Experimental evaluation of the usage of ad hoc networks as stubs for multiservice networks

This paper describes an experimental evaluation of a multiservice ad hoc network, aimed to be interconnected with an infrastructure, operator-managed network. This network supports the efficient delivery of services, unicast and multicast, legacy and multimedia, to users connected in the ad hoc network. It contains the following functionalities: routing and delivery of unicast and multicast services; distributed QoS mechanisms to support service differentiation and resource control responsive to node mobility; security, charging, and rewarding mechanisms to ensure the correct behaviour of the users in the ad hoc network. This paper experimentally evaluates the performance of multiple mechanisms, and the influence and performance penalty introduced in the network, with the incremental inclusion of new functionalities. The performance results obtained in the different real scenarios may question the real usage of ad-hoc networks for more than a minimal number of hops with such a large number of functionalities deployed

A gender-based approach to the influence of personality traits on entrepreneurial intention

While previous studies have demonstrated the importance of personality traits in the decision to pursue a career in entrepreneurship, more empirical evidence is needed to explain the mechanism through which entrepreneurial intention (EI) is strengthened. Accordingly, espousing a gender-based perspective, the current paper identifies characteristics that positively affect EI in a sample of 531 students in France. A fuzzy-set qualitative comparative analysis is performed yielding four alternate combinations that are likely to lead to high EI, of which two are gender specific. The inherent findings advance previous studies by offering entrepreneurship educators in France and similar contexts a new understanding of entrepreneurial intention from a gender perspective. Similarly, the results offer first-hand evidence to inform university students’ career choices

Optimized Link State Routing Protocol for Ad Hoc Networks

In this paper we propose and discuss an optimized link state routing protocol, named OLSR, for mobile wireless networks. The protocol is based on the link state algorithm and it is proactive (or table-driven) in nature. It employs periodic exchange of messages to maintain topology information of the network at each node. OLSR is an optimization over a pure link state protocol as it compacts the size of information sent in the messages, and furthermore, reduces the number of retransmissions to flood these messages in entire network. For this purpose, the protocol uses multipoint relaying technique to efficiently and economically flood its control messages. It provides optimal routes in terms of number of hops, which are immediately available when needed. The proposed protocol is best suitable for large and dense ad hoc networks

Etude fiabiliste d’un barrage de correction torrentielle

National audienceThis paper presents an assessment of the failure probability of a reinforced concrete torrential check-dam according to flow height of torrential floods and debris flows. Some mechanical-probabilistic models have been built: in the one hand finite elements models to study the internal stability of the structure and in the other hand analytical models to assess its external stability. Monte-Carlo simulations based on uncertainties propagation of material properties (siltation soil and concrete) allow obtaining failure probability curves. Results show for instance that the first failure mode to take into account is the structure overturning at the level of the wings. However, convergence problems of the finite elements model still need to be solved in order to better study the internal stability of the dam.Cette communication présente une évaluation de la probabilité de défaillance d’un barrage de correction torrentielle en fonction de la hauteur d’écoulement d’une crue ou d’une lave torrentielle. Plusieurs modèles mécano-fiabilistes ont été mis en place basés d’une part sur la méthode des éléments finis pour l’étude de la stabilité interne de l’ouvrage et, d’autre part, sur des calculs analytiques pour l’étude de sa stabilité externe. Des simulations Monte-Carlo basées sur la propagation des incertitudes liées aux caractéristiques des matériaux (sol d’atterrissement et béton) ont permis d’obtenir diverses courbes de probabilité de défaillance. Les résultats montrent pour l‘instant que le mode de rupture à considérer en premier lieu est un renversement de l’ouvrage au niveau des ailes. Des problèmes de convergence du modèle éléments finis restent cependant encore à résoudre pour mieux appréhender la stabilité interne de la structure

Unprecedented Synthesis of Alkynylphosphine-boranes through Room-Temperature Oxidative Alkynylation

An original and user-friendly synthesis of alkynylphosphine-boranes, useful building blocks in organic synthesis, based on an oxidative P-alkynylation reaction with readily available copper acetylides is reported. The ability of a secondary phosphine protected with a borane to undergo oxidative coupling without oxidation of the P-moiety is demonstrated for the first time. The reaction, which proceeds at room temperature, is applicable to the preparation of enantioenriched and structurally complex alkynylphosphine-boranes.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Vehicle Safety Enhancement System: Sensing and Communication

With the substantial increase of vehicles on road, driving safety and transportation efficiency have become increasingly concerned focus from drivers, passengers, and governments. Wireless networks constructed by vehicles and infrastructures provide abundant information to share for the sake of both enhanced safety and network efficiency. This paper presents the systematic research to enhance the vehicle safety by wireless communication, in the aspects of information acquisition through vehicle sensing, vehicle-to-vehicle (V2V) routing protocol for the highly dynamic vehicle network, vehicle-to-infrastructure (V2I) routing protocol for a tradeoff in real-time performance and load balance, and hardware implementation of V2V system with on-road test. Simulations and experimental result validate the feasibility of the algorithms and communication system

Turning unreactive copper acetylides into remarkably powerful and mild alkyne transfert reagents by oxidative umpolung

International audienceThis is not breaking news: copper acetylides, readily available polymeric rock-stable solids, have been known for more than a century to be unreactive species and piteous nucleophiles. This lack of reactivity actually makes them ideal alkyne transfer reagents that can be easily activated under mild oxidizing conditions. When treated with molecular oxygen in the presence of simple chelating nitrogen ligands such as TMEDA, phenanthroline or imidazole derivatives, they are smoothly oxidized to highly electrophilic species that formally behave like acetylenic carbocations and can therefore be used for the mild and practical alkynylation of a wide range of nitrogen, phosphorus and carbon nucleophiles

Expanding the Oxidative Chemistry of Organocopper Reagents: Facile Oxidative Cross-Coupling of Copper Acetylides with Arylboronic Acids

We have developed an efficient procedure for oxidative cross-coupling between arylboronic acids and alkynylcopper reagents. Upon simple addition of 1,10-phenanthroline in the presence of oxygen, these highly stable, readily available polymeric reagents are easily activated and transfer their alkynyl group after subsequent transmetallation with the boronic acid. These results further expand the oxidative chemistry of organocopper compounds together with providing a user-friendly entry to diaryl acetylenes.SCOPUS: ar.jinfo:eu-repo/semantics/publishe