Dissertations / Theses on the topic 'Mobility metrics'

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without the need for base stations or any other pre–existing network infrastructure. In a peer-to-peer fashion, mobile nodes can communicate with each other by using wireless multihop communication. Due to its low cost, high flexibility, fast network establishment and self-reconfiguration, ad hoc networking has received much interest during the last ten years. However, without a fixed infrastructure, frequent path changes cause significant numbers of routing packets to discover new paths, leading to increased network congestion and transmission latency over fixed networks. Many on-demand routing protocols have been developed by using various routing mobility metrics to choose the most reliable routes, while dealing with the primary obstacle caused by node mobility. ¶ In the first part, we have developed an analysis framework for mobility metrics in random mobility model. Unlike previous research, where the mobility metrics were mostly studied by simulations, we derive the analytical expressions of mobility metrics, including link persistence, link duration, link availability, link residual time, link change rate and their path equivalents. We also show relationships between the different metrics, where they exist. Such exact expressions constitute precise mathematical relationships between network connectivity and node mobility. ¶ We further validate our analysis framework in Random Walk Mobility model (RWMM). Regarding constant or random variable node velocity, we construct the transition matrix of Markov Chain Model through the analysis of the PDF of node separation after one epoch. In addition, we present intuitive and simple expressions for the link residual time and link duration, for the RWMM, which relate them directly to the ratio between transmission range and node speed. We also illustrate the relationship between link change rate and link duration. Finally, simulation results for all mentioned mobility metrics are reported which match well the proposed analytical framework. ¶ In the second part, we investigate the mobility metric applications on caching strategies and hierarchy routing algorithm. When on-demand routing employed, stale route cache information and frequent new-route discovery in processes in MANETs generate considerable routing delay and overhead. This thesis proposes a practical route caching strategy to minimize routing delay and/or overhead by setting route cache timeout to a mobility metric, the expected path residual time. The strategy is independent of network traffic load and adapts to various non-identical link duration distributions, so it is feasible to implement in a real-time route caching scheme. Calculated results show that the routing delay achieved by the route caching scheme is only marginally more than the theoretically determined minimum. Simulation in NS-2 demonstrates that the end-to-end delay from DSR routing can be remarkably reduced by our caching scheme. By using overhead analysis model, we demonstrate that the minimum routing overhead can be achieved by increasing timeout to around twice the expected path residual time, without significant increase in routing delay. ¶ Apart from route cache, this thesis also addresses link cache strategy which has the potential to utilize route information more efficiently than a route cache scheme. Unlike some previous link cache schemes delete links at some fixed time after they enter the cache, we proposes using either the expected path duration or the link residual time as the link cache timeout. Simulation results in NS-2 show that both of the proposed link caching schemes can improve network performance in the DSR by reducing dropped data packets, latency and routing overhead, with the link residual time scheme out-performing the path duration scheme. ¶ To deal with large-scale MANETs, this thesis presents an adaptive k-hop clustering algorithm (AdpKHop), which selects clusterhead (CH) by our CH selection metrics. The proposed CH selection criteria enable that the chosen CHs are closer to the cluster centroid and more stable than other cluster members with respect to node mobility. By using merging threshold which is based on the CH selection metric, 1-hop clusters can merge to k-hop clusters, where the size of each k-hop cluster adapts to the node mobility of the chosen CH. Moreover, we propose a routing overhead analysis model for k-hop clustering algorithm, which is determined by a range of network parameters, such as link change rate (related to node mobility), node degree and cluster density. Through the overhead analysis, we show that an optimal k-hop cluster density does exist, which is independent of node mobility. Therefore, the corresponding optimal cluster merging threshold can be employed to efficiently organise k-hop clusters to achieve minimum routing overhead, which is highly desirable in large-scale networks. ¶ The work presented in this thesis provides a sound basis for future research on mobility analysis for mobile ad hoc networks, in aspects such as mobility metrics, caching strategies and k-hop clustering routing protocols.

In 1985 a settlement and subsistence model of seasonal round mobility was proposed by Statistical Research, Inc. This model proposed four travel routes used by the Late Prehistoric Serrano to access the higher elevation village site known as Rock Camp to gather acorns and pinyon nuts in the fall. This research investigates the proposed routes, as well as an additional route, for energy efficiency and archaeological evidence of use in prehistory. Data collection involved using experimental methods designed to gather controlled physiological data for evaluating the efficiency of traveling each route. Archaeological sites present on the travel routes and within the research area and were analyzed for elements indicative of prehistoric settlement characteristics. A combination of physiological evidence and archaeological evidence are the basis for determinations on which routes were most likely to have been used in prehistory. An analysis of the settlement model is also provided in order to provide future research with guidelines and context for evaluating sites within the region. Suggestions are provided for future studies to focus on chronology and expansion of the settlement model.

