Search results for "Satellite Communications"

showing 4 items of 4 documents

Validation of a mapping and prediction model for human fasciolosis transmission in Andean very high altitude endemic areas using remote sensing data.

2001

The present paper aims to validate the usefulness of the Normalized Difference Vegetation Index (NDVI) obtained by satellite remote sensing for the development of local maps of risk and for prediction of human fasciolosis in the Northern Bolivian Altiplano. The endemic area, which is located at very high altitudes (3800-4100 m) between Lake Titicaca and the valley of the city of La Paz, presents the highest prevalences and intensities of fasciolosis known in humans. NDVI images of 1.1 km resolution from the Advanced Very High Resolution Radiometer (AVHRR) sensor on board the National Oceanic and Atmospheric Administration (NOAA) series of environmental satellites appear to provide adequate …

BoliviaFascioliasisGeographic information systemAdvanced very-high-resolution radiometerVeterinary (miscellaneous)Normalized Difference Vegetation IndexRisk FactorsmedicinePrevalenceHumansFasciolosisbusiness.industryAltitudeEffects of high altitude on humansmedicine.diseaseSatellite CommunicationsField (geography)Infectious DiseasesGeographyRemote sensing (archaeology)Insect ScienceLinear ModelsParasitologySatellitebusinessCartographyActa tropica
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Sensors / Cross-country skiing analysis and ski technique detection by high-precision kinematic global navigation satellite system

2019

Cross-country skiing (XCS) embraces a broad variety of techniques applied like a gear system according to external conditions, slope topography, and skier-related factors. The continuous detection of applied skiing techniques and cycle characteristics by application of unobtrusive sensor technology can provide useful information to enhance the quality of training and competition. (1) Background: We evaluated the possibility of using a high-precision kinematic global navigation satellite system (GNSS) to detect cross-country skiing classical style technique. (2) Methods: A world-class male XC skier was analyzed during a classical style 5.3-km time trial recorded with a high-precision kinemat…

MaleTime FactorsGPSVideo RecordingSTRIDEVideo cameraKinematics01 natural sciencesBiochemistryDisplacement (vector)ArticleAnalytical Chemistrylaw.invention03 medical and health sciences0302 clinical medicineTime trialImaging Three-DimensionallawSkiingHumansElectrical and Electronic Engineeringkinematic GNSSInstrumentationMathematicsbusiness.industryAltitude010401 analytical chemistry030229 sport sciencesGeodesySatellite CommunicationshiihtoAtomic and Molecular Physics and Optics0104 chemical sciencesBiomechanical PhenomenaGNSS applicationssatelliittipaikannusTrajectoryGlobal Positioning Systembusinessclassical techniquecross-country skiing
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A global network for the control of snail-borne disease using satellite surveillance and geographic information systems

2001

Abstract At a team residency sponsored by the Rockefeller Foundation in Bellagio, Italy, 10-14 April 2000 an organizational plan was conceived to create a global network of collaborating health workers and earth scientists dedicated to the development of computer-based models that can be used for improved control programs for schistosomiasis and other snail-borne diseases of medical and veterinary importance. The models will be assembled using GIS methods, global climate model data, sensor data from earth observing satellites, disease prevalence data, the distribution and abundance of snail hosts, and digital maps of key environmental factors that affect development and propagation of snail…

Resource (biology)GIS DayGeographic information systemDatabases FactualInternational CooperationVeterinary (miscellaneous)SnailsGlobal HealthEnvironmental protectionGlobal networkAnimalsHumansSchistosomiasisMedicineGeographyDigital mappingbusiness.industryEnvironmental resource managementSatellite CommunicationsData sharingInfectious DiseasesInsect ScienceParasitologyThe InternetEnterprise GISbusinessActa Tropica
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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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