38 research outputs found

    How effective is to look at a vehicular network under a social perception?

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    International audienceVehicular Mobility is strongly influenced by the speed limits and direction of the public roads. At the same time, the driver's behavior produces great influences in vehicular mobility. People tend to go to the same places, at the same day period, through the same trajectories, which le ad them to the appearance of driver's daily routines. These routines lead us to the study of mobility in VANETs under a social perspective and to investigate how effective is to explore social interactions in this kind of network. The work herein proposed presents the characterization and evaluation of a realistic vehicular trace found in literature. Our aim is to study the vehicles' mobility in accordance to social behaviors. With our analysis is possible to verify the existence of regularity and common interests among the drivers in vehicular networks. Finally, we discuss how the social metrics may be used to improve the performance of protocols and services in Vehicular Networks

    Classificando Comportamentos Sociais em Redes Veiculares

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    National audienceRedes veiculares são redes formadas por veículos que transitam nas cidades e rodovias. Durante suas trajetórias estes veículos interagem uns com outros veículos com o objetivo de tornar o trafego mais seguro e a viagem agradável. Essas interações podem ser influenciadas por diversos fatores. Dentre eles pode-se citar: a velocidade do veículo, as condições das vias e o período do dia. Além disso, o comportamento do condutor e seus interesses podem influenciar em muitas características do veículo. Nesse contexto, surgem as Redes Sociais Veiculares como uma nova perspectiva para as redes veiculares. Essas são redes nas quais os veículos "socializam" e compartilham interesses comuns. Neste trabalho serão avaliados o comportamento dos veículos em dois cenários de mobilidade, com o objetivo de classificá-los de acordo com as interações realizadas, identificando interesses comuns e rotinas semelhantes. Para isso, foram utilizadas métricas de redes complexas e técnicas estatísticas. Resultados comprovam a existência de rotinas e propriedades sociais nas Redes Veiculares

    Extração de Propriedades Sociais em Redes Veiculares

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    National audienceTodos os dias, veículos transitam nas cidades e durante suas trajetórias encontram outros veículos. A frequência destes encontros pode ser influenciada por diversos fatores como: a velocidade dos veículos, os destinos escolhidos, as condições de tráfego e o período do dia. Entretanto, estes fatores são justificados pelos limites das vias públicas e pelo comportamento dos motoristas. Os comportamentos similares dos motoristas e suas rotinas diárias têm um grande impacto na evolução do tráfego diariamente. Neste trabalho, é apresentada uma análise numérica de traces reais e realísticos que descrevem a mobilidade de um conjunto de veículos. Para isso, métricas sociais são computadas e os resultados obtidos são comparados com grafos aleatórios na direção de atestar que as Redes Veiculares apresentam comportamento social. Os resultados comprovam a existência de rotinas e propriedades sociais nas Redes Veiculares. Finalizando, discute-se sobre novas perspectivas sociais em Redes Veiculares

    Understanding Interactions in Vehicular Networks Through Taxi Mobility

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    International audienceVehicular Networks (VANETs) are an emerging network that enables the communication among the vehicles, in order to promote a safe and efficient traffic, avoiding crashes and preventing hazards. These vehicles transit on the streets and highways, and during their trajectories, they can communicate with each other or with another network, through interactions among them and road side units. Aiming to better understand these interactions, in this work, we characterize the vehicular mobility through a detailed analysis of dataset traces, which portray the mobility of a group of taxis in a great city. We perform the analysis using statistical techniques, graph theory and network analysis, extracting properties and behaviors from the mobility traces. The results reveal the existence of regularity and common interests in the studied traces

    Socially Inspired Data Dissemination for Vehicular Ad Hoc Networks

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    International audiencePeople have routines and their mobility patterns vary during the day, which have a direct impact on vehicular mobility. Therefore, proto-cols and applications designed for Vehicular Ad Hoc Networks need to adapt to these routines in order to provide better services. With this issue in mind, in this work, we propose a data dissemination solution for these networks that considers the daily road traffic vari-ation of large cities and the relationship among vehicles. The focus of our approach is to select the best vehicles to rebroadcast data messages according to social metrics, in particular, the clustering coefficient and the node degree. Moreover, our solution is designed in such a way that it is completely independent of the perceived road traffic density. Simulation results show that, when compared to related protocols, our proposal provides better delivery guarantees, reduces the network overhead and possesses an acceptable delay

