1,374 research outputs found
Cellular Controlled Peer to Peer Communications:Overview and Potentials
No full textIn this chapter we present a dynamic approach to bridge cellular and peer-to-peer network architectures, referred to as Cellular Controlled Peer-to-Peer (CCP2P) communication. This approach goes beyond the concepts used in composite networks, which focus mainly on coverage extension and data relaying. In CCP2P networks, besides being connected to an outside world using cellular links, a group of mobile devices in close proximity form a cooperative cluster contributing their onboard capabilities and resources to exploit them a more efficient way. Using peerto- peer technology in combination with cellular networks, CCP2P has the potential to overcomemany important limitations of current cellular networks. The main driver behind such a concept is the short-range communication among mobile devices
Cooperative and Cognitive Networks: A Motivating Introduction:Towards the Age of Enlightenment in Wireless Communication Networks
No full textIn this introductory chapter, some key trends and emerging concepts for wireless communication networks are explored, highlighting chiefly those exploiting cooperative and cognitive principles. After discussing some key promising directions of development, a motivating overview of cooperative techniques in wireless networks in presented, followed by an overview of cognitive techniques and their use in wireless networks. The joint exploitation of these complementary principles are also considered in this chapter. Finally some visions on promising developments and possible evolutionary steps are included. The introductory discussions presented here serve as a an initial motivation to the rest of the book, where many of the concepts and techniques discussed here are explained in detail
Analysis of Cooperative Power Saving Strategies with NetLogo
No full textAfter a detailed introduction to NetLogo programming language, given in the previous chapter, here we aim to present and discuss some results obtained with this tool. Our focus is a model for analyzing cooperative power saving strategies in a mobile wireless network. The promising outcomes of the simulation in terms of highly reduced power consumption underline both the success of cooperative strategies for a specific fundamental network application and the effectiveness of using NetLogo agent-based approach for modeling decentralized communication systems
On the Energy Saving Potential in DVB-H Networks Exploiting Cooperation among Mobile Devices
No full textIn this chapter we focus on cooperative strategies for IP-services over DVB-H networks to save energy. It demonstrates the potential of non-altruistic cooperation between mobile devices. The envisioned cooperation is based on cellular reception of DVB-H data, which is then shared among mobile devices within each others’ proximity over short-range links. The short-range communication is realized by Bluetooth, where a cross-platform design approach is introduced to optimize the signalling communication in the Bluetooth system. Three different cooperative algorithms are designed for the short-range link (Bluetooth) communication. Numerical results show that a energy saving of over 50% can be achieved by cooperative networking of three mobile devices in fully cooperating mode
Introduction to NetLogo
No full textNetLogo is a multi-agent modeling environment originally conceived by the complex systems community for simulating natural and social phenomena. Despite its simplicity, NetLogo is a powerful tool in many fields of research. It is especially well suited for modeling large collections of independent agents developing over time, thus being a promising solution for simulating and analyzing distributed systems such as modern wireless networks. In this chapter we illustrate the feasibility of this approach, by providing a detailed tutorial about the application of NetLogo to wireless communications
Robust Header Compression for WiMAX Femto Cells
