Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-06-18T13:33:01Z No. of bitstreams: 1 Dissertação- Daniel da Costa Bottencourt.pdf: 3937728 bytes, checksum: 07fb74a6a3bf5522f79663c19c839ab5 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-18T20:32:47Z (GMT) No. of bitstreams: 1 Dissertação- Daniel da Costa Bottencourt.pdf: 3937728 bytes, checksum: 07fb74a6a3bf5522f79663c19c839ab5 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-19T20:44:46Z (GMT) No. of bitstreams: 1 Dissertação- Daniel da Costa Bottencourt.pdf: 3937728 bytes, checksum: 07fb74a6a3bf5522f79663c19c839ab5 (MD5) / Made available in DSpace on 2015-06-19T20:44:46Z (GMT). No. of bitstreams: 1 Dissertação- Daniel da Costa Bottencourt.pdf: 3937728 bytes, checksum: 07fb74a6a3bf5522f79663c19c839ab5 (MD5) Previous issue date: 2013-03-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / New protocols and network technologies must be substantiated in performance evaluations so it behavior and e_ciency should be very_ed and proven. In Delay Tolerant Netorks - DTN there is a lack of tools where these performance evaluations can be developed. Such lack makes researchers often being using small scale real networks or one of the few DTN simulators available. This work presents a diferentiated approach on conducing performance evaluations in DNT that is based on a recent movement of the scienti_c community towards the usage of hybrid enviroments, based on the bene_ts and on the growth of virtualization techonologies. We propose and implemente an enviroment for performance evaluation of DTN, based on virtualization and completely implemented in software, that takes into account the node's mobility and the replication of the sthocastic characteristics of wireless networks between them. As results we obtain a correct reprodution of contats that were observed in a real netwok, the identi_cation of new ones from thre data traces used and the error estmation between the two testbeds. / Novos protocolos e tecnologias de redes devem estar embasados em avalia ções de desempenho para que seu comportamento efe c acia sejam veri cados e comprovados. Em redes DTN (Delay Tolerant Networks), h a uma carência de ferramentas por meio das quais essas avalia ções de desempenho são realizadas, recorrendo-se principalmente a solu ções de redes reais em pequena escala ou a utiliza ção dos poucos simuladores DTN existentes. Este trabalho apresenta uma abordagem diferenciada para a realiza ção de avaliações de desempenho em redes DTN que se baseia em um movimento recente no meio cientifi co de utiliza ção de ambientes h íbridos, valendo-se das vantagens e do crescimento das tecnologias de virtualiza ção. Propomos e implementamos um ambiente para avalia ção de desempenho em DTN baseado em virtualiza ção e totalmente implementado em software, que leva em consideração a mobilidade dos n os e a replica ção das caracer sticas estoc asticas de redes sem- o entre os mesmos. Como resultados obtemos a correta reprodu ção da ocorrência de contatos observada em uma rede real, a identi ca ção de novos contatos baseados nos traces utilizados e a estimativa do erro entre os dois ambientes de teste.

Magíster en Ciencias, Mención Computación. Ingeniera Civil en Computación / Establecer canales de comunicación confiables en minas subterráneas es crucial para poder llevar a cabo operaciones eficientes y seguras; sin embargo, las condiciones extremas propias del entorno y la topología de túneles dificultan la comunicación y limitan su fiabilidad. Actualmente, no existe una estrategia única que sea capaz de solucionar la totalidad de obstáculos que implica el establecimiento de canales de comunicación subterráneos, lo que ha conllevado una demora en la incorporación de nuevas tecnologías ya probadas y asimiladas en la minería a rajo abierto, incluyendo la automatización de las operaciones y el monitoreo remoto. En este trabajo, se propone el uso de Redes Tolerantes al Delay (DTN por sus siglas en inglés) en minas subterráneas, las que pueden proveer de un sistema de comunicaciones robusto con requerimientos mínimos de infraestructura y sin interferir en las operaciones regulares de minería, a través de la utilización de operadores y máquinas como nodos móviles. Dado que el desempeño de los protocolos DTN es condicional al escenario en donde se utilizan, se propone un modelo de movilidad sintético, Simple Mine Area (SMA), para capturar las interacciones básicas entre nodos en minas subterráneas y ser utilizado como banco de pruebas para el diseño y evaluación de protocolos. Con el objeto de mejorar el desempeño del enrutamiento en DTNs y enriquecer los datos recopilados en los nodos, se propone una estrategia de posicionamiento para ambientes subterráneos basado en la generación de mapas locales utilizando las distancias entre los nodos móviles y un número reducido de nodos estáticos. Esta estrategia provee una aproximación de la posición de los nodos móviles en entornos donde los servicios como GPS no están disponibles. El protocolo de enrutamiento propuesto, MineProp, utiliza la estrategia de posicionamiento previamente descrita, obteniendo latencia y tasa de entrega comparables con protocolos DTN modernos con un costo de entrega (overhead) reducido; estas propiedades, junto a una alta configurabilidad que permite mejorar el desempeño de distintas métricas según lo requerido por los distintos servicios y las topologías propias, convierten a MineProp en un candidato apropiado para el establecimiento de canales de comunicación subterráneos.

