• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1045
  • 402
  • 315
  • 176
  • 112
  • 106
  • 37
  • 34
  • 29
  • 24
  • 17
  • 14
  • 13
  • 12
  • 7
  • Tagged with
  • 2738
  • 785
  • 529
  • 323
  • 319
  • 296
  • 254
  • 248
  • 231
  • 225
  • 220
  • 219
  • 195
  • 180
  • 173
  • 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.
181

Multipath TCP and Measuring end-to-end TCP Throughput : Multipath TCP Descriptions and Ways to Improve TCP Performance

BONAM, VEERA VENKATA SIVARAMAKRISHNA January 2018 (has links)
Internet applications make use of the services provided by a transport protocol, such as TCP (a reliable, in-order stream protocol). We use this term Transport Service to mean the end-to- end service provided to application by the transport layer.   That service can only be provided correctly if information about the intended usage is supplied from the application. The application may determine this information at the design time, compile time, or run time, and it may include guidance on whether a feature is required, a preference by the application, or something in between. Multipath TCP (MPTCP) adds the capability of using multiple paths to a regular TCP session. Even though it is designed to be totally backward compatible to applications. The data transport differs compared to regular TCP, and there are several additional degrees of freedom that the particular application may want to exploit.   Multipath TCP is particularly useful in the context of wireless networks using both Wi-Fi and a mobile network is a typical use case. In addition to the gains in throughput from inverse multiplexing, links may be added or dropped as the user moves in or out of coverage without disrupting the end-to-end TCP connection. The problem of link handover is thus solved by abstraction in the transport layer, without any special mechanisms at the network or link level.   Handover functionality can then be implemented at the endpoints without requiring special functionality in the sub-networks according to the Internet's end-to-end principle. Multipath TCP can balance a single TCP connection across multiple interfaces and reach very high throughput.
182

Multifaceted regulation of V(D)J recombination

January 2012 (has links)
abstract: V(D)J recombination is responsible for generating an enormous repertoire of immunoglobulins and T cell receptors, therefore it is a centerpiece to the formation of the adaptive immune system. The V(D)J recombination process proceeds through two steps, site-specific cleavage at RSS (Recombination Signal Sequence) site mediated by the RAG recombinase (RAG1/2) and the subsequent imprecise resolution of the DNA ends, which is carried out by the ubiquitous non-homologous end joining pathway (NHEJ). The V(D)J recombination reaction is obliged to be tightly controlled under all circumstances, as it involves generations of DNA double strand breaks, which are considered the most dangerous lesion to a cell. Multifaceted regulatory mechanisms have been evolved to create great diversity of the antigen receptor repertoire while ensuring genome stability. The RAG-mediated cleavage reaction is stringently regulated at both the pre-cleavage stage and the post-cleavage stage. Specifically, RAG1/2 first forms a pre-cleavage complex assembled at the boarder of RSS and coding flank, which ensures the appropriate DNA targeting. Subsequently, this complex initiates site-specific cleavage, generating two types of double stranded DNA breaks, hairpin-ended coding ends (HP-CEs) and blunt signal ends (SEs). After the cleavage, RAG1/2 proteins bind and retain the recombination ends to form post-cleavage complexes (PCC), which collaborates with the NHEJ machinery for appropriate transfer of recombination ends to NHEJ for proper end resolution. However, little is known about the molecular basis of this collaboration, partly attributed to the lack of sensitive assays to reveal the interaction of PCC with HP-CEs. Here, for the first time, by using two complementary fluorescence-based techniques, fluorescence anisotropy and fluorescence resonance energy transfer (FRET), I managed to monitor the RAG1/2-catalyzed cleavage reaction in real time, from the pre-cleavage to the post-cleavage stages. By examining the dynamic fluorescence changes during the RAG-mediated cleavage reactions, and by manipulating the reaction conditions, I was able to characterize some fundamental properties of RAG-DNA interactions before and after cleavage. Firstly, Mg2+, known as a physiological cofactor at the excision step, also promotes the HP-CEs retention in the RAG complex after cleavage. Secondly, the structure of pre-cleavage complex may affect the subsequent collaborations with NHEJ for end resolution. Thirdly, the non-core region of RAG2 may have differential influences on the PCC retention of HP-CEs and SEs. Furthermore, I also provide the first evidence of RAG1-mediated regulation of RAG2. Our study provides important insights into the multilayered regulatory mechanisms, in modulating recombination events in developing lymphocytes and paves the way for possible development of detection and diagnotic markers for defective recombination events that are often associated immunodeficiency and/or lymphoid malignancy. / Dissertation/Thesis / Ph.D. Molecular and Cellular Biology 2012
183

