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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.
61

Measurements and analysis of UDP transmissions over wireless networks

Berglund, Joel January 2018 (has links)
The growth and expansion of modern society rely heavily upon well-functioning data communication over the internet. This phenomenon is seen at the company Net Insight where the need for transferring a large amount of data in the form of media over the internet in an effective manner is a high priority. At the moment most internet traffic in the modern world is done by the use of the internet protocol TCP (Transmission Control Protocol) instead of the simpler protocol UDP (User Datagram Protocol). Although TCP works in an excellent manner for most kinds of data communication it seems that this might not always be the case, so the use of UDP might be the better option in some occurrences. It is therefore of high interest at Net Insight to see how different types of wireless networks behave under different network circumstances when data is sent in different ways through the use of UDP. Thereby this report focuses on the measurement and analysis of how different wireless networks, specifically 4G, 5.0 GHz and 2.4 GHz WLAN networks, behaves when exposed to varied network environments where data is transmitted by the use of UDP in different ways. To perform a network-analysis data is collected, processed, and then analyzed. This network-analysis resulted in many conclusions regarding network behavior and performance for the different wireless networks.
62

[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.
63

Observator för frontlinjen på surfplatta / Target Based Forward Observer

Bergstedt, Martin, Gillström, Tobias January 2017 (has links)
Detta projekt har utförts på Saab Dynamics. Projektets syfte var att utveckla en applikation, TBFO, för att rapportera information om hur missilen GLSDB ska slå till ett mål. TBFO är ämnat för att användas i närheten av målet och information skickas till planeringssystemet GLSDB MPS. Applikationen byggdes runt 3D-motorn Vricon och är anpassat för lättast möjliga användning med pekskärm. Huvuddelen av arbetet berörde utveckling av gränssnitt för pekskärm och utveckling av systemets applikationsprotokoll. Denna rapport redogör för framtagning av systemet samt de verktyg och metoder som användes. Rapporten fördjupar sig inom utveckling av applikationer anpassade för pekskärm. Slutsatsen som kan dras från resultatet av detta projekt är att idén om systemet som utvecklats är användbart för processen att planera angrepp med GLSDB MPS. / This project has been carried out at Saab Dynamics. The project's purpose was to develop an application, TBFO, for reporting information containing how the missile GLSDB would strike a target. TBFO is intended to be used in the proximity of the target and information is sent to the planning system GLSDB MPS. The application was built around the 3D engine from Vricon and is developed to fit for use of touch devices. The main part of the work concerns the development of user interface for touch input and the system’s application protocol. This report describes the processes of developing the system, including what tools and methods that have been used during development. The report also provides an in-depth look at processes used when developing applications for touch devices. The conclusion from the results of this project is that the idea of the described system is useful for the process of planning an assault with GLSDB MPS.
64

Alteração da composição dos polissacarídeos da parede celular de Nicotiana tabacum, pela modulação da expressão do gene uxs que codifica a enzima UDP-D-glucuronato descarboxilase (EC 4.1.1.35) / Alteration in the composition of cell wall polysaccharides in Nicotina tabacum by modulating the expression of the uxs gene, coding for UDP-D-glucuronic acid decarboxylase enzyme (EC 4.1.1.35)

