Les réseaux de capteurs sans l (RCSF) sont des systèmes embarqués, autonomes, auto-con gurables, auto-organisables et déployés dans diverses applications de contrôle et de sécurité. Dans leur architecture, les batteries de ces capteurs ne peuvent en aucun cas être remplacées ou chargées. Pour cela, il faut penser à réduire l'énergie consommée lors de la capture, du traitement et de la transmission de données. Devant la diversité des problèmes qui se posent dans les RCSF, le challenge de la consommation de l'énergie est toujours abordé dans divers travaux de recherche en vue d'optimiser la consommation d'énergie et de maximiser la durée de vie du réseau. A cet effet, nous avons évoqué l'axe des technologies et standards implémentés dans ces capteurs, en vue de révéler leurs impacts sur la consommation d'énergie. Ensuite, nous avons soulevé les techniques de localisation affectant à leur tour cette énergie, notamment lors de l'utilisation de GPS (Global Positioning System), considéré comme solution gourmande en énergie. Le volet de sécurité a été abordé, vu qu'il se base sur la technique de la cryptographie et ôte pour la gestion des clefs pour assurer la communication entre les noeuds du réseau. Cette technique est connue par son traitement aggravé épuisant davantage l'énergie du capteur, devant la coexistence d'une multitude d'attaques qui visent la mort prématurée du réseau. Au niveau routage, la problématique d'énergie perdue lors de l'utilisation des mécanismes de découverte de routes, ouvre un champ très fertile, que nous avons attaqué, pour la conception d'algorithmes optimisés et protocoles de routage qui économisent mieux l'énergie de diffusion des messages RREQ (Route REQuest). Notre but principal dans cette thèse, est de répondre à l'ensemble de ces dé s en agissant sur les fonctionnalités d'un capteur, notamment celle de localisation, de sécurité, de routage ainsi que celle qui concerne la technologie adoptée pour assurer la communication. Des applications ont été envisagées pour mettre en place ces fonctionnalités en l'occurrence le transport, la santé, la domotique, l'industrie et le maritime. C'est ainsi que nous présentons des travaux qui favorisent une meilleure con figuration de ces fonctionnalités, tout en octroyant plus d'intérêt à des solutions qui optimisent de plus en plus la consommation de l'énergie de la batterie des capteurs, pour leur permettre une longue longévité et de pro ter pleinement de leurs avantages.

Wireless multi-hop relay systems are the newest amendment to the IEEE 802.16 standard for local and metropolitan area networks, else known as WiMAX. Relay systems come in different flavours, based on their capabilities and have the potential to offer many advantages over the single-hop technology. Upcoming broadband wireless technologies, that utilize multi-hop relays, need good network planning and design in order to achieve their full potential. There are two main types of multi-hop relay stations: transparent, which are not able to transmit control information and non-transparent, which have the capability to transmit such information. This study focuses mainly on non-transparent relay stations due to their complexity and ability to operate in a more than two hop environment. Currently, the latest IEEE amendment provides two different frame structures − single and multi-frame − for utilization in multi-hop relay networks, to allocate bandwidth. The purpose of this thesis is to evaluate the two proposed frame structures, in various network scenarios in terms of delay, throughput, rate, and user capacity. In addition, we will discuss some of the issues that need to be considered to cost effectively plan and design a multi-hop relay network. The evaluation methodology that we utilize is in accordance with the Multi-hop Relay System Evaluation Methodology developed by the IEEE 802.16 Broadband Wireless Access Working Group. To evaluate the above frame structures we developed an evaluation model for use in the network simulator 2 (ns2) from University of California Berkeley, by modifying the light WiMAX (LWX) add-on from Taiwan University. Unlike the original LWX module, which supports only transparent relay configurations, our module supports both multi-frame and single frame structures, as well as non-transparent multi-hop relay environments. To our knowledge there is no previous work, which analyzes the performance of the single frame and multi-frame system in multi-hope relay environments using the guidelines from the latest amendment to the standard (IEEE 802.16j-2009). Moreover, there is no publicly available software that will enable the study of such performance. The resulting source code of our work has been made publicly available and can be obtained from our website. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-09-09 23:55:00.995

