99 research outputs found
X-TCP: A Cross Layer Approach for TCP Uplink Flows in mmWave Networks
Millimeter wave frequencies will likely be part of the fifth generation of
mobile networks and of the 3GPP New Radio (NR) standard. MmWave communication
indeed provides a very large bandwidth, thus an increased cell throughput, but
how to exploit these resources at the higher layers is still an open research
question. A very relevant issue is the high variability of the channel, caused
by the blockage from obstacles and the human body. This affects the design of
congestion control mechanisms at the transport layer, and state-of-the-art TCP
schemes such as TCP CUBIC present suboptimal performance. In this paper, we
present a cross layer approach for uplink flows that adjusts the congestion
window of TCP at the mobile equipment side using an estimation of the available
data rate at the mmWave physical layer, based on the actual resource allocation
and on the Signal to Interference plus Noise Ratio. We show that this approach
reduces the latency, avoiding to fill the buffers in the cellular stack, and
has a quicker recovery time after RTO events than several other TCP congestion
control algorithms.Comment: 6 pages, 5 figures, accepted for presentation at the 2017 16th Annual
Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET
Reliable Video Streaming over mmWave with Multi Connectivity and Network Coding
The next generation of multimedia applications will require the
telecommunication networks to support a higher bitrate than today, in order to
deliver virtual reality and ultra-high quality video content to the users. Most
of the video content will be accessed from mobile devices, prompting the
provision of very high data rates by next generation (5G) cellular networks. A
possible enabler in this regard is communication at mmWave frequencies, given
the vast amount of available spectrum that can be allocated to mobile users;
however, the harsh propagation environment at such high frequencies makes it
hard to provide a reliable service. This paper presents a reliable video
streaming architecture for mmWave networks, based on multi connectivity and
network coding, and evaluates its performance using a novel combination of the
ns-3 mmWave module, real video traces and the network coding library Kodo. The
results show that it is indeed possible to reliably stream video over cellular
mmWave links, while the combination of multi connectivity and network coding
can support high video quality with low latency.Comment: To be presented at the 2018 IEEE International Conference on
Computing, Networking and Communications (ICNC), March 2018, Maui, Hawaii,
USA (invited paper). 6 pages, 4 figure
Global wave parametrices on globally hyperbolic spacetimes
In a recent work the first named author, Levitin and Vassiliev have
constructed the wave propagator on a closed Riemannian manifold as a single
oscillatory integral global both in space and in time with a distinguished
complex-valued phase function. In this paper, first we give a natural
reinterpretation of the underlying algorithmic construction in the language of
ultrastatic Lorentzian manifolds. Subsequently we show that the construction
carries over to the case of static backgrounds thanks to a suitable reduction
to the ultrastatic scenario. Finally we prove that the overall procedure can be
generalised to any globally hyperbolic spacetime with compact Cauchy surfaces.
As an application, we discuss how, from our procedure, one can recover the
local Hadamard expansion which plays a key role in all applications in quantum
field theory on curved backgrounds.Comment: 28 pages, final version accepted for publicatio
NR V2X Communications at Millimeter Waves: An End-to-End Performance Evaluation
3GPP NR V2X represents the new 3GPP standard for next-generation vehicular
systems which, among other innovations, supports vehicle-to-vehicle (V2V)
operations in the millimeter wave (mmWave) spectrum to address the
communication requirements of future intelligent automotive networks. While
mmWaves will enable massive data rates and low latency, the propagation
characteristics at very high frequencies become very challenging, thereby
calling for accurate performance evaluations as a means to properly assess the
performance of such systems. Along these lines, in this paper MilliCar, the new
ns-3 module based on the latest NR V2X specifications, is used to provide an
end-to-end performance evaluation of mmWave V2V networks. We investigate the
impact of different propagation scenarios and system parameters, including the
inter-vehicle distance, the adopted frame numerology, and the modulation and
coding scheme, and provide guidelines towards the most promising V2V deployment
configurations.Comment: 6 pages, 7 figures. Submitted to IEEE Globecom 202
PW08-03 The use of drugs for mood disorders in Italy: Preliminary results
Background:Some community surveys in Italy have shown that a proportion of subjects without lifetime psychiatric diagnosis (anxiety/depression) used antidepressants. The prescription of AD in bipolar depression appears to be another largely underestimated problem in the clinical practice and is difficult to recognise by means of traditional epidemiological methods (lay interview and structured diagnostic tools).Objectives:The purpose is to use defined and validated international semi-structured interview as diagnostic instrument administered by expert clinicians to evaluate appropriateness and amount of over and under prescription of psychotropic drugs in different Italian community areas. The focus is on general antidepressant use and use in subjects with bipolar disorder and in subsyndromal depression.Methods:Study design: Community survey. Study population: sample randomly drawn, after stratification by sex and age, from the adult population of Municipal records in 6 Italian Regions: about 4000 persons will be interviewed. Tools: Questionnaire on psychotropic drugs consumption, prescription, health services utilisation;diagnostic Structured Clinical Interview np version;Mood Disorders Questionnaire; Short Form Health Survey. Ethical aspects: a signed informed consent for each candidate. The study was approved by the ethical committee of theItalain National Health Institute.Expected results:The study aims to identify the frequency of over and under prescription of psychotropic drugs in different Italian regions and the determinants of prescription related to physicians, patients, comorbidity and symptoms and to establish the basis for a cohort prospective study to assess the future changes
Modello di stima dei costi sanitari e della capacity delle terapie intensive in Italia nel trattamento di pazienti affetti da COVID-19: valutazione dell’impatto di remdesivir
Introduction: Coronavirus disease 2019 (COVID-19) is caused by a severe acute respiratory syndrome coronavirus 2,
which is a human coronavirus responsible for a pandemic. Direct interventions, i.e. physical distancing and use
of protective devices, can prevent or limit contagions, however, it is also required to evaluate the optimization
of limited resources, such as the Intensive Care Unit (ICU). For this purpose, it is relevant to estimate the impact
of therapeutic solutions that reduce the probability that the patient transits to ICU in symptomatic subjects and
in need of hospitalization. The therapeutic solutions allow a more rapid recovery of the patient and save scarce
resources that can be used in the treatment of other patients.
Methods: A forecasting model is designed to estimate the impact of one therapeutic solution, i.e. the antiretroviral
Remdesivir,
on
both
the
capacity
of
intensive
care
and
the
healthcare
costs
for
hospitals
when
managing
the
current emergency. A base case is presented as well as a best and a worst case scenario deriving from the
sensitivity analyses.
Results: The introduction of Remdesivir in patients receiving low-flow oxygen therapy with the purpose of reducing
ICU
accesses
and
deaths
leads
to
431
million
euros
cost
savings
and
avoids
17,150
hospitalizations
in
intensive
care
and 6,923 deaths. In the best case, 294 million euros savings are estimated, whilst in the worst case the
model estimates a saving of 512 million euros.
Conclusions: Remdesivir has the potential to reduce the negative effects of the Coronavirus disease, improving
patient conditions and reducing death tolls, and can also save scarce healthcare resources during this pandemic,
resulting in a shorter hospital stay and fewer ICU admissions
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