39 research outputs found
Ătude de l'intermodalitĂ© pour le dĂ©lestage des rĂ©seaux d'infrastructure
National audienceNous proposons de tirer parti des dĂ©placements des vĂ©hicules des particuliers sur les routes pour permettre aux rĂ©seaux d'infrastructure de dĂ©lester une partie de leur trafic de maniĂšre opportuniste. Pour rĂ©aliser un tel service, les donnĂ©es sont rĂ©parties sur les vĂ©hicules Ă©quipĂ©s de disques durs. La sĂ©lection des vĂ©hicules se fait en fonction de leur itinĂ©raire et ce afin de rĂ©pondre aux contraintes qui caractĂ©risent les donnĂ©es Ă transfĂ©rer. L'allocation des transferts de donnĂ©es s'avĂšre ĂȘtre un problĂšme complexe pour un rĂ©seau routier Ă trĂšs grande l'Ă©chelle. Aussi, nous proposons un algorithme de rĂ©duction de l'infrastructure routiĂšre qui calcule un rĂ©seau de recouvrement dont les liens logiques agrĂšgent plusieurs segments de route. Nous formulons alors le problĂšme de l'allocation des transferts de donnĂ©es sous forme d'un modĂšle de programmation linĂ©aire. Ce modĂšle dĂ©finit une stratĂ©gie d'allocation des donnĂ©es qui maximise le dĂ©bit total rĂ©alisĂ© par les flots de vĂ©hicules impliquĂ©s dans ces transferts
Vehicular Carriers for Big Data Transfers
International audienceIn the latest years, Internet traffic has increased at a significantly faster pace than its capacity, preventing efficient bulk data transfers such as datacenter migrations and high-definition user-generated multimedia data. In this paper, we propose to take advantage of the existing worldwide road infrastructure as an offloading channel to help the legacy Internet assuage its burden. One of the motivations behind our work is that a significant share of the Internet traffic is elastic and tolerates a certain delay before consumption. Our results suggest that piggybacking data on vehicles can easily lead to network capacity in the petabyte range. Furthermore, such a strategy exceeds by far the performance of today's alternatives that, although yielding good performance levels, still rely on the legacy Internet and inherent then its intrinsic limitations. We show through a number of analyses that our proposal has the potential to obtain remarkable reductions in transfer delays while being economically affordable
Increasing the maturity of compost used affects the soil chemical properties and the stability of microbial activity along a mediterranean post-fire chronosequence
Information Delivery: Past Struggles & New Directions
The main topic of this HDR is the design and the analysis of information delivery systems in the context of challenging environments and disruptive usage patterns. The driving motivation of the work I will present can be stated as follow: How to handle the mobility in its many incarnations, whether we consider the migration or replication of content between fixed repositories or the movements of the hosting nodes if mobile? In this presentation, I will address the mobility, first as a challenge and then, as an enabler. The contributions of this HDR are organized into two main parts:* Content, the big âCâ of computer networkingThis first part consists of three pieces of work related to content delivery in the context of various environments. We first consider the core of large-scale conventional networks such as the Internet. We address the limitations resulting of the host-centric design of the Internet. We propose a query-based search approach that leverages the replication of popular content. In a second piece of work, we address the mismatch between the available capacity of cellular wireless networks and the increasing demand for content on the move. We propose a radio resource-saving strategy for disseminating delay-tolerant content in cellular environments. In the third and last work of this part, we address the problem of disseminating content in vehicular networks.* Tapping into everyday mobility:This second part presents a number of contributions that take advantage of the alternative communication channel resulting of the movements of entities such as vehicles equipped with storage capabilities. We use this alternative communication channel to supplement or in replacement of conventional infrastructure-based data networks. We exploit the existing mobility of surrounding entities to overcome various limitations of conventional data networks. In a first work, we use the routine journeys daily taken by private cars equipped with data storage devices to extend cost-effectively the capacity of the Internet. In the second and last work, I present two vehicular cloud services exploiting the mobility of public transit buses in urban scenarios
Vers plus d'hétérogénéité et d'interopérabilité dans Internet
International audienceCe papier explore la question de l'interopĂ©rabilitĂ© de rĂ©seaux hĂ©tĂ©rogĂšnes, en vue d'un Internet plus diversifiĂ© du point de vue des fonctions d'identification et de routage. En effet, les paradigmes de routage sont multiples et aucun d'eux ne peut se prĂ©valoir d'ĂȘtre adaptĂ© Ă l'ensemble des scĂ©narios de communication.Aussi, Internet doit permettre des scĂ©narios de communication globale rĂ©sultant de la composition de diffĂ©rents paradigmes d'identification et de routage Ă travers plusieurs Ăźlots de connectivitĂ©. Nous proposons une abstraction permettant de modĂ©liser une variĂ©tĂ© de rĂ©seaux et ensuite discutons les diffĂ©rentes dimensions de la question de l'interopĂ©rabilitĂ©.Ce travail pourra servir de base Ă la dĂ©finition de protocoles de composition pour des rĂ©seaux hĂ©tĂ©rogĂšnes dans un contexte ambiant et autonome
Magnet: A Content Centric Routing Protocol for Large Scale Networks
International audienceContent routing is aimed to provide location-independent access to an object without relying on the maintenance of network connections between the source and the destination of the object. This paradigm enables the usage patterns in terms of applications involving data objects retrieval or services access by giving emphasis to the content rather than the location. Messages are routed on the basis of their descriptions rather than host locations.In this paper, we propose a novel content routing protocol designed for retrieving data objects in large-scale networks. Our routing scheme is based on two algorithms: request filtering and content dissemination. The design of these algorithms allows our protocol being more adapted to large scale networks than the classical content routing protocols.Our solution is based on a set of metrics and design principles aimed to achieve a compromise between the matching efficiency and the cost of communication and storage. Through conducted simulations, we show that our protocol is successful in achieving this compromise necessary for large-scale networks
A Data-driven Analysis of YouTube Community Features
International audienceThe success of YouTube has profoundly changed the face of industries dealing with digital content as it provides new means of distribution and promotion. While YouTube poses new opportunities for content creators to quickly reach a large audience of viewers, all videos posted online do not compete on the same footing with regard to popularity. To better understand the variation in the popularity of videos, we investigate the role of social interactions between users. In this way, our work is in stark contrast to prior research that studied user generated content video systems but without considering the structure of social relationships within those systems. In this paper, we conduct measurements on YouTube by applying a novel methodology to identify all the users interacting within the same community of interest. Using user information and the meta-data of posted videos, we analyze the influence of the community-based features of YouTube on the popularity of content posted online. Our analysis shows that users posting videos under a specific category get a better recognition than those actively posting videos belonging to a large variety of categories