Search results for "DETECT"
showing 10 items of 5902 documents
A 3D CZT hard x-ray polarimeter for a balloon borne payload
2012
Currently, it is widely recognised that a measurement of the polarization status of cosmic sources high energy emission is a key observational parameter to understand the active production mechanism and its geometry. Therefore new instrumentation operating in this energy range should be optimized also for this type of measurement. In this framework, we present the concept of a small high-performance spectrometer designed for polarimetry between 100 and 500 keV suitable as a stratospheric balloon-borne payload dedicated to perform an accurate and reliable measurement of the polarization status of the Crab pulsar, i.e. the polarization level and direction. The detector with 3D spatial resolut…
Josephson-junction-based axion detection through resonant activation
2022
We discuss the resonant activation phenomenon on a Josephson junction due to the coupling of the Josephson system with axions. We show how such an effect can be exploited for axion detection. A nonmonotonic behavior, with a minimum, of the mean switching time from the superconducting to the resistive state versus the ratio of the axion energy and the Josephson plasma energy is found. We demonstrate how variations in switching times make it possible to detect the presence of the axion field. An experimental protocol for observing axions through their coupling with a Josephson system is proposed.
The Large Area Detector onboard the eXTP mission
2022
The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, a…
Carbon nanotubes thin filters for x-ray detectors in space
2022
In this paper, we present the first results from an investigation performed on nanometric thin pellicles based on carbon nanotubes (CNT) of potential interest for manufacturing large area optical blocking filters to protect soft X-ray detectors in astrophysics space missions. In order to evaluate the effective capability of such materials to block UV/VIS/IR radiation, while being highly transparent in the soft X-rays and strong enough to withstand the severe launch stresses, we have performed a suite of characterization measurements. These include: UV/VIS/IR and X-ray absorption spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy on bare and Al coated small self-…
Early warnings of Rhynchophorus ferrugineus infestation of Phoenix canariensis: a proximity thermal sensing approach
2011
Phoenix canariensis represents one of the most relevant ornamental plants within Mediterranean environment. In the last few years the infestation of a curculio coleopteron, namely the Rhynchophorus ferrugineus, caused a widespread decimation of these palms. Unluckily damages caused by the insect are evident only in the advanced phase of the disease making futile almost any plant treatment. Early warning of this disease may represents the only way to setup efficient actions to fight the coleopteron in trees where it takes over, thus limiting its spreading in contiguous palms. This research aims to achieve the former result by processing: i) short and long-wave images of the crown acquired du…
A Non-Parametric Parallel Harris-Affine Detector
2009
This paper describes a parallel version of a new automatic Harris-based corner detector. A simple but effective client-server based scheduler has been implemented in order to dynamically distribute the workload on heterogeneous parallel architectures such as Grid systems. Results obtained on the COMETA Grid show the effectiveness and the robustness of the proposed approach.
Sviluppi della Intelligenza Computazionale: l'esempio del Sarcasm Detection
2016
Dopo un periodo prolungato in cui vigeva uno scarto persistente tra l’ottimismo dato dai grandi proclami di ricerca e la scarsità e frammentarietà di risultati veri e tangibili, viviamo (finalmente) nell’era delle grandi conquiste dell’Intelligenza Artificiale
A Quantum-Inspired Classifier for Early Web Bot Detection
2022
This paper introduces a novel approach, inspired by the principles of Quantum Computing, to address web bot detection in terms of real-time classification of an incoming data stream of HTTP request headers, in order to ensure the shortest decision time with the highest accuracy. The proposed approach exploits the analogy between the intrinsic correlation of two or more particles and the dependence of each HTTP request on the preceding ones. Starting from the a-posteriori probability of each request to belong to a particular class, it is possible to assign a Qubit state representing a combination of the aforementioned probabilities for all available observations of the time series. By levera…
A Harris-based Region Detector on a Computational Grid
2007
This paper introduces a new Harris-based feature detector algorithm, characterized by no parameters tuning to detect region of interest. Preliminary results show that the proposed methodology returns good results with respect to standard detectors which need a set of parameters. An uncommon parallel implementation of the proposed algorithm is presented to support the high computational workload which is required to avoid the approximation of the results. Our parallel approach differs from the conventional one because an internal scheduler, based on the expected running time, is used to balance the data distribution on a client-server model. The aim of this paper is also to underline the adv…
Improving Harris corner selection strategy
2011
This study describes a corner selection strategy based on the Harris approach. Corners are usually defined as interest points for which intensity variation in the principal directions is locally maximised, as response from a filter given by the linear combination of the determinant and the trace of the autocorrelation matrix. The Harris corner detector, in its original definition, is only rotationally invariant, but scale-invariant and affine-covariant extensions have been developed. As one of the main drawbacks, corner detector performances are influenced by two user-given parameters: the linear combination coefficient and the response filter threshold. The main idea of the authors' approa…