Uppsatsen beskriver utveckling av medvetandets filosofi i science fiction mellan 1800-talet och mitten av 1900-talet. För analysen används Mary Shelleys Frankenstein och Isaac Asimovs the Bicentennial Man. Utvecklingen i science fiction går parallellt med utveckling inom filosofin. Utvecklingen går mot en fysikalisk lösning på kropp och medvetande problemet med argument från behaviorismen, identitetsteorin, samt funktionalismen.

<div>Today, networks contribute signicantly to everyone's life. The enormous usefulness of networks for various services and data storage motivates adversaries to launch attacks on them. Network Intrusion Detection Systems (NIDSs) are used as security measure inside the organizational networks to identify any intrusions and generate alerts for them. The idea of deploying an NIDS is quite known and has been studied and adopted in both academia and industry. However, most of the NIDS literature have emphasized to detect the attacks that originate externally in a wired network infrastructure. In addition, Wi-Fi and wired networks are treated the same for the NIDSs. The open infrastructure in Wi-Fi network makes it different from the wired network. Several internal attacks that could happen in a Wi-Fi network are not pos-</div><div>sible in a wired network. The NIDSs developed using traditional approaches may fail to identify these internal attacks.</div><div><br></div><div><div>The thesis work attempts to develop a Multi-Level Network Intrusion Detection System (ML-NIDS) for Wi-Fi dominant networks that can detect internal attacks specic to Wi-Fi networks as well as the generic network attacks that are independent of network infrastructure. In Wi-Fi dominant networks, Wi-Fi devices (stations) are prevalent at the edge of campus and enterprise networks and integrated with the fixed wired infrastructure at the access. The implementation is proposed for Wi-Fi dominant networks; nevertheless, it aims to work for the wired network as well. We develop the ML-NIDS using an ensemble learning method that combines several weak</div><div>learners to create a strong learner.</div></div><div><br></div>

Aujourd’hui, les appareils mobiles sont présents dans le monde entier. Ces appareils permettent aux utilisateurs d'accéder à l’Internet notamment par l'intermédiaire des réseaux WiFi. La diversité et le nombre de déploiements sans coordination centrale (y compris les utilisateurs à leur domicile) conduit à des déploiements qu’on peut qualifier de chaotiques. En conséquence, les réseaux WiFi sont largement déployés avec une forte densité dans les zones urbaines. Dans ce contexte, les utilisateurs et les opérateurs tentent d’exploiter ces déploiements pour obtenir une connectivité omniprésente, et éventuellement d'autres services. Cependant, pour tirer parti de ces déploiements, il faut des stratégies pour identifier les réseaux utilisables et choisir les plus adaptés aux besoins. Pour cela, nous étudions le processus de découverte des réseaux dans le contexte de ces déploiements. Ensuite, nous présentons une plateforme de partage de mesures sans fil, un système d'information collaboratif où les stations mobiles recueillent des mesures du réseau et les envoient à un système central. En rassemblant mesures provenant de différents utilisateurs, la plateforme donne accès à des caractéristiques du déploiement précieuses. Nous évaluons l'utilité de cette plateforme collaborative grâce à deux applications : (1) l’ensemble minimal de points d'accès, afin de réduire l'énergie nécessaire pour offrir une couverture WiFi dans une zone donnée. (2) l'optimisation des paramètres de recherche de réseau, afin de réduire le temps nécessaire pour découvrir les réseaux existants. Ensuite, nous étudions une méthode passive pour déterminer si un réseau fonctionne dans un canal saturé. / Nowadays, mobile devices are present worldwide, with over 4.40 Billion devices globally. These devices enable users to access the Internet via wireless networks. Different actors (e.g., home users, enterprises) are installing WiFi networks everywhere, without central coordination, creating chaotic deployments. As a result, WiFi networks are widely deployed all over the world, with high accesspoint (AP) density in urban areas. In this context, end-users and operators are trying to exploit these dense network deployments to obtain ubiquitous Internet connectivity, and possibly other services. However, taking advantage of these deployments requires strategies to gather and provide information about the available networks. In this dissertation, we first study the network discovery process within the context of these deployments. Then, we present the Wireless Measurements Sharing Platform, a collaborative information system, to which mobile stations send simple network measurements that they collected. By gathering and processing several network measurements from different users, the platform provides access to valuable characteristics of the deployment. We evaluate the usefulness of this collaborative platform thanks to two applications: (1) the minimal access point set, to reduce the energy needed to offer WiFi coverage in a given area.(2) The optimization of the scanning parameters,to reduce the time a mobile station needs for the network discovery. Finally, we describe a method to identify whether an AP operates ina saturated channel, by passively monitoring beacon arrival distribution.