    Exploring Interactions in Vehicular Networks

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    International audienceVehicular networks are networks comprised by vehicles trav-eling cities and highways. During their trajectories, these vehicles interact with other vehicles and road side units in order to make safer and enjoyable trac. These interactions may be influenced by several factors. To mention a few: vehicle speed, roads condition, time of day and weather. Moreover, driver behavior and its interests can influence in vehicle features. In this context, the Vehicular Social Networks arise as a new perspective to vehicular networks, where the vehicles " socialize " and share common interests. In this work, we evaluate the behavior of vehicles using two mobility scenarios, in order to classify them according to the interactions performed, identifying common interests and similar routines. Thus, we use metrics of complex networks and statistical techniques. Results prove the existence of routines and human features in Vehicular Networks

    Data Communication in VANETs: Survey, Applications and Challenges

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    International audienceVANETs have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaboration and participation, while they are on the road. Although, considered as a special case of a Mobile Ad Hoc Network, the high but constrained mobility of vehicles bring new challenges to data communication and application design in VANETs. This is due to their highly dynamic and intermittent connected topology and different application's QoS requirements. In this work, we survey VANETs focusing on their communicationand application challenges. In particular, we discuss the protocol stack of this type of network, and provide a qualitative comparison between most common protocols in the literature. We then present a detailed discussion of dfferent categories of VANET applications. Finally, we discuss open research problems to encourage the design of new VANET solutions

    Acute Effects of Whole-Body Vibration Exercise on Pain Level, Functionality, and Rating of Exertion of Elderly Obese Knee Osteoarthritis Individuals: A Randomized Study

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    Introduction: Among chronic diseases, knee osteoarthritis (KOA) is a joint disease that causes important progressive alterations in the articular and periarticular structures, including synovial inflammation. Exercise has been suggested as an intervention to KOA individuals, and studies suggest that whole-body vibration (WBV) exercise decreases pain levels and favours the functionality of KOA individuals. Objective: The aim of the present study is to analyze the acute effects of WBV exercise on pain levels, functionality (Timed Up and Go (TUG test), anterior trunk flexion (ATF)), and rating of exertion of elderly obese KOA individuals. Methods: Thirty-seven individuals with KOA were allocated to a WBV exercise group (WBVEG), n = 19 (15 females/4 males), and a control group (CG), n = 18 (15 females/3 males). WBVEG performed one session of WBV exercise (11 min, using 5 Hz, 2.5, 5.0, and 7.5 mm, 0.12, 0.25, and 0.37 g). Three bouts were performed (working time of 3 min and rest time of 1 min) using a side-alternating vibrating platform (VP). The same position was used in CG; however, the VP was turned off and there was equipment coupled to the VP that emitted a sound like the vibrations. The pain level was evaluated using a visual analog scale (VAS). Functionality was evaluated with a TUG test and ATF. The rating of subjectively perceived exertion was measured with the category ratio CR-10 (BORG Scale CR-10), Results: A reduction of pain levels in WBVEG after the intervention (p = 0.001) and intergroups (p = 0.041) was found. A decrease of TUG test time in both groups (p = 0.001) and intergroups (p = 0.045) was found, while no statistical changes were observed in the Borg Scale score. Significant improvements of flexibility in both groups (p = 0.001) and intergroups (p = 0.043) were found. Conclusion: One session of WBV exercise can lead to important improvements in individuals with KOA, possibly triggered by physiological responses. However, more studies are needed, in this clinical context, to confirm these results

    Effect of the Combined Intervention with Passive Whole-Body Vibration and Auriculotherapy on the Quality of Life of Individuals with Knee Osteoarthritis Assessed by the WHOQOL-Bref: A Multi-Arm Clinical Trial

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    The aim of this study was to determine the effect on the quality of life of two non-pharmacological interventions isolated or in combination: (i) passive whole-body vibration exercise (WBVE), and (ii) auriculotherapy (AT). One hundred three participants with knee osteoarthritis (KOA) were allocated to: (a) a vibration group (WBVEG; n = 17) that performed WBVE (peak-to-peak displacement: 2.5 to 7.5 mm, frequency: 5 to 14 Hz, Peak acceleration: 0.12 to 2.95 g), two days/weekly for five weeks, (b) an AT group (ATG; n = 21), stimulation of three specific auriculotherapy points (Kidney, Knee and Shenmen) in each ear pavilion, (c) WBVE + AT (WBVE + AT; n = 20) and (d) respective control groups (WBVE_CG, n = 15; AT_CG, n = 12; WBVE + AT_CG, n = 18). The participants filled out the WHOQOL-bref Questionnaire before the first and after the last sessions. Statistical differences in the various domains of the WHOQOL-bref were not found. In conclusion, WBVE or AT alone or combined did not contribute in altering the quality of life of individuals exposed to these interventions
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