Multipath TCP and Measuring endto-end TCP Throughput : Measuring TCP Metrics and ways to improve TCP Throughput performance

SANA, VINEESHA January 2018 (has links)
Internet applications make use of the services provided by a transport protocol, such as TCP (a reliable, in-order stream protocol). We use the term Transport Service to mean the endtoend service provided to application by the transport layer. That service can only be provided correctly if information about the intended usage is supplied from the application. The application may determine this information at the design time, compile time, or run time, and it may include guidance on whether a feature is required, a preference by the application, or something in between. Multipath TCP (MPTCP) adds the capability of using multiple paths to a regular TCP session. Even though it is designed to be totally backward compatible to applications. The data transport differs compared to regular TCP, and there are several additional degrees of freedom that the particular application may want to exploit. Multipath TCP is particularly useful in the context of wireless networks using both Wi-Fi and a mobile network is a typical use case. In addition to the gains in throughput from inverse multiplexing, links may be added or dropped as the user moves in or out of coverage without disrupting the end-to-end TCP connection. The problem of link handover is thus solved by abstraction in the transport layer, without any special mechanisms at the network or link level. Handover functionality can then be implemented at the endpoints without requiring special functionality in the sub-networks according to the Internet's end-to-end principle. Multipath TCP can balance a single TCP connection across multiple interfaces and reach very high throughput.
184

Logística reversa no setor automobilístico brasileiro: uma aplicação para o estado de São Paulo / Reverse logistics in the Brazilian automotive sector: an application to the State of São Paulo

Nadja Nara Lima Heiderich 29 August 2016 (has links)
A presente pesquisa teve como principal objetivo propor uma estrutura inicial para a implantação da logística reversa no setor automobilístico brasileiro. Para tanto, foi utilizado o método de pesquisa misto, compreendendo tanto a pesquisa qualitativa como a quantitativa. Para a parte qualitativa foram aplicados questionários a empresas do setor automobilístico, uma representando as montadoras, outra representando as seguradoras, desmanches e uma empresa que opera com sucata, no intuito de captar a percepção das mesmas quanto ao tema. Para a parte quantitativa, o ferramental utilizado foi o método de programação linear, sendo a aplicação do modelo realizada para o estado de São Paulo, devido à sua representatividade no setor automobilístico brasileiro e às ações já encaminhadas, neste estado, no sentido de implantação de uma logística reversa de automóveis de forma padronizada. Foram especificados seis cenários, para melhor análise do modelo, considerando, diferentes disponibilidades na oferta de automóveis, na capacidade instalada de sucateiros e no número de sucateiros. Na parte qualitativa, os resultados apontaram para a divergência quanto à opinião dos agentes, sugerindo que não há um consenso formado quanto à implantação da logística reversa no setor automobilístico brasileiro. Na parte quantitativa, os resultados da aplicação do modelo matemático apontam para a viabilidade de implantação deste processo e para a necessidade de ampliação da capacidade de instalada para reciclagem de metais. / This research aimed at proposing an initial framework for the implementation of reverse logistics in the Brazilian automotive industry. For this, it was used the mixed research method, comprising both qualitative and quantitative research. For the qualitative part, questionnaires were applied to companies in the automotive sector, representing the automakers, another representing insurers, miscarriages and also a company that operates scrap in order to capture the perception of them for the subject. In the quantitative part, the tool used was the linear programming method, being the application made to State of São Paulo, due to its share in the Brazilian automotive industry and the actions already under way in this state, to implement reverse logistics vehicles in a standardized way. Six scenarios were specified, for better analysis of the model, considering different availabilities in car supply, the installed capacity of scrap and the number of scrap dealers. In the qualitative part, the results pointed to the divergence for the views of the agents, suggesting that there is no consensus formed about the implementation of reverse logistics in the Brazilian automotive industry. In the quantitative part, the results of the application of the mathematical model point out to the implementation of this process feasibility and the need for the increase in the installed capacity for metal recycling.
185

