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Multilayer optimization in radio resource allocation for the packet transmission in wireless networks

Nascimento, Alberto Jesus de
Fonte: Universidade da Madeira Publicador: Universidade da Madeira
Tipo: Tese de Doutorado
Publicado em //2009 Português
Relevância na Pesquisa
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In the last decade mobile wireless communications have witnessed an explosive growth in the user’s penetration rate and their widespread deployment around the globe. It is expected that this tendency will continue to increase with the convergence of fixed Internet wired networks with mobile ones and with the evolution to the full IP architecture paradigm. Therefore mobile wireless communications will be of paramount importance on the development of the information society of the near future. In particular a research topic of particular relevance in telecommunications nowadays is related to the design and implementation of mobile communication systems of 4th generation. 4G networks will be characterized by the support of multiple radio access technologies in a core network fully compliant with the Internet Protocol (all IP paradigm). Such networks will sustain the stringent quality of service (QoS) requirements and the expected high data rates from the type of multimedia applications to be available in the near future. The approach followed in the design and implementation of the mobile wireless networks of current generation (2G and 3G) has been the stratification of the architecture into a communication protocol model composed by a set of layers...

A dinâmica da utilização das redes sociais no processo de comunicação pelas micro e pequenas empresas têxteis: um estudo exploratório; The dynamic use of social networks in the communication process by micro and small textile enterprises: an exploratory study.

Favero, Marcela Bortotti
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 12/03/2014 Português
Relevância na Pesquisa
35.93%
O estudo aborda a utilização das redes sociais como plataforma de comunicação das micro e pequenas empresas de confecção. A pesquisa se torna relevante por discutir temas importantes na atualidade: comunicação de marketing por meio de redes sociais e micro e pequenas empresas de confecção, justificando-se ainda, pela dificuldade que as micro e pequenas empresas apresentam de realizar ações de comunicação de marketing devido ao elevado investimento que as mídias tradicionais exigem. A proposta do estudo é identificar como as micro e pequenas empresas de moda estão utilizando as redes sociais para a comunicação com seu público consumidor. Para atender a esse objetivo foram definidos os seguintes passos: (a) Identificar um panorama geral da utilização das redes sociais pelas micro e pequenas empresas de moda; (b) Mapear as ações desenvolvidas no Facebook por essas empresas; (c) Verificar a resposta dos usuários em relação às publicações das empresas;(d) Levantar as postagens dos usuários nas fan pages das empresas; (e) Identificar o potencial de propagação das mensagens. A pesquisa realizada foi de caráter exploratório, qualitativo e descritivo. Os dados foram coletados em dois momentos, uma observação não participante das páginas das empresas selecionadas e a aplicação de questionário nos gestores destas. A análise dos dados permitiu observar que embora a literatura apresente como vantagem da utilização das redes sociais o contato mais próximo com o consumidor facilitando assim o diálogo com baixo investimento...

Processo e práticas de comunicação em empresas públicas da esfera federal: análise das redes sociais digitais; Communication process and practices in public companies from the Federal sector: an analysis of digital social networks

Nascimento, Lebna Landgraf do
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 20/05/2014 Português
Relevância na Pesquisa
35.92%
A sociedade contemporânea vivencia processos de comunicação mediados pelas plataformas digitais em nível local e global que alteraram profundamente as relações entre os diversos atores sociais. Após o surgimento da internet, os processos de comunicação deixam de privi-legiar os modelos lineares de disseminação de informação para ressaltar os processos de co-municação multidirecionais e interativos. Neste contexto, as redes sociais digitais tornaram-se poderosos canais de comunicação no Brasil. A partir deste novo comportamento comunicaci-onal, o objetivo desta pesquisa é compreender quais são os processos e as práticas de comuni-cação nas redes sociais digitais de cinco empresas públicas da esfera federal. Foi realizado um estudo empírico composto de análise de conteúdo sobre as mensagens institucionais e dos cidadãos nas fanpages das empresas da amostra e cinco entrevistas com os coordenadores de comunicação e com os responsáveis pelas redes sociais digitais destas empresas públicas. A partir dos resultados obtidos na análise dos dados, pode-se afirmar que as redes sociais digi-tais são relevantes canais de relacionamento entre as empresas públicas e os cidadãos porque facilitam o acesso às informações de interesse coletivo...

