gierer–Meinhardt model with regular diffusion, and the normal and anomalous systems' properties are juxtaposed. It is shown that a Hopf bifurcation occurs in the sub-diffusive system for larger values of the time parameter τo as compared to the normal counterpart, rendering the anomalous system more stable. Asymptotic solutions are obtained near important values of the diffusion anomaly index γ and collectively shown to be valid over most of the applicable range 0 < γ < 1. A bifurcation delay scenario is described for the sub-diffusive system, and the WKB exponent is computed analytically.

APA, Harvard, Vancouver, ISO, and other styles

38

Al-Mashrafi, Khaled. "The influence of longitudinal diffusion on the transport of dust particles emitted from a fixed source." International Journal of Applied Mathematical Research 5, no. 1 (January 9, 2016): 11. http://dx.doi.org/10.14419/ijamr.v5i1.5367.

Full text

Abstract:

<p>The mathematical model for the diffusion of dust particles emitted from a fixed source in the presence of the longitudinal diffusion and absence of latitudinal and vertical diffusions, is investigated. The diffusion of dust particles in the atmosphere is governed by the atmospheric diffusion equation. In the previous paper [1], the general case of the time-dependent diffusion equation in the presence of a point source whose strength is dependent on time, was solved. The calculations showed that the diffusion parameters play an important role in the spread of the dust particles in the atmosphere. In the previous paper, we examined the model in the presence of vertical diffusion and absence of other diffusions to show that for small times, the dust spreads with a front that travels with the speed of the wind. In the current paper, the vertical and latitudinal diffusions are absent while the longitudinal diffusion is present. It is found that the solution depends on the source of time dependence. To study the nature of the solution, two special cases of the source are specified. In the both cases, it is found that there is no discontinuity front, and the dust particles spread slowly into the direction of the wind.</p>

APA, Harvard, Vancouver, ISO, and other styles

39

Holperin, Michelle Moretzsohn. "Difusão e adaptação do modelo de agência reguladora no Brasil." Revista de Administração Pública 53, no. 6 (December 2019): 1116–37. http://dx.doi.org/10.1590/0034-761220170384.

Full text

Abstract:

Abstract This article examines the diffusion of independent regulatory agencies (IRAs) in Brazil, demonstrating how important domestic factors interplayed with traditional mechanisms of diffusion lead to an expressive process of agencification. Although top-down, bottom-up and horizontal mechanisms played an important role in the Brazilian agencification process, they fail to explain the creation of IRAs in unexpected sectors or the frequent modifications that occurred at subnational levels in a short period of time. To understand how local political actors adapted the regulatory agency model to the Brazilian institutional legacies, field research was conducted, based on bibliographical, documental, and interviews with key political actors. The specificities of Brazilian federalism and the strategic role of the film industry, bureaucrats and politicians in (re)interpreting the agency model helped to boost the diffusion of IRAs in Brazil.

APA, Harvard, Vancouver, ISO, and other styles

40

Covington, Leroy, Kamalesh Munirathinam, Akand Islam, and Kenneth Roberts. "Synthesis and characterization of nanostructured molybdenum & tungsten carbide materials, and study of diffusion model." Polish Journal of Chemical Technology 14, no. 1 (January 1, 2012): 28–34. http://dx.doi.org/10.2478/v10026-012-0055-8.

Full text

Abstract:

Synthesis and characterization of nanostructured molybdenum & tungsten carbide materials, and study of diffusion model Powders of two molybdenum carbides (Mo2C and MoC1-x) and tungsten carbide (WC) were prepared by means of temperature programmed reaction (TPR) method. Mo2C and MoC1-x were synthesized by reacting MoO3 with a preselected molar ratio of methane/hydrogen and carbon monoxide/hydrogen gas mixtures respectively. WC was prepared using tungsten oxide (WO3) and a methane/hydrogen gas mixture. These carbides were ultrasonically dispersed in de-ionized water. Samples were characterized using room temperature x-ray diffraction and scanning microscopy. A kinetic diffusion model is also studied to determine diffusivities in solids where the diffusing species desorbs or reacts at the external surfaces, and where the diffusivity does not vary appreciably with concentrations. The method involves measuring the flux of the diffusive species into the solid under the influence of a temperature program.