Made available in DSpace on 2016-04-04T18:31:26Z (GMT). No. of bitstreams: 1 Marcelus Guirardello.pdf: 2153688 bytes, checksum: be50be16f89d021ebb7cf89fb146485c (MD5) Previous issue date: 2008-11-21 / This work presents a proposal of politic that prioritize the access to the wireless medium, considering environment conditions. The QoS policy considers the propagation conditions, through the analyze of the signal to noise ratio and type of service. The prioritization proposal considers each access category (AC) of the 802.11e standard, using queues with different priorities. The proposal uses the parameters specified by the 802.11e, through a dedicated firmware. This prioritization enables a new strategy for the QoS policy, for example to provide the station with the highest rate of transmission a biggest probability to access the medium. This work presents an experimental approach, through a channel emulator. The tests consider three different scenarios to evaluate the performance of the original MAC and the performance of queue priority, considering the effects of the parameters CWmin and AIFSN. The experiments developed in the work demonstrate the effectiveness of the proposed policy. / Este trabalho apresenta uma proposta de pol?tica que priorize o acesso sem fio ao meio, considerando as condi??es do ambiente. A pol?tica de QoS considera as condi??es de propaga??o, atrav?s da an?lise da rela??o sinal ru?do e do tipo de servi?o. A prioriza??o proposta considera o acesso cada categoria (AC), do padr?o 802.11e, utilizando filas com diferentes prioridades. A proposta utiliza os par?metros definidos pela 802.11e, atrav?s de um firmware dedicado. Essa prioriza??o possibilita uma nova estrat?gia para a pol?tica de QoS, por exemplo, para fornecer a uma esta??o com taxa mais alta maior probabilidade de acesso ao meio. Este trabalho apresenta uma abordagem experimental, atrav?s de um emulador de canal. Os testes consideram tr?s cen?rios diferentes para avaliar o desempenho da MAC original e do desempenho da prioriza??o de fila proposta, considerando os efeitos dos par?metros CWmin e AIFSN. As experi?ncias desenvolvidas no ?mbito do trabalho demonstram a efic?cia da pol?tica proposta.

Over the past few decades, wireless local area networks (WLANs) have been widely deployed for data communication in indoor environments such as offices, houses, and airports. In order to fairly and efficiently use the unlicensed frequency band that Wi-Fi devices share, the devices follow a set of channel access rules, which is called a wireless medium access control (MAC) protocol. It is known that wireless devices following the 802.11 standard MAC protocol, i.e. the distributed coordination function (DCF), suffer from packet collisions when multiple nodes simultaneously transmit. This significantly degrades the throughput performance. Recently, several studies have reported access techniques to reduce the number of packet collisions and to achieve a collision free WLAN. Although these studies have shown that the number of collisions can be reduced to zero in a simple way, there have been a couple of remaining issues to solve, such as dynamic parameter adjustment and fairness to legacy DCF nodes in terms of channel access opportunity. Recently, In-Band Full Duplex (IBFD) communication has received much attention, because it has significant potential to improve the communication capacity of a radio band. IBFD means that a node can simultaneously transmit one signal and receive another signal in the same band at the same time. In order to maximize the performance of IBFD communication capability and to fairly share access to the wireless medium among distributed devices in WLANs, a number of IBFD MAC protocols have been proposed. However, little attention has been paid to fairness issues between half duplex nodes (i.e. nodes that can either transmit or receive but not both simultaneously in one time-frequency resource block) and IBFD capable nodes in the presence of the hidden node problem.

