92 research outputs found
Planning UAV Activities for Efficient User Coverage in Disaster Areas
Climate changes brought about by global warming as well as man-made
environmental changes are often the cause of sever natural disasters. ICT,
which is itself responsible for global warming due to its high carbon
footprint, can play a role in alleviating the consequences of such hazards by
providing reliable, resilient means of communication during a disaster crisis.
In this paper, we explore the provision of wireless coverage through UAVs
(Unmanned Aerial Vehicles) to complement, or replace, the traditional
communication infrastructure. The use of UAVs is indeed crucial in emergency
scenarios, as they allow for the quick and easy deployment of micro and pico
cellular base stations where needed. We characterize the movements of UAVs and
define an optimization problem to determine the best UAV coverage that
maximizes the user throughput, while maintaining fairness across the different
parts of the geographical area that has been affected by the disaster. To
evaluate our strategy, we simulate a flooding in San Francisco and the car
traffic resulting from people seeking safety on higher ground
The newer opioid agonist treatment with lower substitutive opiate doses is associated with better toxicology outcome than the older harm reduction treatment
Background: Charge-free heroin use disorder treatment in Italy follows two main approaches, i.e., harm reduction treatment (HRT) strategy in community low-threshold facilities for drug addiction and opioid agonist treatment (OAT) in high-threshold facilities for opioid addiction, focusing on pharmacological maintenance according to the Dole and Nyswander strategy. We aimed to compare the impact of HRT and OAT on patient outcome, as assessed through negativity for drugs on about 1-year urinalyses. Methods: We examined retrospectively the urinalyses of HRT and OAT patients for which at least four randomly sampled urinalyses per month were available for about 1 year, during which patients were undergoing methadone or buprenorphine maintenance; urinalyses focused on heroin, cocaine, cannabinoids, and their metabolites. Results: Included were 189 HRT and 58 OAT patients. The latter were observed for a significantly longer period. There was a higher proportion of heroin- and cocaine-clean urinalyses in OAT patients, with cocaine-clean urinalyses discriminating best between the two groups. OAT patients were older, with longer dependence duration, more severe addiction history, and received lower methadone doses. Buprenorphine maintenance was more often associated with heroin-clean urinalyses. The higher the methadone doses, the lower were the percentage of heroin-clean urinalyses in HRT patients (negative correlation). Conclusions: The OAT approach was related to higher recovery and polyabuse abstinence rates compared to the HRT approach, despite greater severity of substance use, psychiatric and physical comorbidities. Our results are consistent with the possibility to use lower maintenance opiate doses (after induction and stabilization in methadone treatment according to Dole and Nyswander methodology) in treating heroin addiction. This seemed to be impossible adopting the currently accepted HRT model
Localization and Equipartition of Energy in the beta-FPU Chain : Chaotic Breathers
The evolution towards equipartition in the -FPU chain is studied
considering as initial condition the highest frequency mode. Above an
analytically derived energy threshold, this zone-boundary mode is shown to be
modulationally unstable and to give rise to a striking localization process.
