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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Implementace vrstvy RS-FEC pro 400 Gb/s Ethernet / RS-FEC layer implementation for 400Gb/s ethernet

Zahálka, Patrik January 2020 (has links)
Tato diplomová práce se věnuje problematice VLSI návrhu a implementaci vrstvy RS-FEC pro 400 Gb/s Ethernet do FPGA Intel® Stratix® 10 DX 2100. V práci je charakterizován současný stav rychlostí Ethernetu, význam a kontext samoopravných kódů v rámci protokolu Ethernet. Dále je popsána výroba PLD čipů i matematická podstata RS sa moopravných kódů. V části praktické je představen návrh řešení systému RS-FEC, který byl realizován genericky pomocí jazyka VHDL. Zároveň byly jeho komponenty implementovány a v závěrečné diskusi je popsáno jeho řešení, dosažené výsledky včetně jeho budoucího rozšíření.
82

Coding and Decoding of Reed-Muller Codes / Kodning och avkodning av Reed-Muller koder

Meyer, Linda January 2021 (has links)
In this thesis some families of linear error correcting codes are presented. The reader will find a general description of binary codes and more specific details about linear codes such as Hamming, repetition codes, Reed-Muller codes, etc. To fully immerse ourselves in the methods of coding and decoding, we will introduce examples in order to contribute to the understanding of the theories.   In these times of much communication through computer technology, our daily lives involve a substantial amount of data transmission. It is essential that these data are transmitted without errors through the communication channels. Therefore, the scientific field of error-correcting codes holds a significant importance in many aspects of todays society.   The main goal of this thesis is to study linear block codes which belong to the class of binary codes. In this case we will attribute a more prominent role to first order Reed-Muller codes. / I den här uppsatsen kommer flera varianter av linjära felrättande koder att presenteras. Läsaren får ta del av en allmän beskrivning av binära koder och en mer detaljerad framställning av linjära koder så som Hamming, repetitionskod, Reed-Muller kod m.m. Tillsammans med en fördjupning i ämnet, avseende metoder för kodning och avkodning, kommer vi att ge exempel för att bidra till förståelsen.   Den digitala eran, som vi lever i, innefattar att datatransmission är en del av vår vardag. Vår frekventa användning av mobila enheter visar på hur viktigt det är att data överförs korrekt via kommunikationskanalerna. Av den anledningen är vetenskapen om felrättande koder högaktuell i dagens samhälle.   Det huvudsakliga syftet med uppsatsen är att studera linjära block-koder som tillhör klassen binära koder. I det här fallet kommer vi att fokusera lite extra på Reed-Muller koder av första ordningen.
83

Variace Reed-Solomonových kódů nad jinými algebraickými strukturami / Variants of Reed-Solomon codes over other algebraic structures

Končický, Václav January 2022 (has links)
Reed-Solomon codes are a well known family of error-correcting codes with many good properties. However, they require a finite field to operate, limiting the alphabet size to a prime power. In this work, we build a weaker algebraic structure which supports alphabet of any integer size and requires only standard addition, multiplication and division to implement. Then we study a family of error-correcting codes based on matrix multiplication over this structure. We also adapt the Reed-Solomon code principle on this code family and study its properties. We prove and verify experimentally that while a random code of this family has high distance, the Reed-Solomon adaptation fails to perform well. 1
84

Mezidruhová hybridizace u rákosníků rodu Acrocephalus / Interspecific hybridization in Acrocephalus warblers.

Majerová, Veronika January 2012 (has links)
Acrocephalus warblers have gone through the adaptive radiation during last severalmillion years, which gave rise to thirty one species occupying mainly Eurasia,Africa and Australia. The majority of species are morphologically very similar,however, they differ in ecological requirements, migration strategy, and song.Interspecific hybridization seems to be quite common among Acrocephaluswarblers, not only between sister species, but also between more distantly relatedtaxa. The main goal of this study was to determine whether this hybridization leadsto gene flow between species and which factors affect the rate of interspecific geneflow. For this purpose we conducted population-genetic analysis in three Europeanspecies of the Acrocephalus warblers of the subgenus Notiocichla: reed warbler (A.scirpaceus), marsh warbler (A. palustris), and blyth's reed warbler (A. dumetorum).Our results based on the analysis of sequence data from eight nuclear loci indicate,that gene flow between the studied species occurs, but only in one direction. Thegene flow is higher between genetically more related species than betweenecologically more similar species. We also estimated that the reed warbler and themarsh warbler diverged approximately 1,1 million years ago. The blyth's warblerand ancestor of the reed and marsh warbler...
85