Les Technologies d’Information et de Communication (TIC) facilitent la collecte et le traitement d’informations numériques, aussi nombreuses que variées, et sont de plus en plus sollicitées dans différents domaines (géographie, informatique, économie, statistiques etc.). La thèse a pour objectif de montrer les apports des TIC dans l’étude d’objets ou phénomènes géographiques dont la distribution est variable dans l’espace. Dans un premier temps, des inégalités territoriales de diffusion d’infrastructures Internet sont observées à différentes échelles, ce qui est communément appelé « la fracture numérique ». Pour remédier à ces inégalités, en particulier dans des espaces peu densément peuplés, la solution proposée est d’envisager une desserte maximale du territoire par la technologie non-filaire (Wi-Fi). Cette solution a été appliquée pour une commune drômoise (La Roche-sur-le-Buis). Les données (bâti) sont de type images et nécessitent un dispositif de repérage et de collecte approprié qui fait l’objet du second temps de la recherche. L’objectif a été de trouver une méthode relativement simple et accessible d’extraction de données du bâti sous un logiciel de géo-localisation en accès libre (type Google Earth). Ce logiciel permet d’accéder à des bases de données d’images raster grand public couvrant le monde entier. A une échelle fine, les méthodes habituelles de télédétection n’étant pas assez satisfaisantes, une autre méthode basée sur une stratégie de choix de la cible, de l’image (bonne résolution spatiale) et de la méthode de détection de l’objet spatial (bâti) à l’aide d’un Système d’Information Géographique (SIG) est proposée en mode vecteur. Elle est testée en France et en Syrie à différentes échelles. Les résultats montrent que la qualité de cette approche semi-automatique, voire automatique, est liée à certains paramètres dans les trois phases de la méthode : phase de choix des données, phase de traitement et phase d’analyse / The Information and communications technology (ICT) facilitate the collection and processing of digital information, both numerous and varied, and are increasingly used in various fields (geography, computer science, economics, statistics, etc.). This thesis aims to show the contribution of ICT to the study of geographical objects or phenomena whose distribution varies in space. Initially, the territorial inequalities dissemination of Internet infrastructure, are observed at different scales, which is commonly called « digital divide ». To address these inequalities especially in sparsely populated areas, the proposed solution is to consider a maximum coverage of the territory by non-wireline technology (Wi-Fi). This solution was applied to the case of a common selected Drôme (La Roche-sur-le-Buis). In this type of application, the data (built) are of the images and require a tracking device and the appropriate collection that is the subject of the second stage of research. The objective was to find a relatively simple and accessible data extraction software built in geo-location with free access (like Google Earth). This software allows access to databases of public and raster images covering the world. At a fine scale, the usual methods of remote sensing is not quite satisfactory, another method based on a strategy for target selection, image (good spatial resolution) and the detection method of the object space (built) using a Geographic Information System (GIS) is proposed in vector mode. It is tested in France and Syria at different scales. The results show that the quality of this approach semi-automatic or automatic is related to certain parameters in the three phases of the method: choice phase of data, processing phase and analysis phase

Pour un grand nombre d'applications, les sources laser impulsionnelles femtoseconde (fs) doivent fournir des puissances toujours plus importantes. En régime impulsionnel, on recherche d'une part une forte puissance crête par impulsion, et d'autre part une forte puissance moyenne, c'est à dire un taux de répétition élevé. Parmi les technologies existantes, les amplificateurs à fibre optique dopée ytterbium présentent de nombreux avantages pour l'obtention de fortes puissances moyennes, cependant le fort confinement des faisceaux dans la fibre sur de grandes longueurs d'interaction induit inévitablement des effets non-linéaires, et limite ainsi la puissance crête accessible. Nous avons étudié lors de cette thèse la combinaison cohérente d'impulsions fs appliquée aux systèmes fibrés. Ayant déjà fait ses preuves dans les régimes d'amplification continu et nanoseconde, la combinaison cohérente de faisceaux (dite combinaison spatiale) permet de diviser une seule et unique source en N voies indépendantes, disposées en parallèle et incluant chacune un amplificateur. Les faisceaux amplifiés sont ensuite recombinés en espace libre en un seul et unique faisceau, qui contient toute la puissance des N amplificateurs sans accumuler les effets non-linéaires. Cette architecture permet théoriquement de monter d'un facteur N le niveau de puissance crête issu des systèmes d'amplification fibrés. Au cours de cette thèse, nous avons démontré la compatibilité et l'efficacité de cette méthode en régime d'amplification fs avec deux amplificateurs, selon différents procédés. Les expériences démontrent d'excellentes efficacités de combinaison ainsi qu'une très bonne préservation des caractéristiques temporelles et spatiales initiales de la source. Les procédés de combinaison cohérente nécessitent cependant un accord de phase entre différents amplificateurs stable dans le temps, assuré en premier lieu par une boucle de rétroaction. Nous avons poursuivi notre étude en concevant une architecture totalement passive, permettant une implémentation plus simple d'un système de combinaison à deux faisceaux sans asservissement électronique. Enfin, une méthode passive de combinaison cohérente dans le domaine temporel est étudiée et caractérisée dans le domaine fs, et implémentée simultanément avec la méthode passive de combinaison spatiale proposée précédemment. Ces expériences démontrent la validité et la variété des concepts proposés, ainsi que leurs nombreuses perspectives pour les systèmes d'amplification fs fibrés.