Unit testing the User Interface : Automatic tests of web UI's in React

Christersson Frend, Paul January 2016 (has links)
No description available.
186

Fuzzy Front End de inovações sistêmicas: quadro conceitual e estudo de casos. / Fuzzy Front End of systemic innovation: conceptual framework and case studies.

Silvia Mayumi Takey 08 June 2016 (has links)
Inovações sistêmicas são aquelas que requerem reajustes significativos em co-opetidores do ecossistema de inovação. A relevância de inovações sistêmicas tem crescido por diversos motivos, tais como o caráter sistêmico de inovações relacionadas ao desenvolvimento sustentável, o amadurecimento da sociedade em rede e a disseminação da inovação aberta. O fuzzy front end, ou seja, a etapa inicial e difusa do processo de inovação, tem sido explorado considerando-se principalmente relações díades empresa-consumidor. O objetivo desta dissertação é explorar como se diferencia o fuzzy front end em inovações sistêmicas, em ecossistemas de inovação complexos, que demandam a coordenação com diferentes entidades externas ao controle direto da empresa focal. Para tanto, a metodologia conta com três macroetapas: revisão sistemática da literatura de fuzzy front end e inovação sistêmica, estudo de caso piloto de caráter preliminar e estudos de caso exploratórios em empresas em diferentes posicionamentos do ecossistema de negócios de Redes Inteligentes (Smart Grid) com análises intra e inter casos. / Systemic innovations are those that require significant changes in co-opetitors within the innovation ecosystems in which they are inserted. The relevance of systemic innovations has grown due to several reasons, such as the systemic characteristic of sustainable development innovation projects, the higher maturity of the network society and the dissemination of open innovation practices. The fuzzy front end, the initial and diffuse phase of the innovation process, has been explored considering mainly dyadic relations between company and consumers. The goal of this dissertation is to explore how does the fuzzy front end differentiate in systemic innovations, in complex innovation ecosystems, considering the need for coordination with external entities outside the control of the focal company. Therefore, the methodology has three macro-steps: a systematic literature review of fuzzy front end and systemic innovation, a pilot case study and exploratory case study with intra and cross-case analysis in different positions in the Smart Grid business ecosystems.
187

Exploração de uma biblioteca genômica de Passiflora edulis f. flavicarpa por sequenciamento de BAC-ends / Exploitation of a genomic library of Passiflora edulis f. flavicarpa using BAC-end sequencing

