707 research outputs found
Il ruolo della robustezza strutturale nella impostazione ingegneristica della sicurezza antincendio
A data-science pipeline to enable the Interpretability of Many-Objective Feature Selection
Many-Objective Feature Selection (MOFS) approaches use four or more
objectives to determine the relevance of a subset of features in a supervised
learning task. As a consequence, MOFS typically returns a large set of
non-dominated solutions, which have to be assessed by the data scientist in
order to proceed with the final choice. Given the multi-variate nature of the
assessment, which may include criteria (e.g. fairness) not related to
predictive accuracy, this step is often not straightforward and suffers from
the lack of existing tools. For instance, it is common to make use of a tabular
presentation of the solutions, which provide little information about the
trade-offs and the relations between criteria over the set of solutions.
This paper proposes an original methodology to support data scientists in the
interpretation and comparison of the MOFS outcome by combining post-processing
and visualisation of the set of solutions. The methodology supports the data
scientist in the selection of an optimal feature subset by providing her with
high-level information at three different levels: objectives, solutions, and
individual features.
The methodology is experimentally assessed on two feature selection tasks
adopting a GA-based MOFS with six objectives (number of selected features,
balanced accuracy, F1-Score, variance inflation factor, statistical parity, and
equalised odds). The results show the added value of the methodology in the
selection of the final subset of features.Comment: 8 pages, 5 figures, 6 table
Physical properties of the nuclear region in Seyfert galaxies derived from observations with the European VLBI Network
We report on sensitive dual-frequency (1.7 and 5 GHz) European VLBI Network
observations of the central region of nine Seyfert galaxies. These sources are
among the faintest and least luminous members of a complete sample of nearby
(d<22 Mpc) low luminosity AGNs. We detect radio emission on milliarcsecond
scale in the nuclei of 4 galaxies, while for the other five sources we set an
upper limit of <~100 microJy. In three sources, namely NGC 3227, NGC 3982, and
NGC 4138, radio emission is detected at both 1.7 and 5 GHz and it is resolved
in two or more components. We describe the structural and spectral properties
of these features; we find that in each of these three nuclei there is one
component with high brightness temperature (typically T_B >10^7.5 K) and
flat/intermediate spectral index (0.3\leq alpha \leq 0.6, S(nu) \sim
nu^(-alpha), accompanied by secondary steep spectrum extended components. In
these cases, non-thermal emission from jets or outflows is thus the most
natural explanation. A faint feature is detected in NGC 4477 at 5 GHz; keeping
in mind the modest significance of this detection (~5sigma), we propose the hot
corona as the origin of non-thermal emission, on the basis of the unrealistic
magnetic field values required by synchrotron self-absorption. Finally, the
five non-detected nuclei remain elusive and further observations on
intermediate scales will be necessary to investigate their nature.Comment: Accepted for publication in MNRA
A 40 Gb/s InP-monolithically integrated DPSK-demolulator enhanced by cross-gain-compensation in an SOA
We fabricated and experimentally tested a novel monolithically integrated Indium Phosphide optical circuit for differential phase-shift keying demodulation, which is robust to noise degradations of the received signal. The circuit consists of a one-bit-delay interferometer that demodulates the incoming signal and a semiconductor optical amplifier where the constructive and destructive demodulated outputs synchronously counter-propagate experiencing a reshaping effect. The novel optical circuit has been fabricated for 40 Gb/s signals, and the amplitude signal restoration is demonstrated by comparing the obtained output eye diagrams with those of a commercial fiber-based demodulator. We find a net improvement in the signal to noise ratio when the circuit is fed with a noisy input signal
Thermo-mechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near infrared pump-probe diffraction experiments
The ultrafast thermal and mechanical dynamics of a two-dimensional lattice of
metallic nano-disks has been studied by near infrared pump-probe diffraction
measurements, over a temporal range spanning from 100 fs to several
nanoseconds. The experiments demonstrate that, in these systems, a
two-dimensional surface acoustic wave (2DSAW), with a wavevector given by the
reciprocal periodicity of the array, can be excited by ~120 fs Ti:sapphire
laser pulses. In order to clarify the interaction between the nanodisks and the
substrate, numerical calculations of the elastic eigenmodes and simulations of
the thermodynamics of the system are developed through finite-element analysis.