Doutoramento em Engenharia Eletrotécnica -Telecomunicações
Recent paradigms in wireless communication architectures describe environments where nodes present a highly dynamic behavior (e.g., User Centric Networks). In such environments, routing is still performed based on the regular packet-switched behavior of store-and-forward. Albeit sufficient to compute at least an adequate path between a source and a destination, such routing behavior cannot adequately sustain the highly nomadic lifestyle that Internet users are today experiencing. This thesis aims to analyse the impact of the nodes’ mobility on routing scenarios. It also aims at the development of forwarding concepts that help in message forwarding across graphs where nodes exhibit human mobility patterns, as is the case of most of the user-centric wireless networks today. The first part of the work involved the analysis of the mobility impact on routing, and we found that node mobility significance can affect routing performance, and it depends on the link length, distance, and mobility patterns of nodes. The study of current mobility parameters showed that they capture mobility partially. The routing protocol robustness to node mobility depends on the routing metric sensitivity to node mobility. As such, mobility-aware routing metrics were devised to increase routing robustness to node mobility. Two categories of routing metrics proposed are the time-based and spatial correlation-based. For the validation of the metrics, several mobility models were used, which include the ones that mimic human mobility patterns. The metrics were implemented using the Network Simulator tool using two widely used multi-hop routing protocols of Optimized Link State Routing (OLSR) and Ad hoc On Demand Distance Vector (AODV). Using the proposed metrics, we reduced the path re-computation frequency compared to the benchmark metric. This means that more stable nodes were used to route data. The time-based routing metrics generally performed well across the different node mobility scenarios used. We also noted a variation on the performance of the metrics, including the benchmark metric, under different mobility models, due to the differences in the node mobility governing rules of the models.
Os paradigmas recentes de arquiteturas de comunicação sem fios consistem em ambientes onde os dispositivos apresentam um comportamento dinâmico (e.g., Redes Centradas no Utilizador). Nestes ambientes, o encaminhamento de dados ainda é realizado com base no comportamento de armazenamento e encaminhamento da comutação clássica de pacotes. Embora seja suficiente para calcular, pelo menos, um caminho adequado entre uma origem e um destino, tal comportamento de encaminhamento não é adequado nas redes móveis e sem fios atuais. Esta tese tem como objetivo analisar o impacto da mobilidade dos utilizadores sobre os diferentes cenários de encaminhamento. A tese também visa o desenvolvimento de conceitos de encaminhamento que ajudam na distribuição de dados através de grafos, nos quais os vértices exibem padrões de mobilidade humana, como é o caso hoje em dia para a maior parte das redes sem fios centradas no utilizador. A primeira parte desta tese envolveu a análise do impacto da mobilidade dos utilizadores no encaminhamento, com a análise de que a mobilidade, para afetar o desempenho do encaminhamento, depende do comprimento do caminho entre a origem e o destino, da distância entre os dispositivos, e dos diferentes padrões de mobilidade. O estudo dos atuais parâmetros de mobilidade mostrou que eles capturam parcialmente a mobilidade dos utilizadores. A robustez dos protocolos de encaminhamento depende da sensibilidade das métricas no que concerne a esta mobilidade. Assim, foram concebidas métricas de encaminhamento baseadas na mobilidade dos utilizadores para aumentar a robustez do encaminhamento em relação à mobilidade. As duas categorias de métricas de encaminhamento criadas foram métricas que têm como base o tempo e a correlação espacial. Para a validação das métricas foram utilizados vários modelos de mobilidade, incluindo os modelos que imitam padrões de mobilidade humana. As métricas foram implementadas utilizando a ferramenta Network Simulator e considerando dois protocolos de encaminhamento por múltiplos saltos amplamente utilizados, o Optimized Link State Routing (OLSR) e o Adhoc On Demand Distance Vector (AODV). Com a utilização das métricas propostas observa-se que a frequência de realização de novos cálculos de caminhos de comunicação foi reduzida em relação à métrica de referência. Isto significa que foram usados caminhos mais estáveis para encaminhar dados. As métricas de encaminhamento baseadas no tempo apresentam geralmente um bom desempenho nos diferentes cenários de mobilidade utilizados. Observou-se também uma variação no desempenho das métricas, incluindo a métrica de referência, nos diferentes modelos de mobilidade considerados, devido a diferenças nas regras de mobilidade dos utilizadores dos diferentes modelos.