An optimal control approach to dynamic routing in data communication networks : part I--principles

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 72 p.; application/pdf
Português
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Franklin H. Moss and Adrian Segall.; Bibliography: p. 72.; "September 1978."; Supported by the Advanced Research Project Agency (monitored by ONR) under Contract no. N00014-75-C-1183 Technion Research and Development Foundation Ltd. no. 050-383

An optimal control approach to dynamic routing in data communication networks : part II--geometrical interpretation

Fonte: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology Publicador: Laboratory for Information and Decision Systems, Massachusetts Institute of Technology
Formato: 42 p.; application/pdf
Português
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Franklin H. Moss and Adrian Segall.; Bibliography: p. 42.; "September 1978."; Supported by the Advanced Research Project Agency (monitored by ONR) under Contract no. N00014-75-C-1183 Technion Research and Development Foundation Ltd. no. 050-383

Simple LCD Transmitter Camera Receiver Data Link

Katabi, Dina; Raskar, Ramesh; Mohan, Ankit; Woo, Grace
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Formato: 5 p.
Português
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We demonstrate a freespace optical system using a consumer camera and projector in indoor environments using available devices for visual computing. Through design, prototype and experimentation with this commodity hardware, we analyze a practical optical solution as well as the drawbacks for current wireless challenges unmet by classic RF wireless communication. We summarize and introduce some new applications enabled by such similar setups.

MOBILITY MODELS, MOBILE CODE OFFLOADING, AND P2P NETWORKS OF SMARTPHONES ON THE CLOUD

KOSTA, SOKOL
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
35.94%
It was just a few years ago when I bought my first smartphone. And now, (almost) all of my friends possess at least one of these powerful devices. International Data Corporation (IDC) reports that smartphone sales showed strong growth worldwide in 2011, with 491.4 million units sold – up to 61.3 percent from 2010. Furthermore, IDC predicts that 686 million smartphones will be sold in 2012, 38.4 percent of all handsets shipped. Silently, we are becoming part of a big mobile smartphone network, and it is amazing how the perception of the world is changing thanks to these small devices. If many years ago the birth of Internet enabled the possibility to be online, smartphones nowadays allow to be online all the time. Today we use smartphones to do many of the tasks we used to do on desktops, and many new ones. We browse the Internet, watch videos, upload data on social networks, use online banking, find our way by using GPS and online maps, and communicate in revolutionary ways. Along with these benefits, these fancy and exciting devices brought many challenges to the research area of mobile and distributed systems. One of the first problems that captured our attention was the study of the network that potentially could be created by interconnecting all the smartphones together. Typically...

Convergence in Information and Communication Technology : Strategic and Regulatory Considerations

Singh, Rajendra; Raja, Siddhartha
Fonte: World Bank Publicador: World Bank
Português
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This book is a compilation of two recently completed works on the convergence of information and communication technology (ICT) (Singh and Raja 2008, 2009). Since then, convergence, the eroding of boundaries among previously separate ICT services, networks, and business practices, has accelerated and deepened. At the time these reports were written, convergence was already a reality and was picking up pace in low-income countries, as in the rest of the world. Now, as this introduction summarizes, broadband networks are reaching deeper into previously unserved areas. The growing number of people connected to broadband networks are consuming, sharing, and creating new multimedia content and applications. And they are doing this on handheld and portable devices that are less costly and do more than before. All sorts of users, governments, businesses, individuals, and ICT firms, are looking to cut costs while capturing greater value. Taken together, these trends indicate that convergence is set to accelerate even through the ongoing global economic downturn. Countries that enable convergence through appropriate policy and regulatory responses will realize significant benefits in terms of expanded access...