Cette thèse étudie la faisabilité de la diffusion de contenu sur un réseau tolérant aux délais (DTN) dans une zone urbaine. L'application cible est la distribution de la version électronique d'un journal dans une grande ville. Bien que des contraintes de temps ne s'appliquent pas de manière stricte, il est tout de même attendu que la diffusion d'information se fasse dans un délai raisonnable. Deux métriques de performance sont considérés~: le délai de message et le temps de propagation. Le délai de message est le délai nécessaire pour transmettre un contenu à partir d'un n{\oe}ud mobile à un autre n{\oe}ud, tandis que le temps de propagation est le délai nécessaire pour diffuser un contenu sur un ensemble de n{\oe}uds du réseau. Premièrement, notre objectif est de mesurer de manière analytique les performances d'un environnement DTN simple lorsqu'un contenu est distribué exclusivement à travers des contacts entre les n{\oe}uds mobiles. Nos contributions résultent de la prise en compte de la probabilité d'intérêt/acceptation dans l'expression en forme fermée et l'expression asymptotique du délai moyen de message. La probabilité d'intérêt/acceptation représente la probabilité qu'un contenu soit accepté par un n{\oe}ud qui manifeste de l'intérêt pour ce contenu lors d'un contact. L'expression asymptotique permet de déterminer des moyens efficaces d'améliorer le délai moyen de messages dans une zone où la densité des n{\oe}uds mobiles est basse ou haute. Nous montrons aussi une relation entre le délai moyen de message et le temps moyen de propagation dans de tels environnements. Deuxièmement, si le délai est jugé excessif, nous suggérons un déploiement de kiosques de données dans l'environnement afin d'améliorer les performances de la diffusion de contenu. Les kiosques de données sont des dispositifs simples qui reçoivent les contenus directement depuis leur source, le plus souvent en utilisant des réseaux filaires ou cellulaires. Un des problèmes posés pour concevoir efficacement un tel réseau est le nombre de kiosques de données qu'il faut déployer pour satisfaire aux objectifs de performance. Pour répondre à ce problème, nous déterminons les valeurs de la borne supérieure et de la borne inférieure du nombre de kiosques de données nécessaires pour distribuer le contenu dans une zone géographique en optimisant un temps moyen de propagation pris comme objectif. Nous montrons aussi une propriété importante que ces bornes varient linéairement avec le taux de contact entre un n{\oe}ud mobile et un kiosque de données. Enfin, nous considérons le problème de l'emplacement optimal des kiosques de données dans un scénario plus réaliste où les utilisateurs se déplacent en utilisant un système de transport (comme le métro ou le train de banlieue) qui relie plusieurs régions. Nous analysons le choix des stations de métro où installer un kiosque de données pour optimiser le temps moyen de propagation. Les résultats de l'analyse confirment que l'emplacement optimal des kiosques de données n'est pas seulement influencé par les caractéristiques d'une région, mais aussi par le nombre d'utilisateurs mobiles qui recevront le contenu. Nous validons nos résultats analytiques par des simulations en prenant différents modèles de mobilité ainsi que des données de mobilité résultant de mesures réelles.

