Search results for " Codes"

showing 10 items of 147 documents

QR kodu kā tirdzniecības instrumenta atbilstība uzņēmumiem

2021

Tā kā tehnoloģija ir pārņēmusi mārketinga pasauli, visefektīvākais mārketinga veids ir mobilais mārketings, un, mainoties tendencēm, daudzi mārketinga rīki ir praktizējuši, lai sniegtu produktīvu reklāmu. QR kodi pēdējos gados ir kļuvuši par jauno mārketinga tendenci, taču problēma ir tā, vai šie QR kodi patiešām ir produktīvi viņu centienos. Šī pētījuma mērķis ir analizēt, vai uzņēmumi, kas izmanto QR kodus kā savu mārketinga rīku, var sasniegt savus mērķus vai neietekmē mārketinga shēmas, kā arī noskaidrot, vai cilvēki zina QR kodus un vai tie tos ietekmē / piesaista. Pētījuma rezultāti acīmredzami atrisina pētījuma problēmu, uzņēmumi, kas izmanto QR kodus kā mārketinga rīku, sasniedz sav…

QR codesInfluence/AttractionEkonomika un uzņēmējdarbībaMobile MarkeingAwareness
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Comparison between different sources of atmospheric profiles for land surface temperature retrieval from single channel thermal infrared data

2012

Abstract Different sources of atmospheric water vapor and temperature profiles were used with a radiative transfer model for retrieving land surface temperature (LST) from thermal infrared remote sensing data with the so-called single channel (SC) method. Retrieved LSTs were compared to concurrent ground measurements over homogeneous rice fields to assess the accuracy of the atmospheric profiles. These included radiosonde balloons launched at the test site near-concurrently to satellite overpasses, re-analysis profiles from the National Centers for Environmental Prediction (NCEP), and satellite sounder products from the Atmospheric Infrared Sounder (AIRS) and the Moderate Imaging Spectrorad…

RadiometerSoil ScienceGeologyAATSRAtmospheric scienceslaw.inventionAdvanced Spaceborne Thermal Emission and Reflection RadiometerSpectroradiometerAtmospheric radiative transfer codeslawAtmospheric Infrared SounderEmissivityRadiosondeEnvironmental scienceComputers in Earth SciencesRemote sensingRemote Sensing of Environment
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Application of the SKYRAD Improved Langley plot method for the in situ calibration of CIMEL Sun-sky photometers

2007

The in situ procedure for determining the solar calibration constants, originally developed for the PREDE Sun-sky radiometers and based on a modified version of the Langley plot, was applied to a CIMEL instrument located in Valencia, Spain, not integrated into AERONET. Taking into account the different mechanical and electronic characteristics of the two radiometers, the method was adapted to the characteristics of the CIMEL instrument. The iterative procedure for the determination of the solar calibration constants was applied to a 3-year data set. The results were compared with the two sets of experimental calibration constants determined during this period using the standard Langley plot…

Radiometerbusiness.industryMaterials Science (miscellaneous)451SKYNETPhotometerIndustrial and Manufacturing EngineeringPlot (graphics)AERONETlaw.inventionOpticslawOCIS codes: 010.1290 010.1110CalibrationRadianceEnvironmental scienceBusiness and International ManagementbusinessAtmospheric opticsRemote sensingApplied Optics
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Rateless codes implementation, optimization and application to Free Space Optics links affected by optical turbulence

In this work, I have implemented, optimized and tested the most advanced rateless codes available up to now, i.e., RaptorQ codes. In detail, a multiplatform data transmission software has been appositely developed in order to verify the effectiveness of the above-mentioned codes to decrease packet loss and hence to improve the link quality, under different network and channel conditions. Several simulative and experimental investigations have been carried out to evaluate the performance of the encoding and decoding schemes and the relative recovery capabilities under different test scenarios. In particular, I have applied the software embedding RaptorQ codes to Free Space Optics communicati…

RaptorQ codesoptical turbulenceFree Space Opticrateless codeGamma-Gamma modelSettore ING-INF/01 - Elettronica
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SVG Rendering by Watershed Decomposition

2005

Scalable Vector Graphics Watershed Decomposition Raster to Vector Chain Codes representation
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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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Luby Transform Performance Tests on Time-Correlated Channel Model for Geo Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniSettore ING-INF/01 - ElettronicaFree Space Optics Luby Transform Codes Rateless Codes Channel Modeling Geo Free Space Optics Downlinks
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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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