Ana Letícia Ferreira Bertolo 14 February 2007 (has links)
A parede celular vegetal, estrutura essencial para as plantas, é extremamente importante para a economia humana, já que apresenta diversas utilidades, como por exemplo, fabricação de papel, fibras de vestuário, construção civil, entre outras. A maior parte da parede celular vegetal primária (aproximadamente 90%), é formada por polissacarídeos como celulose, hemiceluloses e pectinas. Os monossacarídeos, unidades formadoras dos polissacarídeos, são sintetizados, nas plantas, a partir de diferentes açúcares nucleotídeos, sendo que, o suprimento desses, pode afetar a biossíntese dos polissacarídeos da parede celular. Visando analisar o impacto da alteração do fluxo metabólico do carbono na composição da parede celular, o presente projeto de pesquisa teve como objetivo alterar a composição dos polissacarídeos da parede celular de Nicotiana tabcum, através da modulação da expressão do gene uxs, responsável pela codificação da enzima UDP-D-glucuronato descarboxilase (UDPGlcADC, EC 4.1.1.35) que converte UDP-D-glucuronato em UDP-D-xilose, importante açúcar nucleotídeo, precursor do monossacarídeo xilose. Para isso, após a clonagem do gene uxs de ervilha, foram obtidas plantas transgênicas de tabaco superexpressando esse gene. Diversas análises foram realizadas para determinação da composição química da parede celular primária e secundária dessas plantas. Pela análise de FTIR da parede celular primária, verificou-se que três linhagens transgênicas apresentaram espectrotipos consistentes, indicando uma redução na quantidade de pectinas e ligações ésteres carboxílica nessas linhagens transgênicas. Apesar de não terem sido detectadas alterações na proporção dos monossacarídeos ramnose, xilose, arabinose, manose e galactose, e na quantidade de celulose, na parede celular primária das plantas transgênicas, foram observadas diferenças na proporção de galactose não esterificada, nas linhagens que apresentaram espectrotipo. Com relação à parede celular secundária, observou-se que algumas linhagens transgênicas apresentaram maior concentração de lignina solúvel relacionada a uma redução no conteúdo de lignina insolúvel. / The plant cell wall is not only an essential structure for plants, but also an extremely important raw material in human economy. The plant cell wall has diverse utilities, for example, papermaking, textile fiber, civil construction. Polysaccharides, such as cellulose, hemicelluloses and pectins, are the major components of the primary plant cell wall (approximately 90%). These polysaccharides are formed by monosaccharides, which are synthesized in the plant from different nucleotide sugars. The suppliment of the nucleotide sugars can affect plant cell wall polysaccharides biosynthesis. Aiming at analyzing the impact of the alteration in the metabolic carbon flux on cell wall composition, the objective of this research project was to alterate the plant cell wall polysaccharides composition by the modulation of the uxs gene. This gene encodes the UDP-D-glucuronic acid decarboxylase enzyme (UDPGlcADC, EC 4.1.1.35) that promotes the conversion of UDP-D-glucuronic acid to UDP-D-xylose, an important sugar nucleotide precursor of xylose monosaccharide. To achieve this goal, the pea uxs gene was cloned and transgenic tobacco plants overexpressing this gene were obtained. Several analyses were performed to determinate the primary and secondary cell wall composition of those transgenic plants. The primary cell wall analysis by FTIR identified three transgenic lines that show different spectrotypes compared to wild type and those transgenic spectrotypes had the same features. The results indicate a reduction of pectin and ester carbonyl binding in the transgenic plants. No alterations were detected in the monosaccharide (rhamnose, xylose, arabinose, manose and galactose) proportions and the amount of cellulose in the primary cell wall of the transgenic plants. Nevertheless, differences in the proportion of unesterified galactose were observed in the same transgenic lines that showed spectrotypes. With regard to secondary cell wall, some transgenic lines showed an increase in soluble lignin which is related to a reduction in insoluble lignin.
65

Porovnání sekvenčních variant genů pro biotransformační enzymy u různých typů karcinomů / Comparison of sequence variations in genes of biotransfromation enzymes in some carcinoma

