Search results for " LT"

showing 10 items of 23 documents

Correlated Channel Model for terrestrial Free Space Optics and project specifications evaluation of LT code in OOK modulation

2011

Free Space Optics is a wireless line-of-sight communication system able to offer good bandwidth performance as well as straightforward installation and relocation. So that it represents a modern technology that allow to realize large bandwidth communication particularly when it is not possible to employ physical cable or radio technologies. Examples of FSO applications are: wireless backaul, fiber backup, temporary links, metro network extension and last mile access[1]. FSO is based on optical signals propagation in air and that is why it suffers of impairments which depend on atmospheric conditions. In detail, FSO suffers of scattering (i. e. Rayleigh and Mie) losses, absorption and scinti…

Settore ING-INF/02 - Campi ElettromagneticiFree Space Optics FSO OOK LT code Luby Tranform Channel model correlation outage Gamma Gamma Rytov parameterSettore ING-INF/01 - Elettronica
researchProduct

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
researchProduct

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
researchProduct

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
researchProduct

Granzyme A is an additional marker for tuberculosis (TB) to discriminate between patients with active disease and subjects with latent infection.

2013

TuberculosisTuberculosis granzyme A ELISA LTBI Cytotoxic molecules TB patientsbusiness.industryImmunologyImmunologyActive diseaseGranzyme AmedicineImmunology and Allergymedicine.diseasebusinessVirologyFrontiers in Immunology
researchProduct

SIA “SBE Latvia Ltd” mārketinga vides analīze un konkurētspējas novērtējums

2017

Kvalifikācijas darba autore: Sanita Ziediņa. Kvalifikācijas darba tēma: SIA’’SBE Latvia Ltd’’mārketinga vides analīze un konkurētspējas novērtējums. Kvalifikācijas darba vadītāja: pasniedzēja,Mg.pead.Inta Kalniņa Pētījuma mērķis: veikt SIA„SBE Latvia Ltd.” mārketinga vides analīzi un konkurētspējas novērtējumu. Pētījuma uzdevumi: 1.Analizēt literatūru par mārketinga vidi; 2.Uzzināt kas ir konkurence, kas nosaka konkurētspēju, kas regulē konkurenci Latvijā; 3.Izpētīt uzņēmumu SIA ‘’SBE Latvia Ltd’’; 4.Novērtēt situāciju uzņēmumā un analizēt konkurentus; 5.Veikt SVID analīzi; 6.Veikt klientu aptauju; 7.Prognozēt SIA ‘’SBE Latvia Ltd’’pilnveidošanās iespējas; 8.Izstrādāt priekšlikumus uzņēmuma…

Uzņēmējdarbības vadībaMārketingsSIA''SBE Latvia Ltd''KonkurenceNākotnes perspektīvas vietējā tirgū
researchProduct

Pētījums par izmaksu pārvaldību un SF Express optimizāciju

2022

Termins "izmaksu pārvaldība" ir izmantots vēsturiski. Ir parādījušās jaunas pieejas korporatīvo izmaksu pārvaldībai, piemēram, uz laiku balstītas darbības izmaksu aprēķināšanas izmaksas.Pretēji gaidītajam lielākā daļa izmaksu samazināšanas pasākumu tiek izmantoti tradicionālajā rūpniecisko izmaksu kontrolē, reti aptverot jaunas un strauji mainīgas nozares.Šajā tēzē analizēti vēsturnieku nozīmīgie sasniegumi, lasot attiecīgo literatūru un apkopojot teorētiskās zināšanas.SF Express Co. lauka pētījums, Ltd. Tie ietver firmas struktūru, tirgus attīstību, produktu struktūru un biznesa procesu.Finanšu dati ietver 2015.-2019. gada pārskatus un izmaksu projektu datus.Salīdzinājumam tika iegūti arī …

Vadībzinātnecost managementoptimization measuresSF Express Co. Ltd.express industry
researchProduct

Mārketinga komunikāciju pilnveidošanas iespējas uzņēmumā SIA "Later Ltd".

2017

Bakalaura darba tēma ir “Mārketinga komunikāciju pilnveidošanas iespējas uzņēmumā SIA “Later Ltd””. Bakalaura darba mērķis ir pamatojoties uz teorētiskām atziņām, klientu aptaujas un SIA “Later Ltd” pārstāvja intervijas rezultātiem, izpētīt uzņēmuma SIA “Later ltd” mārketinga komunikācijas, atklāt nepilnības un izstrādāt ieteikumus uzņēmuma mārketinga komunikāciju uzlabošanai. Darba teorētiskajā daļā ir izmantoti dažādu autoru darbi, lai no teorētiskā aspekta raksturotu mārketinga komunikāciju būtību un to veidus, kas ir reklāma, produkta pārdošanas veicināšana, sabiedriskās attiecības un personiskā pārdošana. Pētnieciskajā daļā tiks izmantotas gan kvantitatīva pētniecības metode (154 “Pica…

Vadībzinātnemārketinga komunikācijasreklāmaSIA “Later Ltd”pārdošanas veicināšanaPica Lulū
researchProduct

The discursive legitimation strategies of a nascent market

2017

Since the introduction of Gold&Green Foods Ltd’s Pulled Oats (Nyhtökaura) to the Finnish market in the spring 2016, the Finnish media has been increasingly reviewing different plant-based protein products. Gold&Green Ltd’s Pulled Oats has experienced extensive media coverage amongst other Finnish plant-based protein products which have been launched during 2016 such as VersoFood Ltd’s Härkis, Viipurilainen Kotileipomo’s Puhtikaura etc. It has yet to be seen whether the sudden inception of several plant-based protein product innovations will be defined as a pivotal era in the Finnish food industry or just a passing trend. Finnish media has aldo categorized MiFu as one of the up and coming fo…

Verso Food LtdMiFulegitimation strategiesValio Ltdorganization studiescritical discourse analysismaitoproteiinitcategorizationGold&Green Foods Ltdmarkkinat (taloustiede)markkinatplant-based proteinsdairy-based proteinsPulled Oatsnascent marketself-categorizationHärkiskasviproteiinit
researchProduct

ScaleSem : model checking and semantic web

2012

The increasing development of networks and especially the Internet has greatly expanded the gap between heterogeneous information systems. In a review of studies of interoperability of heterogeneous information systems, we find that all the work in this area tends to be in solving the problems of semantic heterogeneity. The W3C (World Wide Web Consortium) standards proposed to represent the semantic ontology. Ontology is becoming an indispensable support for interoperability of information systems, and in particular the semantics. The structure of the ontology is a combination of concepts, properties and relations. This combination is also called a semantic graph. Several languages have bee…

[SPI.OTHER]Engineering Sciences [physics]/Other[ SPI.OTHER ] Engineering Sciences [physics]/Other[SPI.OTHER] Engineering Sciences [physics]/OtherVérification de graphes sémantiques[INFO.INFO-OH]Computer Science [cs]/Other [cs.OH]OntologieNo english keywordRequête en logique temporelle (Query Checking)Logique temporelle CTLModel Checking[INFO.INFO-OH] Computer Science [cs]/Other [cs.OH]Méthodes formellesModel Checker SPINLogique temporelleRDF\OWLModel Checker NuSMVGraphe sémantique[ INFO.INFO-OH ] Computer Science [cs]/Other [cs.OH]Incohérence d’ontologieÉvolution d’ontologieLogique temporelle LTLWeb sémantique
researchProduct