Página 17 dos resultados de 2591 itens digitais encontrados em 0.032 segundos

Análise de sistemas de comunicação para computação paralela em clusters.; Communication system analysis for cluster parallel computing.

Rosa, Bruno Otto Theodoro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/02/2002 Português
Relevância na Pesquisa
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Apesar do aumento constante da largura de banda das tecnologias de rede de computadores as aplicações de processamento paralelo ainda necessitam de uma latência de comunicação mais baixa que a oferecida. Este aspecto não tem sido contemplado por estas tecnologias de rede pois está relacionado à maneira como o sistema operacional utiliza-se dos recursos do hardware com relação aos dados enviados pelas aplicações dos usuários. Neste trabalho apresentamos um estudo da técnica para diminuição desta latência e as características necessárias para implementação deste tipo de sistemas, incluindo mecanismos de transferência de dados, técnicas para tradução de endereços, proteção, transferência de controle, grau de confiabilidade e implementação de "Multicasting". Apresentamos também o estudo de um sistema já implementado, chamado M-VIA, comparando seu desempenho com o TCP/IP tradicional.; Despite the constant bandwidth increase in computer networks parallel processing tasks still require a lower communication latency than offered. This necessity has not been addressed by these network technologies because it is related to how operating systems use hardware resources to send user data through network. In this work we present strategies to lower latency and the requirements to implement these systems...

Seleção adaptativa e interativa de serviços móveis em ambientes convergentes heterogêneos.; Adaptive and interactive mobile service selection in convergent and heterogeneous environments.

Dutra, Rogério Garcia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 19/01/2012 Português
Relevância na Pesquisa
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A crescente mobilidade de pessoas e recursos materiais exige um esforço constante na exploração das capacidades oferecidas pelas diferentes tecnologias disponíveis, que convergem para o fornecimento de informações e serviços em qualquer lugar com movimento, a qualquer tempo, e por meio de qualquer dispositivo, objetivos da rede mundial de cooperação e comunicação, conhecida como Internet. Em resposta a essa crescente demanda, a atual Internet está evoluindo do modelo de compartilhamento de informações para o modelo de contribuição e em um futuro próximo, para o modelo de colaboração entre provedores e consumidores, denominada de Internet do Futuro. Embora a atual Internet seja extraordinariamente bem sucedida, como um meio ubíquo de comunicação, sua atual arquitetura impõe limites para o provisionamento de serviços em ambientes heterogêneos e convergentes, demandando novas soluções que superem os desafios tecnológicos necessários ao estabelecimento da Internet do Futuro. Estas novas soluções basear-se-ão nos princípios da computação orientada a serviços, formando os componentes de um novo arcabouço de serviços para a Internet do Futuro, denominada de Internet de Serviços. Na Internet de Serviços...

Utilização de redes neurais artificiais na previsão do VTEC visando a geração de estações de referência virtuais em tempo-real.; Use of artiificial neural networks to predict VTEC aiming to generate virtual reference stations in real-time.

Machado, Wagner Carrupt
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/06/2012 Português
Relevância na Pesquisa
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Dentre as técnicas de posicionamento utilizando os sistemas de navegação por satélite globais (GNSS - Global Navigation Satellite Systems), merece destaque a que utiliza dados de uma rede de estações GNSS para gerar estações de referência virtuais. Desde que as estações da rede não estejam separadas por mais de 100 km e o receptor do usuário esteja dentro da região interna à rede de referência, esta técnica de posicionamento pode proporcionar posicionamento com precisão melhor que 10 cm a usuários de receptores de uma frequência. No entanto, o posicionamento em tempo-real pode ser inviabilizado caso ocorra problema de comunicação com as estações da rede de referência. Tendo em vista a relação do conteúdo total de elétrons (TEC - Total Electron Content) com o atraso ionosférico de primeira ordem, esta pesquisa apresenta uma forma de se prever 72 horas do TEC na direção vertical (VTEC - Vertical Total Electron Content) regionalmente com a arquitetura de redes neurais artificiais (RNA) denominada perceptrons de múltiplas camadas (MLP MultiLayer Perceptrons). A metodologia de previsão do VTEC proposta foi empregada na geração de estações de referência virtuais, onde arquivos de previsão do atraso troposférico zenital...

