49 research outputs found
A Mobile and Web Platform for Crowdsourcing OBD-II Vehicle Data
On-Board Diagnostics 2 (OBD-II) protocol allows monitoring vehicle status parameters. Analyzing them is highly useful for Intelligent Transportation Systems (ITS) research, applications and services. Unfortunately, large-scale OBD datasets are not publicly available due to the effort of producing them as well as due to competitiveness in the automotive sector. This paper proposes a framework to enable a worldwide crowdsourcing approach to the generation of OBD-II data, similarly to OpenStreetMap (OSM) for cartography. The proposal comprises: (i) an extension of the GPX data format for route logging, augmented with OBD-II parameters; (ii) a fork of an open source Android OBD-II data logger to store and upload route traces, and (iii) a Web platform extending the OSM codebase to support storage, search and editing of traces with embedded OBD data. A full platform prototype has been developed and early scalability tests have been carried out in various workloads to assess the sustainability of the proposal
Quantum Zeno and Anti-Zeno probes of noise correlations in photon polarisation
We experimentally demonstrate, for the first time, noise diagnostics by
repeated quantum measurements. Specifically, we establish the ability of a
single photon, subjected to random polarisation noise, to diagnose
non-Markovian temporal correlations of such a noise process. In the frequency
domain, these noise correlations correspond to colored noise spectra, as
opposed to the ones related to Markovian, white noise. Both the noise spectrum
and its corresponding temporal correlations are diagnosed by probing the photon
by means of frequent, (partially-)selective polarisation measurements. Our main
result is the experimental demonstration that noise with positive temporal
correlations corresponds to our single photon undergoing a dynamical regime
enabled by the quantum Zeno effect (QZE), while noise characterized by negative
(anti-) correlations corresponds to regimes associated with the anti-Zeno
effect (AZE). This demonstration opens the way to a new kind of noise
spectroscopy based on QZE and AZE in photon (or other single-particle) state
probing
Phase Noise in Real-World Twin-Field Quantum Key Distribution
We investigate the impact of noise sources in real-world implementations of
Twin-Field Quantum Key Distribution (TF-QKD) protocols, focusing on phase noise
from photon sources and connecting fibers. Our work emphasizes the role of
laser quality, network topology, fiber length, arm balance, and detector
performance in determining key rates. Remarkably, it reveals that the leading
TF-QKD protocols are similarly affected by phase noise despite different
mechanisms. Our study demonstrates duty cycle improvements of over 2x through
narrow-linewidth lasers and phase-control techniques, highlighting the
potential synergy with high-precision time/frequency distribution services.
Ultrastable lasers, evolving toward integration and miniaturization, offer
promise for agile TF-QKD implementations on existing networks. Properly
addressing phase noise and practical constraints allows for consistent key rate
predictions, protocol selection, and layout design, crucial for establishing
secure long-haul links for the Quantum Communication Infrastructures under
development in several countries.Comment: 18 pages, 8 figures, 2 table
Infection fatality ratio of SARS-CoV-2 in Italy
We analyzed 5,484 close contacts of COVID-19 cases from Italy, all of them
tested for SARS-CoV-2 infection. We found an infection fatality ratio of 2.2%
(95%CI 1.69-2.81%) and identified male sex, age >70 years, cardiovascular
comorbidities, and infection early in the epidemics as risk factors for death
Probability of symptoms and critical disease after SARS-CoV-2 infection
We quantified the probability of developing symptoms (respiratory or fever
\geq 37.5 {\deg}C) and critical disease (requiring intensive care or resulting
in death) of SARS-CoV-2 positive subjects. 5,484 contacts of SARS-CoV-2 index
cases detected in Lombardy, Italy were analyzed, and positive subjects were
ascertained via nasal swabs and serological assays. 73.9% of all infected
individuals aged less than 60 years did not develop symptoms (95% confidence
interval: 71.8-75.9%). The risk of symptoms increased with age. 6.6% of
infected subjects older than 60 years had critical disease, with males at
significantly higher risk.Comment: sample increased: results updated with new records coming from the
ongoing serological survey
Multifragment production in Au+Au at 35 MeV/u
Multifragment disintegration has been measured with a high efficiency
detection system for the reaction at . From the event
shape analysis and the comparison with the predictions of a many-body
trajectories calculation the data, for central collisions, are compatible with
a fast emission from a unique fragment source.Comment: 9 pages, LaTex file, 4 postscript figures available upon request from
[email protected]. - to appear in Phys. Lett.
Mass and charge identification of fragments detected with the Chimera Silicon-CsI(Tl) telescopes
Mass and charge identification of charged products detected with
Silicon-CsI(Tl) telescopes of the Chimera apparatus is presented. An
identification function, based on the Bethe-Bloch formula, is used to fit
empirical correlation between Delta E and E ADC readings, in order to
determine, event by event, the atomic and mass numbers of the detected charged
reaction products prior to energy calibration.Comment: 24 pages, 7 .jpg figures, submitted to Nucl.Instr.
Exploring reaction mechanisms and their competition in 58Ni+48Ca collisions at E = 25 AMeV
OPEN ACCESS; International audience; Latest results concerning the study of central collisions in 58Ni+48Ca reactions at Elab(Ni)=25 AMeV are presented. The experimental data, collected with the CHIMERA 4Ď€ device, have been analyzed in order to investigate the competition among different reaction mechanisms for central collisions in the Fermi energy domain. The method adopted to perform the centrality selection refers to the global variable "flow angle", that is related to the event shape in momentum space, as it is determined by the eigenvectors of the experimental kinetic-energy tensor. The main features of the reaction products were explored by using different constraints on some of the relevant observables, such as mass and velocity distributions and their correlations. Much emphasis was devoted to the competition between fusion-evaporation processes with subsequent identification of a heavy residue and a prompt multifragmentation mechanism. The reaction mechanism was simulated in the framework of transport theories (dynamical stochastic BNV calculations, followed by sequential SIMON code) and further comparison with dynamical calculations from transport model (QMD, CoMD) are in progress. Moreover, an extension of this study taking into account for the light particles has been envisaged