The present dissertation deals with how to use the precious wireless resources that are usually wasted by under-utilization of networks. We have been particularly interested by all resources that can be used in an opportunistic fashion using different technologies. We have designed new schemes for better and more efficient use of wireless systems by providing mathematical frameworks. In the first part, We have been interested in cognitive radio networks, where a cellular service provider can lease a part of its resources to secondary users or virtual providers. In the second part, we have chosen delay-tolerant networks as a solution to reduce the pressure on the cell traffic, where mobile users come to use available resources effectively and with a cheaper cost. We have focused on optimal strategy for smartphones in hybrid wireless networks. In the last part, an alternative to delay-tolerant networks, specially in regions that are not covered by the cellular network, is to use Ad-hoc networks. Indeed, they can be used as an extension of the coverage area. We have developed a new analytical modeling of the IEEE 802.11e DCF/EDCF. We have investigated the intricate interactions among layers by building a general cross-layered framework to represent multi-hop ad hoc networks with asymmetric topology and traffic

DTN(Delay Tolerant Networks)是一種缺乏網路基礎設備的網路架構，在這類的網路架構下，無線節點之間的通訊連線並非同時存在，而是間歇式建立的。因為節點的移動、或是裝置省電模式運作與環境因素的影響，造成連線可能不定時的失效。有不保證連線特性的網路，在DTN網路中節點間相遇的機會很少，節點間利用 Store-Carry-Forward 的方式傳遞訊息，且有相當長的傳遞延遲(Propagation Delay)。在這樣的網路特性下，傳統的文獻中，都是假設所有節點都會幫忙傳遞。但不幸的，在現實生活中有自私節點(Selfish Nodes)的存在，因自己本身設備資源有限，如電力資源、網路資源...等，節點不願意幫忙傳送訊息，這些自私節點的存在，會對DTN網路架構造成破壞，導致無法傳送訊息到目的地。為了解決自私節點的問題，我們提出了MTBIS(Mobile Trusted Bank of Incentive Strategies)，當發送節點(Source Node)要求傳送訊息時，給予回饋給幫忙轉傳訊息的節點，來鼓勵節點間互相幫忙傳送訊息，我們稱這些回饋為Incentive Credit。而節點也可利用Incentive Credit來要求別的節點幫忙轉傳訊息。另外也加入SI(Social Incentive)機制，與DGT(Dynamic Grudger Threshold) ，吸引自私節點願意幫忙轉傳訊息，改進了 MTBIS 在自私節點環境下的不足， 利用經濟學的角度來解決節點運用Credit的問題，借此提高訊息的傳遞率(Delivery Ratio)。 本篇研究也注重於自私節點的模擬，利用四種不同特性的節點： Sucker(傻瓜)、Cheater (騙子)、Grudger(小氣鬼)、Ecci(投機者)， 這些自私節點會照成DTN在設計上無法使用，甚至降低訊息的傳達率，因此我們模擬了這些自私節點的行為，並且使用我們所提出的獎勵機制，來解決這些自私節點的問題，實驗結果也證明，Grudger可以有效的抑制自私節點對效能大幅降低的問題，與傳統的演算法相較，效能高出34%。 / DTN (Delay Tolerant Networks) is a network structure without need to use any infrastructure. In DTNs, wireless connections between nodes do not always exist, i.e., nodes are connected intermittently. Due to the mobility, power issues, or surrounding environment of nodes, connections between nodes may be disruptive occasionally or randomly. In a DTN, nodes usually transfer the message to the encountering nodes. By this way, the messages are stored, carried, and forwarded to the next nodes, possibly the destination. However, in reality, nodes may not be willing to help each other for the message forwarding. More specifically, there are “Selfish nodes” which refuse to forward messages due to issues such as energy and network bandwidth. Thus it will prevent messages from being forwarded to its destination. In order to solve the problem of message forwarding failure caused by selfish nodes, we proposed an Incentive Strategy called “MTBIS (Mobile Trusted Bank and Incentive Strategies)”. We construct a rewarding scheme called “Incentive Credit” for nodes who forward the messages for the source node. In addition, to increase the intention of the selfish nodes for forwarding messages, we add two more mechanism called SI(Social Incentive) and DGT(Dynamic Grudger Threshold). The DGT uses credits to solve selfish node problems from an economics point of view to enhance MTBIS to work with existence of selfish nodes. In this thesis, we emphasis on the simulation of the behaviors of selfish nodes, using four different types of nodes: the “Sucker”, the “Cheater”, the “Grudger”, and the “Ecci”. These selfish nodes will decrease the success rate of message forwarding, and even make the DTN unusable. We simulated the behaviors of these selfish nodes, using the rewarding scheme we proposed. From the results of our experiment, we see that the Grudger can effectively deal with performance issues caused by selfish nodes, and the system can gain 34% in performance compared to the traditional algorithms.