Anselmo Azevedo dos Santos 03 July 2013 (has links)
O maracujá-amarelo (Passiflora edulis f. flavicarpa) é uma frutífera de importância econômica no Brasil, sendo apreciado para a produção de suco concentrado e para o consumo in natura, além de ser usado pela indústria farmacêutica na extração da passiflorina. O presente trabalho visou à exploração da biblioteca genômica inserida em BACs (Ped-B-Flav) por meio da técnica de BAC-end sequencing, visando prover os primeiros insights sobre a composição e organização genômica da espécie, além de gerar novos candidatos a marcadores moleculares. Ao todo foram realizadas 9.979 reações de sequenciamento com eficiência média de 89 %, resultando em 8.821 BES de alta qualidade, com tamanho variando entre 100 pb e 1.255 pb, tendo em média 596 pb, totalizando cerca de 5,7 Mpb de informação genômica. Foram identificados, ao todo, 610 potenciais novos marcadores microssatélites. Os motivos de tetranucleotídeos foram os mais abundantes, ou seja, 28,9 % do total, sendo as repetições AATT aquelas observadas com maior frequência, com 131 ocorrências. Foram identificados e classificados 4.394 (19,69 %) elementos repetitivos. Dentre estes elementos, os grupos dos retrotransposons gypsy e copia-like foram os mais abundantes, correspondendo a 10,08 % e 7,93 % das ocorrências, respectivamente. Além disso, foram encontradas 767 (8,7 %) sequências com alta identidade a regiões codificadoras de proteínas. Estas sequências foram classificadas e anotadas de acordo com o vocabulário controlado GeneOntology. Análises de mapeamento genômico comparativo revelaram três regiões microssintênicas com o genoma de Populus trichocarpa, uma com o genoma de Vitis vinifera e uma com o genoma de Arabdopisis thaliana, além de evidenciarem uma série de regiões rearranjadas em relação aos genomas de referência. O presente estudo mostrou que os BES de Passiflora edulis são uma excelente fonte de informações sobre o genoma da espécie, principalmente no que tange à diversidade gênica, identificação de elementos transponíveis e ao potencial para o desenvolvimento de novos marcadores genéticos. Igualmente, foi possível empregar essas sequências na identificação de regiões microssintênicas entre o genoma do maracujá-amarelo e de outras espécies vegetais próximas. / Yellow passion fruit (Passiflora edulis f. flavicarpa) is of considerable economic importance to Brazil. It is used to produce juice concentrate and also marketed for consumption as a fresh fruit. In the pharmaceutical industry, it is used to produce passiflora extract. The aim of this study was to explore the BAC (Bacterial Artificial Chromosome) genomic library (Ped-B-Flav) using BAC-end sequencing (BES) to provide some initial insights into the composition and organization of the species genome, and to generate new candidates for molecular markers. Altogether, 9,979 sequencing reactions were performed, with an average efficiency of 89 %, resulting in 8,821 high-quality BES, of average length ranging from 100 bp to 1255 bp, and consisting of an average 596 bp, totaling some 5.7 Mb of genomic information. In all, we identified 610 potential new microsatellite markers. Tetranucleotide motifs (28.9%) were the most abundant and AATT was the most frequently observed motif, with 131 occurrences. We identified and classified 4,394 (19.69 %) repetitive elements. Retrotransposon gypsy (10.8%) and copia-like (7.93%) elements were the most abundant. Furthermore, we found 767 (8.7 %) sequences very similar to those of protein coding regions. These sequences were classified and annotated according to gene ontology controlled vocabulary. Comparative genomic mapping revealed three regions showing microsynteny with the genome of Populus trichocarpa, one with Vitis vinifera genome and one with the Arabdopisis thaliana genome. In addition it revealed a series of rearranged regions in comparison to the reference genomes. This study showed that Passiflora edulis BES form an excellent source of information on the genome of the species, especially in regard to genetic diversity, identification of transposable elements and potential for the development of new genetic markers. It was also possible, using these sequences, to identify regions showing microsynteny with other plant species.
188