Broadband for Africa : Developing Backbone Communications Networks

Williams, Mark D. J.
Fonte: World Bank Publicador: World Bank
Português
Relevância na Pesquisa
35.92%
Many countries in Sub-Saharan Africa see information and communication technology (ICT) as a necessary foundation for long-term economic development. While the region has been very successful in increasing access to basic voice communications, there has been no comparable improvement in broadband connectivity. In fact, the broadband access gap between Sub-Saharan Africa and the rest of the world is getting wider just as the gap in basic voice communications is getting smaller. Increasing access to broadband connectivity is therefore emerging as a high priority for policy makers across the continent. This book begins with a brief review of the ICT market and considers the extent of demand for broadband and the ICT services that high-capacity backbone networks make possible. This is followed by a review of the existing coverage of backbone networks in the region, a discussion of how this compares with other parts of the world, and an analysis of the possible explanations for the current pattern of network development. Finally...

Building Broadband : Strategies and Policies for the Developing World

Kim, Yongsoo; Kelly, Tim; Raja, Siddhartha
Fonte: World Bank Publicador: World Bank
Português
Relevância na Pesquisa
36.02%
This book suggests an ecosystem approach to broadband policy that could help in the design of strategies, policies, and programs that support network expansion, have the potential to transform economies, improve the quality and range of services, enable application development, and broaden adoption among users. To identify emerging best practices to nurture this ecosystem, this volume analyzes the Republic of Korea and other leading broadband markets. It identifies three building blocks to support the growth of the broadband ecosystem: defining visionary but flexible strategies, using competition to promote market growth, and facilitating demand. An important but often neglected building block is demand facilitation. This includes raising awareness about the benefits of broadband and improving affordability and accessibility for the largest number of users. Successful countries have often focused on creating a suite of useful applications that increase the relevance of broadband to the widest base of users. Programs to mainstream information and communication technology (ICT) use in education...

2009 Information and Communications for Development : Extending Reach and Increasing Impact

World Bank
Fonte: World Bank Publicador: World Bank
Português
Relevância na Pesquisa
35.92%
The information and communication technology (ICT) is transforming interactions between people, governments, and firms worldwide. In developing countries, farmers receive updated crop prices and public health officials monitor medical inventories by text messages. Women are empowered to make decisions and access new opportunities through online information. Entrepreneurs obtain business licenses in a fraction of the standard time by applying for them through municipal government web sites. And in an increasingly integrated global economy, ICT enables people to access and share knowledge and services around the world. The first report, Information and Communications for Development (IC4D) 2006: global trends and policies, analyzed lessons on developing access to ICT, examined the roles of the public and private sectors in this process, and identified the benefits and challenges of adopting and expanding ICT use in businesses. This second report, IC4D 2009: extending reach and increasing impact, takes a close look at mobile and broadband connectivity. It analyzes the development impact of high-speed Internet access in developing countries and provides policy options for rolling out broadband networks and addressing the opportunities and challenges of convergence between telecommunications...

Broadband Wireless Access in Egypt

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Português
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35.98%
This paper discusses current and future developments in wireless technology and infastructure in Egypt. One of the important regulatory decisions made in Egypt is that policy related to broadband wireless will be technology neutral. Consequently, the regulator cannot decide about which operators should use specific technologies. This approach is beneficial for the overall development of the market and deployment of networks because: It allows operators and service providers to decide on which technology or mix of technologies is best for given service and market requirements, budget outlays, and deployment scenarios. Such an approach promotes technical and economic efficiency since each service providerwill attempt to maximize revenues and their subscriber base. The flexibility allows the regulator to ensure that the market can deploy the latest technology with the least regulatory overhead. Allowing only one technology into the market place will restrict the range of choices available to consumers.

