1,115 research outputs found
Game theory in models of pedestrian room evacuation
We analyze the pedestrian evacuation of a rectangular room with a single door
considering a Lattice Gas scheme with the addition of behavioral aspects of the
pedestrians. The movement of the individuals is based on random and rational
choices and is affected by conflicts between two or more agents that want to
advance to the same position. Such conflicts are solved according to certain
rules closely related to the concept of strategies in Game Theory, cooperation
and defection. We consider game rules analogous to those from the Prisoner's
Dilemma and Stag Hunt games, with payoffs associated to the probabilities of
the individuals to advance to the selected site. We find that, even when
defecting is the rational choice for any agent, under certain conditions,
cooperators can take advantage from mutual cooperation and leave the room more
rapidly than defectors
Competition Among Companies: Coexistence and Extinction
We study a spatially homogeneous model of a market where several agents or
companies compete for a wealth resource. In analogy with ecological systems the
simplest case of such models shows a kind of "competitive exclusion" principle.
However, the inclusion of terms corresponding for instance to "company
efficiency" or to (ecological) "intracompetition" shows that, if the associated
parameter overcome certain threshold values, the meaning of "strong" and "weak"
companies should be redefined. Also, by adequately adjusting such a parameter,
a company can induce the "extinction" of one or more of its competitors.Comment: 5 pages, 3 figures include
Correlation effects in a simple model of small-world network
We analyze the effect of correlations in a simple model of small world
network by obtaining exact analytical expressions for the distribution of
shortest paths in the network. We enter correlations into a simple model with a
distinguished site, by taking the random connections to this site from an Ising
distribution. Our method shows how the transfer matrix technique can be used in
the new context of small world networks.Comment: 10 pages, 3 figure
The Next Steps: Thoughts of a Medical Student-Watcher
Speech given at the Albert Einstein College of Medicine Class of 2011 Transition Ceremony, April 2, 2009
Why, when, and how fast innovations are adopted
When the full stock of a new product is quickly sold in a few days or weeks,
one has the impression that new technologies develop and conquer the market in
a very easy way. This may be true for some new technologies, for example the
cell phone, but not for others, like the blue-ray. Novelty, usefulness,
advertising, price, and fashion are the driving forces behind the adoption of a
new product. But, what are the key factors that lead to adopt a new technology?
In this paper we propose and investigate a simple model for the adoption of an
innovation which depends mainly on three elements: the appeal of the novelty,
the inertia or resistance to adopt it, and the interaction with other agents.
Social interactions are taken into account in two ways: by imitation and by
differentiation, i.e., some agents will be inclined to adopt an innovation if
many people do the same, but other will act in the opposite direction, trying
to differentiate from the "herd". We determine the conditions for a successful
implantation of the new technology, by considering the strength of advertising
and the effect of social interactions. We find a balance between the
advertising and the number of anti-herding agents that may block the adoption
of a new product. We also compare the effect of social interactions, when
agents take into account the behavior of the whole society or just a part of
it. In a nutshell, the present model reproduces qualitatively the available
data on adoption of innovation.Comment: 11 pages, 13 figures (with subfigures), full paper (EPJB 2012) on
innovation adoption mode
What's Ahead for Med Ed?
In response to biomedical advances and changes in the practice environment, medical education is always in the process of change. This paper deals primarily with educational changes involving the integration of the disciplines of genomics, prevention and population health, global health and integrative medicine into the curriculum. External and internal forces that tend to impede development of professional and humanistic values are also discussed along with the call to action for developing strategies that mitigate these forces.
What’s Ahead for Med Ed?
In response to biomedical advances and changes in the practice environment, medical education is always in the process of change. This paper deals primarily with educational changes involving the integration of the disciplines of genomics, prevention and population health, global health and integrative medicine into the curriculum. External and internal forces that tend to impede development of professional and humanistic values are also discussed along with the call to action for developing strategies that mitigate these forces.
Comparison of voter and Glauber ordering dynamics on networks
We study numerically the ordering process of two very simple dynamical models
for a two-state variable on several topologies with increasing levels of
heterogeneity in the degree distribution. We find that the zero-temperature
Glauber dynamics for the Ising model may get trapped in sets of partially
ordered metastable states even for finite system size, and this becomes more
probable as the size increases. Voter dynamics instead always converges to full
order on finite networks, even if this does not occur via coherent growth of
domains. The time needed for order to be reached diverges with the system size.
In both cases the ordering process is rather insensitive to the variation of
the degreee distribution from sharply peaked to scale-free.Comment: 12 pages, 12 figure
Effects of Mass Media and Cultural Drift in a Model for Social Influence
In the context of an extension of Axelrod's model for social influence, we
study the interplay and competition between the cultural drift, represented as
random perturbations, and mass media, introduced by means of an external
homogeneous field. Unlike previous studies [J. C. Gonz\'alez-Avella {\it et
al}, Phys. Rev. E {\bf 72}, 065102(R) (2005)], the mass media coupling proposed
here is capable of affecting the cultural traits of any individual in the
society, including those who do not share any features with the external
message. A noise-driven transition is found: for large noise rates, both the
ordered (culturally polarized) phase and the disordered (culturally fragmented)
phase are observed, while, for lower noise rates, the ordered phase prevails.
In the former case, the external field is found to induce cultural ordering, a
behavior opposite to that reported in previous studies using a different
prescription for the mass media interaction. We compare the predictions of this
model to statistical data measuring the impact of a mass media vasectomy
promotion campaign in Brazil.Comment: 10 pages, 3 figures; minor changes; added references. To appear in
IJMP
- …