Goppovy kódy a jejich aplikace / Goppa codes and their applications

Kotil, Jaroslav January 2013 (has links)
Title: Goppa codes and their applications Author: Bc. Jaroslav Kotil Department: Department of algebra Supervisor: prof. RNDr. Aleš Drápal, CSc., DSc. Abstract: In this diploma paper we introduce Goppa codes, describe their para- metres and inclusion in Alternant codes, which are residual Generalized Reed- Solomon codes, and Algebraic-geometry codes. Aftewards we demonstrate deco- ding of Goppa codes and introduce Wild Goppa codes. We also describe post- quantum cryptography member: McEliece cryptosystem for which no effective attacks with quantum computers are known. We outline a usage of this crypto- system with Goppa codes and describe the security of the cryptosystem together with possible attacks of which the most effective ones are based on information- set decoding. Keywords: Goppa codes, Generalized Reed-Solomon codes, Algebraic-geometry codes, Post-quantum cryptography, McEliece cryptosystem 1
86

Duas revoluções: o percurso estético-político na literatura de John Reed / Two revolutions: The aesthetical and political development in John Reeds literature

Bustamante, Fernando 24 June 2014 (has links)
Estudo da evolução estética e política na obra de John Silas Reed (1897-1920) a partir de, fundamentalmente, duas de suas obras: seu primeiro livro, Insurgent Mexico (México Insurgente 1914) e seu último livro publicado em vida, Ten Days that Shook the World (Dez dias que abalaram o mundo 1919). A partir da crítica materialista-dialética a dissertação aborda o percurso de John Reed e procura demonstrar, numa leitura comparada entre as duas obras, como a transformação da visão política de seu autor se expressa na transformação estética de suas obras. Também se procura fazer uma leitura crítica da recepção de John Reed e a interpretação de sua obra nas décadas posteriores à sua morte / A study regarding the aesthetical and political development within the work of John Silar Reed (1897-1920) based upon, fundamentally, two of his books: his first one, Insurgent Mexico (1914), and the last one published in his lifetime, Ten Days that Shook the World (1919). From the dialetical-materialistic standpoint, the study approaches John Reeds life and tries to demonstrate, through a compared Reading between these two books, how the transformation in the authors political view is related to the aesthetical transformation in his writing and literary composition. John Reed works reception and criticism is also critically regarded
87