APA, Harvard, Vancouver, ISO, and other styles

41

Ala-Nissila, T., J. Kjoll, S. C. Ying, and R. A. Tahir-Kheli. "Model for diffusion on deformable lattices. I. Collective diffusion." Physical Review B 44, no. 5 (August 1, 1991): 2122–32. http://dx.doi.org/10.1103/physrevb.44.2122.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Ala-Nissila, T., J. Kjoll, S. C. Ying, and R. A. Tahir-Kheli. "Model for diffusion on deformable lattices. II. Tracer diffusion." Physical Review B 44, no. 5 (August 1, 1991): 2133–41. http://dx.doi.org/10.1103/physrevb.44.2133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Doremus, R. H. "Diffusion of water in rhyolite glass: diffusion–reaction model." Journal of Non-Crystalline Solids 261, no. 1-3 (January 2000): 101–7. http://dx.doi.org/10.1016/s0022-3093(99)00604-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Lee, Ching-Hor, and Shi-Ping Teng. "A dual period diffusion model for measuring diffusion parameters." Waste Management 13, no. 1 (January 1993): 15–24. http://dx.doi.org/10.1016/0956-053x(93)90031-q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Liu, Guoqi, Lin Sun, and Shangwang Liu. "Efficient and Enhanced Diffusion of Vector Field for Active Contour Model." Mathematical Problems in Engineering 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/343159.

Full text

Abstract:

Gradient vector flow (GVF) is an important external force field for active contour models. Various vector fields based on GVF have been proposed. However, these vector fields are obtained with many iterations and have difficulty in capturing the whole image area. On the other hand, the ability to converge to deep and complex concavity with these vector fields is also needed to improve. In this paper, by analyzing the diffusion equation of GVF, a normalized set is defined and a dynamically normalized constraint of vector fields is used for efficient diffusion, which makes the edge vector diffusing rapidly to the entire image region. In order to improve the ability to converge to concavity, an enhanced diffusion term is integrated into the original energy functional. With the dynamically normalized constraint and enhanced diffusion term, new vector fields of EDGVF (efficient and enhanced diffusion for GVF) and EDNGVF (efficient and enhanced diffusion of NGVF) are obtained. Experimental results demonstrate that vector fields with proposed method capture the entire image and are obtained with less iterations and computational times. In particular, EDNGVF greatly improves the ability to converge to concavity.

APA, Harvard, Vancouver, ISO, and other styles

46

Гулевська, К. В., Л. О. Шумова, and В. І. Мохонько. "Mathematical model of diffusion process for solving hydroecological problems." ВІСНИК СХІДНОУКРАЇНСЬКОГО НАЦІОНАЛЬНОГО УНІВЕРСИТЕТУ імені Володимира Даля, no. 5(253) (September 5, 2019): 44–46. http://dx.doi.org/10.33216/1998-7927-2019-253-5-44-46.

Full text

Abstract:

The article discusses the actual tasks of adaptive control of local water treatment plants to ensure the rational use of water. The software solutions for modeling the diffusion process in a porous medium with the absorption of a diffusing substance on the pore surface are considered in detail.

APA, Harvard, Vancouver, ISO, and other styles

47

Rout, Smruti Sourav, Burkhard C. Schmidt, and Gerhard Wörner. "Constraints on non-isothermal diffusion modeling: An experimental analysis and error assessment using halogen diffusion in melts." American Mineralogist 105, no. 2 (February 1, 2020): 227–38. http://dx.doi.org/10.2138/am-2020-7193.

Full text

Abstract:

Abstract Diffusion chronometry on zoned crystals allows constraining duration of magmatic evolution and storage of crystals once temperatures are precisely known. However, non-isothermal diffusion is common in natural samples, and thus timescales may not be determined with confidence while assuming isothermal conditions. The “non-isothermal diffusion incremental step (NIDIS) model” (Petrone et al. 2016) is proposed for such cases for a non-isothermal diffusive analysis. We conducted diffusion experiments with stepwise temperature changes to analyze and test the model, evaluated the associated errors and improved the accuracy by suggesting an alternative algorithm to model diffusion times. We used Cl and F (≤0.4 wt%) as the diffusing elements in nominally anhydrous (H2O ≤ 0.3 wt%) phonolitic melt with composition of Montana Blanca (Tenerife, Spain) in an experimental setup that successively generates multiple diffusive interfaces for different temperatures by adding glass blocks of different Cl and F concentrations. This compound set of two diffusion interfaces represents distinct compositional zones that diffusively interact at different temperatures, which can be taken as an equivalent to non-isothermal diffusion in zoned magmatic crystals. The starting temperature ranged from 975 to 1150 °C, and each set of experiments included a temperature change of 85–150 °C and a total duration of 8–12 h. The experiments were carried out in an internally heated pressure vessel equipped with a rapid quench device at 1 kbar pressure. Cl and F concentration profiles were obtained from the quenched samples by electron microprobe analysis. Although the estimated diffusion times from the NIDIS-model matched well with true experimental values, the errors on estimated timescales, due to errors in curve-fitting and uncertainty in temperature, were ±10–62% (1σ). The errors are much larger at 61–288% (1σ) when the uncertainty in diffusivity parameters is included. We discuss the efficiency and limitations of the model, assess the contribution from different sources of error, and their extent of propagation. A simpler alternative algorithm is proposed that reduces errors on the estimates of diffusion time to 10–32% (1σ) and 60–75% (1σ), with and without including uncertainty in diffusivity parameters, respectively. Using this new algorithm, we recalculated the individual diffusion times for the clinopyroxene crystals analyzed by Petrone et al. (2016) and obtained a significantly reduced error of 26–40% compared to the original error of 61–100%. We also analyzed a sanidine megacryst from Taapaca volcano (N. Chile) as a test case for non-isothermal modeling and obtained diffusion times of 1.5–9.4 ky, which is significantly different from isothermal analyses including a previous study on similar sample. In this analysis, the error estimated by our new method is reduced by 63–70%.