Le virus respiratoire syncytial (RSV) est un virus à ARN de polarité négative. Les études démontrent que toute la population sera infectée par ce virus au moins deux fois avant l’âge de 3 ans. Le RSV peut provoquer plusieurs pathologies respiratoires telles que la bronchiolite aiguë et la pneumonie. Les infections sévères corrèlent avec le développement de l’asthme. Lors d’une infection virale, les particules du RSV sont détectées par le senseur RIG-I qui induit l’activation des facteurs de transcription NF-κB et IRF-3. Respectivement, les facteurs de transcription activeront les réponses inflammatoire et antivirale. Au coeur des pathologies induites par le RSV se trouve une réponse immunitaire mal adaptée. Plus précisément, par l’entremise de NF-κB, le RSV provoque une production exagérée de cytokines et chimiokines qui induisent une réponse inflammatoire démesurée provoquant du dommage tissulaire. Paradoxalement, le RSV est capable d’échapper à la réponse antivirale. Ces deux phénomènes sont contrôlés par l’entremise des protéines non structurales NS1 et NS2. Le mécanisme délimitant le mode d’action de NS1 et NS2 sur la réponse antivirale reste à être déterminé. Avec pour objectif d’élucider comment NS1 et NS2 inhibent la réponse antivirale, nous avons investigué le mécanisme de reconnaissance de l’hôte vis-à-vis de RSV. Nous démontrerons, pour la première fois, que le senseur cytosolique MDA5 est impliqué dans la réponse antivirale contre le RSV. Nous présenterons des résultats préliminaires qui suggèrent que le rôle de MDA5 est non redondant à RIG-I. À l’aide d’ARN interférant dirigé contre RIG-I et de transfection de MDA5, nous démontrerons que MDA5 ne contribue pas à la phosphorylation d’IRF-3, mais plutôt qu’elle régit la stabilité du facteur de transcription. Nous démontrerons aussi que, contrairement à l’hypothèse actuelle sur le fonctionnement de NS1 et NS2, l’inhibition de ces derniers ne provoque pas une augmentation de la cytokine antivirale IFN−β. Cependant, l’expression ectopique de NS1 et NS2 réduit l’activité du promoteur de l’IFN-β et de la protéine cytoplasmic antivirale ISG56 lorsqu’elle est mesurée par essai luciférase. / Respiratory Syncytial Virus (RSV) is a RNA virus with negative polarity. RSV infections are the most common cause of hospitalization among infants. Among populations at risk, infection of RSV can be quite severe. RSV infections can cause bronchiolitis, pneumonia, while severe infections are linked to the development of asthma. Early in the infectious cycle of RSV, the cytosolic sensor RIG-I captures viral particles, and activates the immune response by engaging the transcription factors IRF-3 and NF-κB. At the heart of RSV mediated pathologies is a skewed immune response. More precisely, RSV over stimulates the release of proinflammatory chemokines and cytokines. Intriguingly, while RSV is able to stimulate the production of proinflammatory cytokines and chemokines, RSV under stimulates the antiviral response. The ability of RSV to evade the antiviral response is thought to be mediated by its non-structural proteins: NS1 and NS2. However, the mechanism by which NS1 and NS2 enable RSV to evade the antiviral response remains to be determined. In this memoir we investigated, how RSV is recognized by the innate immune response in airway epithelial cells. With this information we hope to improve our understanding of how NS1 and NS2 allow RSV to circumvent the antiviral response. We show for the first time that cytosolic sensor MDA5 plays a role in the recognition of RSV particles. Using a combination of interfering RNA directed against RIG-I, and transfection of MDA5, we show that MDA5 does not contribute to the phosphorylation of IRF-3. According to the data presented, we suggest that MDA5’s role in the immune response is to prevent the degradation of IRF-3. Contrary to previous research, we show that the inhibition of the nonstructural protein does not increase the production of the antiviral cytokine IFN-β. However, the ectopic expression of NS1 and NS2 does lead to a reduction of the promoter activity of IFN-β and the antiviral protein ISG56 when measured by luciferase assay. This research highlights the importance of MDA5 as a potential therapeutic target in the development of a cure for RSV.

The aim of the study is to investigate what impact the use of VPN has on network performance. An empirical investigation using quantitative research methods was carried out. Two sample scenarios were involved in the study: scenario without VPN and scenario with VPN. In both scenarios, three applications were used in turns, an HTTP, an FTP, and a CBR. FTP was configured to use window size and packet size, while CBR used connection rate and packet size. On the other side, the number of connection was the only parameter used for HTTP. These applications were injected in a 100 Mbps fixed link of an NS2 simulation environment. Throughput and delay averages were measured respectively for the two scenarios and values compared using Student’s t-test. While the TCP and HTTP throughputs were found decreasing, the UDP throughput was not affected by the presence of this VPN. Concerning the delay; the TCP, UDP and HTTP delay were found increasing. / Electrical Engineering / M. Tech. (Electrical Engineering (Computer Systems))

The master's thesis solve the problem of setting new TCP variants for high-speed IP networks. The first goal was to describe in detail the behaviour of TCP and then analyse a problem of utilization the available bandwidth with standard TCP in high-speed network. Work consequently deals with selection and description the most perspective ones. Further the reader is familiarized with reasonable simulation tools of existing problems and their brief description. Main part of this thesis presents examination of performance of new TCP variants for high-speed network. During the examination the aspects on efficiency and fairness of competition flows on shared bottleneck are taken. The results are tabularly displayed plus compared with each other.