Les réseaux sans fil sont sujets à des perturbations voire des pannes de liens et de noeuds en raison des caractéristiques intrinsèques de leur support de communication ; ces pannes sont aggravées par les particularités de relayage et de mobilité des noeuds dans les réseaux ad hoc. Ces réseaux requièrent donc la conception et la mise oeuvre des protocoles robustes au niveau de toutes les couches protocolaires. Dans cette thèse, nous choisissons une approche de robustesse pour améliorer les performances des communications dans un réseau mobile ad hoc. Nous proposons et étudions deux architectures de protection (protection par une analyse prédictive et protection par redondance de routes) qui sont couplées avec une restauration de niveau routage. Concernant la phase de détection, le protocole de routage utilise les notifications de niveau liaison pour détecter les pannes de liens. La première solution repose sur un protocole de routage réactif unipath dont le critère de sélection de routes est modifié. L’idée est d’utiliser des métriques capables de prédire l’état futur des routes dans le but d’améliorer leur durée de vie. Pour cela, deux métriques prédictives reposant sur la mobilité des noeuds sont proposées : la fiabilité des routes et une combinaison fiabilité-minimum de sauts. Pour calculer ces métriques prédictives, nous proposons une méthode analytique de calcul de la fiabilité de liens entre noeuds. Cette méthode prend compte le modèle de mobilité des noeuds et les caractéristiques de la communication sans fil notamment les collisions inter-paquets et les atténuations du signal. Les modèles de mobilité étudiés sont les modèles Random Walk et Random Way Point. Nous montrons l’impact de ces métriques sur les performances en termes de taux de livraison de paquets, de surcoût normalisé et de ruptures de routes. La seconde solution est une protection par redondance de routes qui s’appuie sur un protocole de routage multipath. Dans cette architecture, l’opération de recouvrement consiste soit à un basculement sur une route secondaire soit à une nouvelle découverte. Nous montrons que la redondance de routes améliore la robustesse de la communication en réduisant le temps de restauration. Ensuite, nous proposons une comparaison analytique entre les différentes politiques de recouvrement d’un protocole multipath. Nous en deduisons qu’un recouvrement segmenté donne les meilleurs résultats en termes de temps de restauration et de fiabilité
Due to the unreliability characteristics of wireless communications, and nodes mobility, Mobile Ad hoc Networks (MANETs) suffer from frequent failures and reactivation of links. Consequently, the routes frequently change, causing significant number of routing packets to discover new routes, leading to increased network congestion and transmission latency. Therefore, MANETs demand robust protocol design at all layers of the communication protocol stack, particularly at the MAC, the routing and transport layers. In this thesis, we adopt robustness approach to improve communication performance in MANET. We propose and study two protection architectures (protection by predictive analysis and protection by routes redundancy) which are coupled with a routing level restoration. The routing protocol is responsible of the failure detection phase, and uses the mechanism of link-level notifications to detect link failures. Our first proposition is based on unipath reactive routing protocol with a modified route selection criterion. The idea is to use metrics that can predict the future state of the route in order to improve their lifetime. Two predictive metrics based on the mobility of nodes are proposed : the routes reliability and, combining hop-count and reliability metrics. In order to determine the two predictive metrics, we propose an analytical formulation that computes link reliability between adjacent nodes. This formulation takes into account nodes mobility model and the the wireless communication characteristics including the collisions between packets and signal attenuations. Nodes mobility models studied are Random Walk and Random Way Point. We show the impact of these predictive metrics on the networks performance in terms of packet delivery ratio, normalized routing overhead and number of route failures. The second proposition is based on multipath routing protocol. It is a protection mechanism based on route redundancy. In this architecture, the recovery operation is either to switch the traffic to alternate route or to compute a new route. We show that the routes redundancy technique improves the communication robustness by reducing the failure recovery time. We propose an analytical comparison between different recovery policies of multipath routing protocol. We deduce that segment recovery is the best recovery policy in terms of recovery time and reliability

A mobile ad-hoc network is an assortment of wireless mobile hosts, which establishes a momentary network without any assist of centralized administrator. The characteristics of an ad-hoc network can be explored on the base of routing protocols. The dynamic topology is the vital characteristic in which nodes frequently change their position. In the ad-hoc networks, there are mobile nodes such as Personal Digital Assistance (PDA), smart phone and laptops; they have limited operational resources like battery power and bandwidth. The control traffic is to be minimized, which is the main responsibility of routing protocols by selecting the shortest path and controlling the traffic. In this study work, we focus on performance issues of routing protocols, Optimized Link State Routing (OLSR), Ad Hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR), and Temporally Ordered Routing Algorithm (TORA) in mobility and standalone ad-hoc networks. For this purpose, we first study and explain these protocols and then we use the Optimized Network Engineering Tool (OPNET) modeler tool and analyze the performance metrics delay, throughput and network load.

