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We analyse features of the patterns formed from a simple model for a martensitic phase transition. This is a fragmentation model that can be encoded by a general branching random walk. An important quantity is the distribution of the…

Probability · Mathematics 2018-10-19 Pierluigi Cesana , Ben Hambly

In this paper we review the importance of the Lyman alpha forest as a probe of structure formation in the universe. We first discuss the statistics used to describe the Lyman alpha forest and the numerical techniques used to produce…

Astrophysics · Physics 2007-05-23 Marie E. Machacek , Greg L. Bryan , Peter Anninos , Avery Meiksin , Michael L. Norman

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body…

Astrophysics · Physics 2008-02-03 David H. Weinberg , Neal Katz , Lars Hernquist

A probabilistic framework to study the dependence structure induced by deterministic discrete-time state-space systems between input and output processes is introduced. General sufficient conditions are formulated under which output…

Machine Learning · Statistics 2025-03-13 Juan-Pablo Ortega , Florian Rossmannek

Computational models for understanding and predicting fire in wildland and managed lands are increasing in impact. Data characterizing the fuels and environment is needed to continue improvement in the fidelity and reliability of fire…

Applications · Statistics 2023-11-23 Grant Hutchings , James Gattiker , Braden Scherting

We study the constitutive behaviour, the damage process, and the properties of bursts in the continuous damage fiber bundle model introduced recently. Depending on its two parameters, the model provides various types of constitutive…

Statistical Mechanics · Physics 2019-05-15 Raul Cruz Hidalgo , Ferenc Kun , Hans. J. Herrmann

Modelling wildfire events has been studied in the literature using the Poisson process, which essentially assumes the independence of wildfire events. In this paper, we use the fractional Poisson process to model the wildfire occurrences in…

Applications · Statistics 2024-11-22 Sudeep R. Bapat , Aditya Maheshwari

We present new simulations of the flux power spectrum of the Lyman $\alpha$ forest as a means to investigate the effects of time-dependent dark energy on structure formation. We use a linearized parameterization of the time-dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-18 Jared W. Coughlin , Grant J. Mathews , Lara Arielle Phillips , Ali P. Snedden , In-Saeng Suh

In this article we consider a class of state-dependent delay differential equations which is modelling the dynamics of the number of adult trees in forests. We prove the boundedness of solutions for a single species model as well as a…

Analysis of PDEs · Mathematics 2017-05-25 Pierre Magal , Zhengyang Zhang

We establish a general framework using a diffusion approximation to simulate forward-in-time state counts or frequencies for cladogenetic state-dependent speciation-extinction (ClaSSE) models. We apply the framework to various two- and…

Populations and Evolution · Quantitative Biology 2024-06-26 Albert C. Soewongsono , Michael J. Landis

We investigate the growth of clusters within the forest fire model of R\'{a}th and T\'{o}th [22]. The model is a continuous-time Markov process, similar to the dynamical Erd\H{o}s-R\'{e}nyi random graph but with the addition of so-called…

Probability · Mathematics 2014-12-15 Edward Crane , Nic Freeman , Bálint Tóth

A stochastic model relating the parameters of astrophysical structures to the parameters of their granular components is applied to the formation of hierarchical, large-scale structures from galaxies assumed as point-like objects. If the…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-20 S. Capozziello , S. Funkhouser

We describe two recent additions to WRF coupled with a fire spread model. Fire propagation is strongly dependent on fuel moisture, which in turn depends on the history of the atmosphere. We have implemented a equilibrium time-lag model of…

Atmospheric and Oceanic Physics · Physics 2012-08-28 Adam K. Kochanski , Jonathan D. Beezley , Jan Mandel , Minjeong Kim

We propose Partition Tree, a novel tree-based framework for conditional density estimation over general outcome spaces that supports both continuous and categorical variables within a unified formulation. Our approach models conditional…

Machine Learning · Computer Science 2026-05-13 Felipe Angelim , Alessandro Leite

Tree-size distribution is one of the most investigated subjects in plant population biology. The forestry literature reports that tree-size distribution trajectories vary across different stands and/or species, while the metabolic scaling…

Populations and Evolution · Quantitative Biology 2012-12-04 Tommaso Anfodillo , Marco Carrer , Filippo Simini , Ionel Popa , Jayanth R. Banavar , Amos Maritan

Consider critical site percolation on a "nice" planar lattice: each vertex is occupied with probability $p = p_c$, and vacant with probability $1 - p_c$. Now, suppose that additional vacancies ("holes", or "impurities") are created,…

Probability · Mathematics 2018-11-30 Jacob van den Berg , Pierre Nolin

We propose a model based on coupled multiplicative stochastic processes to understand the dynamics of competing species in an ecosystem. This process can be conveniently described by a Fokker-Planck equation. We provide an analytical…

Populations and Evolution · Quantitative Biology 2012-03-13 Simone Pigolotti , Alessandro Flammini , Amos Maritan

We describe the physical model, numerical algorithms, and software structure of WRF-Fire. WRF-Fire consists of a fire-spread model, implemented by the level-set method, coupled with the Weather Research and Forecasting model. In every time…

Atmospheric and Oceanic Physics · Physics 2012-03-27 Jan Mandel , Jonathan D. Beezley , Adam K. Kochanski

In this article we present an example of a random oriented tree model on d-dimensional lattice, that is a forest in d=3 with positive probability. This is in contrast with the other random tree models in the literature which are a forest…

Probability · Mathematics 2010-03-23 Siva Athreya , Sreekar Vadlamani

In surveys, the interest lies in estimating finite population parameters such as population totals and means. In most surveys, some auxiliary information is available at the estimation stage. This information may be incorporated in the…

Methodology · Statistics 2022-08-23 Mehdi Dagdoug , Camelia Goga , David Haziza
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