APA, Harvard, Vancouver, ISO, and other styles

48

Hutzenthaler, Martin, and Jesse Earl Taylor. "Time reversal of some stationary jump diffusion processes from population genetics." Advances in Applied Probability 42, no. 4 (December 2010): 1147–71. http://dx.doi.org/10.1239/aap/1293113155.

Full text

Abstract:

We describe the processes obtained by time reversal of a class of stationary jump diffusion processes that model the dynamics of genetic variation in populations subject to repeated bottlenecks. Assuming that only one lineage survives each bottleneck, the forward process is a diffusion on [0,1] that jumps to the boundary before diffusing back into the interior. We show that the behavior of the time-reversed process depends on whether the boundaries are accessible to the diffusive motion of the forward process. If a boundary point is inaccessible to the forward diffusion then time reversal leads to a jump diffusion that jumps immediately into the interior whenever it arrives at that point. If, instead, a boundary point is accessible then the jumps off of that point are governed by a weighted local time of the time-reversed process.

APA, Harvard, Vancouver, ISO, and other styles

49

Hutzenthaler, Martin, and Jesse Earl Taylor. "Time reversal of some stationary jump diffusion processes from population genetics." Advances in Applied Probability 42, no. 04 (December 2010): 1147–71. http://dx.doi.org/10.1017/s0001867800004560.

Full text

Abstract:

We describe the processes obtained by time reversal of a class of stationary jump diffusion processes that model the dynamics of genetic variation in populations subject to repeated bottlenecks. Assuming that only one lineage survives each bottleneck, the forward process is a diffusion on [0,1] that jumps to the boundary before diffusing back into the interior. We show that the behavior of the time-reversed process depends on whether the boundaries are accessible to the diffusive motion of the forward process. If a boundary point is inaccessible to the forward diffusion then time reversal leads to a jump diffusion that jumps immediately into the interior whenever it arrives at that point. If, instead, a boundary point is accessible then the jumps off of that point are governed by a weighted local time of the time-reversed process.

APA, Harvard, Vancouver, ISO, and other styles

50

Frank, Andreas O., C. J. Charles Chuong, and Robert L. Johnson. "A finite-element model of oxygen diffusion in the pulmonary capillaries." Journal of Applied Physiology 82, no. 6 (June 1, 1997): 2036–44. http://dx.doi.org/10.1152/jappl.1997.82.6.2036.

Full text

Abstract:

Frank, Andreas O., C. J. Charles Chuong, and Robert L. Johnson. A finite-element model of oxygen diffusion in the pulmonary capillaries. J. Appl. Physiol. 82(6): 2036–2044, 1997.—We determined the overall pulmonary diffusing capacity (Dl) and the diffusing capacities of the alveolar membrane (Dm) and the red blood cell (RBC) segments (De) of the diffusional pathway for O2 by using a two-dimensional finite-element model developed to represent the sheet-flow characteristics of pulmonary capillaries. An axisymmetric model was also considered to assess the effect of geometric configuration. Results showed the membrane segment contributing the major resistance, with the RBC segment resistance increasing as O2 saturation ([Formula: see text]) rises during the RBC transit: RBC contributed 7% of the total resistance at the capillary inlet ([Formula: see text] = 75%) and 30% toward the capillary end ([Formula: see text] = 95%) for a 45% hematocrit (Hct). Both Dm and Dlincreased as the Hct increased but began approaching a plateau near an Hct of 35%, due to competition between RBCs for O2 influx. Both Dm and Dl were found to be relatively insensitive (2∼4%) to changes in plasma protein concentration (28∼45%). Axisymmetric results showed similar trends for all Hct and protein concentrations but consistently overestimated the diffusing capacities (∼2.2 times), primarily because of an exaggerated air-tissue barrier surface area. The two-dimensional model correlated reasonably well with experimental data and can better represent the O2 uptake of the pulmonary capillary bed.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!