15,604 research outputs found
Applications of Temporal Graph Metrics to Real-World Networks
Real world networks exhibit rich temporal information: friends are added and
removed over time in online social networks; the seasons dictate the
predator-prey relationship in food webs; and the propagation of a virus depends
on the network of human contacts throughout the day. Recent studies have
demonstrated that static network analysis is perhaps unsuitable in the study of
real world network since static paths ignore time order, which, in turn,
results in static shortest paths overestimating available links and
underestimating their true corresponding lengths. Temporal extensions to
centrality and efficiency metrics based on temporal shortest paths have also
been proposed. Firstly, we analyse the roles of key individuals of a corporate
network ranked according to temporal centrality within the context of a
bankruptcy scandal; secondly, we present how such temporal metrics can be used
to study the robustness of temporal networks in presence of random errors and
intelligent attacks; thirdly, we study containment schemes for mobile phone
malware which can spread via short range radio, similar to biological viruses;
finally, we study how the temporal network structure of human interactions can
be exploited to effectively immunise human populations. Through these
applications we demonstrate that temporal metrics provide a more accurate and
effective analysis of real-world networks compared to their static
counterparts.Comment: 25 page
Dynamics of interacting diseases
Current modeling of infectious diseases allows for the study of complex and
realistic scenarios that go from the population to the individual level of
description. However, most epidemic models assume that the spreading process
takes place on a single level (be it a single population, a meta-population
system or a network of contacts). In particular, interdependent contagion
phenomena can only be addressed if we go beyond the scheme one pathogen-one
network. In this paper, we propose a framework that allows describing the
spreading dynamics of two concurrent diseases. Specifically, we characterize
analytically the epidemic thresholds of the two diseases for different
scenarios and also compute the temporal evolution characterizing the unfolding
dynamics. Results show that there are regions of the parameter space in which
the onset of a disease's outbreak is conditioned to the prevalence levels of
the other disease. Moreover, we show, for the SIS scheme, that under certain
circumstances, finite and not vanishing epidemic thresholds are found even at
the thermodynamic limit for scale-free networks. For the SIR scenario, the
phenomenology is richer and additional interdependencies show up. We also find
that the secondary thresholds for the SIS and SIR models are different, which
results directly from the interaction between both diseases. Our work thus
solve an important problem and pave the way towards a more comprehensive
description of the dynamics of interacting diseases.Comment: 24 pages, 9 figures, 4 tables, 3 appendices. Final version accepted
for publication in Physical Review
Distributed Community Detection in Dynamic Graphs
Inspired by the increasing interest in self-organizing social opportunistic
networks, we investigate the problem of distributed detection of unknown
communities in dynamic random graphs. As a formal framework, we consider the
dynamic version of the well-studied \emph{Planted Bisection Model}
\sdG(n,p,q) where the node set of the network is partitioned into two
unknown communities and, at every time step, each possible edge is
active with probability if both nodes belong to the same community, while
it is active with probability (with ) otherwise. We also consider a
time-Markovian generalization of this model.
We propose a distributed protocol based on the popular \emph{Label
Propagation Algorithm} and prove that, when the ratio is larger than
(for an arbitrarily small constant ), the protocol finds the right
"planted" partition in time even when the snapshots of the dynamic
graph are sparse and disconnected (i.e. in the case ).Comment: Version I
Improved Bounds on Information Dissemination by Manhattan Random Waypoint Model
With the popularity of portable wireless devices it is important to model and
predict how information or contagions spread by natural human mobility -- for
understanding the spreading of deadly infectious diseases and for improving
delay tolerant communication schemes. Formally, we model this problem by
considering moving agents, where each agent initially carries a
\emph{distinct} bit of information. When two agents are at the same location or
in close proximity to one another, they share all their information with each
other. We would like to know the time it takes until all bits of information
reach all agents, called the \textit{flood time}, and how it depends on the way
agents move, the size and shape of the network and the number of agents moving
in the network.
We provide rigorous analysis for the \MRWP model (which takes paths with
minimum number of turns), a convenient model used previously to analyze mobile
agents, and find that with high probability the flood time is bounded by
, where agents move on an
grid. In addition to extensive simulations, we use a data set of
taxi trajectories to show that our method can successfully predict flood times
in both experimental settings and the real world.Comment: 10 pages, ACM SIGSPATIAL 2018, Seattle, U
Financing issues in proposed HIV/AIDS intervention of providing anti-retroviral drugs to selected regions in India
The development of antiretroviral therapy has given a new hope for people living with acquired immuno deficiency syndrome. In the face of increased disease burden due to HIV the global and political commitment towards controlling the pandemic has received renewed thrust in recent times. The Government of India has initiated antiretroviral treatment as a part of national public health programme in the six high-prevalence states. The aim of the paper is to provide the programme planners and other stakeholders, information about the impact of initiating antiretroviral therapy programme in the country. The paper discusses the global commitment towards fighting the disease in the light of the development in affordability and accessibility of antiretroviral drugs therapy. The paper highlights the importance of infrastructure and logistic requirement for developing a comprehensive treatment programme for the affected population in India. Finally, the paper has drawn broad financial implications of the antiretroviral therapy under different treatment scenarios. The estimated financial requirement for treatment vary from Rs. 92 crores per annum if focusing on 400,000 HIV/AIDs cases to identify patients requiring ARV Therapy to 1008 crores per annum if all 4 million patients are screened for coverage. Against this NACO has allocated total of Rs. 113 crores for treatment part of the proposed intervention. Even under the most conservative estimate achieving the treatment target in India with the proposed programme budget will be a challenging task.
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