Session-Oriented Communication System for Truly Reliable and Robust Smart Grid

Neto, Augusto; Cerqueira, Eduardo; Souza, Neuman; Pirmez, Luci; Gomes, Danielo; Aguiar, Rui
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Português
Relevância na Pesquisa
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Environmental sustainability issues and the costs of new power generation and transmission have increased the interest in evolving current power grid to new technologies. The Smart Grid is a promising technology, since it allows a distributed computing approach with potentials for selfdiagnosing/-healing, reliable multi-user communication and fast hard real-time control. However, the missing standardization associated with heterogeneity of legacy systems and wide-area service demands, makes very challenging to adopt Smart Grid in a cost-effective way. By considering this, we propose the Session-Oriented communication System (SOCSys) to overcome the above issues by enhancing Smart Grid with truly reliable and robust capabilities over heterogeneous environments. SOCSys achieves this goal by orchestrating session-control with innovative network-centric facilities operating over a wireless mesh Information Network compliant with IEEE 802.11e/s standard. The simulation results show that SOCSys improved network performance in terms of bandwidth utilization and minimization of delay, while consuming low network resources. Graphical analyses showed that SOCSys supported multimedia sessions with excellent quality, where it outperforms the experiments with regular settings. In this field...

Smart Query Answering for Marine Sensor Data

Shahriar, Md. Sumon; de Souza, Paulo; Timms, Greg
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 03/03/2011 Português
Relevância na Pesquisa
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We review existing query answering systems for sensor data. We then propose an extended query answering approach termed smart query, specifically for marine sensor data. The smart query answering system integrates pattern queries and continuous queries. The proposed smart query system considers both streaming data and historical data from marine sensor networks. The smart query also uses query relaxation technique and semantics from domain knowledge as a recommender system. The proposed smart query benefits in building data and information systems for marine sensor networks.

Estimação de vazão baseada em modelagem e simulação do controle de acesso ao meio em redes PLC; Throughput estimation based on modeling and simulation of medium access control in PLC networks

VASQUES, Thiago Lara
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Elétrica e de Computação; Engenharia Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Elétrica e de Computação; Engenharia
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
35.7%
We carried out a study on throughput estimation based on analysis and modeling of the medium access control in HomePlug 1.0 standard based PLC networks. The data communication using electrical energy wires has advantages such as presenting characteristics of ubiquity due to the existent infrastructure, but faces significant obstacles as fading and noise. The main standard of this kind of home network is the HomePlug, which defines a protocol based on the method of multiple access with collision avoidance (CSMA/CA). The HomePlug adds to the CSMA/CA a technique called deferral counter (DC) that adapts the contention of the nodes in accessing the medium according to network load. The objective of this work is todo a comparative study of the throughput, which is the ratio of the packet payload, i.e., the amount of data that is inserted into the body of the datagram, and the frame transmission time. To this end, we evaluate what is the theoretical maximum throughput of the PLC channel, we developed a simulator for the CSMA/CA and we propose a simple probabilistic model to describe the throughput on the network PLC. Finally, we make a comparison between the results obtained with the simulator and the probabilistic model to those observed from a real PLC network...

Green markov - uma abordagem h?brida de pol?tica markoviana e simula??o discreta para planejamento de aloca??o de usu?rios em redes macro-femto

CARDOSO, Jorge Amaro de Sarges
Fonte: Universidade Federal do Pará Publicador: Universidade Federal do Pará
Tipo: Dissertação de Mestrado
Português
Relevância na Pesquisa
35.7%
O uso da comunica??o de voz e dados atrav?s de dispositivos m?veis vem aumentando significativamente nos ?ltimos anos. Tal expans?o traz algumas dificuldades inerentes, tais como: amplia??o constante de capacidade das redes e efici?ncia energ?tica. Neste contexto, vem se consolidando o conceito de Green networks, que se concentra no esfor?o para economia de energia e redu??o de CO2. Neste sentido, este trabalho prop?e validar um modelo de uma pol?tica baseado em processo markoviano de decis?o, visando a otimizar o consumo de energia, QoS e QoE, na aloca??o de usu?rios em redes macrocell e femtocell. Para isso o modelo foi inserido no simulador NS-2, aliando a solu??o anal?tica markoviana ? flexibilidade caracter?stica da simula??o discreta. A partir dos resultados apresentados na simula??o, a pol?tica obteve uma economia significativa no consumo energ?tico, melhorando a efici?ncia energ?tica em at? 4%, al?m de melhorar a qualidade de servi?o em rela??o ?s redes macrocell e femtocell, demonstrando-se eficaz, de modo a alterar diretamente as m?tricas de QoS e de QoE.; ABSTRACT: The use of voice and data communication via mobile devices has increased significantly in recent years. This expansion brings some difficulties such as: continuous expansion of network capacity and energy efficiency. In this context...