Temporal patterns of communication in social networks

Miritello, Giovanna
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado Formato: application/pdf
Português
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This thesis has been a joint project between Universidad Carlos III de Madrid and Telefónica Research (Spain). Specifically, the research has been conducted at the GISC (Grupo Interdisciplinar de Sistemas Complejos), group of Universidad Carlos III and at the analytics and data mining and user modelling research teams of Telefónica Research. The main interest of this research has been in understanding and characterizing large networks of human interactions as continuously changing objects, which members appear and disappear over time and which interactions are characterized by temporal correlations and inhomogeneities. This constitutes a very challenging and novel topic. In fact, although many real social networks are temporal or dynamical networks, which elements and properties continuously change over time, traditional approaches to social network analysis are essentially static: ties (and tie weights) are given by the aggregated activity observed in a given time period, nodes and ties are considered persistent over time, temporal inhomogeneities and correlations between interaction events are neglected, etc. Within this frame, therefore, the time dimension of human behavior has typically been projected out. Although much effort has been devoted in the last years to characterize the temporal patterns of human interaction...

Path-moose: a scalable all-path bridging protocol

Ibáñez, Guillermo; Marsá Maestre, Iván; Lopez Carmona, Miguel A.; Pérez Ibáñez, Ignacio; Tanaka, Jun; Crow Croft, Jon
Fonte: The Institute of Electronics, Information and Communication Engineers Publicador: The Institute of Electronics, Information and Communication Engineers
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article
Publicado em //2013 Português
Relevância na Pesquisa
45.58%
This paper describes Path-Moose, a scalable tree-based shortest path bridging protocol. Both ARP-Path and Path-Moose protocols belong to a new category of bridges that we name All-path, because all paths of the network are explored simultaneously with a broadcast frame distributed over all network links to find a path or set a multicast tree. Path-Moose employs the ARP-based low latency routing mechanism of the ARP-Path protocol on a bridge basis instead of a per-single-host basis. This increases scalability by reducing forwarding table entries at core bridges by a factor of fifteen times for big data center networks and achieves a faster reconfiguration by an approximate factor of ten. Reconfiguration time is significantly shorter than ARP-Path (zero in many cases) because, due to the sharing of network paths by the hosts connected to same edge bridges, when a host needs the path it has already been recovered by another user of the path. Evaluation through simulations shows protocol correctness and confirms the theoretical evaluation results.; This work was supported in part by grants from Comunidad de Madrid and Universidad de Alcal´a through the following projects: MEDIANET-CM (S-2009/TIC-468), EMARECE (PII1I09-0204-4319) and CMAC (UAH2011/EXP-016).

Design of a retransmission strategy for error control in data communication networks

Fonte: Electronic Systems Laboratory, Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology Publicador: Electronic Systems Laboratory, Dept. of Electrical Engineering and Computer Science, Massachusetts Institute of Technology
Formato: 110 p.; application/pdf
Português
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by Seyyed J. Golestaani.; Bibliography: p.107-108.; Prepared under Grant NSF-ENG75-14103. Originally presented as the author's thesis, (M.S.) in the M.I.T. Dept. of Electrical Engineering and Computer Science, 1976.

Small Worlds: Strong Clustering in Wireless Networks

Brust, Matthias R.; Rothkugel, Steffen
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.65%
Small-worlds represent efficient communication networks that obey two distinguishing characteristics: a high clustering coefficient together with a small characteristic path length. This paper focuses on an interesting paradox, that removing links in a network can increase the overall clustering coefficient. Reckful Roaming, as introduced in this paper, is a 2-localized algorithm that takes advantage of this paradox in order to selectively remove superfluous links, this way optimizing the clustering coefficient while still retaining a sufficiently small characteristic path length.; Comment: To appear in: 1st International Workshop on Localized Algorithms and Protocols for Wireless Sensor Networks (LOCALGOS 2007), 2007, IEEE Compuster Society Press