Στην παρούσα διπλωματική εργασία παρουσιάζεται μια νέα αρχιτεκτονική δικτύων που ονομάζεται DTN,για δίκτυα τα οποία αντιμετωπίζουν δυσκολίες στην επικοινωνία και στη συνδεσιμότητα των κόμβων τους. Τα δίκτυα αυτά αντιμετωπίζουν τέτοιες δυσκολίες λόγω του δυσμενoύς περιβάλλοντος στο οποίο βρίσκονται,όπως για παράδειγμα ένα δίκτυο στο διάστημα. Έτσι προχωρήσαμε στο σχεδιασμό ενός δικού μας DTN δικτύου που ονομάζεται planet-ece επιλέγοντας την DTN2 υλοποίηση του πρωτοκόλλoυ bundle για τους κόμβους μας καθώς είναι ιδανικότερη για όποιον θέλει να πειραματιστεί. Η ανάπτυξη αυτού του δικτύου έγινε με σκοπό να ερευνηθούν θέματα όπως της διαχείρισης ενός τέτοιου δικτύου (network management) και της ασφάλειας του (security).Βασιζόμενοι τώρα στο εγκατεστημένο πια DTN δίκτυό μας planet-ece και αφού έχει ελεγχθεί η σωστή του λειτουργία, το επόμενο βήμα ήταν να υλοποιηθεί ένας μηχανισμός παρακολούθησης (moniroting), ο οποίος θα μας επιτρέπει να εποπτεύουμε την κατάσταση του δικτύου και της ανταλλασόμενης κίνησης σε επίπεδο DTN. Έπειτα προχωρήσαμε στην υλοποίηση ενός συστήματος παρακολούθησης έξυπνων καμερών μέσω του DTN δικτύου μας planet-ece. Σε αυτή την υλοποίηση λοιπόν, αξιολογούμε την ασφάλεια και τη συμπεριφορά του συστήματος, εστιάζοντας στην επικοινωνία μέσω του δικτύου DTN με σκοπό να εκτιμήσουμε πώς συμπεριφέρεται ένα τέτοιο δίκτυο σε διάφορες πιθανές καταστάσεις, από γεγονότα και δικτυακή διαθεσιμότητα, με ή χωρίς ασφάλεια και σε σύγκριση με υπάρχουσες μεθόδους επικοινωνίας. / This thesis presents a new network architecture called DTN, for networks with difficulties in communication and connectivity. These networks are facing such difficulties due to extreme environmental surroundings, such as a network in space. So we proceeded to design our own DTN network called planet-ece selecting DTN2 implementation of Bundle Protocol for our nodes because is ideal for anyone who wants to experiment. The development of this network was designed to investigate issues such as management of such a network and security. Based now to our installed DTN network named planet-ece and after having verified the correct function, the next step was to implement a monitoring mechanism, which will allow us to monitor the network status and traffic in a DTN level. Then we proceeded to implement a secure DTN-based smart camera surveillance system through our DTN network planet-ece. In this implementation, therefore, we evaluate the safety and behavior of the system, focusing on communication via the DTN network in order to appreciate how such a system behaves in different possible situations, events and network availability, with or without security and in comparison with existing methods of communication.

