3,223 research outputs found
Note sur l'ouvrage de M. Maggiora-Vergano intitulé : Sovra d'una moneta inedita di Francesco I di Francia. Asti, 1864, in-4°.
No full textLongpérier Adrien de. Note sur l'ouvrage de M. Maggiora-Vergano intitulé : Sovra d'una moneta inedita di Francesco I di Francia. Asti, 1864, in-4°.. In: Comptes rendus des séances de l'Académie des Inscriptions et Belles-Lettres, 8ᵉ année, 1864. pp. 356-358
An Innovative Harmonic Radar to Track Flying Insects: the Case of Vespa velutina
No full textOver the last 30 years, harmonic radars have been effective only in tracking insects flying at low altitude and over flat terrain. We developed an innovative harmonic radar, implementing the most advanced radar techniques, which covers a large field of view in elevation (with an angular aperture of about 24°) and can track insects up to a range of 500 m. We show all the components of this new harmonic radar and its first application, the tracking of Vespa velutina (yellow-legged Asian hornet). This is an invasive species which, although indigenous to South-East Asia, is spreading quickly to other regions of the world. Because of its fast diffusion and the serious threat it poses to both honeybee colonies and to humans, control measures are mandatory. When equipped with a small passive transponder, this radar system can track the flight trajectory of insects and locate nests to be destroyed. This tool has potential not only for monitoring V. velutina but also for tracking other larger insects and small size vertebrates
Modelling of antenna radiation pattern of a re-entry vehicle in presence of plasmaIEEE Antennas and Propagation Society Symposium, 2004.
No full textIterative channel estimation for non-binary LDPC-coded OFDM signals
No full textThis work deals with the issue of channel estimation in the context of non-binary LDPC-coded
OFDM systems over doubly selective multipath channels. In particular, we show how to derive an
iterative Wiener-filter-based estimation method using both time and frequency channel correlation and
considering the particular characteristics of the channel code. The proposed algorithm can use either
soft information or hard decisions fed back by the decoder to refine the channel estimation, so as to
improve the system performance at the expense of an increased receiver complexity. Simulation results
under typical working conditions are presented to compare the performance of the proposed method
with respect to classical techniques.</jats:p
An harmonic radar prototype for insect tracking in harsh environments
No full textHarmonic entomological radars have been used in the last decades to track small and lightweight passive tags carried by various insects, usually flying at low altitude and over flat terrain. Despite being exploited in many applications, not a lot of progress was achieved in terms of performances over the years. This paper reviews the research work done in this topic throughout the European LIFE project STOPVESPA, from 2015 to 2019. The main objective of LIFE STOPVESPA was to contain the invasive Asian hornet (Vespa velutina) and prevent it from further invading Italy. Among the foreseen activities, a new harmonic radar has been developed as an effective tool to locate the hornets nests to be destroyed. A preliminary prototype, based on a magnetron generator, was tested in 2015, showing a detection range of about 125 m. A first upgrade of this prototype was released in 2016, allowing to increase the detection range up to 150 m. A new approach, based on a solid state power amplifier and a digitally modulated signal, was then adopted for the second prototype developed in 2017 and extensively run in 2018; the detection range raised to 500 m. A last engineered prototype was eventually built for the 2019 summer campaign with additional improvements. This tool has been extensively validated over the last years with the Asian hornet but it has potential for tracking and monitoring many other flying insects
RF potentials analysis using TOPICA
No full textRadio-frequency (RF) heating is fully dependent on edge plasma conditions and particularly on the acceleration of charged particles which can damage the antennas and surroundings. Rectified RF field induces drifts on ions that can hit the first wall, causing hot spots, sputtering, impurities, fuel dilution and, eventually, disruption. These phenomena mainly depend on the antenna geometry and materials, on the plasma density profile at the edge and on the connection patterns. The heat flux attributed to accelerated ions is somehow proportional to the RF potential in front of the antenna. Because of this, the understanding of the RF potential generation in front of the antenna is crucial for every high RF power systems, in order to predict the deleterious particle flux and therefore mitigate its effect by means of a proper design. The TOPICA code, an innovative tool realized for the analysis and design of ICRH and LH antennas, has been upgraded to evaluate the RF potential in front of the antenna. The solution of the Maxwell's equations in plasma combined with the RF field map at the plasma edge (standard outputs of TOPICA calculation) allow for the computation of the RF fields also in the plasma region. A new TOPICA module has been developed to account for a rigorous procedure to obtain the RF potentials and RF potential mitigation techniques through antenna geometrical modifications have been studied and will be presented
FLR mode conversion effects in the coupling analysis of the ICRFstrap antenna in the IGNITOR machine
No full text- …