Systematisk bedömning av våtmarksväxter som substrat för biogasproduktion

Haglund, Emelie January 2014 (has links)
Två miljöproblem idag är ökade koncentrationer av växthusgaser i atmosfären och övergödning. Därför är två utmaningar att reducera utsläppen av växthusgaser och flöden av näringsämnen. Ytterligare en utmaning är att trygga energiförsörjningen i en värld där efterfrågan på energi ökar. Nya förnybara energikällor behöver utvecklas både för att trygga energiförsörjningen men även för att minska användandet av fossil energi. En förnybar energikälla är biogas som kan användas till el, värme och fordonsgas. Det förutspås att substrat för biogasproduktion kommer vara en bristvara i framtiden, därför behöver nya substrat utvärderas. Våtmarksväxter är ett alternativt substrat för biogasproduktion och utvärderades i den här studien. Våtmarker och dess växter är intressanta att studera eftersom de kan reducera koncentrationen näringsämnen som når sjöar och hav och kan därför bidra till att minska problemen med övergödning.    Studien genomfördes inom ett projekt vid Biogas Research Center och var en litteraturstudie med studie av ett fall. Metoden som användes har arbetats fram i projektet och är en multikriteriaanalys, (MCA), vilket innebär att det är flera olika områden som studeras. Områdena tar hänsyn till biologiska, ekonomiska, kemiska, miljömässiga och tekniska aspekter. För att strukturera upp informationen användes en matris som bestod av de olika huvudområdena som studerades. För att tydliggöra möjligheter och hinder gjordes en semi-kvalitativ bedömning av varje huvudområde.   Fallet som studerades var en våtmark i odlingslandskapet. Våtmarken är 5 ha och återskapades för några år sedan för att fungera som kväve- och fosforkälla. Det finns ingen växtlighet i våtmarken eftersom den är relativt ny. De växter som studerades under studien var därför växter som är tänkbara att växa i våtmarken i framtiden. Växterna som studerades var vass, rörflen och bredkaveldun. I våtmarken finns möjlighet att reglera vattennivån och därmed tömma den på vatten för att underlätta skörd.   Resultatet visade att den teknik som finns idag för skörd och sönderdelning behöver utvecklas eftersom den inte motsvarar de krav som ställs. Det finns olika tekniker för rötning och eftersom växterna har hög torrsubstanshalt är torrötning att föredra eller ett tvåstegssystem där första steget är torrötning. En våtmark ger en relativt liten mängd biomassa och därför passar det bättre att röta växterna tillsammans med andra substrat till exempel på en gårdsbiogasanläggning.   Våtmarksväxter är inte godkända substrat för certifiering av biogödsel, vilket kan vara ett hinder. Biogödseln har även ett lågt värde eftersom växterna innehåller låg halt näringsämnen. Våtmarker reducerar mängden näringsämnen och skörd kan bidra till att retentionen av fosfor ökar. Samtidigt avger våtmarker metan och lustgas som påverkar växthuseffekten.  Idag finns det ingen ekonomisk lönsamhet att skörda våtmarker. Ett system där ersättning fås för miljönyttan som skörd ger är ett alternativ för att öka lönsamheten. / Two environmental problems today are the increased concentrations of greenhouse gases in the atmosphere and eutrophication.  Therefore, two challenges are reducing greenhouse gas emissions and fluxes of nutrients. Another challenge is to secure the energy supply in a world where energy demand is increasing. New renewable energy sources need to be developed both to secure the energy supply, but also to reduce the use of fossil energy. A renewable energy source is biogas that can be used for electricity, heating and as vehicle fuel. It is predicted that substrate for biogas production will be a limitation in the future, therefore, new substrate need to be evaluated. Wetland plants are an alternative substrate for biogas production and evaluated in this study.  Wetlands and it is plants are interesting to study because they can reduce the concentration of nutrients and therefore help to reduce the problem of eutrophication.  The study was performed within a project at Biogas Research Center and was a literature study with the study of a case. The method used has been developed in the project and is a Multi Criteria Assessment (MCA), which means that there are several different areas being studied. Areas taking into account the biological, economic, chemical, environmental and technological aspects. In order to structure the data, a matrix consisting of the different key areas was used. To clarify the opportunities and obstacles a semi-qualitative assessment was done for each key area. The case studied was a wetland in an agricultural landscape. The wetland is 5 ha and was constructed a few years ago to work as nitrogen and phosphorous trap. There is no vegetation in the wetland because it is relatively new. The plants that were studied during the study was therefore plants that are potential to grow in the wetland in the future. The studied plants were reed, reed canary grass and cattail. In the wetland it is possible to regulate the water and thereby drain the water to facilitate harvesting.   The results showed that the technology available today for the harvesting and chopping needs to be developed because it does not meet the required standards. There are various techniques for digestion, but since the dry matter is high for the plants dry fermentation is preferable, or a two-stage system in which the first step is dry digestion. A wetland provides a relatively small amount of biomass and therefore it is better to co-digest the plants on a farm biogas plant.  Wetland plants are not approved substrates for certification of bio fertilizer, which can be an obstacle. The bio fertilizer also has a low value because the plants contain low levels of nutrients.Wetlands reduce the amount of nutrients and harvest of wetland plants contributes to the retention of phosphorus increases. Wetlands emit methane and nitrous oxide that affect global warming.Today, there is no economic viability of harvesting wetlands. A system in which compensation is obtained for the environmental benefit that harvest provides is an option to increase profitability.
88

