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As mathematical model for the evolutionary equations of species the masterequation is choiced. Two formulations will be demonstrated to include the changes of parameters into the masterequation - that is, on the one hand, the formation of a…

Populations and Evolution · Quantitative Biology 2007-05-23 Ingrid Hartmann

Multivariate probability density functions of returns are constructed in order to model the empirical behavior of returns in a financial time series. They describe the well-established deviations from the Gaussian random walk, such as an…

Condensed Matter · Physics 2007-08-23 E. Alessio , V. Frappietro , M. I. Krivoruchenko , L. J. Streckert

In this paper, dynamical systems theory and bifurcation theory are applied to investi- gate the rich dynamical behaviours observed in three simple disease models. The 2- and 3-dimensional models we investigate have arisen in previous…

Dynamical Systems · Mathematics 2015-04-22 Wenjing Zhang , Pei Yu , Lindi M. Wahl

This paper introduces a class of copula models for spatial data, based on multivariate Pareto-mixture distributions. We explore the tail properties of these models, demonstrating their ability to capture both tail dependence and asymptotic…

Methodology · Statistics 2026-01-28 Pavel Krupskii

We consider a parametric modelling approach for survival data where covariates are allowed to enter the model through multiple distributional parameters, i.e., scale and shape. This is in contrast with the standard convention of having a…

Methodology · Statistics 2021-11-17 Fatima-Zahra Jaouimaa , Il Do Ha , Kevin Burke

Let $(X,f)$ be a dynamical system with the specification property and $\varphi$ be continuous functions. In this paper, we establish some conditional variational principles for the upper and lower Bowen/packing metric mean dimension with…

Dynamical Systems · Mathematics 2024-07-23 Tianlong Zhang , Ercai Chen , Xiaoyao Zhou

Recently a multifractal object, $Q_{mf}$, was proposed to study percolation properties in a multifractal support. The area and the number of neighbors of the blocks of $Q_{mf}$ show a non-trivial behavior. The value of the probability of…

Statistical Mechanics · Physics 2015-06-24 L. S. Lucena , J. E. Freitas , G. Corso , R. F. Soares

Research over the past few decades has assumed the richness (number of species) to be the primary driver of the biodiversity and ecosystem function (BEF) relationship. However, biodiversity is multi-dimensional, and richness alone does not…

Complementarity among species with different traits is one of the basic processes affecting biodiversity, defined as the number of species in the ecosystem. We present here a soluble model ecosystem in which the species are characterized by…

Disordered Systems and Neural Networks · Physics 2009-11-07 Viviane M. de Oliveira , J. F. Fontanari

There has been a considerable effort to understand and quantify the spatial distribution of species across different ecosystems. Relative species abundance (RSA), beta diversity and species area relationship (SAR) are among the most used…

Populations and Evolution · Quantitative Biology 2012-09-18 Jacopo Grilli , Sandro Azaele , Jayanth R Banavar , Amos Maritan

In recent decades, it has been emphasized that the evolving structure of networks may be shaped by interaction principles that yield sparse graphs with a vertex degree distribution exhibiting an algebraic tail, and other structural traits…

Statistical Mechanics · Physics 2025-07-01 Dario Borrelli

Function diversity, the range of tasks individuals perform, and specialization, the distribution of function abundances, are fundamental to complex adaptive systems. In the absence of overarching principles, these properties have appeared…

Multifractal systems usually have singularity spectra defined on bounded sets of H\"older exponents. As a consequence, their associated multifractal scaling exponents are expected to depend linearly upon statistical moment orders at high…

Fluid Dynamics · Physics 2021-06-30 L. Moriconi

We use the techniques developed in [1] to study the local average of random fields with spectral density $1/f^{\alpha}$. We study their scaling properties and show that the self-similarity of $1/f$ random fields is preserved under the local…

Adaptation and Self-Organizing Systems · Physics 2007-05-23 Hai Lin

We propose models and algorithms for learning about random directions in two-dimensional simplex data, and apply our methods to the study of income level proportions and their changes over time in a geostatistical area. There are several…

Methodology · Statistics 2022-05-24 Rayleigh Lei , XuanLong Nguyen

A cellular model introduced for the evolution of the fluvial landscape is revisited using extensive numerical and scaling analyses. The basic network shapes and their recurrence especially in the aggregation structure are then addressed.…

Statistical Mechanics · Physics 2009-10-31 G. Caldarelli

We present a Bayesian approach for modeling multivariate, dependent functional data. To account for the three dominant structural features in the data--functional, time dependent, and multivariate components--we extend hierarchical dynamic…

Methodology · Statistics 2019-07-02 Daniel R. Kowal , David S. Matteson , David Ruppert

This article describes mathematical methods for estimating the top-tail of the wealth distribution and therefrom the share of total wealth that the richest $p$ percent hold, which is an intuitive measure of inequality. As the data base for…

Applications · Statistics 2018-07-11 Christoph Dalitz

A contribution is presented to the study of hadron spectroscopy through the use of fractals and discrete scale invariance implying log-periodic corrections to continuous scaling. The masses of mesons and baryons, reported by the Particle…

General Physics · Physics 2011-05-11 Boris Tatischeff

The search for more realistic modeling of financial time series reveals several stylized facts of real markets. In this work we focus on the multifractal properties found in price and index signals. Although the usual Minority Game (MG)…

Trading and Market Microstructure · Quantitative Finance 2008-12-10 Antonio F. Crepaldi , Camilo Rodrigues Neto , Fernando F. Ferreira , Gerson Francisco
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