41,873 research outputs found
Modeling Public Opinion
The population dynamics of public opinion have many similarities to those of epidemics. For example, models of epidemics and public opinion share characteristics like contact rates, incubation times, and recruitment rates. Generally, epidemic dynamics have been presented through epidemiological models. In this paper we adapt an epidemiological model to demonstrate the population dynamics of public opinion given two opposing viewpoints. We find equilibrium solutions for various cases of the system and examine the local stability. Overall, our system provides sociological insight on the spread and transition of a public opinion
A model of dengue fever
BACKGROUND: Dengue is a disease which is now endemic in more than 100 countries of Africa, America, Asia and the Western Pacific. It is transmitted to the man by mosquitoes (Aedes) and exists in two forms: Dengue Fever and Dengue Haemorrhagic Fever. The disease can be contracted by one of the four different viruses. Moreover, immunity is acquired only to the serotype contracted and a contact with a second serotype becomes more dangerous. METHODS: The present paper deals with a succession of two epidemics caused by two different viruses. The dynamics of the disease is studied by a compartmental model involving ordinary differential equations for the human and the mosquito populations. RESULTS: Stability of the equilibrium points is given and a simulation is carried out with different values of the parameters. The epidemic dynamics is discussed and illustration is given by figures for different values of the parameters. CONCLUSION: The proposed model allows for better understanding of the disease dynamics. Environment and vaccination strategies are discussed especially in the case of the succession of two epidemics with two different viruses
SIRS Epidemics on Complex Networks: Concurrence of Exact Markov Chain and Approximated Models
We study the SIRS (Susceptible-Infected-Recovered-Susceptible) spreading
processes over complex networks, by considering its exact -state Markov
chain model. The Markov chain model exhibits an interesting connection with its
-state nonlinear "mean-field" approximation and the latter's corresponding
linear approximation. We show that under the specific threshold where the
disease-free state is a globally stable fixed point of both the linear and
nonlinear models, the exact underlying Markov chain has an mixing
time, which means the epidemic dies out quickly. In fact, the epidemic
eradication condition coincides for all the three models. Furthermore, when the
threshold condition is violated, which indicates that the linear model is not
stable, we show that there exists a unique second fixed point for the nonlinear
model, which corresponds to the endemic state. We also investigate the effect
of adding immunization to the SIRS epidemics by introducing two different
models, depending on the efficacy of the vaccine. Our results indicate that
immunization improves the threshold of epidemic eradication. Furthermore, the
common threshold for fast-mixing of the Markov chain and global stability of
the disease-free fixed point improves by the same factor for the
vaccination-dominant model.Comment: A short version of this paper has been submitted to CDC 201
The Effect of Disease-induced Mortality on Structural Network Properties
As the understanding of the importance of social contact networks in the
spread of infectious diseases has increased, so has the interest in
understanding the feedback process of the disease altering the social network.
While many studies have explored the influence of individual epidemiological
parameters and/or underlying network topologies on the resulting disease
dynamics, we here provide a systematic overview of the interactions between
these two influences on population-level disease outcomes. We show that the
sensitivity of the population-level disease outcomes to the combination of
epidemiological parameters that describe the disease are critically dependent
on the topological structure of the population's contact network. We introduce
a new metric for assessing disease-driven structural damage to a network as a
population-level outcome. Lastly, we discuss how the expected individual-level
disease burden is influenced by the complete suite of epidemiological
characteristics for the circulating disease and the ongoing process of network
compromise. Our results have broad implications for prediction and mitigation
of outbreaks in both natural and human populations.Comment: 23 pages, 6 figure
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