Mobile Communications
Mostrando 1-12 de 47 artigos, teses e dissertações.
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1. Investigation of Dosimetry in Four Human Head Models for Planar Monopole Antenna with a Coupling Feed for LTE/WWAN/WLAN Internal Mobile Phone
Abstract The objective of the present study is to evaluate the Specific Absorption Rate (SAR) within the human head model exposed to the radiation of planar monopole antenna with T-shaped coupling feed and an inductive shorting strip. The presented design has a compact structure, a planar configuration and occupying a small size of 36×20mm2. Two wide bands
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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2. 4iPay : modelo para sistemas de pagamento móvel em comércio ubíquo
This work aims at presenting a usability and architectural model for a mobile payment system. In our model, we assume independence of devices, of location, of mobile operator, and of administrator, to allow all kinds of payment in ubiquitous environments (Ubiquitous Commerce). In this work, we begin describing motivation, goals, and fundamental concepts, in
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2012
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3. Journalism in context of convergence: implications of multiplatform distribution in the expansion of the contracts of communication of devices in ¿Zero Hora¿ / Jornalismo em contexto de convergência : implicações da distribuição multiplataforma na ampliação dos contratos de comunicação dos dispositivos de Zero Hora
This research was aimed at investigating how the performance of multiplatform production instance of the company "Zero Hora" in the context of convergence journalism, the contracts of communication, offered to its public, are extended. Is considered the hypothesis that when a communication vehicle launches traditional versions of their products on the web an
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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4. EFFECT OF MOVING PLATFORMS ANTENNA POINTING ERRORS ON THE PERFORMANCE OF DIGITAL SATELLITE LINKS / EFEITO DO ERRO DE APONTAMENTO DE ANTENAS FIXADAS EM PLATAFORMAS MÓVEIS NO DESEMPENHO DE SISTEMAS DE COMUNICAÇÃO DIGITAL POR SATÉITE
O dimensionamento de enlaces digitais de comunicação e realizado com base em objetivos de desempenho a serem satisfeitos por determina- dos parâmetros, considerando o comportamento aleatório das fontes de degradação do sinal. Em sistemas de comunicação móvel por satélite, o de- sempenho pode ser fortemente afetado pelo erro de apontamento da antena
Publicado em: 2011
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5. Uma arquitetura de comunicação oportunística
Mobile computing devices often present high processing power and include several wireless network interfaces. 4G networks promise to provide a unified IP based infrastructure with QoS and security support for the communications using such devices. Transmission delays, and network disruptions, however, are often common when considering the current transmissio
Publicado em: 2010
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6. Segurança em sistemas de comunicação pessoal : um modelo de arquitetura de protocolos para a interconexão de sistemas heterogêneos / Security in personal communications systems. one model of protocol architecture for the interworking of heterogeneous systems
A evolução dos sistemas de comunicação sem fio ou wireless apresentam até agora três gerações em menos de duas décadas. Fazendo parte desta evolução estão os sistemas de telefonia celular e os emergentes Sistemas de Comunicação Pessoal ou PCS (Personal Communications Systems). Este trabalho visa apresentar duas questões importantes na evoluç�
Publicado em: 2010
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7. Códigos LDPC quaternários aplicados à técnica de transmissão OFDM / Quaternary LDPC codes applied to OFDM transmission technique
This dissertation addresses the study of error correcting codes based on sparse non-binary matrices. The LDPC (Low Density Parity Check) codes constitute a efficient family of codes generated by sparse parity check matrices and it is considered as one of the classes of codes that presents the best performance in digital communications systems. LDPC codes ove
Publicado em: 2010
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8. Impacto da utilização de tecnicas de lifting explorando diferença entre ferramentas interpretada e compilada na velocidade computacional da codificação wavelet de imagens estaticas / Impact of using lifting techniques to explore the differences between interpreted and compiled tools in the computational speed of wavelet static image coding
The field of analysis and compression of images has been received special attention of the scientific community because of including in the main systems of digital TV, satellite communications and mobile communications. In this context, the Discrete Transform Wavelet (TWD) arise how a powerful tool and its many advantages allowed your insertion in important
Publicado em: 2009
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9. 3D routing with context awareness
The emergence of low-cost, wireless network interfaces in the market and the ever increasing growth in demand of mobile devices (such as SmartPhones, PDAs, Internet Tablets and Laptops) enabled scenarios where network services for mobile users may exist in an ad hoc fashion, with no pre-existing communications infrastructure. However, the creation of such dy
Publicado em: 2009
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10. Análise teórica e experimental de superfícies seletivas de freqüência e suas aplicações em antenas planares
This work presents a theoretical and numerical analysis of structures using frequency selective surfaces applied on patch antennas. The FDTD method is used to determine the time domain reflected fields. Applications of frequency selective surfaces and patch antennas cover a wide area of telecommunications, especially mobile communications, filters and WB ant
Publicado em: 2009
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11. Aplicação comercial do sistema omnisat da autotrac e qualcomm com o uso de terminais móveis e análise de técnicas de múltiplo acesso em sistemas via satélites
The purpose of this work is to show the OmniSAT system of data mobile communication and tracking vehicles of Autotrac, applied to vehicles fleet market. The OmniTRACS system was developed in the United States by Qualcomm Incorporated and implements, besides security and logistic, also bi-directional mobile communications applied to government and utilities m
Publicado em: 2008
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12. FROM THE TECHNOLOGICAL SUBLIME TO THE FLOW CARTOGRAPHIES / DO SUBLIME TECNOLÓGICO ÀS CARTOGRAFIAS DOS FLUXOS
Recently, a growing number of artists and designers are producing interactive artworks equipped with mobile and wireless communications devices, including mobile phones, PDAs and laptops, connected to computer networks and location-based systems. These artworks are mapping new forms of flow that accumulate invisibly in space in layers of our technological li
Publicado em: 2008