A new fault tolerant architecture for time sensitive automation networks

Kleineberg, Oliver
Fonte: University of Limerick Publicador: University of Limerick
Tipo: info:eu-repo/semantics/doctoralThesis; all_ul_research; ul_published_reviewed; ul_theses_dissertations
Português
Relevância na Pesquisa
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peer-reviewed; Networked control systems have been widely used in Industrial Automation since the latter part of the 20st century. Such networks have evolved from small systems with proprietary and slow Fieldbus technology to a much larger scope. Today, Ethernet-based automation systems encompass whole factories and carry large amounts of data traffic with differing latency requirements. Proprietary real-time Ethernet technologies such as Profinet IRT (Isochronous Real-Time) have demonstrated the feasibility of real-time Ethernet for even the most demanding applications such as functional safety and motion control. The drawback of these vendor-specific solutions is their dependence on proprietary ASICs (Application-Specific Integrated Circuit) and their very limited compatibility to standard Ethernet and Bridging as defined by IEEE (Institute of Electrical and Electronics Engineers) 802.3 and IEEE 802.1. Up to the present day, this has limited the widespread success of Ethernet as a real-time network solution. With the emerging AVB (Audio- and Video Bridging) technology, IEEE 802.1 has defined the first vendor-neutral real-time Ethernet, enabling the possibility of a standardised solution for Industrial Automation. However...

Random access schemes for multichannel communication and multipacket reception in wireless networks.

Lee, Hyukjin
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011 Português
Relevância na Pesquisa
35.7%
Random access schemes have used advanced capabilities of the physical layer to achieve reliable data transmissions over wireless communication channels. These capabilities include multichannel communication and multipacket reception. Incorporating the advanced capabilities into the access schemes, as a cross-layer design, is a challenging task because a more sophisticated approach is required to interface the physical layer and the medium access control (MAC) layer. This thesis presents development of research into the efficient random access schemes that provide a better set of cross-layer design approaches by taking into account the capabilities of multichannel communication and multipacket reception. The consideration is to propose multichannel random access schemes that use a channel outage concept of fading and interference. The system performance of the proposed schemes is then analysed. By considering imperfect channel information, a random backoff access scheme that operates with a channel sensing policy is developed. The sensing and access problem is formulated as a partially observable Markov decision process, and is solved with simple and efficient heuristic approaches. A new joint random access scheme that resolves packet collisions in the time and frequency domains is then proposed to enable effective uplink access. The joint scheme cooperates with a sensing method in which users are partially aware of channel conditions. With multipacket reception (MPR) capability...

An Architecture for Distributed Wavelet Analysis and Processing in Sensor Networks

Wagner, Raymond; Baraniuk, Richard G.; Du, Shu; Johnson, David B.; Cohen, Albert; Wagner, Raymond; Baraniuk, Richard G.; Du, Shu; Johnson, David B.; Cohen, Albert
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Conference paper
Português
Relevância na Pesquisa
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Conference paper; Distributed wavelet processing within sensor networks holds promise for reducing communication energy and wireless bandwidth usage at sensor nodes. Local collaboration among nodes de-correlates measurements, yielding a sparser data set with significant values at far fewer nodes. Sparsity can then be leveraged for subsequent processing such as measurement compression, de-noising, and query routing. A number of factors complicate realizing such a transform in real-world deployments, including irregular spatial placement of nodes and a potentially prohibitive energy cost associated with calculating the transform in-network. In this paper, we address these concerns head-on; our contributions are fourfold. First, we propose a simple interpolatory wavelet transform for irregular sampling grids. Second, using ns-2 simulations of network traffic generated by the transform, we establish for a variety of network configurations break-even points in network size beyond which multiscale data processing provides energy savings. Distributed lossy compression of network measurements provides a representative application for this study. Third, we develop a new protocol for extracting approximations given only a vague notion of source statistics and analyze its energy savings over a more intuitive but naive approach. Finally...