[en] FOUNTAIN CODES AND OTHER CHANNEL CODING SCHEMES FOR PROTECTION OF TRANSPORT STREAMS OVER IP NETWORKS WITH PACKET ERASURE / [pt] CÓDIGOS FONTANAIS E OUTROS ESQUEMAS DE CODIFICAÇÃO DE CANAL PARA PROTEÇÃO DE TRANSPORT STREAMS EM REDES IP COM APAGAMENTO DE PACOTES

CLAUDIO ALEJANDRO SZABAS 06 July 2011 (has links)
[pt] Há, nos dias atuais, uma crescente demanda pelo transporte de video sobre IP, i.e., para distribuição de conteúdo pela Internet, por serviços de IPTV em definição padrão e em alta definição e, mesmo para uso interno nas redes de emissoras tradicionais de televisão, que transportam contribuições de elevada qualidade para seus programas. Em tais aplicações, o conteúdo dos programas é transportado usando MPEG-2 ou MPEG-4, sob a forma de MPEG-2 Transport Streams, encapsulados com protocolos tais como RTP, UDP e IP. As redes IP, que são modelizadas como Redes com Apagamento de Pacotes (PEC) não foram, no entanto, concebidas para o transporte de mídias em tempo real, esbarra portanto em problemas comuns como perdas de pacotes e jitter, gerando perturbações que se refletem na recepção do conteúdo. Os métodos tradicionais para superar estas dificuldades, como por exemplo, os que se baseiam em retransmissões usando protocolos ARQ (Automatic Repeat on Request), não são uma solução eficiente para proteger a transmissão de multimídia em tempo real. A proteção de multimídia transmitida em tempo real via IP recorre, neste caso, aos códigos para canal. Há códigos para canal recomendados em RFC s e Padrões, usados amplamente pelos fabricantes de equipamento. Os modernos Códigos Fontanais, possuem características atraentes para o transporte de conteúdos multimídia em tempo real. Neste trabalho, simulações são realizadas, onde o conteúdo encapsulado em Transport Stream, é protegido com Códigos Fontanais antes do encapsulamento para o envio através da rede. A título de comparação, o experimento é realizado também usando outros códigos para canal recomendados. Para realizar a comparação são usadas medições padronizadas do Transport Stream, medições objetivas como artefatos de blocagem e finalmente uma análise subjetiva do conteúdo recebido é usada. O trabalho conclui com a proposta de um Codificador de canal adaptável para Transport Stream. / [en] There is a growing demand for the transport of video over IP today, i.e., for content distribution over the Internet, IPTV services in Standard and High Definition, or even inside traditional broadcasters networks, transporting broadcast quality contributions to the main program. In such applications, the source encoded MPEG-2 or -4 content is transported in the form of MPEG-2 Transport Streams, encapsulated over network protocols. However, IP networks, which can be modeled as Packet Erasure Networks (PEC), were not originally designed for the transport of real time media. There are problems, such as packet drops and jitter, which generate severe impairments in the content that is decoded at the reception. Traditional methods for overcoming these problems, as for example retransmissions performed by Automatic Repeat Request (ARQ) protocols, are not suitable for real-time multimedia protection. Channel coding is the solution of choice for protecting real-time multimedia over IP. There are channel coding schemes specified in open recommendations and Standards, widely adopted by equipment vendors today. Fountain Codes present very attractive characteristics for the transport of real-time multimedia. In the present work, simulations with a Fountain code, protecting Transport Stream contents prior to network encapsulation, are presented. The experiment if repeated with other channel coding techniques commonly employed today. In order to analyze the decoded contents and obtain comparative results, standardized Transport Stream measurements, objective Blocking Artifacts measurements and subjective analysis of the decoded samples are employed. This work is concluded with the proposal of a Transport Stream Adaptive channel encoder, that is explained in Appendix-B.
89

Duas revoluções: o percurso estético-político na literatura de John Reed / Two revolutions: The aesthetical and political development in John Reeds literature