The development of ubiquitous mobile computing devices has fueled the need for dynamic reconfigurable networks. Mobile ad-hoc network (MANET) routing protocols facilitate the creation of such networks, without centralized infrastructure. One of the challenges in the study of MANET routing protocols is the evaluation and design of an effective routing protocol that works at low data rates and responds to dynamic changes in network topology due to node mobility. Several routing protocols have been standardized by the Internet Engineering Task force (IETF) to address ad-hoc routing requirements. The performance of these protocols are investigated in detail in this thesis. A relatively new approach to ad-hoc routing using the concept of a Minimal Connected Dominating Set (MCDS) has been developed at Virginia Tech. The OSPF-MCDS routing protocol is a modified version of the traditional Open Shortest Path First (OSPF) wired routing protocol which incorporates the MCDS framework. Enhancements to the protocol implementation to support multiple-interface routing are presented in this thesis. The protocol implementation was also ported to ns-2, a popular open source network simulator. Several enhancements to the implementation and simulation model are discussed along with simulation specifics. New scenario visualization tools for mobility pattern generation and analysis are described. A generic framework and tutorial for developing new ad-hoc routing simulation models are also presented. The simulation model developed is used to compare the performance characteristics of OSPF-MCDS to three different standardized MANET routing protocols. Simulation results presented here show that no single protocol can achieve optimal performance for all mobility cases. Different observations from simulation experiments are summarized that support the likely candidate for different mobility scenarios. / Master of Science

La dissémination d’information dans les réseaux VANET est une opération fondamentale pour la sécurité routière. Il est dès lors nécessaire de concevoir et mettre en oeuvre des algorithmes efficaces et adaptatifs pour la dissémination d’informations sélectives et pertinentes.Dans ce travail, des approches Bio-inspirées sont proposées, à partir des comportements auto-organisés des essaims comme les colonies de fourmis et d’abeilles. Ces approches visent à fournir à chaque véhicule des informations en provenance de son environnement et alerter les conducteurs. Dans la première approche, le système de communication direct et indirect des fourmis est utilisé. Les fourmis partagent les informations sur les sources de nourriture avec des membres de la colonie en sécrétant la phéromone sur leurs chemins. La deuxième approche est inspirée par le système de communication des abeilles. Les abeilles partagent les informations à propos des sources de nourriture avec les autres membres de la ruche par des messages spécifiques, selon l’importance de ces sources.Une nouvelle mesure de "pertinence" associée aux messages est définie, par analogie à la sécrétion des phéromones des fourmis et au niveau de l’intensité des messages pour les abeilles, pour disséminer des informations de sécurité dans une zone géographique. Les simulations sont effectuées en utilisant le simulateur NS2 pour mesurer l’efficacité des approches proposées sous différentes conditions, en particulier en termes de densités et vitesses des véhicules. / Information dissemination in Vehicular Ad hoc Networks (VANETs) is a fundamental operation to increase the safety awareness among vehicles on roads. Thus, the design and implementation of efficient and scalable algorithms for relevant information dissemination constitutes a major issue that should be tackled.In this work, bio-inspired information dissemination approaches are proposed, that use self-organization principles of swarms such as Ant and Honey Bee colonies. These approaches are targeted to provide each vehicle with the required information about its surrounding and assist drivers to be aware of undesirable road conditions. In the first approach, Ant’s direct and indirect communication systems are used. Ants share information about food findings with colony members by throwing pheromone on the returning to the nest. The second, an RSU-based approach is inspired by the Bee communication system. Bees share profitable food sources with hive-mates in their hive by specific messages.A “relevance” value associated to the emergency messages is defined as an analogue to pheromone throwing in Ant colony, and as an analogue to profitability level in Bee colony, to disseminate safety information within a geographical area. Simulations are conducted using NS2 network simulator and relevant metrics are evaluated under different node speeds and network densities to show the effectiveness of the proposed approaches.