Las comunicaciones multipunto ofrecen, tanto a usuarios como a proveedores, mayor eficiencia, permitiendo desarrollar e implantar nuevos servicios. Para poder desplegarlos adecuadamente sobre la redes de comunicaciones, es necesario contar con protocolos adecuados a todos los niveles.El soporte de conexiones multipunto, que es inmediato en muchas redes de ordenadores, por la existencia de un medio compartido, no lo es en una red ATM o en una red IP. En este tipo de redes, ofrecer una comunicación multipunto requiere de mecanismos complejos que coordinen y controlen la transmisión de información entre las fuentes y los receptores. Esta tesis doctoral estudia las comunicaciones punto a multipunto sobre las redes ATM e IP. En concreto, se diferencian dos objetivos: · Estudiar, analizar y proponer un control de flujo punto a multipunto en la categoría de servicio Available Bit Rate (ABR) en redes ATM.· Diseñar, analizar y simular un protocolo de transporte punto a multipunto fiable con control de congestión de tasa única para redes IP.El control de flujo de ABR fue diseñado para comunicaciones punto a punto. Para el caso multipunto, los conmutadores deben desarrollar mecanismos que limiten y agreguen el tráfico de realimentación. Se ha desarrollado un algoritmo de consolidación que asegura que la agregación de la información de realimentación se realiza de forma correcta, mejorando la convergencia de propuestas anteriores. Este mecanismo se ha modelado matemáticamente, y se ha validado mediante simulación.En cuanto a las comunicaciones multipunto en Internet, en este trabajo se ha desarrollado un protocolo de transporte punto a multipunto fiable, RCCMP, diseñado para ser escalable, fiable y con un control de congestión de tasa única que comparta el ancho de banda equitativamente con TCP.El control de congestión ha sido planteado como una parte esencial del protocolo, y no como ocurre en muchas propuestas, como un componente adicional que debe ser ajustado a un protocolo de transporte. En RCCMP se combinan los objetivos de regular la tasa de transmisión y de conseguir una comunicación fiable, con el fin de simplificar y limitar el número de confirmaciones negativas que se envían desde los receptores. Para la evaluación de las prestaciones de RCCMP, se ha implementado el protocolo en el simulador ns-2. Se ha modelado el caudal de este protocolo de transporte multipunto en función de la tasa de pérdidas y del tiempo de ida y vuelta. La principal contribución de nuestro modelo radica en la caracterización del caudal ante cambios de representante. También, se ha desarrollado un método de análisis para estimar el ancho de banda consumido por cualquier protocolo de transporte. La principal diferencia con otros trabajos es que éstos se centran únicamente en el coste de los procesos del control de errores.Para mejorar el rendimiento de RCCMP, se ha definido y simulado otro protocolo de transporte punto a multipunto fiable de tasa única, RVCMP, que incluye un control de congestión que emula al de la implementación TCP Vegas. / Multicast communications are profitable for service providers increasing intermediate node performance and reducing traffic in their networks. In the other side, multicast benefits also the users, who are able to enjoy collaborative applications and other multicast applications. IP and ATM network were designed to support point to point communications. The new multicast generation applications such multimedia conference, shared workspace, distance learning introduce new requirements in data transmission. There are at least two problems that differentiate between unicast and multicast control schemes in ATM networks with ABR service. First, there is the problem of feedback implosion. The volume of feedback traffic returning to the source increases proportional to the number of destinations. Second, there is the problem of consolidation noise. It can occur when feedback from some leaves is not always received in a timely fashion at the time when RM cells need to be returned by the branch point. One of the proposals to provide multicast communications is to extend unicast traffic management control methods. One of its practical realization schemes is the extension of Enhanced Proportional Rate Control Algorithm (EPRCA) for point to multipoint connections. That proposal suffers from consolidation noise, in order to solve this drawback, a new algorithm is proposed. An analytical approach is used to quantitatively evaluate their performance by using first-order fluid approximation method.About IP multicast communications, we propose a new protocol, called RCCMP (Reliable Congestion Controlled Multicast Protocol). It has been designed to be simple, scalable (NAK suppression), reliable and TCP-friendly. The congestion control is a central part of the protocol, where the feedback of the worse receiver is used to control a transmission window in a TCP-like fashion. The scalability issue is addressed with an exponential timer scheme that is also used to estimate the number of receivers involved in the communication. The protocol neither needs support from network elements nor maintains state information dependent of the number of receivers. This protocol has been developed in ns-2 (network simulator-2) for validating.We develop a simple analytic characterization of the steady-state send rate as a function of loss rate and round trip time (RTT). The main contribution is that our model captures the representative changes. Also, we provide a new approach to estimate the link usage of multicast reliable transport protocols. It can be used as a benchmark to evaluate their scalability. We have chosen, as a case study, a multicast reliable transport protocol called RCCMP. The link cost is due to data, retransmitted data, and characteristic packets of multicast protocols such as control packets: control packets for estimating the number of receivers involved in the session and for getting multicast reliability. For improving performance, we present RVCMP (Reliable Vegas Congestion controlled Multicast Protocol) that has been designed to be simple, scalable, reliable and TCP-friendly. The congestion control developed is a single-rate scheme where the feedback of the worst receiver is used to control a transmission window in a TCP Vegas-like fashion. The proposal takes the advantage from TCP Vegas of operating without inducing packet losses as a signal that there is congestion in the network to achieve a better performance. To evaluate the benefits of Vegas-like congestion control, the performance of RVCMP is compared to an analogous protocol that is based on a TCP Reno congestion control, RCCMP.

