832 research outputs found
Complex network analysis and nonlinear dynamics
This chapter aims at reviewing complex network and nonlinear dynamical
models and methods that were either developed for or applied to socioeconomic
issues, and pertinent to the theme of New Economic Geography. After an introduction
to the foundations of the field of complex networks, the present summary
introduces some applications of complex networks to economics, finance, epidemic
spreading of innovations, and regional trade and developments. The chapter also
reviews results involving applications of complex networks to other relevant
socioeconomic issue
Endemicity and prevalence of multipartite viruses under heterogeneous between-host transmission
Multipartite viruses replicate through a puzzling evolutionary strategy.
Their genome is segmented into two or more parts, and encapsidated in separate
particles that appear to propagate independently. Completing the replication
cycle, however, requires the full genome, so that a systemic infection of a
host requires the concurrent presence of several particles. This represents an
apparent evolutionary drawback of multipartitism, while its advantages remain
unclear. A transition from monopartite to multipartite viral forms has been
described in vitro under conditions of high multiplicity of infection,
suggesting that cooperation between defective mutants is a plausible
evolutionary pathway towards multipartitism. However, it is unknown how the
putative advantages that multipartitism might enjoy at the microscopic level
affect its epidemiology, or if an explicit advantange is needed to explain its
ecological persistence. To disentangle which mechanisms might contribute to the
rise and fixation of multipartitism, we investigate the interaction between
viral spreading dynamics and host population structure. We set up a
compartmental model of the spread of a virus in its different forms and explore
its epidemiology using both analytical and numerical techniques. We uncover
that the impact of host contact structure on spreading dynamics entails a rich
phenomenology of ecological relationships that includes cooperation,
competition, and commensality. We find that multipartitism might rise to
fixation even in the absence of explicit microscopic advantages. Multipartitism
allows the virus to colonize environments that could not be invaded by the
monopartite form, facilitated by homogeneous contacts among hosts. We
conjecture that these features might have led to an increase in the diversity
and prevalence of multipartite viral forms concomitantly with the expansion of
agricultural practices.Comment: 27 pages, 4 figures, 1 tabl
The structure and function of complex networks
Inspired by empirical studies of networked systems such as the Internet,
social networks, and biological networks, researchers have in recent years
developed a variety of techniques and models to help us understand or predict
the behavior of these systems. Here we review developments in this field,
including such concepts as the small-world effect, degree distributions,
clustering, network correlations, random graph models, models of network growth
and preferential attachment, and dynamical processes taking place on networks.Comment: Review article, 58 pages, 16 figures, 3 tables, 429 references,
published in SIAM Review (2003
A dynamic theory of fidelity networks with an application to the spread of HIV/AIDS
We study the dynamic stability of fidelity networks, which are networks that form in a mating economy of agents of two types (say men and women), where each agent desires direct links with opposite type agents, while engaging in multiple partnerships is considered an act of infidelity. Infidelity is punished more severely for women than for men. We consider two stochastic processes in which agents form and sever links over time based on the reward from doing so, but may also take non-beneficial actions with small probability. In the first process, an agent who invests more time in a relationship makes it stronger and harder to break by his/her partner; in the second, such an agent is perceived as weak. Under the first process, only egalitarian pairwise stable networks (in which all agents have the same number of partners) are visited in the long run, while under the second, only anti-egalitarian pairwise stable networks (in which all women are matched to a small number of men) are. Next, we apply these results to find that under the first process, HIV/AIDS is equally prevalent among men and women, while under the second, women bear a greater burden. The key message is that anti-female discrimination does not necessarily lead to higher HIV/AIDS prevalence among women in the short run, but it does in the long run.fidelity networks; anti-female discrimination; stochastic stability; HIV/AIDS; union formation models
Analyzing and Modeling Real-World Phenomena with Complex Networks: A Survey of Applications
The success of new scientific areas can be assessed by their potential for
contributing to new theoretical approaches and in applications to real-world
problems. Complex networks have fared extremely well in both of these aspects,
with their sound theoretical basis developed over the years and with a variety
of applications. In this survey, we analyze the applications of complex
networks to real-world problems and data, with emphasis in representation,
analysis and modeling, after an introduction to the main concepts and models. A
diversity of phenomena are surveyed, which may be classified into no less than
22 areas, providing a clear indication of the impact of the field of complex
networks.Comment: 103 pages, 3 figures and 7 tables. A working manuscript, suggestions
are welcome
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