No full textEven though WiMAX technology offers high data rates, the overall capacity over the air is shared among several WiMAX users. This is especially true for the WiMAX support of femto cells. In this scenario very small wireless cells, covered by short-range technologies such as WLAN or Bluetooth, are wirelessly connected to the Internet backbone by WiMAX links. The number of accumulated users will be high and any means to gain additional capacity are more than welcomed. An effective approach to increase capacity is to utilize header compression. In the wireless world, Robust Header Compression (ROHC), as standardized in RFC3095 (Bormann et al., 2001), is a widely applied header compression scheme. ROHC is a method to reduce the overhead of the packet header information down to 10% or less. This method is especially effective if the payload is relatively small in contrast to the header itself. In this chapter we will motivate the use of ROHC in WiMAX, as proposed in the WiMAX documents (Fitzek et al., 2004), and demonstrate the potential gain of using ROHC for WiMAX femto cells by implementation and measurements. The results presented here are the outcome of a collaborative work of acticom (acticom GmbH , 2008b) and VTT implementing acticom’s ROHC protocol stack in a commercial WiMAX system. As shown throughout this chapter, ROHC demonstrates outstanding performance over the standard system
The Role of WiMAX Technology in Distributed Wide Area Monitoring Applications
No full textThis chapter contains sections titled:
- Monitoring with the WSN Paradigm
- Overall System Architecture
- Efficient Access Management Schemes
- Secure Communications Approaches
- Reference
Parrhesía e loucura no exemplo de Estamira
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Programa de Pós-Graduação em Filosofia, Florianópolis, 2015.Um autor como Michel Foucault (1926-1984), ao apresentar um estudo extenso sobre saber, poder e ética, deixa o leitor com dúvidas e indagações: O sujeitado ao poder não teria como se contrapor à submissão? O poder psiquiátrico, com seus saberes sobre a loucura, seria tão poderoso assim? Na tentativa de responder estas questões, estabeleceu-se como objetivo geral investigar a parrhesía e a loucura no exemplo de Estamira. Como pressuposto metodológico, optou-se pelos escritos de Michel Foucault sobre a temática da loucura. Na análise do documentário a respeito de Estamira, produzido por Marcos Prado em 2004, foram analisadas algumas cenas, fundamentando-se, sobretudo, em seus últimos escritos, de 1980 a 1984, do Collège de France. O pensamento último de Foucault evidencia uma preocupação histórica do que seria o cuidado de si e a parrhesía no período da Grécia Clássica, por volta do séc. IV a.C., o período helênico romano séc. I e II d.C. e os primeiros cristãos (IV a V d.C.). O autor consegue perceber, na antiguidade grega, a existência de uma subjetividade que não segue normas, a qual se torna uma prática de liberdade (práticas ascéticas), uma busca de como dizer a verdade (parrhesía) que leva a uma constituição ética atrelada à estética da existência da vida do sujeito. Conclui-se, com base nas análises históricas foucaultianas, que o exemplo de Estamira nos remete a uma ?ontologia do presente?, ?ontologia dos discursos verdadeiros?, uma concepção de subjetividade, de verdade e de filosofia de vida para o indivíduo, com sua loucura, transformar sua vida e ser diferente do que é, governando a si mesmo pela parrhesía, ser franco, falar a verdade.Abstract : An author such as Michel Foucault (1926-1984) when presenting an extensive study of knowledge, power and ethics, leaves the reader with doubts and questions: The subjected to power could not possibly oppose itself from submission? The psychiatric power, with its knowledge about insanity, would be that powerful? In the attempt to answer these questions, it was established as a general objective to investigate the parrhesia and insanity in the case of Estamira. For the methodological presupposition, it was chosen the writings of Michel Foucault on the theme of madness. In the documentary film analysis about Estamira, produced by Marcos Prado in 2004, some scenes were analyzed mostly based in his later writings, from 1980 to 1984, from the Collège de France. The final thought of Foucault reveals a historical concern of what would be the self care and the Parrhesia in the Classical Greece period from around the IV century B.C., the Roman Hellenistic period during the I and II century A.D. and the early Christians (IV to V A.D.). The author is able to perceive that in Greek antiquity, the existence of a subjectivity that does not follow rules, which turns to a practice of freedom (ascetic practices), a search for how to tell the truth (parrhesia) leading to an ethical constitution tied to the aesthetics of existence of the subject´s life. The conclusion is, based on Foucault's historical analysis, that the example of Estamiranos refers to an "ontology of the present", "ontology of real discourses," a conception of subjectivity, truth and life philosophy for the individual, with his insanity, to transform his life and be different than it is, ruling himself through parrhesia, be honest and to tell the truth
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