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Fractal geometry proved to be an effective mathematical tool for exploring real geographical space based on digital maps and remote sensing images. Whether the fractal theory tool can be applied to abstract geographical space has not been…

Physics and Society · Physics 2023-06-06 Yanguang Chen

Spatial patterns and processes of cities can be described with various entropy functions. However, spatial entropy always depends on the scale of measurement, and it is difficult to find a characteristic value for it. In contrast, fractal…

Physics and Society · Physics 2018-12-19 Yanguang Chen , Jiejing Wang , Jian Feng

The recent implementation of radiative transfer algorithms in numerous hydrodynamics codes has led to a dramatic improvement in studies of feedback in various astrophysical environments. However, because of methodological limitations and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jordan Mirocha , Stephen Skory , Jack O. Burns , John H. Wise

The observed high covering fractions of neutral hydrogen (HI) with column densities above $\sim 10^{17} \rm{cm}^{-2}$ around Lyman-Break Galaxies (LBGs) and bright quasars at redshifts z ~ 2-3 has been identified as a challenge for…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-25 Alireza Rahmati , Joop Schaye , Richard G. Bower , Robert A. Crain , Michelle Furlong , Matthieu Schaller , Tom Theuns

This paper deals with an estimating of the Fractal Dimension of a hydrometeorology variables like an Air temperature or humidity at a different sites in a landscape (and will be further evaluated from the land use point of view). Three…

Data Analysis, Statistics and Probability · Physics 2015-12-04 Jakub Jura , Aleš Antonín Kuběna , Martina Mironovová

We study the porosity properties of fractal percolation sets $E\subset\mathbb{R}^d$. Among other things, for all $0<\varepsilon<\tfrac12$, we obtain dimension bounds for the set of exceptional points where the upper porosity of $E$ is less…

Probability · Mathematics 2020-10-02 Changhao Chen , Tuomo Ojala , Eino Rossi , Ville Suomala

We analyze the dynamical expansion of the HII region, photodissociation region, and the swept-up shell, solving the UV- and FUV-radiative transfer, the thermal and chemical processes in the time-dependent hydrodynamics code. Following our…

Astrophysics · Physics 2009-11-13 Takashi Hosokawa , Shu-ichiro Inutsuka

Analytic derivations of the correlation function and the column density distribution for neutral hydrogen in the IGM are presented, assuming that the non-linear baryonic mass density distribution in the IGM is lognormal. This ansatz was…

Astrophysics · Physics 2009-10-31 T. Roy Choudhury , T. Padmanabhan , R. Srianand

The conventional mathematical methods are based on characteristic length, while urban form has no characteristic length in many aspects. Urban area is a measure of scale dependence, which indicates the scale-free distribution of urban…

Physics and Society · Physics 2020-11-17 Yanguang Chen

We present a method to construct semi-numerical ``simulations'', which can efficiently generate realizations of halo distributions and ionization maps at high redshifts. Our procedure combines an excursion-set approach with first-order…

Astrophysics · Physics 2009-11-13 Andrei Mesinger , Steven Furlanetto

In chaotic reaction-diffusion systems with two degrees of freedom, the modes governing the exponential relaxation to the thermodynamic equilibrium present a fractal structure which can be characterized by a Hausdorff dimension. For long…

Statistical Mechanics · Physics 2009-11-07 I. Claus , P. Gaspard

This thesis focuses on characterizing the distribution of points and galaxies using multifractal analysis. In this attempt the main emphasis is on calculating the Minkowski-Bouligand fractal dimension (Dq) of the distribution of points over…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-06 Jaswant K. Yadav

There are many research papers dealing with fractal dimension of real-valued fractal functions in the recent literature. The main focus of the present paper is to study fractal dimension of complex-valued functions. This paper also…

Dynamical Systems · Mathematics 2022-04-08 Manuj Verma , Amit Priyadarshi , Saurabh Verma

In this report we present experimental results using \emph{Haussdorf-Besicovich} fractal dimension for performing morphological galaxy classification. The fractal dimension is a topological, structural and spatial property that give us…

Computer Vision and Pattern Recognition · Computer Science 2017-06-26 Jorge de la Calleja , Elsa M. de la Calleja , Hugo Jair Escalante

Models for the description of breakup reactions used to study the structure of exotic cluster structures like halos are reviewed. The sensitivity of these models to the projectile description is presented. Calculations are sensitive to the…

Nuclear Theory · Physics 2014-12-17 Pierre Capel

Initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes,…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-28 Meng Zhou , Yi Mao

The presence of dense, neutral hydrogen clouds in the hot, diffuse intra-group and intra-cluster medium is an important clue to the physical processes controlling the survival of cold gas and sheds light on cosmological baryon flows in…

Astrophysics of Galaxies · Physics 2024-04-29 Avinash Chaturvedi , Stephanie Tonnesen , Greg L. Bryan , Gergö Popping , Michael Hilker , Paolo Serra , Shy Genel

This work outlines a diffuse interface method for the study of fracture and fragmentation in ductile metals at high strain-rates in Eulerian finite volume simulations. The work is based on an existing diffuse interface method capable of…

Computational Physics · Physics 2022-10-11 Tim Wallis , Philip T. Barton , Nikolaos Nikiforakis

We present a new, uniform analysis of the HI transmitted flux (F) and HI column density (N(HI)) distribution in the low-density IGM as a function of redshift z for 0<z<3.6 using 55 HST/COS FUV (Delta(z)=7.2 at z<0.5), five HST/STIS+COS NUV…

Large inhomogeneities in neutral hydrogen in the universe can be detected at redshifts $z \leq 10$ using the redshifted 21cm line emission from atomic hydrogen. This paper reviews the expected evolution of neutral hydrogen and presents…

Astrophysics · Physics 2007-05-23 J. S. Bagla