ADM : A Density And Priority Levels Aware Protocol For Broadcasting In Vehicular Ad-Hoc Networks

The broadcasting communication mode is widely used in Vehicular Ad~hoc Networks (VANETs). It is used for sending emergency messages, road-traffic information or to help routing protocols to determine routes. This communication mode is known to be hard to achieve efficiently since it depends on the network density. Indeed, broadcasting methods may cause network congestion if they are not well designed. This paper introduces a novel Autonomic Dissemination Method (ADM) which delivers messages in accordance with given message classes and network density levels. The proposed approach is based on two steps: an offline optimization process and an online adaptation to the network characteristics. ADM allows each node to dynamically adapt its broadcasting strategy not only with respect to the network density, but also according to the class of the message to send: emergency (high-priority), road-traffic (medium-priority) or either comfort message (low-priority). The ultimate goal of ADM is to make effective use of radio resources when there are many messages to send simultaneously. This approach increases the efficiency of the broadcast process in terms of message delivery ratio, latency and interferences reduction. The autonomic computing paradigm improves the robustness of protocols

Algorithme génétique multi-objectifs adaptatif

International audienceCet article présente une version adaptative d’un algorithme génétique multi-objectif appelé GAME. Ce dernier propose une structuration de la population en plusieurs fronts de Pareto et la définition de diverses fonctions de fitness. La version proposée dans cet article, aGAME, introduit un opérateur d’adaptation dynamique qui alterne les phases d’exploration et d’exploitation au cours de l’exécution de l’algorithme. Ces changements de mode de parcours de l’espace de recherche utilisent des indicateurs de performance afin de maintenir un équilibre entre la "convergence" et la diversité des solutions obtenues. aGAME est comparé à la version de base (GAME) ainsi qu’aux trois meilleurs algorithmes de la compétition CEC 2009, sur des problèmes bi-objectifs avec des contraintes. Cette étude comparative montre que aGAME obtient de meilleurs résultats que les quatre algorithmes auxquels il est comparée. Ces résultats valident l’efficacité de l’opérateur d’adaptation dynamique et les performances globales de l’algorithme

Multi-Pareto-Ranking Evolutionary Algorithm

International audienceThis paper proposes a new multi-objective genetic algorithm, called GAME, to solve constrained optimization problems. GAME uses an elitist archive, but it ranks the population in several Pareto fronts. Then, three types of fitness assignment methods are defined: the fitness of individuals depends on the front they belong to. The crowding distance is also used to preserve diversity. Selection is based on two steps: a Pareto front is first selected, before choosing an individual among the solutions it contains. The probability to choose a given front is computed using three parameters which are tuned using the design of experiments. The influence of the number of Pareto fronts is studied experimentally. Finally GAME's performance is assessed and compared with three other algorithms according to the conditions of the CEC 2009 competition

Designing Smart Adaptive Flooding in MANET using Evolutionary Algorithm

International audienceThis paper deals with broadcasting warning / emergency messages in mobile ad hoc networks. Traditional broadcasting schemes tend to focus on usually high and homogeneous neighborhood densities environments. This paper presents a broadcasting protocol that locally and dynamically adapts its strategy to the neighborhood densities. The behavior of the protocol is tuned using various internal parameters. Multiple combinations of those parameters have been pre-computed as optimal solutions for a range of neighborhood densities, and the most relevant one is dynamically chosen depending on the locally perceived environment. The combinations were determined by coupling an evolutionary algorithm and a network simulator, using a statistically realistic radio-propagation model (Shadowing Pattern). This approach is compared with other probabilistic methods while broadcasting an emergency message in vehicular ad hoc networks with variable and heterogeneous vehicle densities. In such a context, it is expected from the network to enable each node to receive the warning message. The results show that our protocol covers the whole network, whereas other methods only have a probability of 0.57 to 0.9 to cover the entire network

Trade-off Between Diversity and Convergence in Multi-objective Genetic Algorithms

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Transmission of Genetic Properties in Permutation Problems: Study of Lehmer Code and Inversion Table Encoding

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Impact of Concurrent Communications in Geographical Broadcasting Protocols for Vehicular Ad hoc Networks

International audienceBringing to the market intelligent vehicles is one of the current challenges faced by car manufacturers. These vehicles must be able to communicate in order to cooperate and be more effective. The issue of inter-vehicle communications is an active research topic. This paper proposes a reliable geographical broadcasting protocol which has a twofold goal: limiting the risk of interference and reducing the dissemination time. To achieve theses goals, two mechanisms are proposed. The first one divides the road (more precisely, each vehicle's coverage area) into several segments depending on the local density. Thereafter, the priority to relay a message is given to nodes that are in the farthest segment from the source node. The second mechanism allows to reduce the waiting time thanks to a periodic update process. This paper also analysis the performance of geographical broadcasting protocols in case of multiple simultaneous communications. The goal is to observe how these protocols behave when the radio channel becomes overloaded. The comparison study (in terms of packet loss and dissemination time) shows that the proposed protocol outperforms two other VANETs' broadcasting protocols.Keyword

An autonomic message dissemination protocol for Vehicular Ad hoc Networks: a density and priority levels aware approach

International audienceThe broadcasting communication mode is widely used in Vehicular Ad hoc Networks. It is used for sending emergency messages, road-traffic information or to help routing protocols to determine routes. This communication mode is known to be hard to achieve efficiently since it depends on the network density. Indeed, broadcasting methods may cause network congestion if they are not well designed. This paper introduces a novel Autonomic Dissemination Method (ADM) which delivers messages in accordance with given message classes and network density levels. The proposed approach is based on two steps: an offline optimization process and an online adaptation to the network characteristics. ADM allows each node to dynamically adapt its broadcasting strategy not only with respect to the network density, but also according to the class of the message to send: emergency (high-priority), road-traffic (medium-priority) or either comfort message (low-priority). The ultimate goal of ADM is to make effective use of radio resources when there are many messages to send simultaneously. This approach increases the efficiency of the broadcast process in terms of message delivery ratio, latency and interferences reduction. The autonomic computing paradigm improves the robustnessof protocols

SREP: An Energy Efficient Relay Protocol for Wireless Sensor Networks

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