The spontaneously created excitations have strong similarity with moving exact
breathers solutions. But they have a finite lifetime and their dynamics is
chaotic. These chaotic breathers are able to collect very efficiently the
energy in the chain. Therefore their size grows in time and they can transport
a very large quantity of energy. These features can be explained analyzing the
dynamics of perturbed exact breathers of the FPU chain. In particular, a close
connection between the Lyapunov spectrum of the chaotic breathers and the
Floquet spectrum of the exact ones has been found. The emergence of chaotic
breathers is convincingly explained by the absorption of high frequency phonons
whereas a breather's metastability is for the first time identified. The
lifetime of the chaotic breather is related to the time necessary for the
system to reach equipartition. The equipartition time turns out to be dependent
on the system energy density only. Moreover, such time diverges as
in the limit and vanishes as
for .Comment: 20 pages, Revtex - Submitted to Physica
q-Breathers and thermalization in acoustic chains with arbitrary nonlinearity index
Nonlinearity shapes lattice dynamics affecting vibrational spectrum,
transport and thermalization phenomena. Beside breathers and solitons one finds
the third fundamental class of nonlinear modes -- -breathers -- periodic
orbits in nonlinear lattices, exponentially localized in the reciprocal mode
space. To date, the studies of -breathers have been confined to the cubic
and quartic nonlinearity in the interaction potential. In this paper we study
the case of arbitrary nonlinearity index in an acoustic chain. We
uncover qualitative difference in the scaling of delocalization and stability
thresholds of -breathers with the system size: there exists a critical index
, below which both thresholds (in nonlinearity strength) tend to
zero, and diverge when above. We also demonstrate that this critical index
value is decisive for the presence or absense of thermalization. For a generic
interaction potential the mode space localized dynamics is determined only by
the three lowest order nonlinear terms in the power series expansion.Comment: 5 pages, 4 figure
Automated deployment and scaling of automotive safety services in 5G-Transformer
There is a growing interest of verticals (in this case, the automotive industry) to reap the benefits of 5G networks. At
the same time, there is a clear trend of the telco industry to under-stand their needs. These are also some of the main goals of the EU 5G-TRANSFORMER (5GT) project. This demo focuses on the need of verticals to dynamically deploy services at the edge and
to adapt the vertical service to network operational conditions. In particular, it is presented the extended virtual sensing (EVS)
service, which deployed on demand at the distributed computing infrastructure (i.e. in the network), complements sensing and
processing functions running in the car to detect the risk of collisions and take appropriate action, even if there is no direct
communication between cars. The stringent latency constraints imposed by the EVS network service leave a limited processing
budget at the vertical service level. Since such processing time is correlated with the CPU consumption of a virtual machine
running a VNF of the EVS network service, in this demo we also show how the vertical service exploits the automated scaling
capabilities offered by the 5GT service orchestrator to deploy a new instance of the EVS VNF upon reception of a CPU
consumption alert generated by the available 5GT monitoring platform.Grant numbers : grant TEC2017-88373-R (5G-REFINE) and Generalitat de Catalunya grant 2017 SGR 1195.© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works
The Fermi-Pasta-Ulam problem revisited: stochasticity thresholds in nonlinear Hamiltonian systems
The Fermi-Pasta-Ulam -model of harmonic oscillators with cubic
anharmonic interactions is studied from a statistical mechanical point of view.
Systems of N= 32 to 128 oscillators appear to be large enough to suggest
statistical mechanical behavior. A key element has been a comparison of the
maximum Lyapounov coefficient of the FPU -model and
that of the Toda lattice. For generic initial conditions, is
indistinguishable for the two models up to times that increase with decreasing
energy (at fixed N). Then suddenly a bifurcation appears, which can be
discussed in relation to the breakup of regular, soliton-like structures. After
this bifurcation, the of the FPU model appears to approach a
constant, while the of the Toda lattice appears to approach
zero, consistent with its integrability. This suggests that for generic initial
conditions the FPU -model is chaotic and will therefore approach
equilibrium and equipartition of energy. There is, however, a threshold energy
density , below which trapping occurs; here the
dynamics appears to be regular, soliton-like and the approach to equilibrium -
if any - takes longer than observable on any available computer. Above this
threshold the system appears to behave in accordance with statistical
mechanics, exhibiting an approach to equilibrium in physically reasonable
times. The initial conditions chosen by Fermi, Pasta and Ulam were not generic
and below threshold and would have required possibly an infinite time to reach
equilibrium.Comment: 24 pages, REVTeX, 8 PostScript figures. Published versio
5G Mobile Transport and Computing Platform for verticals
The support of 5G verticals service requires todesign an efficient Mobile Transport and Computing Platformwhere transport, mobile and MEC must interact effectively. Inthis paper, a novel architecture is proposed providing itsmapping on ETSI NFV. Two relevant use cases, such asautomotive and cloud robotics are presented to assess the novelarchitecture.This work has been partially funded by the EU H2020 5G-Transformer Project (grant no. 761536)
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