Emerging technologies such as Bluetooth and 802.11b (Wi-Fi) have fuelled the growth of the short-range communication industry. Bluetooth, the leading WPAN (wireless personal area network) technology, was designed primarily for cable replacement applications. The first generation Bluetooth products are focused on providing low-cost radio connections among personal electronic devices. In the WLAN (wireless local area network) arena, Wi-Fi appears to be the superior product. Wi-Fi is designed for high speed internet access, with higher radio power and longer distances. Both technologies use the same 2.4GHz ISM band. The differences between Bluetooth and Wi-Fi standard features lead to a natural partitioning of applications. Nowadays, many electronics devices such as laptops and PDAs, support both Bluetooth and Wi-Fi standards to cover a wider range of applications. The cost of supporting both standards, however, is a major concern. Therefore, a dual-mode transceiver is essential to keep the size and cost of such system transceivers at a minimum. A fully integrated low-IF Bluetooth receiver is designed and implemented in a low cost, main stream 0.35um CMOS technology. The system includes the RF front end, frequency synthesizer and baseband blocks. It has -82dBm sensitivity and draws 65mA current. This project involved 6 Ph.D. students and I was in charge of the design of the channel selection complex filter is designed. In the Bluetooth transmitter, a frequency modulator with fine frequency steps is needed to generate the GFSK signal that has +/-160kHz frequency deviation. A low power ROM-less direct digital frequency synthesizer (DDFS) is designed to implement the frequency modulation. The DDFS can be used for any frequency or phase modulation communication systems that require fast frequency switching with fine frequency steps. Another contribution is the implementation of a dual-mode 802.11b/Bluetooth receiver in IBM 0.25um BiCMOS process. Direct-conversion architecture was used for both standards to achieve maximum level of integration and block sharing. I was honored to lead the efforts of 7 Ph.D. students in this project. I was responsible for system level design as well as the design of the variable gain amplifier. The receiver chip consumes 45.6/41.3mA and the sensitivity is -86/-91dBm.

No description available.