[pt] Cada vez mais as redes locais sem fio conhecidas por WLAN estão presentes no meio em que vivemos, seja em nossas casas como em escritórios, aeroportos e outros locais públicos. Na busca de possibilitar que mais aplicações sejam viabilizadas pelas redes sem fio, tais como fluxos de vídeo, a qual requer uma maior largura de banda, o IEEE desenvolveu um novo padrão da família do 802.11, o IEEE 802.11n que é capaz de oferecer uma capacidade de transmissão significativamente maior que os padrões 802.11 anteriores. Em principio, o grande aumento de capacidade na camada física deveria ser suficiente para oferta de aplicações de multimídia, inclusive com vídeo em alta definição. Entretanto, a baixa eficiência da camada de controle de acesso ao meio (camada MAC) e de alguns protocolos da camada física poderiam restringir o uso de aplicações que necessitam de altas taxas de transmissão. Para resolver essa questão o padrão 802.11n contempla o recurso de agregação dos quadros que possui dois métodos distintos, A-MPDU (Aggregated MAC Protocol Data Unit) e A-MSDU (Aggregated MAC Service Data Unit). Neste trabalho foram realizadas simulações com sinais de vídeos reais e apresentados resultados que permitem comparar o desempenho destes métodos e avaliar se o uso de agregação permite efetivamente que o padrão 802.11n atenda os requisitos da transmissão de vídeo. Foram também sugeridos valores para os parâmetros da tecnologia 802.11n que permitem que um melhor desempenho seja alcançado. / [en] Wireless LANs are gradually playing an increasingly important role in our day-to-day life. It is common now to find them in airports, hotels, office buildings as well as in individual residences. Due to this success there was an effort at IEEE to develop a new standard that would allow new high data rate applications, such as video streaming, to be provided through a WiFi access point. This new standard added to the IEEE 802.11 family is known as IEEE 802.11n and it offers a significantly higher capacity physical layer. However, to derive the full benefits of this new very powerful physical layer it was necessary to improve the efficiency of the MAC layer as well as of some physical layer protocols. One of techniques included in the standard, to allow high bandwidth services with good quality, was frame aggregation. The 802.11n standard contemplates two forms of aggregation, namely: A-MPDU (Aggregated MAC Protocol Data Unit) and AMSDU (Aggregated MAC Service Data Unit). In this work, simulations were performed to evaluate the performance of both methods of aggregation when transporting real video signals. The objective was to verify whether 802.11n, with the use of aggregation, can indeed provide video and multimedia services with the required quality. We also suggest values for 802.11n system parameters that provide improved performance.

The aim of this work is to become familiar with simulation environment Network Simulator 2, study the problems of sensor networks and their support in the simulator and implement the selected protocol and verify its funcitonality in a practical simulation.

Les réseaux de capteurs sans fil (RCSFs) sont constitués d’un grand nombre de noeuds de capteurs qui sont généralement alimentés par batterie et conçu pour fonctionner pendant une grande période. Les domaines d’application sont nombreux et variés, tel que le domaine environnementale, médicale et militaire.L’atout majeur de ce dispositif est un déploiement à grande échelle sans aucune maintenance. Les capteurs n’ont pas besoin d’une infrastructure établie pour parvenir à transmettre des données vitales à l’étude de l’environnement. Il est nécessaire également de garantir une bonne qualité de service, car les réseaux de capteurs sans fils doivent intégrer des mécanismes qui permettent aux utilisateurs de prolonger la durée de vie du réseau en entier, car chaque noeud est alimenté par une source d’énergie limitée et généralement irremplaçable.C’est pourquoi, il est nécessaire d’optimiser la consommation d’énergie à tous les niveaux de conception de ce type de réseau. Par conséquent, la minimisation de la consommation d’énergie est un facteur de conception des plus importants dans les réseaux de capteurs.Le but de cette thèse est étudier les différents techniques de routages existant dans un contexte sans fil multi-saut afin d’obtenir de meilleures performances. Nous portons notre étude sur les protocoles de routages les plus connus afin de proposer dans une deuxième partie un nouveau protocole de routage permettant d’optimiser la consommation d’énergie dans les réseaux de capteurs sans fil, en gardant une qualité de service optimale. / Wireless sensor networks (WSNs) are composed of a large number of sensor nodes that are typicallybattery-powered and designed to operate for a long period. Application areas are many and varied, such as the environmental field, medical and military.The major advantage of this device is a large-scale deployment without any maintenance. The sensors do not need to achieve an established infrastructure to transmit vital data to the study of the environment. It is also necessary to ensure good quality service, because without son sensor networks must incorporate mechanisms that allow users to extend the life of the entire network, as each node is supplied by a limited power source and generally irreplaceable. Therefore, it is necessary to optimize the power consumption at all levels of design of this type of network. Accordingly, minimization of power consumption is one of the most important design factors in sensor networks.The aim of this thesis is study the different existing routing techniques in a context without multi-hop son to get better performance. We carry our study of the most popular routing protocols to offer in a second part a new routing protocol for optimizing energy consumption without son sensor networks, keeping an optimal quality of service.