Automatic implementation of TTEthernet-based time-triggered avionics applications

International audienceThe design of safety-critical embedded systems such as those used in avionics still involves largely manual phases. But in avionics the definition of standard interfaces embodied in standards such as ARINC 653 or TTEthernet should allow the definition of fully automatic code generation flows that reduce the costs while improving the quality of the generated code, much like compilers have done when replacing manual assembly coding. In this paper, we briefly present such a fully automatic implementation tool, called Lopht, for ARINC653-based time-triggered systems, and then explain how it is currently extended to include support for TTEthernet networks

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

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

Dissecting dissemination in VANETs

International audienceVehicular ad hoc networks (VANET) are an active area for research and development likely to become an integral part of the communication infrastructure of tomorrow. From road safety to recreation applications, a wide range of services are emerging from the rapid technological advances in vehicles sensing, computing, and wireless capabilities. The key issue with respect to those new purposes is the ability of vehicles to disseminate information collected by on-board sensing devices about their surroundings. In this paper, we propose a component-based approach to analyze existing dissemination protocols for VANETs. Our results help better understand the behavior of each component by avoiding the interplays that may result from their combination. We also identify which technical instantiations best fit to different application profiles and environment parameters, while having regard to the resulting performance issues

SERVUS: Reliable low-cost and disconnection-aware broadcasting in VANETs

International audienceThe future of Vehicular Ad-Hoc Networks (VANET) will rely mainly on the support of efficient information dissemination protocols, whether we talk about safety applications that warn the driver of an imminent collision, a simple update on traffic conditions, or road-side advertisements. One of the greatest challenges when designing such protocols is how to deliver packets efficiently in a highly mobile environments under intermittent connectivity. Surprisingly, this problem has been under-investigated in the literature. In this paper, we propose, design, and evaluate SERVUS1, a robust dissemination protocol that guarantees packet propagation with high delivery ratio and low overhead. SERVUS includes a new broadcast management mechanism that takes advantage of the inherent behavioral properties of the VANET environment. In particular, the proposed protocol can update isolated nodes (or clusters) with missing information while ensuring homogeneous information dispersal at low overhead. Through a number of analyses, we show that SERVUS is highly efficient with regard to the tradeoff between reliability and cost, and overcomes important issues like the broadcast storm problem and the topological temporal fragility