748 research outputs found
Opinion dynamics model with domain size dependent dynamics: novel features and new universality class
A model for opinion dynamics (Model I) has been recently introduced in which
the binary opinions of the individuals are determined according to the size of
their neighboring domains (population having the same opinion). The coarsening
dynamics of the equivalent Ising model shows power law behavior and has been
found to belong to a new universality class with the dynamic exponent and persistence exponent in one dimension. The
critical behavior has been found to be robust for a large variety of annealed
disorder that has been studied. Further, by mapping Model I to a system of
random walkers in one dimension with a tendency to walk towards their nearest
neighbour with probability , we find that for any ,
the Model I dynamical behaviour is prevalent at long times.Comment: 12 pages, 10 figures. To be published in "Journal of Physics :
Conference Series" (2011
Income tax evasion dynamics: Evidence from an agent-based econophysics model
We analyze income tax evasion dynamics in a standard model of statistical mechanics, the Ising model of ferromagnetism. However, in contrast to previous research, we use an inhomogeneous multi-dimensional Ising model where the local degrees of freedom (agents) are subject to a specific social temperature and coupled to external fields which govern their social behavior. This new modeling frame allows for analyzing large societies of four different and interacting agent types. As a second novelty, our model may reproduce results from agent-based models that incorporate standard Allingham and Sandmo tax evasion features as well as results from existing two-dimensional Ising based tax evasion models. We then use our model for analyzing income tax evasion dynamics under different enforcement scenarios and point to some policy implications. --tax evasion,tax compliance,Ising Model,econophysics,numerical simulation
The Naming Game in Social Networks: Community Formation and Consensus Engineering
We study the dynamics of the Naming Game [Baronchelli et al., (2006) J. Stat.
Mech.: Theory Exp. P06014] in empirical social networks. This stylized
agent-based model captures essential features of agreement dynamics in a
network of autonomous agents, corresponding to the development of shared
classification schemes in a network of artificial agents or opinion spreading
and social dynamics in social networks. Our study focuses on the impact that
communities in the underlying social graphs have on the outcome of the
agreement process. We find that networks with strong community structure hinder
the system from reaching global agreement; the evolution of the Naming Game in
these networks maintains clusters of coexisting opinions indefinitely. Further,
we investigate agent-based network strategies to facilitate convergence to
global consensus.Comment: The original publication is available at
http://www.springerlink.com/content/70370l311m1u0ng3
Socioeconomic agents as active matter in nonequilibrium Sakoda-Schelling models
How robust are socioeconomic agent-based models with respect to the details
of the agents' decision rule? We tackle this question by considering an
occupation model in the spirit of the Sakoda-Schelling model, historically
introduced to shed light on segregation dynamics among human groups. For a
large class of utility functions and decision rules, we pinpoint the
nonequilibrium nature of the agent dynamics, while recovering the
equilibrium-like phase separation phenomenology. Within the mean field
approximation we show how the model can be mapped, to some extent, onto an
active matter field description (Active Model B). Finally, we consider
non-reciprocal interactions between two populations, and show how they can lead
to non-steady macroscopic behavior. We believe our approach provides a unifying
framework to further study geography-dependent agent-based models, notably
paving the way for joint consideration of population and price dynamics within
a field theoretic approach.Comment: 12 pages, 7 figure
Jamming and pattern formation in models of segregation
We investigate the Schelling model of social segregation, formulated as an
intrinsically non-equilibrium system, in which the agents occupy districts (or
patches) rather than sites on a grid. We show that this allows the equations
governing the dynamical behaviour of the model to be derived. Analysis of these
equations reveals a jamming transition in the regime of low-vacancy density,
and inclusion of a spatial dimension in the model leads to a pattern forming
instability. Both of these phenomena exhibit unusual characteristics which may
be studied through our approach.Comment: 5 pages, 4 figure
Spatial interactions in agent-based modeling
Agent Based Modeling (ABM) has become a widespread approach to model complex
interactions. In this chapter after briefly summarizing some features of ABM
the different approaches in modeling spatial interactions are discussed.
It is stressed that agents can interact either indirectly through a shared
environment and/or directly with each other. In such an approach, higher-order
variables such as commodity prices, population dynamics or even institutions,
are not exogenously specified but instead are seen as the results of
interactions. It is highlighted in the chapter that the understanding of
patterns emerging from such spatial interaction between agents is a key problem
as much as their description through analytical or simulation means.
The chapter reviews different approaches for modeling agents' behavior,
taking into account either explicit spatial (lattice based) structures or
networks. Some emphasis is placed on recent ABM as applied to the description
of the dynamics of the geographical distribution of economic activities, - out
of equilibrium. The Eurace@Unibi Model, an agent-based macroeconomic model with
spatial structure, is used to illustrate the potential of such an approach for
spatial policy analysis.Comment: 26 pages, 5 figures, 105 references; a chapter prepared for the book
"Complexity and Geographical Economics - Topics and Tools", P. Commendatore,
S.S. Kayam and I. Kubin, Eds. (Springer, in press, 2014
- âŚ