At this light, we unambiguously show that the observed 2DSAW velocity shift
originates from the mechanical interaction between the 2DSAWs and the
nano-disks, while the correlated 2DSAW damping is due to the energy radiation
into the substrate.Comment: 13 pages, 10 figure
Rubbing effects on the structural and optical properties of poly(3hexylthiophene) films
International audienc
Ultracompact microinterferometer-based fiber Bragg grating interrogator on a silicon chip
We report an interferometer-based multiplexed fiber Bragg grating (FBG) interrogator using silicon photonic technology. The photonic-integrated system includes the grating coupler, active and passive interferometers, interferometers, a 12-channel wavelength-division-multiplexing (WDM) filter, and Ge photodiodes, all integrated on a 6x8 mm2 silicon chip. The system also includes optical and electric interfaces to a printed board, which is connected to a real-time electronic board that actively performs the phase demodulation processing using a multitone mixing (MTM) technique. The device with active demodulation, which uses thermally-based phase shifters, features a noise figure of σ = 0.13 pm at a bandwidth of 700 Hz, which corresponds to a dynamic spectral resolution of 4.9 fm/Hz1/2. On the other hand, the passive version of the system, based on a 90º-hybrid coupler, features a noise figure of σ = 2.55 pm at a bandwidth of 10 kHz, also showing successful detection of a 42 kHz signal when setting the bandwidth to 50 kHz. These results demonstrate the advantage of integrated photonics, which allows the integration of several systems with different demodulation schemes in the same chip and guarantees easy scalability to a higher number of ports without increasing the dimensions or the cost
Prospective assessment of integrating the existing emergency medical system with automated external defibrillators fully operated by volunteers and laypersons for out-of-hospital cardiac arrest: the Brescia Early Defibrillation Study (BEDS)
AIMS: There are few data on the outcomes of cardiac arrest (CA) victims when the defibrillation capability of broad rural and urban territories is fully operated by volunteers and laypersons.
METHODS AND RESULTS: In this study, we investigated whether a programme based on diffuse deployment of automated external defibrillators (AEDs) operated by 2186 trained volunteers and laypersons across the County of Brescia, Italy (area: 4826 km(2); population: 1 112 628), would safely and effectively impact the current survival among victims of out-of-hospital CA. Forty-nine AEDs were added to the former emergency medical system that uses manual EDs in the emergency department of 10 county hospitals and in five medically equipped ambulances. The primary endpoint was survival free of neurological impairment at 1-year follow-up. Data were analysed in 692 victims before and in 702 victims after the deployment of the AEDs. Survival increased from 0.9% (95% CI 0.4-1.8%) in the historical cohort to 3.0% (95% CI 1.7-4.3%) (P=0.0015), despite similar intervals from dispatch to arrival at the site of collapse [median (quartile range): 7 (4) min vs. 6 (6) min]. Increase of survival was noted both in the urban [from 1.4% (95% CI 0.4-3.4 %) to 4.0% (95% CI 2.0-6.9 %), P=0.024] and in the rural territory [from 0.5% (95% CI 0.1-1.6%) to 2.5% (95% CI 1.3-4.2%), P=0.013]. The additional costs per quality-adjusted life year saved amounted to euro39 388 (95% CI euro16 731-49 329) during the start-up phase of the study and to euro23 661 (95% CI euro10 327-35 528) at steady state.
CONCLUSION: Diffuse implementation of AEDs fully operated by trained volunteers and laypersons within a broad and unselected environment proved safe and was associated with a significantly higher long-term survival of CA victims
The use of antimicrobials in italian heavy pig fattening farms
Data on antimicrobial use (AMU) in heavy pig production (>150 kg) are limited. The aim of this study was to investigate the AMU in this production. Data from 2015 were collected for 143 fattening farms. The AMU was estimated through a treatment index per 100 days (TI100) using the defined daily dose animal for Italy (DDDAit). When possible, a comparison with the European Medicines Agency’s defined daily doses for animals (DDDvet) was performed. The median TI100 was 10.7 (range, 0.2–49.5). Group treatments represented 94.6% of overall consumption. The AMU calculated using DDDAit and DDDvet were strongly correlated (ρ = 0.976; p < 0.001). The AMU was negatively correlated with injectables use (ρ = −0.46, p < 0.001) and positively correlated with oral products (ρ = 0.21, p = 0.014), premixes (ρ = 0.26, p = 0.002), and mortality (ρ = 0.18; p = 0.027). Farm size was negatively correlated with AMU (ρ = −0.29, p < 0.001). Smaller farms were more frequently above the median TI100 (odds ratio = 2.3, 95% confidence interval = 1.2–4.7), suggesting that they may have lower biosecurity and management standards. The results of this study should provide useful insights for the development of an Italian monitoring system
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