Search

The enantioselective intramolecular oxyamination of unsaturated alkoxyamines using a hybrid catalytic system consisting of Cp*Rh-III/chiral disulfonate/CuOAc is described. Tetrahydrofuran derivatives with a tetrasubstituted chiral center were obtained under the optimized conditions in 91:9-97:3 er. The use of a sterically hindered chiral disulfonate and a Cu additive was essential for the high enantioselectivity.

Purpose: This study aimed to obtain suggestions for health education in order to improve the everyday habits and clarify the effects of the use of Social Networking Systems (SNS) by Japanese junior high school students on their sleeping habits and overall fatigue as measured by scores on the Cumulative Fatigue Symptoms Index (CFSI). Methods: We examined the data from 346 students from nine junior high schools (145 male and 201 female) in the 1st and 2nd year in Niigata City Japan. The study was conducted from December 2013 to January 2014. Data collected included the background of the participants, their everyday habits, their use of communications devices, their use of SNS, and CFSI scores. Results: There were no significant differences in the overall CFSI scores between the two groups (high and low) of SNS users. However, the use of SNS raised the CFSI subscale of “physical disorders” among female students in comparison to those who did not use SNS. The reason that male students had high CFSI was an odds ratio of 2.8 (95% C1: 1.091-7.086) for “Sleeping time.：After 11pm” and for female students, it was an odds ratio of 2.1 (95% C1: 1.12-4.27) for “Owned their own communications devices. ：Yes” In addition, the odds ratio for “What do you do after you get into bed? ：Some activity” was 2.5 (95% C1: 1.126-5.643) for male students and 1.9 (95% C1: 1.017-3.895) for female students. Conclusion: It was clarified that students who owned their own communications devices had developed poor sleeping habits by using SNS, playing games, or sending e-mail after they went to bed but before going to sleep, and they were experiencing fatigue. This suggests the necessity of guidance about the use of electronics devices in order to improve the everyday habits of junior high school students.

International audience; In this paper we apply the Named Data Networking [8], a newly proposed Internet architecture, to networking vehicles on the run. Our initial design, dubbed V-NDN, illustrates NDN's promising potential in providing a unifying architecture that enables networking among all computing devices independent from whether they are connected through wired infrastructure, ad hoc, or intermittent DTN. This paper describes a prototype implementation of V-NDN and its preliminary performance assessment, and identifies remaining challenges.

In this paper we apply the Named Data Networking, a newly proposed Internet architecture, to networking vehicles on the run. Our initial design, dubbed V-NDN, illustrates NDN's promising potential in providing a unifying architecture that enables networking among all computing devices independent from whether they are connected through wired infrastructure, ad hoc, or intermittent DTN. This paper describes the prototype implementation of V-NDN and its preliminary performance assessment.

International audience; In 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.

International audience; The 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.

The IEEE WAVE protocol suite is providing communications services to applications in vehicular networks, by way of promising support for two protocol stacks: the Wave Short Message Protocol (WSMP) and IPv6. While WSMP is developed within the IEEE 1609 family of standards, the authors of this memorandum assert, that considerations for IPv6 operation for WAVE are less developed, and several issues are left unaddressed by the current IEEE 1609 specifications. This memorandum reviews these issues and analyzes the main challenges in providing proper IPv6 operation for WAVE networks.; La suite de protocoles IEEE WAVE fournit des services de communications pour les réseaux véhiculaires, en promettant le support de deux piles de protocoles: le Wave Short Message Protocol (WSMP) d'une part, et IPv6 d'autre part. Si WSMP est spécifié dans la famille de standards IEEE 1609, les auteurs du présent papier affirment que les considérations concernant IPv6 dans WAVE ne sont pas assez dévelloppées, et que par conséquent, plusieurs problèmes ne sont pas résolus. Ce papier passe en revue ces problèmes, et analyse les principaux vérrous concernant le dévelloppement de solutions appropriées à ces problèmes.

International audience; The Mobile IPv6 protocol is a major solution to supply mobility services on the Internet. Many networking vendors have already implemented it in their operating systems and equipments. Moreover, it was recently selected to provide permanent IP addresses to end-users of WiMAX and 3GPP2. Mobile IPv6 relies on a specific router called the home agent that hides location changes of the mobile nodes from the rest of the Internet. To do so, the mobile nodes’ traffic must flow through the home agent. This mandatory deviation produces longer paths and higher communication delays.In order to solve these problems, we describe a new approach to address deployments of Mobile IPv6 based on graph theory and could be applied to any operator’s network. In particular, we use notions of centrality in graphs to quantify increases of communication distances induced by dogleg routing and identify relevant home agents locations. We evaluate this approach using real-world network topologies and show that the obtained Mobile IPv6 performance could be close to direct paths ones. The proposed algorithm is generic and can be used to achieve efficient deployments of Mobile IPv6 as well as Home Agent Migration: a new Mobile IPv6 architecture using several distributed home agents.

International audience; Defined at the IETF, the Mobile IPv6 protocol allows a single mobile node to keep the same IPv6 address independently of its network of attachment. It was recently enhance so as to augment its applicability. One of these extensions, NEMO, NEtwork MObility makes it possible to move a whole network, such as sensors deployed in a car, in the Internet topology. On the other hand, Proxy Mobile IPv6 provides Mobile IPv6-like services to standard IPv6 nodes. While these three protocols are actually heavily supported by the industry and deployed in 3GGP2, WiMAX and ITS, they suffer from several performances issues. Most of them are caused by the Home Agent, a specific router located on the home network, that hides movements of mobile nodes to their correspondents. The restricted position of the home agent is responsible for longer communications delays and higher path lengths. In one of our previous work, Home Agent Migration, we described how to significantly reduce these issues by deploying multiple home agents in the Internet topology. In this paper, we discuss the possible extensions to this specific architecture in order to support and enhance NEMO and Proxy Mobile IPv6. Furthermore, we analyze Home Agent Migration in terms of security so as to provide detailed guidance for secure real life deployments and safe usages.

International audience

International audience; Internet edge mobility has been possible for a number of years: mobile IP[8], allows a host to change its point of at- tachment to the Internet and NEMO [6] allows the same functionality for a group of hosts along with a mobile router. The virtue of NEMO and mobile IP is transparency: a host remains identifiable through the same IP address, and traffic sent to that IP address will be tunneled to arrive at the intended node. NEMO allows "nested networks": a mobile network which attaches to another mobile network to arbitrary depth. However for each level of nesting, traffic is encap- sulated and tunneled to reach the destination. This leads to increased overhead (encapsulation) and to sub-optimal paths (tunneling without consideration for the actual net- work topology). In this paper, we investigate route-optimization in nested NEMO networks. We employ an ad-hoc routing protocol between mobile routers to ensure shortest routes when both source and destination for traffic is within the nested NEMO network. The mechanism also simplifies the requirements for route optimization when the source node is located outside of the nested NEMO network.