Prestaciones de las técnicas Digital Fountain en redes de sensores; Performance of Digital Fountain techniques over Wireless Sensor Networks

Muñoz Corada, Gonzalo
Fonte: Universidade de Cantabria Publicador: Universidade de Cantabria
Tipo: Trabalho de Conclusão de Curso
Português
Relevância na Pesquisa
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RESUMEN: La aplicación de los códigos Digital Fountain son una de las múltiples técnicas que permiten la recuperación de errores en sistemas de transmisión sin tener que realizar retransmisiones. Así se logra optimizar el uso del canal sobre todo en casos donde el transmisor actúa como una fuente continua de datos. Los procedimientos de actualizaciones de los firmwares de equipos distribuidos en una red de sensores son un claro ejemplo de entornos en los que se requiere una mejora y eficiencia de las comunicaciones entre un punto y múltiples destinatarios. De esto surge la posible aplicación de los códigos Digital Fountain a este tipo de procedimientos. Durante el trabajo primeramente se planteará un estudio de las técnicas de codificación y decodificación más utilizadas. Seguidamente, se analizaran las diferentes redes de sensores que se encuentran en el mercado. Por último, se procederá a implementar los algoritmos correspondientes para su correspondiente validación empleando plataformas hardware comercial. Finalmente, se evaluarán las prestaciones derivadas de la utilización de estas técnicas, también conocidas como códigos de Luby, para flujos de datos entre un servidor y varios clientes.; ABSTRACT: The application of the Digital Fountain codes is one of the multiple techniques that enable error correction avoiding retransmissions in communication systems. This way channel use is optimized...

Authentication and privacy in vehicular networks

Fuentes, José María de; González-Tablas, Ana Isabel; Ribagorda, Arturo
Fonte: Novática; CEPIS, Council of European Professional Informatics Societies Publicador: Novática; CEPIS, Council of European Professional Informatics Societies
Tipo: Artigo de Revista Científica Formato: application/pdf; text/plain
Publicado em /02/2010 Português
Relevância na Pesquisa
35.7%
Vehicular ad-hoc networks (VANETs) are composed mainly by vehicles. These communication networks allow data interchanging. In this way, more and better information is provided to drivers, thus achieving a better road safety. Information security is critical in these scenarios, as human lives are at stake. Particularly, spreading false data should be prosecuted, so sender identification and authentication is needed. However, it could allow vehicle tracking. In this way, privacy protection must also be achieved. In this work, mechanisms to fulfill this authentication-privacy compromise are analyzed.; This work is partly funded by the Spanish Ministry of Science and Innovation, within the National Plan for Scientific Reserarch, Technologic Development and Innovation 2008-2011, under contract TIN2009-13461 (project E-SAVE); Monograph: Identity and Privacy Management

Analysis and optimal configuration of distributed opportunistic scheduling techniques in wireless networks

García Saavedra, Andrés
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
35.7%
The phenomenon of fading in wireless communications has traditionally been considered as a source of unreliability that needs to be mitigated. In contrast, Opportunistic Scheduling (OS) techniques exploit quick channel quality oscillations in fading links, during the assignment of transmission opportunities, to improve the performance of wireless networks. While centralized mechanisms rely on a central entity with global knowledge, Distributed Opportunistic Scheduling (DOS) techniques have recently been proposed to work in distributed networks, i.e., where either such a central entity is not available, or the communication overhead to feed timely information to this central entity is prohibitive. With DOS, each station contends for the channel with a certain access probability. If a contention is successful, the station measures the channel conditions and transmits if the channel quality is above a certain threshold. Otherwise, the station does not use the transmission opportunity, allowing all stations to recontend. Given the fact that different stations, in different time instances, experience different channel conditions, it is likely that the channel is used by a link with better conditions, improving overall performance. In this thesis we first propose ADOS...

