9,753 research outputs found
Epcast: Controlled Dissemination in Human-based Wireless Networks by means of Epidemic Spreading Models
Epidemics-inspired techniques have received huge attention in recent years
from the distributed systems and networking communities. These algorithms and
protocols rely on probabilistic message replication and redundancy to ensure
reliable communication. Moreover, they have been successfully exploited to
support group communication in distributed systems, broadcasting, multicasting
and information dissemination in fixed and mobile networks. However, in most of
the existing work, the probability of infection is determined heuristically,
without relying on any analytical model. This often leads to unnecessarily high
transmission overheads.
In this paper we show that models of epidemic spreading in complex networks
can be applied to the problem of tuning and controlling the dissemination of
information in wireless ad hoc networks composed of devices carried by
individuals, i.e., human-based networks. The novelty of our idea resides in the
evaluation and exploitation of the structure of the underlying human network
for the automatic tuning of the dissemination process in order to improve the
protocol performance. We evaluate the results using synthetic mobility models
and real human contacts traces
Probing defects and correlations in the hydrogen-bond network of ab initio water
The hydrogen-bond network of water is characterized by the presence of
coordination defects relative to the ideal tetrahedral network of ice, whose
fluctuations determine the static and time-dependent properties of the liquid.
Because of topological constraints, such defects do not come alone, but are
highly correlated coming in a plethora of different pairs. Here we discuss in
detail such correlations in the case of ab initio water models and show that
they have interesting similarities to regular and defective solid phases of
water. Although defect correlations involve deviations from idealized
tetrahedrality, they can still be regarded as weaker hydrogen bonds that retain
a high degree of directionality. We also investigate how the structure and
population of coordination defects is affected by approximations to the
inter-atomic potential, finding that in most cases, the qualitative features of
the hydrogen bond network are remarkably robust
- …