71 research outputs found
Analysis of Liquid Water and Water Vapor Time Series and Rainy Period Detection from a Two Channel Microwave Radiometer
No full textPrediction of Microwave Attenuation Across a Satellite Link From the ERA-Interim Global Atmospheric Database
No full textThe high time and space resolution of the ERAInterim
atmospheric database is exploited here to predict the
components of microwave attenuation across a satellite link
which can be, for instance, used in the design of advanced
satellite telecommunication systems based on adaptive technique
Statistical Assessment of New Methods to Optimize the Power Flux Distribution in TV-sat Broadcasting at 20 GHz
No full textIn this paper we present the results of a statistical performance assessment of a new advanced TV-sat system operating in the ka band. The on-board transmission system is based on the idea of reconfigurable antenna, i.e. the antenna directivity can be modified so as to irradiate more power to the regions affected by bad weather. The core is a power flux distribution optimizer based on the “derivative slicing” method, whose mathematical basis is described in the companion paper [1] presented at this Conference. Here, the above technique is assessed by verifying the system performance through a statistical analysis over six-months.
The simulations make use of a meteorological database provided by the European Centre for Medium-range Weather Forecasts (ECMWF). The constraints unavoidably posed by the usage of a physically realizable Beam-Forming Network (BFN) are taken into account as well. The results presented allow a preliminary assessment of the predicted advantage (in terms of availability) of an adaptive system over non-adaptive systems currently implemented, which are based on long-term climatological data. The BFN used to distribute the signal power across the service area (Europe) is constituted by a set of 8x8 multiport amplifiers, each driven by a Butler-Like Matrix (BLM), covering the area with 64 beams. The BFN excitation coefficients are refreshed every 3-6 hours, in accordance with the update rate of the input meteorological data. Our analysis shows that the number of users lost due to atmospheric effects is reduced by a factor of about 5 with respect to the case of a non-reconfigurable system fed by the same transmitted power. Morevoer, the theoretical reduction factor achievable by the "derivative slicing” method removing the system constraints (i.e. the BLM elements) would increase to 10
An attempt to classify the types of clouds by a dual frequency microwave radiometer
No full textThis work presents a new approach for the classification of cloud types (CT) from a dual frequency microwave radiometer time series. The algorithm is based on the identification of fixed relationships relating the Integrated Liquid Water Content (ILWC) and the Integrated Water Vapor Content (IWVC) retrieved from brightness temperatures measured at two frequencies. Results indicate that the cloud classification thresholds, identified from long-term radiosonde observations (RAOBS), apply to the radiometric measurements as well. The probability of occurrences of each CT, as calculated from RAOBS and MWR data, is found to be in good agreement. Results also show that rain events occur only in presence of two out of the four cloud types considered (Cloud Type CT3 and CT4)
Presentation of the analysis tool for design of onboard reconfigurable antenna for broadband SatCom and broadcast services
No full textReconfigurable on-board antenna systems are a potential solution to mitigate the effect of atmospheric fades in broadband
SatCom. The on-board power is dynamically shared among the users according to the time and space-varying meteorological
conditions in the service area by tuning the antenna radiation pattern. An efficient algorithm of dynamic on-board power allocation is presented here. Preliminary results show the superiority of the adaptive technique over a state-of-the-art fixed antenna system in terms of on-board power reduction to achieve a given service availability target
Single-Objective Genetic Algorithm for Dynamic Optimization of Reconfigurable Antenna Systems
No full text— Modern satellite telecommunications are moving
toward the use of large capacity systems exploiting fade
mitigation techniques such as reconfigurable on-board antenna
systems to face channel attenuation. In this work we propose a
new Single-Objective Genetic Algorithm (SOGA) able to
optimize the spatial distribution of the radiated power, taking
into account the effect of non-ideal antenna components. A
preliminary analysis shows that the genetic algorithm, due to its
flexibility, is more effective in handling the system non-ideality
than standard optimization methods based on a deterministic
approach
A theoretical approach for the dynamic reconfiguration of an on-board antenna pattern and its performance assessment
No full textsupplementaryfig – Supplemental material for Prognostic role of primary tumor, nodal neck, and retropharyngeal GTVs for unresectable sinonasal cancers treated with IMRT and chemotherapy
No full textSupplemental material, supplementaryfig for Prognostic role of primary tumor, nodal neck, and retropharyngeal GTVs for unresectable sinonasal cancers treated with IMRT and chemotherapy by Letizia Ferella, Anna Cavallo, Rosalba Miceli, Nicola Alessandro Iacovelli, Tommaso Giandini, Emanuele Pignoli, Giuseppina Calareso, Paolo Bossi, Carlo Resteghini, Giovanni Luca Gravina, Piero Nicolai, Paolo Castelnuovo, Cesare Piazza, Lisa Licitra, Carlo Fallai and Ester Orlandi in Tumori Journal</p
Supplementary_submission_PROGNOSTIC_ROLE_OF_PIK3CA_AND_TP53 – Supplemental material for Prognostic role of PIK3CA and TP53 in human papillomavirus–negative oropharyngeal cancers
No full textSupplemental material, Supplementary_submission_PROGNOSTIC_ROLE_OF_PIK3CA_AND_TP53 for Prognostic role of PIK3CA and TP53 in human papillomavirus–negative oropharyngeal cancers by Carlo Resteghini, Federica Perrone, Rosalba Miceli, Cristiana Bergamini, Salvatore Alfieri, Ester Orlandi, Marco Guzzo, Roberta Granata, Donata Galbiati, Stefano Cavalieri, Laura Locati, Lisa Licitra and Bossi Paolo in Tumori Journal</p
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