Turková, Lucie January 2017 (has links)
Xenobiotic biotransformation process and its capacity is crucial for xenobiotic chemicals elimination that may cause damage toward cell structures. The effectiveness of the enzymes included in this process depends on the gene variants that encodes them. The aim of this work was to compare certain polymorphisms of selected genes between cases and control groups. Studied polymorphisms were null genotypes of the glutathione S-transferase gene M1 and T1 and the insertion of TA dinucleotide in the promotor region of UDP-glucuronosyl transferase 1A1. The number of cases group was six included patients with colorectal, lung, prostate, breast, pancreatic and head and neck cancer. Total number of analysed individuals was 1 118 for cancer cases and 470 for healthy controls. The control group was divided into two groups, the first one was called general and the second one was called special included healthy individuals with no cancer history in their closest family members. Gilbert syndrome (GS) is caused by homozygous insertion of the TA dinucleotide in the TATA box of the gene UGT1A1 and it causes elevated bilirubin levels. Bilirubin is a potent antioxidant in human body, so the aim was to attest its protective effect toward cancer. We expected lower frequency of GS as a protective factor in the cases groups compared with controls. This hypothesis was confirmed in the breast cancer group (GS frequency 10,0 %) and pancreatic cancer group (GS frequency 11,1 %). In the general and special control groups the frequency of GS was 16,0 % and 15,4 % respectively. Although the other case groups show lower frequency of GS, the results weren´t statistically significant. Null GSTM1 genotype was observed with 50,4 % frequency in the general control groups and with 55,3 % frequency in the special control group. Neither the one of the cases groups hasn´t showed significantly lower percentage of null genotype. Despite expectation we observed statistically significant lower frequency of null genotype in the group of lung and pancreatic cancer group (37,4 % and 39,3 % respectively). According to this study, we can say that the lack of glutathione S-transferase M1 activity is not a risk factor for cancer development. Null genotype of GSTT1 wasn´t identified in both control groups at all. In case groups of breast and prostate cancer, there was only one individual carrying the null GSTT1 genotype. Statistically significant higher frequency of this polymorphism was observed in patients with colorectal cancer (9,7 %), lung cancer (17,2 %), pancreatic cancer (3,0 %) and head and neck cancer (15,9 %). In these groups the lack of glutathion S-transferase T1 activity might be considered as risk factor for cancer development. Nevertheless, for further verification it needs to take more investigation in this field, especially enlarge the number of patient in the case groups of head and neck, lung and pancreatic cancer.
66

Evaluation of communication protocols between vehicle and server : Evaluation of data transmission overhead by communication protocols

Wickman, Tomas January 2016 (has links)
This thesis project has studied a number of protocols that could be used to communicate between a vehicle and a remote server in the context of Scania’s connected services. While there are many factors that are of interest to Scania (such as response time, transmission speed, and amount of data overhead for each message), this thesis will evaluate each protocol in terms of how much data overhead is introduced and how packet loss affects this overhead. The thesis begins by giving an overview of how a number of alternative protocols work and what they offer with regards to Scania’s needs. Next these protocols are compared based on previous studies and each protocol’s specifications to determine which protocol would be the best choice for realizing Scania’s connected services. Finally, a test framework was set up using a virtual environment to simulate different networking conditions. Each of the candidate protocols were deployed in this environment and setup to send sample data. The behaviour of each protocol during these tests served as the basis for the analysis of all of these protocols. The thesis draws the conclusion that to reduce the data transmission overhead between vehicles and Scania’s servers the most suitable protocol is the UDP based MQTT SN. / I den här rapporten har jag undersökt ett antal protokoll som kan användas för att kommunicera mellan server och lastbil och därmed användas för Scanias Connected Services. Då det är många faktorer som är intressanta när det kommer till kommunikation mellan lastbil och server för Scania som till exempel responstid, överföringshastighet och mängden extra data vid överföring så har jag valt att begränsa mig till att utvärdera protokollen utifrån hur mycket extra data de använder vid överföring och hur detta påverkas av paketförlust. Rapporten börjar med att ge en överblick över vilka tänkbara protokoll som kan användas och vad de kan erbjuda gällande Scanias behov. Efter det så jämförs protokollen baserat på tidigare studier och protokollens specifikationer för att avgöra vilket protokoll som är bäst lämpat att användas i Scanias Connected Services. Sists så skapas ett virtuellt ramverk för att simulera olike nätverksförhållanden. Här testas varje protokoll och får sända olike datamängder för att sedan få sin prestanda utvärderad baserat på hur mycket extra data som sändes. Dessa resultat ligger sedan till grund för den analys och slutsats angående vilket protokoll som är bäst lämpat att användas av Scania. Rapporten drar slutsatsen att baserat på den information som finns tillgänglig och de resultat som ficks av testerna så skulle den UDP baserade MQTT-SN vara bäst lämpad för att minimera mängden extra data som skickas.
67

