24,155 research outputs found

    Quantifying Link Stability in Ad Hoc Wireless Networks Subject to Ornstein-Uhlenbeck Mobility

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    The performance of mobile ad hoc networks in general and that of the routing algorithm, in particular, can be heavily affected by the intrinsic dynamic nature of the underlying topology. In this paper, we build a new analytical/numerical framework that characterizes nodes' mobility and the evolution of links between them. This formulation is based on a stationary Markov chain representation of link connectivity. The existence of a link between two nodes depends on their distance, which is governed by the mobility model. In our analysis, nodes move randomly according to an Ornstein-Uhlenbeck process using one tuning parameter to obtain different levels of randomness in the mobility pattern. Finally, we propose an entropy-rate-based metric that quantifies link uncertainty and evaluates its stability. Numerical results show that the proposed approach can accurately reflect the random mobility in the network and fully captures the link dynamics. It may thus be considered a valuable performance metric for the evaluation of the link stability and connectivity in these networks.Comment: 6 pages, 4 figures, Submitted to IEEE International Conference on Communications 201

    Multimedia communications in vehicular adhoc networks for several applications in the smart cities

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    [EN] Road safety applications envisaged for vehicular ad hoc networks (VANETs) depend largely on the exchange of messages to deliver information to concerned vehicles. Safety applications as well as inherent VANET characteristics make data dissemination an essential service and a challenging task. We are developing a decentralized efficient solution for broadcast data dissemination through two game-theoretical mechanisms. Besides, VANETs can also include autonomous vehicles (AVs). AVs might represent a revolutionary new paradigm that can be a reality in our cities in the next few years. AVs do not need a driver to work; instead, they should copy a proper human behavior to adapt the driving according to the current circumstances, such as speed limit, pedestrian crossing street or wheather conditions. We will develop an AV software module including artificial intelligence (AI) techniques so that AVs can interact with the dynamic scenario throughout time. Finally, we also will include electrical vehicles (EV) in the VANET, so that special services such as finding and reserving an EV charging station place will be welcome. In addition, we are developing a multimetric geographic routing protocol for VANETs to transmit H.265 video (traffic accident, traffic state, commercial….) over VANETs.This work was partly supported by the Spanish Government through the project TEC2014-54335-C4- 1-R INcident monitoRing In Smart COmmunities, QoS and Privacy (INRISCO). Cristian Iza is recipient of a grant from Secretaria Nacional de Educación Superior, Ciencia y Tecnología SENESCYT. Ahmad Mohamad Mezher is a postdoctoral researcher with the Information Security Group (ISG) at the Universitat Politècnica de Catalunya (UPC).Iza Paredes, C.; Uribe Ramírez, JA.; López Márquez, N.; Lemus, L.; Mezher, A.; Aguilar Igartua, M. (2018). Multimedia communications in vehicular adhoc networks for several applications in the smart cities. Editorial Universitat Politècnica de València. 212-215. https://doi.org/10.4995/JITEL2017.2017.6584OCS21221

    ESTRATÉGIAS DE ATUALIZAÇÃO E QUALIFICAÇÃO DA REVISTA INTERDISCIPLINAR DE PROMOÇÃO DA SAÚDE

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    The Interdisciplinary Journal of Health Promotion (RIPS) is a journal of the Stricto Sensu Graduate Program in Health Promotion and of the Department of Health Sciences at the University of Santa Cruz do Sul and was republished in 2018 in order to increase its thematic scope and encompass studies on Health Promotion and Collective Health, from reformulation to suitability to suit the criteria of the Qualis Web System. The present study aims to present the strategies adopted by the editorial team to qualify the RIPS editions. This is a qualitative study of the documentary, exploratory and descriptive type, carried out from records of the editorial team's actions from 2018 to 2021. The results identify the establishment of a calendar of monthly meetings, review of publication guidelines, renewal of the editorial staff, increase in the number of ad hoc reviewers, the publication of the journal at the national level, the number of submitted manuscripts and exogenous publications, and preparation of calls for special thematic issues. The publication guidelines have been revised and organized into a template in order to facilitate the submission process. It is concluded that the strategies adopted resulted in an increase in the amount of manuscript submission and in a greater visualization of published studies. However, efforts are still needed to update the periodicity of the RIPS, increase aspects of the exogenousness of the authors of the articles and the number of manuscript submissions, views and accesses, both on its website and on social networks in order to increase its dissemination.A Revista Interdisciplinar de Promoção da Saúde (RIPS) é um periódico do Programa de Pós-Graduação Stricto Sensu em Promoção da Saúde (PPGPS) e do Departamento de Ciências da Saúde da Universidade de Santa Cruz do Sul e foi reeditado em 2018 a fim de aumentar sua abrangência temática e englobar os estudos sobre Promoção de Saúde e Saúde Coletiva, a partir de reformulação para adequação aos critérios do Sistema Web Qualis. O presente estudo objetiva apresentar as estratégias adotadas pela equipe editorial para qualificar as edições da RIPS. Trata-se de estudo qualitativo, do tipo pesquisa documental, exploratória e descritiva realizado a partir de registros das ações da equipe editorial de 2018 a 2021. Os resultados identificam o estabelecimento de um calendário de reuniões mensais, revisão das diretrizes de publicação, renovação do corpo editorial, ampliação do número de avaliadores Ad Hoc, da divulgação do periódico ao nível nacional, do número de manuscritos submetidos e de publicações exógenas e elaboração de chamadas para edições temáticas especiais. As diretrizes de publicação foram revisadas e organizadas em um template com o intuito de facilitar o processo de submissão. Conclui-se que as estratégias adotadas resultaram no aumento na quantidade de submissão dos manuscritos e na maior visualização dos estudos publicados. Contudo, esforços ainda são necessários para atualizar a periodicidade da RIPS, incrementar aspectos da exogenia dos autores dos artigos e do número de submissões de manuscritos, visualizações e acessos, tanto em seu site quanto em redes sociais com o intuito de incrementar sua divulgação

    Improving transparency and scientific rigor in academic publishing.

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    Progress in basic and clinical research is slowed when researchers fail to provide a complete and accurate report of how a study was designed, executed, and the results analyzed. Publishing rigorous scientific research involves a full description of the methods, materials, procedures, and outcomes. Investigators may fail to provide a complete description of how their study was designed and executed because they may not know how to accurately report the information or the mechanisms are not in place to facilitate transparent reporting. Here, we provide an overview of how authors can write manuscripts in a transparent and thorough manner. We introduce a set of reporting criteria that can be used for publishing, including recommendations on reporting the experimental design and statistical approaches. We also discuss how to accurately visualize the results and provide recommendations for peer reviewers to enhance rigor and transparency. Incorporating transparency practices into research manuscripts will significantly improve the reproducibility of the results by independent laboratories

    A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

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    This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan
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