Transnational networks and identifications of Australia's Diaspora in the USA

McDougall, K.
Fonte: Routledge Publicador: Routledge
Tipo: Artigo de Revista Científica
Publicado em //2012 Português
Relevância na Pesquisa
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A contemporary global situation fuelling highly skilled, temporary and circular mobility and transnational migration experiences has led to increasing interest from origin countries in understanding emigration and diaspora. Little research about emigration and diaspora has been undertaken in high-income countries, therefore, there is limited data available to help understand these populations. Using data collected in an online survey of 1,581 Australians living in the USA, this paper explores the international mobility patterns and transnational networks and identifications kept by the Australian diaspora living in the USA. The Australian diaspora in the USA maintain transnational livelihoods with regular return visits to Australia, frequent long-distance communication and continued identification with Australia as ‘home’. These migrants also keep an open attitude towards future mobility; in the current global context, this is not restricted by distance. The paper concludes with the argument that the Australian diaspora should be seen as a distinct part of Australia’s population and a potential resource for Australia.; Kelly L. Parker

Scaling Up Handwashing and Rural Sanitation : Findings from a Baseline Survey in Tanzania

Briceño, Bertha; Yusuf, Ahmad
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
Português
Relevância na Pesquisa
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Since 2007, the Water and Sanitation Program (WSP) has provided technical assistance to local and national governments implementing large rural sanitation and handwashing promotion programs in various countries. In Tanzania, handwashing with soap and sanitation programs were phased into 10 rural districts in the second half of 2009. This report presents summary descriptive statistics for key demographic, socioeconomic, hygiene, health, and child development variables based on a survey of approximately 1,500 households. It offers a glimpse at the general status of sanitation and hygiene practices in some of the program's target areas before the beginning of implementation activities. In the targeted areas in rural Tanzania, the typical household is headed by a male and comprises five members. Most houses are single detached dwellings with mud or brick walls and clay floors. Households typically use kerosene for lighting and wood for cooking, and about half of households own a few animals and a bicycle. Handwashing behavior is known to be difficult to assess. In this study...

Performance study on a dual prohibition Multiple Access protocol in mobile Ad Hoc and Wireless Mesh networks

Wu, Qian
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 462158 bytes; application/pdf
Português
Relevância na Pesquisa
35.7%
Wireless networks are less reliable than wired networks because channels are “exposed” to the surrounding environment that is susceptible to interference and noise. To minimize losses of data due to collisions, wireless networks need a mechanism to regulate the access on the transmission medium. Medium Access Control (MAC) protocols control access to the shared communication medium so that it can be used efficiently. In this thesis, we first describe the collision-controlled Dual Prohibition Multiple Access (DPMA) protocol [45]. The main mechanisms implemented in DPMA, such as binary dual prohibition, power control, interference control, and support for differentiated services (DiffServ), are presented in detail. We conducted a thorough simulation study on DPMA protocol from several aspects. First, we conduct simulations to observe the effects of binary competition number (BCN), unit slot length and safe margin on the performance of DPMA. Secondly, the DiffServ capability of DPMA is demonstrated through simulation results. Finally, we compare the DPMA protocol with the CSMA/CA protocol and find that DPMA with optimal configuration has better performance than CSMA/CA under both low and high network density.; Thesis (Master, Electrical & Computer Engineering) -- Queen's University...

Organic-inorganic hybrid materials towards passive and active architectures for the next generation of optical networks

Ferreira, Maria R.; Andre, Paulo; Carlos, Luís
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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The advances in optoelectronics over the last three decades have been quite dramatic, namely the mass manufacturing of low cost integrated circuits, revolutionizing the speed and the capability of computing and communication. However, today's ever-increasing demand for high-bandwidth data is outgrowing the performance of electronics in many applications, such as in telecommunications where the traffic demand has been increasing steadily and, therefore, the transmission technology requires bandwidth that exceeds the one provided by actual copper based networks. In this context, the fabrication of low-cost integrated optics (IO) devices using sol-gel derived organic-inorganic hybrid (OIH) materials has received increasing attention in the last years. This review will focus on examples of OIHs that can be used in IO devices for the next generation of optical networks. Emphasis will be given to passive (planar and channel waveguides, couplers and multimode interference splitters) and active (lasers and optical amplifiers) optical architectures for long haul/metro and access/indoor networks. (c) 2010 Elsevier B.V. All rights reserved.; FEDER; PTDC/CTM/72093/2006; PTDC/EEA-TEL/72025/2006; PTDC/CTM/101324/2008