Fernando Bustamante 24 June 2014 (has links)
Estudo da evolução estética e política na obra de John Silas Reed (1897-1920) a partir de, fundamentalmente, duas de suas obras: seu primeiro livro, Insurgent Mexico (México Insurgente 1914) e seu último livro publicado em vida, Ten Days that Shook the World (Dez dias que abalaram o mundo 1919). A partir da crítica materialista-dialética a dissertação aborda o percurso de John Reed e procura demonstrar, numa leitura comparada entre as duas obras, como a transformação da visão política de seu autor se expressa na transformação estética de suas obras. Também se procura fazer uma leitura crítica da recepção de John Reed e a interpretação de sua obra nas décadas posteriores à sua morte / A study regarding the aesthetical and political development within the work of John Silar Reed (1897-1920) based upon, fundamentally, two of his books: his first one, Insurgent Mexico (1914), and the last one published in his lifetime, Ten Days that Shook the World (1919). From the dialetical-materialistic standpoint, the study approaches John Reeds life and tries to demonstrate, through a compared Reading between these two books, how the transformation in the authors political view is related to the aesthetical transformation in his writing and literary composition. John Reed works reception and criticism is also critically regarded
90

New techniques for the characterisation of single reeds in playing conditions / Nouvelles techniques pour la caractérisation des anches simples en situation de jeu

Muñoz Arancón, Alberto 28 September 2017 (has links)
Ce travail porte sur la caractérisation d'anches simples utilisées pour la clarinette ou le saxophone. Sachant que les musiciens perçoivent des différences importantes dans la qualité des anches de caractéristiques identiques (même marque, coupe et force), cette thèse propose des nouveaux outils pour la caractérisation des anches en situation de jeu.Un bec instrumenté utilisant des capteurs embarqués est développé de façon à mesurer le déplacement de l'anche et la différence de pression de part et d’autre de l'anche. À partir de ces signaux, il est possible d'estimer des paramètres d'anche associés à différents modèles physiques. Les résultats obtenus montrent que la complexité du modèle décrivant le comportement de l'anche doit augmenter avec la nuance de jeu. Le bec instrumenté est utilisé dans une campagne de mesures comportant 7 musiciens et 20 anches, et permet de quantifier la variabilité des résultats due aux musiciens. Des tests subjectifs sont réalisés avec ces mêmes musiciens, et montrent que les différences entre les anches se réduisent à une seule dimension (facilité de jeu ou timbre). Les corrélations entre les descripteurs subjectifs et les paramètres objectifs mesurés sont étudiées afin de mieux comprendre les différences perçues entre les anches, permettant le développement d'un modèle prédictif de la qualité des anches.De façon à éviter la variabilité produite par le musicien, une bouche artificielle aspirante est développée. La comparaison des mesures réalisées par la bouche artificielle et par un musicien permet d'identifier la plage de fonctionnement optimale où la bouche artificielle imite au mieux le jeu du musicien. / This work deals with the characterisation of single cane reeds used for clarinet or saxophone. Musicians perceive important differences of quality between reeds of the same brand, cut and strength. This thesis proposes new tools for reed characterisation in playing conditions.An instrumented mouthpiece is developed to enable the measurement of reed displacement and pressure difference on both sides of the reed using embedded sensors. From these signals, it is possible to estimate reed parameters of different physical models. Results reveal that the complexity of the physical model describing the reed behaviour must increase with the dynamic level.The instrumented mouthpiece is used in a measurement campaign involving 7 players and 20 reeds, quantifying the variability of the results due the musicians. Subjective tests conducted with these musicians show that reeds can be mainly described by one dimension (ease of playing or timbre). The correlations between the subjective descriptors and the measured objective parameters are studied to better understand the perceived differences between reeds, developing a predictive model of reed quality.In order to avoid the variability of the musician, an aspirating artificial mouth is developed. It uses the instrumented mouthpiece and it can be played by a musician or artificially. The comparison of the measurements made in both cases allows for the identification of the optimal working range in which the artificial mouth best reproduces the musician's playing according to intonation and playing level.

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