Mac Layer
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. MÃtodo para avaliaÃÃo de aspectos de camada fÃsica e MAC de redes 802.11. / Method to evaluate physical and MAC layer aspects of 802.11 networks.
The present dissertation proposes a 802.11 network evaluation sequence which can be adopted, independently of the equipment used at the network. The log-distance path loss model is used for the environment characterization (by the model β parameter) where the network is evaluated. The specific objectives of each evaluation stage are presented and contex
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/12/2012
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2. Um estudo de escalonamento UPLINK considerando a camada física OFDM do padrão IEEE 802.16 / A study of uplink scheduling considering the OFDM physical layer of IEEE 802.16 standard
O padrão IEEE 802.16 define as especificações para a camada de controle de acesso ao meio (MAC - Medium Access Control ) e os parâmetros para a camada física (PHY - Physical Layer), os quais possibilitam estruturar a arquitetura para o provimento QoS (Quality of Service) às redes de acesso em banda larga sem fio [1, 2]. No entanto, deixa em aberto a fo
Publicado em: 2011
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3. Projeto integrado para coleta de dados em redes de sensores sem fio
In Wireless Sensor Networks, the nodes have severe energy constraints due to the fact of having a small battery and being located in places of difficult access for humans. Therefore, these networks need protocols that are efficient regarding energy consumption. Unlike the traditional networks that are designed to accommodate a wide variety of applications, W
Publicado em: 2009
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4. Proposed Threshold-Based Connection Admission Control (CAC) Algorithm for IEEE 802.16 Networks / Proposta de algoritmo de controle de admissão de conexões baseado em Threshold para as Redes IEEE 802.16
IEEE 802.16 standard, also called WiMAX (Worldwide Interoperability for Microwave Access), is one of the most promising technologies for BWA (Broadband Wireless Access) networks. The IEEE 802.16 standard provides specification of MAC and physical layer. The standard adds to the BWA networks some advantages over other technologies, such as wide area of covera
Publicado em: 2009
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5. Caracterizando distorções em redes ad hoc
Ad hoc networks work under the assumption that the devices composing the network are willing to collaborate with one another. Nevertheless, in a collaborative environment, selfish and misbehaving nodes may have a negative impact on the whole network. Hence, means to characterize and identify such behavior is necessary as its impact may affect the entire netw
Publicado em: 2008
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6. Análise e simulação do sistema de comunicações WiMAX(IEEE 802.16 - 2004) com ADS (Advanced Design System). / Analysis and simulation of communication system WiMAX (IEEE 802.16 2004) with ADS (Advanced Design System).
Este trabalho apresenta uma visão geral do modo de transmissão OFDM do padrão IEEE 802.16. O controle de acesso ao meio (MAC) e da camada física (PHY) são descritos em detalhes. Especialmente a estrutura do frame na camada (PHY). Além disso, as diferentes configurações da camada PHY com diferentes níveis de robustez são analisadas. Em seguida a sim
Publicado em: 2008
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7. Um estudo comparativo do desempenho das disciplinas de escalona-mento WRR e WFQ no suporte à QoS em ambientes de redes de acesso IEEE 802.16
The incipient technology of wireless access networks of the IEEE 802.16 Standard aggregates to the BWA systems many advantages over concur technologies, such as radio signal wide coverage, even in difficult access regions or needy of conventional infrastructure of network, as the case of some urban and rural areas of Brazil. Moreover, enables access to the I
Publicado em: 2008
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8. Analise comparativa entre protocolos de camada MAC para redes ad-hoc sem fio / Comparative analysis between MAC-level protocols for ad-hoc wireless networks
Este trabalho visa o estudo de redes ad hoc sem fio, em especial, os protocolos da subcamada MAC do modelo OSI. Neste tipo de rede sem controle centralizado, o acesso ao meio se torna uma parte crítica no processo de comunicação entre terminais. Assim sendo, a principal motivação deste trabalho é investigar como os protocolos da subcamada MAC podem afe
Publicado em: 2007
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9. Arquiteturas Cross-layer para Redes de Sensores sem Fio
The majority of proposed communications protocols in sensor networks thrive on the collaborative nature of sensor nodes to optimize a number of important operational aspects such as routing, energy consumption, load balancing and traffic optimization. Common to all the proposed solutions are the fact of these networks also are projected on the traditional la
Publicado em: 2007
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10. O uso de geocomposto como camada indutora para redução de tensões sobre estruturas enterradas / The use of geocomposite as compressible layer to reduce vertical stress on buried structures
Este trabalho apresenta resultados de ensaios laboratoriais e de análises paramétricas, realizadas através do método dos elementos finitos, para a avaliação do comportamento do geocomposto MacDrain 2S quando utilizado como elemento compressível na técnica da trincheira induzida para redução de tensões sobre estruturas enterradas. Mostra-se que est
Publicado em: 2006
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11. Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor
Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01
Brazilian Journal of Medical and Biological Research. Publicado em: 2004-12
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12. High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors
Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the part
Materials Research. Publicado em: 2004-03