Eletrônica de front-end do experimento Neutrinos-Angra

Costa, José Abritta 29 August 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-24T20:53:39Z No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:23:58Z (GMT) No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) / Made available in DSpace on 2017-04-25T15:23:58Z (GMT). No. of bitstreams: 1 joseabrittacosta.pdf: 19821453 bytes, checksum: 97adfa8b62deaa442a2059908995d6b3 (MD5) Previous issue date: 2014-08-29 / O experimento Neutrinos Angra visa desenvolver um detector compacto e novas técnicas para medir o fluxo de antineutrinos das reações nucleares que ocorrem no interior dos reatores de usinas nucleares, permitindo o monitoramento da sua dissipação de energia instantânea e revelando a composição físsil de combustível nuclear. Este trabalho apresenta o desenvolvimento da eletrônica de front-end do Detector Neutrinos Angra. Esta eletrônica deve realizar o condicionamento dos sinais provenientes de tubos fotomultiplicados, visando fornecer ao sistema de aquisição de dados um pulso que facilite a identificação do fluxo de antineutrinos que passa pelo detector. Neste trabalho, as especificações do front-end foram definidas com base nos requisitos do experimento, que são: faixa linear de operação de 0 a 50 fótons; capacidade para identificar um fóton; duração do pulso menor do que alguns µs; largura de banda do pulso menor do que 60 MHz; excursão máxima na saída de até 2 V. Para isto, uma topologia do circuito de front-end foi proposta, sendo composta por quatro subsistemas: circuito de alimentação; circuito de condicionamento do sinal; circuito de controle de offset na saída e de limiar de tensão; e circuito discriminador. Oito módulos foram produzidos para equipar o detector. Neste trabalho, três módulos foram avaliados. Os testes mostraram que o desempenho dos três módulos atenderam as especificações, apresentando uma calibração média de 7,4±0,6 V/V , tempo de subida de 26±1 ns, tempo de descida de 81 ±2,5 ns, largura a meia altura de 74±1 ns, não-linearidade menor do que 2,2% para toda a faixa dinâmica de entrada e a saturação iniciando em aproximadamente 1,4 V. / The Neutrinos Angra Experiment aims to develop a compact detector and new techniques to measure the antineutrinos flow of nuclear reactions occurring inside the nuclear power plant reactors, allowing monitoring of its instant energy dissipation and revealing the composition of fissile nuclear fuel. This study presents the development of the Front-end electronics of the Neutrinos Angra detector. The electronics should perform the conditioning of the signals from photomultiplier tubes, aiming to provide a fast pulse for the data acquisition system whitch could facilitate the identification of the antineutrinos flow through the detector. In this work, the specifications of the front-end were defined based on the experiment requirements, which are: linear operating range 0-50 photons; ability to identify a single photon; the pulse duration less than a few µs; bandwidth of the pulse smaller than 60 MHz; maximum range in the output up to 2 V. For this, a topology of the front-end circuit has been proposed, consisting of four subsystems: power circuit; signal conditioning circuit; offset control circuit and discriminator circuit. Eight modules were produced to equip the detector. In this study three modules were evaluated. Tests showed that the performance of three modules met the specifications, with an average calibration of 7.4±0.6 V/V , rise time of 26 ±1 ns, falltime of 81 ±2.5 ns, width at half height of 74±1 ns, linearity better than 2.2% and saturation starting around 1.4 V.
189

End-to-end Delay Analysis and Measurements in Wireless Sensor Networks

Chen, Hao January 2012 (has links)
Wireless sensor networks have arrived because of further developments of themodern Internet, and this has been considered to be one of the most importanttechnologies of the 21st century. Currently, the wireless sensor network has becomean important technology in a variety of areas and is widely used in thefield of national defense, national security, environmental monitoring, trafficmanagement, anti-terrorism, anti-disaster, and so on. The majority of these applicationsrequire real-time communication as the WSNs are required to sendthe data to the data center within a specified time. In order to meet the real-timedemand for wireless sensor networks, this work mainly focuses on the analysisand measurement of the end-to-end delay, including both single-hop and multihopdelays. This thesis first analyzes the composition of the end-to-end delayand then describes the end-to-end delay measurement algorithms and methods.The measurement is implemented in TelosB motes within TinyOS. Finally thereport will show the evaluation of the end-to-end delay in wireless sensor networks.
190

Employing Android Security Features for Enhanced Security and Privacy Preservation

Wakim, Mike January 2017 (has links)
In this thesis, we examine the architecture and the security framework underlying the Android operating system. We explore existing Android end-to-end encrypted (E2EE) messaging applications and derive four categories of common issues that are applicable to these applications. We then provide an overview of the known issue of privilege escalation wherein a malicious privileged application can utilize inter-process communication techniques to send protected data to an unauthorized application on a user’s device. We demonstrate through a proof of concept how this behavior can be achieved in real applications, and we suggest potential countermeasures that can help prevent this issue. Furthermore, in the interest of diminishing the common issues that are applicable to E2EE messaging applications, we propose a new design for such applications that employs some of the principal security features offered by the Android operating system. We explain how our design can help eliminate trust-related issues associated with such applications, as well as how it can help minimize issues in other categories. Finally, we demonstrate how our proposed design can be used in practice by implementing a proof of concept.

Page generated in 0.04 seconds