Orientador: Gustavo Garcia Manzato
Resumo: O trabalho apresentado teve como objetivo principal avaliar as relações entre características espaciais das cidades e a resiliência em relação à mobilidade urbana, considerando os diferentes portes de municípios, em um estudo aplicado para o estado de São Paulo. Para atingir tal objetivo, foi proposto o desenvolvimento de um método de avaliação da resiliência na mobilidade urbana considerando viagens não motorizadas (caminhada e bicicleta), utilizando como inovação a Grade Estatística do IBGE. Em geral, para o modo a pé foi observado que cerca de 46% dos municípios analisados seriam totalmente resilientes, sendo que esta proporção é composta pelos munícipios de menor porte. Já os municípios que apresentaram uma baixa resiliência compreendem aproximadamente 11% do total de municípios e são caracterizados por aqueles de maior porte e mais populosos do estado. Para o modo bicicleta a situação é diferente, nota-se que apenas os municípios de São Paulo e Ilhabela apresentam baixa resiliência. Além disso, é observado que 91% dos municípios são totalmente resilientes em relação a esse modo de deslocamento. A partir dos resultados do método, buscou-se relacionar essa resiliência com métricas espaciais das cidades por meio de índices de forma urbana, a saber: Densidade, Concentração, Agrupamento e Centralidade. Dessa maneira, concluiu-se que a Densidade Domiciliar é o parâmetro que mais se destaca, uma vez que quanto maior o porte do município, maior foi o valor observado para essa mé... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The objective of this work was to evaluate the relationship between spatial characteristics of cities and the resilience in urban mobility, considering the different sizes of the municipalities, in a study applied to the state of São Paulo. To achieve this objective, we proposed the development of a method for assessing the resilience in urban mobility considering non-motorized trips (walking and cycling), using the Statistical Grid of the Brazilian Institute of Geography and Statistics as an innovation. In general, for walking, we observed that around 46% of the municipalities would be totally resilient, and this proportion corresponds to the smaller municipalities. On the other hand, the municipalities that show a lower resilience comprise approximately 11% of the total and are characterized by the largest and most populous municipalities in the state. For cycling the situation is different. We noted that only the municipalities of São Paulo and Ilhabela present a low resilience rate. In addition, we observed that 91% of the municipalities are totally resilient to this travel mode. In turn, we sought to establish a relationship between this resilience with spatial metrics of the cities through urban form indexes: Density, Concentration, Clustering and Centrality. Thus, we concluded that the household density is the parameter that stands out the most, since the larger the size of the municipality, the higher the value for this metric. For the other metrics (Concentration, Cl... (Complete abstract click electronic access below)
Mestre

L'avenir de la communication est perçu comme étant quasiment exclusivement constitué de nœuds mobiles évoluant dans un réseau mobile. Dans ce contexte, différentes approches contribuent continuellement à l'amélioration directe ou indirecte des délais d'acheminement des informations échangées entre les utilisateurs, dont :- l'analyse des traces;- l'évaluation des performances ;- les services de localisation;- le routage. Nous décrivons chacun de ses thèmes et proposons des solutions faisant évoluer l'état de l'art. Celles-ci prennent appui sur des méthodes et outils tels que :- les Réseaux de Petri, pour l'analyse des traces ;- les modèles de mobilité, pour l'évaluation des performances;- l'introduction du social dans les services de localisation;- la mise en place d'une nouvelle métrique pour le routage. Nous montrons comment ces solutions concourent de façon complémentaire les unes avec les autres, à améliorer l'expérience de l'utilisateur.