Scalable Tensor Factorizations for Incomplete Data

Acar, Evrim; Kolda, Tamara G.; Dunlavy, Daniel M.; Morup, Morten
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/05/2010 Português
Relevância na Pesquisa
45.64%
The problem of incomplete data - i.e., data with missing or unknown values - in multi-way arrays is ubiquitous in biomedical signal processing, network traffic analysis, bibliometrics, social network analysis, chemometrics, computer vision, communication networks, etc. We consider the problem of how to factorize data sets with missing values with the goal of capturing the underlying latent structure of the data and possibly reconstructing missing values (i.e., tensor completion). We focus on one of the most well-known tensor factorizations that captures multi-linear structure, CANDECOMP/PARAFAC (CP). In the presence of missing data, CP can be formulated as a weighted least squares problem that models only the known entries. We develop an algorithm called CP-WOPT (CP Weighted OPTimization) that uses a first-order optimization approach to solve the weighted least squares problem. Based on extensive numerical experiments, our algorithm is shown to successfully factorize tensors with noise and up to 99% missing data. A unique aspect of our approach is that it scales to sparse large-scale data, e.g., 1000 x 1000 x 1000 with five million known entries (0.5% dense). We further demonstrate the usefulness of CP-WOPT on two real-world applications: a novel EEG (electroencephalogram) application where missing data is frequently encountered due to disconnections of electrodes and the problem of modeling computer network traffic where data may be absent due to the expense of the data collection process.

Entropy Rate of Diffusion Processes on Complex Networks

Gomez-Gardenes, Jesus; Latora, Vito
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/12/2007 Português
Relevância na Pesquisa
45.65%
The concept of entropy rate for a dynamical process on a graph is introduced. We study diffusion processes where the node degrees are used as a local information by the random walkers. We describe analitically and numerically how the degree heterogeneity and correlations affect the diffusion entropy rate. In addition, the entropy rate is used to characterize complex networks from the real world. Our results point out how to design optimal diffusion processes that maximize the entropy for a given network structure, providing a new theoretical tool with applications to social, technological and communication networks.; Comment: 4 pages (APS format), 3 figures, 1 table

Comparative Analysis of dynamic graph techniques and data strucutre

Tyagi, Megha; Garg, Deepak
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/09/2012 Português
Relevância na Pesquisa
45.61%
Dynamically changing graphs are used in many applications of graph algorithms. The scope of these graphs are in graphics, communication networks and in VLSI designs where graphs are subjected to change, such as addition and deletion of edges and vertices. There is a rich body of the algorithms and data structures used for dynamic graphs. The paper overview the techniques and data structures used in various dynamic algorithms. The effort is tried to find out the comparison in these techniques namely the hierarchical decomposition of graphs and highlighting the ingenuity used in designing these algorithms.

Group data communication with M2MI

Cheng, Kay
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Masters Project Formato: 476049 bytes; 269391 bytes; application/pdf; application/pdf
Português
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The Anhinga Project is developing an infrastructure that supports board range of collaborative systems running on small proximal wireless devices in ad-hoc networks. The core of Anhinga Infrastructure is a new method invocation technology called the Many-to-Many Invocation (M2MI). In this technology, every method invocation is broadcasted through the network and all the objects that implement the same method execute it. M2MI is layered on a new network protocol, Many-to-Many Protocol (M2MP), which is designed for broadcasting messages within small wireless devices in Ad hoc network. In this project, I will provide three different design patterns of M2MI-based collaborative systems, implement and simulate those designs in LAN environment, and compare the advantages and disadvantages of the M2MI-based solutions with RMI-based solutions of those three different problems, collaborative groupware, multiple participants chat system, and the distributed solution of shared resource allocation. This project has the following research concepts: a) Investigate the design pattern and model design of collaborative groupware; b) Investigate the JAVA design and implementation of the collaborative groupware; c) Investigate M2MI mechanism using in the three different problems in ad hoc environment; d) Investigate the architecture...