Offloading Workloads from CPU of Multiplayer Game Server to FPGA : SmartNIC implementation with UDP Communication / Avlastning av arbetsbelastningar från CPU till FPGA för multiplayer Game Server : SmartNIC-implementering med UDP Kommunikation

Bao, Junwen January 2022 (has links)
For multiplayer games, the performance of the server’s Central Processing Unit (CPU) is the main factor that limits the number of players on the server at the same time. Compared with the CPU, the Field-Programmable Gate Array (FPGA) architecture has no instructions set and no shared memory. Offloading some tasks from the CPU to the FPGA may help the CPU improve processing efficiency. This thesis explores which tasks on a CPU can be offloaded to a FPGA and how to design such a circuit system. The performance of the developed system also needs to be measured. We decided to offload communication tasks and data processing tasks to an FPGA. The result is that the FPGA server is available for work, the maximum number of users is 80, and the maximum network latency is 30-40 ms. The most important result is that a FPGA can be used as a multi-player server. One of the severe limitations of this design is the number of hardware resources. A 7-series FPGA is divided into several similar clock regions, which means the number of Flip Flop (FF)s near the same clock edge is fixed. If adding more FFs in the same component, the routing delay can not meet the set-up time requirements. Previously, people used the FPGA as the support accelerator to the server CPU. The CPU still works as a paramount communication link with one or several multi-connection parts and connects to the FPGA via the Peripheral Component Interconnect Express (PCIe) to use the FPGA to process data or pack/unpack Ethernet frames. We have designed and implemented a whole multi-connection server in a Hardware Description Language (HDL) and downloaded the resulting hardware in an FPGA. / I spel med flera spelare är serverns CPU-prestanda (Central Processing Unit) den viktigaste faktorn som begränsar antalet spelare som servern samtidigt kan hantera. Jämfört med CPU:n har en FPGA (Field-Programmable Gate Array) inga instruktioner och inget delat minne. Avlastning av vissa uppgifter från den CPU till FPGA:n kan hjälpa CPU:n att förbättra bearbetningseffektiviteten. I denna avhandling undersöks vilka uppgifter på en CPU som kan överföras till en FPGA och hur man utformar ett sådant kretsystem. Prestandan hos det utvecklade systemet måste också mätas. Vi har beslutat att avlasta kommunikationsuppgifter och databehandlingsuppgifter. till en FPGA. Resultatet är att FPGA-servern är tillgänglig för arbete, det maximala antalet användare är 80, och den maximala nätverksfördröjningen är 30-40 ms. Det viktigaste resultatet är att en FPGA kan användas som en server för flera spelare. En av de allvarliga begränsningarna med denna konstruktion är antalet hårdvaruresurser. En FPGA i 7-serien är uppdelad i flera liknande klockregioner, vilket innebär att antalet Flip Flop (FF)s nära en klocka är fast. Om man lägger till fler FF:er i samma komponent, kommer fördröjningen inte att uppfylla tidskraven för setup. Tidigare har folk använt sig av FPGA:n som en stödaccelerator till serverprocessorn. CPU:n fungerar fortfarande som en viktig kommunikationslänk med en eller flera anslutningar och ansluter till FPGA:n via Peripheral Component Interconnect Express (PCIe) för att använda FPGA:n till att bearbeta data och paketera/packa upp Ethernet-ramar. Vi har implementerat en hel server med flera anslutningar med hjälp av hårdvaruvarubeskrivande språk (HDL) och laddat ner den resulterande designen i en FPGA.
68