Cette thèse consiste en une géographie des lieux et des circulations de l’émergence artistique dans une métropole du Sud. Elle se situe au croisement entre une géographie urbaine, soucieuse des agencements socio-spatiaux à l’intérieur desquels s’organise l’existence « ordinaire » d’une activité en train de se faire, et une géographie de l’art qui place les trajectoires spatiales des faits artistiques au cœur de l’analyse. Capitale postcoloniale, métropole est-africaine et périphérie d’une « économie mondiale d’archipel », Nairobi est un terrain de la rencontre entre métropolisation et globalisation. Dans le sillon des théories géographiques de la mondialisation, cette recherche propose de documenter et de cartographier les reconfigurations de l’espace artistique qui résultent de ces dynamiques. L’originalité de cette thèse est de rassembler l’ensemble des scènes et des productions artistiques d’une ville sur le dénominateur commun de la dimension spatiale de leurs circulations. Le matériau étudié (discours et curriculum vitae d’artistes, activités et archives de centres d’art) permet de confronter des circulations effectives à des horizons d’accomplissement différenciés, dont la trame est faite d’une ruralité encore prégnante et la connectivité d’une métropole mondialisée. La méthode développée relève de la traçabilité, dont la base est l’enquête par observation. Une exposition, une performance, une bourse de voyage, la visite d’un commissaire d’exposition, d’un collectionneur ou d’un mécène, les circulations quotidiennes d’un artiste et ses modes de socialisation, tous ces déplacements individuels, matériels, idéels et financiers constituent la matière première de la géographie proposée dans cette thèse. Comprise comme l’articulation entre, d’une part, les compétences et les tactiques spatiales des artistes et, d’autre part, les moyens matériels et institutionnels de gestion de la distance, la mobilité artistique interroge les conditions et le sens des déplacements autant que le devenir des acteurs engagés
This Ph.D. thesis tackles the places and circulations involved in the making of art in a southern metropolis. It is situated at the crossroads of an urban geography concerned with the social and spatial layout through which this “ordinary” activity is organized, and a geographical approach of art that places actors’ trajectories at the heart of the analysis. Capital city in a postcolonial State, East African metropolis and periphery of the “global archipelagic economy”, Nairobi is a case of the encounter between metropolization and globalization. In the trail of the theories on the worlding of material geography, this study aims at documenting and mapping the reconfigurations of art space triggered by these dynamics. The novelty of this thesis is to assemble the entire range of art scenes and products of a city, using the common thread that is the spatial dimension of their circulations. The material studied (artists’ discourse and curriculum vitae; art centres activity and archive) takes on both the measureable circulations of artists while confronting them to their horizon of accomplishment. These are made up of the persistence of strong rural ties and the connectivity of a globally connected city. The method deployed relies on the notion of traceability and is based on a qualitative survey through observation. An exhibition, a performance, a mobility grant, a visiting curator, collector or benefactor, the daily circulations and socializing of an artist: all these individual, material, ideal or financial movements constitute the raw material of this research. The notion of art mobility is here understood as the articulation between artists’ agency and spatial tactics on the on hand, and the material and institutional means of dealing with distance on the other hand. Art mobility questions the conditions, directions and meanings of these movements as much as the growth of the actors engaged

Avec le succès des communications sans fil, il devient possible d'accéder au réseau partout et à tout moment sans avoir recours à connecter physiquement les appareils communicants à une infrastructure. Les nœuds (ordinateurs portables, smartphones, etc) peuvent analyser les différents canaux radio afin de pouvoir s'associer à un réseau sans fil disponible (station de base, point d'accès, etc.). Un avantage indéniable de ses technologies sans fil est la possibilité d'être mobile tout en restant connecté. Cependant, la mobilité est une tâche difficile à gérer car elle doit être abordée à différentes couches pour être transparente aux utilisateurs. Dans les MANET (Mobile Ad hoc Network), les protocoles de routage utilisent des métriques pour sélectionner les meilleures routes. Les métriques peuvent refléter la qualité de la liaison sans fil et aider à gérer la mobilité.Mais, un retard important entre l'estimation des métriques et leur inclusion dans le processus de routage rend cette approche inefficace.Les travaux de cette thèse s'intéressent à la proposition de nouvelles méthodes de calcul des métriques de routage pour gérer le problème de la mobilité dans les réseaux ad hoc. Les nouvelles métriques doivent refléter la qualité du lien et être sensibles à la mobilité en même temps. Nous considérons les métriques classiques, en particulier ETX (Expected Transmission Count) et ETT (Expected Transmission Time). Nous introduisons de nouvelles méthodes pour anticiper les valeurs de ces métriques en utilisant des algorithmes de prédiction. Nous utilisons une approche Cross layer, qui permet l'utilisation conjointe de l'information à partir des couches 1, 2 et 3. La validation de nouvelles méthodes de calcul des métriques de routage nécessite une évaluation au travers d'un véritable banc d'essai. Nous avons donc également mis en œuvre les nouvelles métriques de routage dans un testbed afin d'évaluer et de comparer leurs performances avec les métriques classiques
With the success of wireless communications, it becomes possible to access the network anywhere at any time without the need for physically connect communicating devices in an infrastructure. The nodes (laptops, smartphones, etc.) can analyze different radio channels to be able to associate with an available wireless network (base station, access point, etc.). An undeniable advantage of wireless technologies is the ability to be mobile while staying connected. However, mobility is difficult to manage because it must be addressed at different layers to be transparent to users. In MANET (Mobile Ad hoc Network) routing protocols use metrics to select the best routes. The metric can reflect the quality of the wireless link and help manage mobility.But a significant delay between the estimate metrics and their inclusion in the routing process makes this approach ineffective.The work of this thesis are interested in proposing new methods for calculating routing metrics to manage the problem of mobility in ad hoc networks. The new metrics should reflect the quality of the link and be sensitive to the mobility simultaneously. We consider the classical metrics, particularly ETX (Expected Transmission Count) and ETT (Expected Transmission Time). We introduce new methods to predict the values of these metrics using prediction algorithms.We use a cross layer approach, which allows the joint use of information from layers 1, 2 and 3. The validation of new methods for calculating routing metrics requires evaluation through a real bench test. So we also implemented new routing metrics in a testbed to assess and compare their performance with classical metrics

