Search results for " Raptor"

showing 10 items of 20 documents

Breeding abundance of threatened raptors as estimated from occurrence data

2008

A model derived from the negative binomial distribution (NBD) has been proposed to solve the problem of predicting abundance of species from occurrence maps. The viability of NBD was explored for predicting the breeding abundance of five threatened species of raptor: Bonelli's Eagle Hieraaetus fasciatus, Golden Eagle Aquila chrysaetos, Peregrine Falco peregrinus, Lanner Falco biarmicus and Lesser Kestrel Falco naumanni. First, the accuracy of the NBD was tested in a reference area where the species abundance and occurrence were known through intensive field surveys. Next, an estimation of regional abundance derived from NBD was made for each species. These estimates were then compared to th…

Settore BIO/05 - Zoologiadistribution atlaseagle falcon raptor modelling negative binomial distribution
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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Correlated channel model for terrestrial Free Space Optics: performance analysis of rateless codes

2012

We describe a novel correlated channel model able to predict random temporal fluctuations of optical signal irradiance caused by scintillation. With regards to the same channel, we also report simulation results on the error mitigation performance of Luby-Transform and Raptor codes.

Settore ING-INF/03 - TelecomunicazioniFree Space Optics channel modeling Raptor codes RaptorQ codes LT codes rateless codesSettore ING-INF/02 - Campi ElettromagneticiSettore ING-INF/01 - Elettronica
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Performance Investigation of Fountaine Codes on a Simulated Terrestrial Free Space Optical Channel

2012

Settore ING-INF/03 - TelecomunicazioniSettore ING-INF/02 - Campi ElettromagneticiSettore ING-INF/01 - ElettronicaFree Space Optics Channel Modeling Fountain Codes Raptor Codes RaptorQ Codes Luby Transform Codes Rateless Codes
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Optical wireless GEO satellite-to-ground downlinks: rateless codes as solution for scintillation fading

2013

Scintillation fading can corrupt a satellite-to-ground optical wireless links with burst errors. Rateless codes, suitable for erasure channel, are able to eliminate or to reduce these communication errors. We analyzed the performances of three different rateless codes in a simulated Geo satellite-to-ground downlink.

Settore ING-INF/03 - TelecomunicazioniSettore ING-INF/02 - Campi ElettromagneticiSettore ING-INF/01 - ElettronicaFree Space Optics Rateless codes LT codes Raptor codes RaptorQ codes channel modeling
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Spring raptor migration at Ustica, southern Italy

2004

The island of Ustica, lying at 38°42’N 13°12’E in the Tyrrhenian Sea, is approximately 60 km north of western Sicily and 270 km northeast of the Cap Bon promontory in Tunisia (fig.1). Although covering an area of only 7,600 ha, its isolation makes it attractive to migrant birds. In order to establish the importance of Ustica for the spring migration of raptors in the Mediterranean basin, counts of migrating raptors were made from the highest point of the Falconiera promontory, which dominates the northeast coast of the island, between 22nd March and 20th May 2002.Each spring, thousands of raptors cross the Mediterranean Sea between Africa and southern Italy during their northward migration …

Spring raptor migrationSettore AGR/11 - Entomologia Generale E Applicata
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The role of natural science collections in the biomonitoring of environmental contaminants in apex predators in support of the EU’s zero pollution am…

2022

Movalli, Paola et al.

WIMEKSettore BIO/05 - ZoologiaEU chemicals regulationMarine mammalToxicologyPollutionZero pollutionEcology and EnvironmentOtterApex predatorRaptorCHEMICALSChemistryBiomonitoringEXPOSUREEU chemicals regulation Zero pollution Biomonitoring Chemicals of emerging concern Apex predator Raptor Marine mammal OtterBiologyBiomonitoring ; Marine mammal ; EU chemicals regulation ; Raptor ; Apex predator ; Chemicals of emerging concern ; Zero pollution ; OtterToxicologieVLAGChemicals of emerging concern
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Spatial analysis of lanner falcon habitat preferences: Implications for agro-ecosystems management at landscape scale and raptor conservation

2014

Abstract Sicily hosts the largest European population of the endangered lanner falcon, a poorly known species which needs conservation planning based on habitat preferences. A distribution model on 10 × 10 km cells of Sicily was described using Generalized Linear Models and variation partitioning methods. This modelling approach extracted explanatory factors, pure and joint effects of greatest influence from subsets of variables controlled for multi-collinearity and spatial autocorrelation. Analytical cartography used the environmental favourability function to assess habitat preferences, and the insecurity index estimated the degree to which lanner falcon occupancy is represented in the Na…

education.field_of_studyFalco biarmicus feldeggii Raptor conservation Generalized Linear Model Mediterranean steppe-like habitats Collaborative agri-environment schemes cAES Favourability modellingbiologyOccupancyEcologyPopulationEndangered speciesSettore BIO/05 - ZoologiaVegetationbiology.organism_classificationGeographyHabitatmedia_common.cataloged_instanceRaptor conservationLanner falconEuropean unioneducationEcology Evolution Behavior and SystematicsNature and Landscape Conservationmedia_common
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The first inventory of birds of prey in sicilian museum collections (Italy)

2020

Natural History Museums are places of scientific dissemination and informal education, and have a fundamental role in scientific research and in preserving the historical heritage of a territory and its biodiversity. The island of Sicily, thanks to its geographic position as an inter-continental bridge in the Mediterranean, presents a notable ornithological diversity, with both sedentary species and species that migrate between Africa and Europe. For this reason, and thanks to a strong hunting tradition, Sicilian collections also depict the avifaunal assemblage historically present in the region, particularly for birds of prey, the group we focus on because of its particular ecological char…

inventoryItalybirdsInventory birds raptors collections Sicily ItalySicilyraptors collections
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FREE SPACE OPTICS LINKS AFFECTED BY OPTICAL TURBULENCE: CHANNEL MODELING, MEASUREMENTS AND CODING TECHNIQUES FOR ERROR MITIGATION

2014

FSO is an optical wireless line-of-sight communication system able to offer good broadband performance, electromagnetic interference immunity, high security, license-free operation, low power consumption, ease of relocation, and straightforward installation. It represents a modern technology, significantly functional when it is impossible, expensive or complex to use physical connections or radio links. Unfortunately, since the transmission medium in a terrestrial FSO link is the air, these communications are strongly dependent on various atmospheric phenomena (e.g., rain, snow, optical turbulence and, especially, fog) that can cause losses and fading. Therefore, in worst-case conditions, i…

optical turbulencescintillationrateless codes LT codes Raptor codes RaptorQ codes error mitigation fading mitigation.Free Space Optictime-serieSettore ING-INF/01 - Elettronica
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