PROTOCOL LAYERING

Grebe, David L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The advent of COTS based network-centric data systems brings a whole new vocabulary into the realm of instrumentation. The Communications and computer industries have developed networks to a high level and they continue to evolve. One of the basic techniques that has proven itself useful with this technology is the use of a “layered architecture.” This paper is an attempt to discuss the basic ideas behind this concept and to give some understanding of the vocabulary that has grown up with it.
69

Molecular studies of galactan biosynthesis in red algae

Hector, Stanton Bevan Ernest 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Sulfated galactans (agarans and carrageenans) are accumulated in the cell wall of various red algae (Rhodophyta) species. These polysaccharides are of commercial importance in the food, pharmaceutical and biotechnology industries due to their unique physicochemical properties. Although having received significant research attention over the last 20 years, events regarding their biosynthesis have not been elucidated. Aiming for the identification of galactosyltransferase (GalT) genes involved in sulfated galactan biosynthesis, cDNA expression libraries were constructed from the prolific agar-producing South African red seaweed Gelidium pristoides (Turner) Kützing and screened by functional complementation of UDP-galactose 4-epimerase deficient mutants (E. coli and S. cerevisiae). Regretfully, no GalTs were identified. The study however yielded the first UGE enzyme described for a red seaweed. Southern hybridization indicated the presence of two UGE copies and confirmed the gene originated from G. pristoides. Bioinformatic analysis of G. pristoides UGE shows amino acid sequence homology to known UGEs from various organisms. The enzyme was shown to be functional in E. coli crude extracts and showed affinity for UDP-D-galactose, similar to other UDP-galactose 4-epimerases. Further, the isolated G. pristoides UGE (GpUGE) was biochemically characterized and its kinetic parameters determined. We found that there was no kinetic difference between this enzyme and previously described UGE enzymes except enhanced activity in the presence of exogenously added NAD+. The UDP-galactose 4-epimerase (UDP-glucose 4-epimerase, UGE, EC 5.1.3.2) is an essential Leloir pathway enzyme facilitating the catalytic inter-conversion between UDP-D-glucose and UDP-D-galactose. UDP-D-galactose is the nucleotide sugar required by galactosyltransferases for the production of red algae sulfated galactans. UGE is suspected as being responsible for supplying UDP-D-galactose for the synthesis of sulfated galactans. In planta monitoring of GpUGE transcript levels with respect to dark and light cycling indicated high expression of the enzyme at night, while expression diminished during the day. The occurrence of increased nocturnal UGE expression correlates with floridean starch breakdown at night. Evidence for hydrolysis of floridean starch is also reflected in obtained G. pristoides transcriptome sequence data. In red algae, floridean starch degradation coincides with sulfated galactan production. The detection of starch hydrolysis enzyme transcripts alongside increased expression of GpUGE suggests the enzyme plays a role in supplying UDP-Dgalactose for sulfated galactan production. As far as we know, this the first report of sequencing and biochemical characterization of a UGE from red seaweed.
70

One-year UDP: a cost/benefit analysis of a proposed alternative to the Marine Corps' Unit Deployment Program for fighter aviation

Hacker, Earl W. 12 1900 (has links)
Approved for public release; distribution is unlimited / The author examines the incremental costs and benefits associated with a change from six-month unit deployments to one-year unit deployments. The analysis is based primarily on five fighter squadrons participating in the Marine Corps' Unit Deployment Program and takes in the period July 1976 to October 1988. Regression analysis is used to project transportation cost savings of $4 million in real terms from FY 1989 through FY 1993. With a change to a one-year Unit Deployment Program, fighter squadrons should experience net increases in aircraft readiness, aircrew training readiness, and personnel retention. / http://archive.org/details/oneyearudpcostbe00hack / Lieutenant Colonel, United States Marine Corps

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