Every day data communication networks carry more and more information, which sometimes is very important and needs to be delivered in time. To achieve that, data transfer networks must meet quality requirements that are formed in SLA contracts between clients and service providers. Supplied data transfer link’s quality is described by worldwide defined quality metrics, which include: one way delay, IP delay variation, link loss and round trip time. In order to measure these metrics, special software was created during projects “QoS monitoring system” first phase. This paper continues the project and explores available tuning methods for created software including time synchronization and mobility problems in order to provide better accuracy with higher mobility. New system topology and time offset correction using measurement packets were proposed during the analysis part. Possible system improvements were put to test in order to evaluate the efficiency during the experiment.

Les scènes urbaines, en raison de la richesse de leur contenu, présentent l'inconvénient de générer un flux d'informations visuelles qui sollicite en permanence le système visuel de l'automobiliste. On identifie, sous la terminologie de bruit visuel, la nuisance générée par un tel environnement pour détecter les signaux routiers. L'objectif de la thèse est la définition d'une métrique, automatique et objective, du bruit visuel des scènes urbaines nocturnes. On a fait l'hypothèse qu'il était possible d'estimer l'intensité du bruit visuel généré, par un environnement urbain nocturne, à l'aide d'un paramètre physique quantifiant sa complexité visuelle. On a recherché, parmi les techniques de traitements d'images, celles qui permettaient au mieux d'estimer la complexité visuelle d'un environnement urbain. Les méthodes suivantes de traitement d'images ont été étudiées : l'analyse de l'histogramme des luminances, des techniques d'analyse de texture et l'analyse par ondelettes. On a, également, proposé une méthode, inspirée du calcul de la luminance de voile, pour décrire la répartition radiale de zones à forte luminance autour du signal. Une méthodologie statistique associant l'analyse factorielle et l'analyse typologique, a été retenue pour comparer le pouvoir de discrimination de la complexité visuelle, offert par chacune de ces méthodes. La métrique du bruit visuel proposée regroupe l'ensemble de ces outils. On a ensuite validé l'hypothèse initiale en comparant l'évaluation subjective, par des observateurs, du niveau du bruit visuel généré par un environnement et l'évaluation objective et automatique proposée

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without the need for base stations or any other pre–existing network infrastructure. In a peer-to-peer fashion, mobile nodes can communicate with each other by using wireless multihop communication. Due to its low cost, high flexibility, fast network establishment and self-reconfiguration, ad hoc networking has received much interest during the last ten years. However, without a fixed infrastructure, frequent path changes cause significant numbers of routing packets to discover new paths, leading to increased network congestion and transmission latency over fixed networks. Many on-demand routing protocols have been developed by using various routing mobility metrics to choose the most reliable routes, while dealing with the primary obstacle caused by node mobility. ¶ In the first part, we have developed an analysis framework for mobility metrics in random mobility model. ... ¶ In the second part, we investigate the mobility metric applications on caching strategies and hierarchy routing algorithm. ...