ProFlex: A Probabilistic and Flexible Data Storage Protocol for Heterogeneous Wireless Sensor Networks

This paper presents ProFlex, a proactive data distribution protocol for heterogeneous wireless sensor networks (HWSNs). ProFlex guarantees robustness in data retrieval by intelligently managing data replication among selected storage nodes in the network. Contrarily to related protocols in the literature, ProFlex considers the resource constraints of sensor nodes and constructs multiple data replication structures, which are managed by more powerful nodes. Additionally, ProFlex takes profit of the higher communication range of such powerful nodes in the network and use the long link to improve data distribution. When compared with Supple -- a related protocol, we show by simulation that Proflex increases the network resilience under failures circumstances, decreases the overhead of transmitted messages, and decreases the number of hops to find a specific data in the network.Cet article porte sur la proposition d'un protocole de données proactif de distribution pour les réseaux de capteurs sans fil hétérogènes (HWSNs). Notre protocole, ProFlex, garantit la robustesse de la récupération des données grâce à sa gestion intelligente de la réplication des données entre les nœuds de stockage sélectionnés dans le réseau. Contrairement à d'autres protocoles dans la littérature, ProFlex considère les contraintes de ressources de capteurs et construit plusieurs structures de réplication des données, qui sont gérés par des nœuds plus puissants. En outre, ProFlex profite de la meilleure communication radio de ces nœuds plus puissants et utilise ces longues portée pour améliorer la distribution des données. Nous avons comparé ProFlex avec le protocole Supple et nous avons montré par simulation que Proflex augmente la résilience du réseau, même dans des circonstances des pertes de messages, diminue la surcharge de messages transmis, et diminue le nombre de sauts nécessaire pour trouver un ensemble de données spécifiques dans le réseau

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

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

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

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

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

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

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

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