Uma proposta de otimização no processo de integração entre redes infra-estruturadas e MANET's; A optimization proposal on integration process between infraestructured networks and MANETs

Schneiders, Luis Antônio
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
35.7%
Uma Rede Móvel Ad Hoc (MANET) consiste em uma coleção de terminais que possuem uma interface de transmissão e recepção sem fio (wireless) e que se movimentam em uma determinada área de abrangência. Geralmente esses terminais fazem uso de freqüências de rádio nas comunicações e configuram uma rede não infraestruturada. As MANETs, também conhecidas como independentes, não necessitam de qualquer infra-estrutura pré-existente para prover comunicação entre os nós, contudo, são utilizadas, principalmente quando integradas à Internet. Essa integração, apesar de possível, normalmente necessita de um gateway que encaminhe os pacotes entre as redes de computadores, respeitando as suas características individuais. Problemas, assim como atrasos e perdas de pacotes, podem ser provocados pelas diferenças intríncias aos protocolos de roteamento. Embora o Internet Engineering Task Force (IETF) proponha diversos protocolos de roteamento para as MANETs, o presente trabalho investiga o protocolo de roteamento Ad hoc On-Demand Distance Vector (AODV), por ser considerado um dos protocolos mais implementados e estudados pelo grupo de trabalho do IETF. O nodo gateway, embora já esteja implementado no protocolo de roteamento AODV (HAMIDIAN...

Moda ética: a consciencialização através da comunicação; Ethical fashion: awareness through communication

Cohen, Nathalie
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Dissertação de Mestrado
Publicado em //2015 Português
Relevância na Pesquisa
35.7%
Dissertação de mestrado em Design e Comunicação de Moda; Diante do atual cenário de questões sociais e ambientais, verifica-se uma crise de valores generalizada, traduzida pelas ações do homem como a extração de uma quantidade excessivamente maior de recursos da natureza do que esta é capaz de repor, assim como a exploração dos trabalhadores e dos animais. Como resposta a este paradigma, surge a moda ética enquanto um conjunto de aspectos como sustentabilidade, comércio justo, proteção dos animais, entre outros, que permeiam todo o sistema da moda. Este movimento que vem ganhando força ao longo dos últimos anos e incide em não só na cadeia de produção, mas igualmente na venda, na comunicação e no descarte dos produtos de moda. O presente estudo tem como objetivo analisar a comunicação realizada por marcas e campanhas de moda a fim de perceber como estas abordam a questão da moda ética e se tencionam educar o público para um comportamento de consumo mais consciente. A partir disto, desenvolveu-se uma pesquisa contemplando 44 marcas de moda associadas ao Ethical Trading Initiative. Utilizando do método de análise de conteúdo, baseou-se na informação disponível nos websites e redes sociail das marcas para a recolha de dados. Foi ainda realizada uma segunda análise...

Empowered by Wireless Communication: Self-Organizing Traffic Collectives

Fekete, Sándor P.; Schmidt, Christiane; Wegener, Axel; Hellbrück, Horst; Fischer, Stefan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/05/2010 Português
Relevância na Pesquisa
35.71%
In recent years, tremendous progress has been made in understanding the dynamics of vehicle traffic flow and traffic congestion by interpreting traffic as a multi-particle system. This helps to explain the onset and persistence of many undesired phenomena, e.g., traffic jams. It also reflects the apparent helplessness of drivers in traffic, who feel like passive particles that are pushed around by exterior forces; one of the crucial aspects is the inability to communicate and coordinate with other traffic participants. We present distributed methods for solving these fundamental problems, employing modern wireless, ad-hoc, multi-hop networks. The underlying idea is to use these capabilities as the basis for self-organizing methods for coordinating data collection and processing, recognizing traffic phenomena, and changing their structure by coordinated behavior. The overall objective is a multi-level approach that reaches from protocols for local wireless communication, data dissemination, pattern recognition, over hierarchical structuring and coordinated behavior, all the way to large-scale traffic regulation. In this article we describe three types of results: (i) self-organizing and distributed methods for maintaining and collecting data (using our concept of Hovering Data Clouds); (ii) adaptive data dissemination for traffic information systems; (iii) methods for self-recognition of traffic jams. We conclude by describing higher-level aspects of our work.; Comment: 28 pages...