846 research outputs found
Recensione a Marotta G., Vanelli L., 2021, Fonologia e prosodia dell’italiano, Carocci Editore, 311
No full textRecensione a Marotta G., Vanelli L., 2021, Fonologia e prosodia dell’italiano, Carocci Editore, 31
The experimental setup of FAMU to measure the proton Zemach radius
No full textThe FAMU experiment data acquisition is approaching. During September 2022 the full experimental setup is going to measure for the first time the muonic hydrogen ground state hyperfine splitting and obtain a precise measurement of the proton Zemach radius, shedding some new light on the proton radius puzzle. This result will not be possible without a complete system which joins nuclear and laser physics. The FAMU setup is formed by a
gas cryogenic target filled with a mixture of hydrogen and oxygen in which muons injected from the RIKEN-RAL facility (UK) are stopped. The muonic hydrogen produced is then exposed to a tunable infrared laser beam, unique for its energy and narrow linewidth, able to induce the hyperfine energy jump. The transition will be measured as a variation of the muonic transfer rate from hydrogen to oxygen, observed through the detection of the X-rays
emitted during the de-exitation of muonic oxygen. This presentation will describe the final setup which is being installed in all its parts
Control System Optimization Techniques for Real-Time Applications in Fusion Plasmas: The RFX-mod Experience
No full textA series of techniques is presented that has been developed to optimize the output magnetic field of the feedback control system on the RFX-mod reversed field pinch device. With the aim of minimizing the harmonic distortion and correcting localized error fields, these methods should be lightweight for real-time application and effective in improving the performance of a system that is routinely used for active control of magnetohydrodynamic plasma instabilities. The implementation of simple, linear algebra based, real-time optimization methods will be described along with proof of the beneficial effects sought. The focus of this paper is set on a spurious harmonics reduction technique based on the decoupling of sensors and actuators; a description of its derivation will be given together with the implementation in the control loop. A similar procedure for the compensation of faulted actuators will also be mentioned
ITSoneWB: Profiling global taxonomic diversity of eukaryotic communities on Galaxy
No full textITSoneWB (ITSone WorkBench) is a Galaxy-based bioinformatic environment where comprehensive and high-quality reference data are connected with established pipelines and new tools in an automated and easy-to-use service targeted at global taxonomic analysis of eukaryotic communities based on Internal Transcribed Spacer 1 variants high-throughput sequencing
White noise characterization and thermo-mechanical analysis of DTT pick-up coils
No full textThe Divertor Tokamak Test (DTT) [1] is presently in the start-up phase of construction. Among diagnostics, the magnetic ones are the first components that will have to be ready for installation and commissioning when DTT vacuum vessel and magnets will be assembled. In this paper, the white noise characterization of DTT in-vessel pick up coil measurements and the thermo-mechanical analysis of ex-vessel pick up coils will be presented referring to the 2021 probe configuration. In particular, the systematic error due to white noise affecting the 80 internal pick-up coil measurements on plasma position reconstruction has been assessed. Such plasma reconstruction has been done by assuming a filamentary representation of the plasma current density. The effect of noise on the measurements is characterized evaluating the mean error, the mean square error and the standard deviation, on the difference between the noisy inverse reconstruction and the ideal inverse reconstruction evaluated on suitable plasma-wall gaps.
Moreover, a feasibility study of mounting a torlon pick-up coil between the vacuum vessel and the thermal shield, in terms of bulk has been developed. In addition, the probe thermomechanical stresses are preliminarily investigated for backing and operative conditions, assuming a welding as mounting solution. The study shows that no bulk criticality is present for mounting the external pick-up coil. The operative temperature results to be far from thermomechanical critical condition. On the contrary, the baking temperature T = 220 °C presents some critical issues. The achieved results are propaedeutic to make more detailed choice in the following design steps, such as the probe fixing solution, the bolt dimension and the materials. When detailed pick-up coils mounting solution will be defined, the stresses on the contact region between the pick-up coils and the vacuum vessel accurately evaluate
A tool to support the construction of reliable disruption databases
No full textAn algorithm for detection and automatic calculation of disruption main quantities has been proposed and tested on the discharges of recent campaigns in both JET and ASDEX Upgrade. The purpose of this paper is to describe a tool to support the construction of a reliable database, which is theoretically applicable to a wide variety of tokamaks and can support the operators in a very time consuming activity, reducing significantly the possibility of human errors. The algorithm performs its calculations on the basis of common and well defined criteria discussed with the Plasma and Control Operation Groups of the considered devices. Moreover, being the algorithm fully parameterized, it can be easily customized to other tokamaks and/or used for statistical purposes, according to criteria adopted in the framework of each study
Validity of Feature Importance in Low-Performing Machine Learning for Tabular Biomedical Data
No full textIn tabular data analysis, high model accuracy is often regarded as a prerequisite for discussing feature importance. This assumption stems from the expectation that the validity of feature importance correlates with model performance. In this work, we challenge this prevailing belief by demonstrating that even low-performing models can provide reliable feature importance on biomedical datasets. We conduct experiments to observe how feature importance rankings change as model performance progressively degrades. Using three synthetic datasets and four real-world biomedical datasets, we compare feature rankings from the full datasets to those obtained after reducing either the number of samples (samples removal) or the number of features (features removal), using different feature stability indices. Our results reveal that, in both synthetic and real datasets, feature rankings remain stable during performance degradation caused by features removal. In contrast, sample removal introduces greater discrepancies in feature importance rankings as performance deteriorates more severely. By analyzing the distribution of feature importance values and theoretically examining the probability that the model fails to distinguish importance between features, we show that models can still reliably identify feature importance despite performance degradation due to features removal. We conclude that the validity of feature importance can be preserved even at suboptimal model performance levels, as long as the degradation stems from insufficient features rather than insufficient samples. This has a considerable impact on biomedical research, where feature importance analysis plays a pivotal role in clinical decision support and translational bioinformatics
Application of the mirror procedure to the robustness and fault analysis of Divertor Tokamak Test facility
No full textDue to the critical impact on the plasma control, the reliability of the magnetic diagnostic system in a tokamak should be continuously supervised. A new procedure based on a robust estimation of the expected field in the probe region and its comparison with the actual measurement has been recently proposed and assessed on several devices. The application of the procedure in the case of the Divertor Tokamak Test facility is here discussed
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