L'internet des Objets (IoT) est habituellement présenté comme l'ensemble d'objets interconnectés à travers un réseau qui est, en pratique, Internet. Or, il existe beaucoup de cas où la connectivité est intermittente à cause des interfaces radio courte-portées et des contraintes d'économie d'énergie. L'architecture de réseautage tolérant les délais (DTN) ainsi que le Bundle Protocole (BP) sont considérés comme des solutions viables pour résoudre ce genre de challenges grâce au mécanisme store-carry-and-forward. Cette thèse vise à fournir des supports de programmation adaptés autant à l'IoT qu'au contexte DTN. Dans ce but, les challenges relevant du DTN et de l'IoT (DT-IoT) sont étudiés et quelques principes de design logiciels sont proposés. Ces principes ont pour but d'optimiser la réactivité et l'efficacité des applications ayant pour cible un contexte DT- IoT. La première contribution est la définition d'un support de programmation orienté ressources, nommé BoaP. Ce support fournit un protocole de requête/réponse grâce à une transposition de CoAP (Contrained Application Protocol). Cette transposition est composée d'ajustements fondamentaux et d'améliorations pour utiliser BP en tant que couche de transport. BoaP a été implémenté et testée dans un petit réseau physique. Une méthode pour évaluer des intergiciels dans des réseaux DTNs est présentée. Un outil implémentant cette méthode a été développé. Il repose sur une plateforme de virtualisation qui simule les contacts réseaux tout en émulant les nœuds du réseau. Cet outil a été utilisé pour exécuter des expériences pour évaluer la validité de BoaP. Enfin, un autre support de programmation est examiné. Celui-ci adopte une approche orientée service et respecte les contraintes REST (Representational State Transfer). Il se repose sur BoaP a été créé avec l'IoT en tête et est adapté à l’environnement DTN. La découverte exploite une interface de publications/souscriptions. Les descripteurs de services contiennent des champs spécifiques pour informer de la disponibilité de leur fournisseurs. / The Internet of Things (IoT) is usually presented as a set of THINGS interconnected through a network that is, in practice, Internet. However, there exist many contexts in which the connectivity is intermittent due to short-range wireless communication means or energy constraints. The Delay Tolerant Networking (DTN) architecture and the Bundle Protocol (BP) are known to overcome this communication challenge as they provide communication means by relying on a store-carry-and- forward mechanism. This thesis aims to provide programming supports adapted to both IoT and DTN contexts. For this, both DTN and IoT (DT-IoT) challenges are studied and several design principles are proposed. These principles aim to optimize reactivity and efficiency of applications targeting the DT-IoT context. The first contribution is the definition of a resource-oriented programming support, named BoaP, to enable a DT-IoT. It provides a protocol based on request/response thanks to a transposition of CoAP (Contrained Application Protocol). This transposition consists of fundamental adjustments and enhancements to use BP as the underlying transport protocol. BoaP has been implemented and tested in a small physical network. A method to evaluate middleware systems in DTNs is presented. A tool implementing this method has been developed. It relies on a virtualization platform that simulates network contacts and emulates network devices. This tool was used to run experimentations that assessed the validity of BoaP. Finally, another programming support is investigated. It follows a service-oriented approach and respects REST (Representational State Transfer) constraints. It is built on top of BoaP with IoT in mind and is adapted to DTN environments. Its discovery/advertisement exploits a publish/subscribe interface. Service descriptors contain specific fields to inform on the availability of the service providers. %Finally, requests are extended with some options to enforce conditions on geographic or time context.

Small mobile devices with networking capabilities are becoming more and more readily available and used. These devices can be used to form mobile ad hoc networks to communicate, where no infrastructure for network communication exist or where it has been destroyed or is overloaded e.g. in a natural disaster such as a hurricane. Such networks are almost never fully connected, and are part of the category of delay/disruption-tolerant networks (DTN) and suffer from limited resources e.g. bandwidth, storage and limited energy supply. The Opportunistic DTN Routing With Window-aware Adaptive Replication (ORWAR) is a delaytolerant protocol intended to be used in disaster relief efforts or emergency operations were a DTN could be a fast way to establish communication. In these kinds of scenarios high success rate together with efficient usage of the networks resources are critical to the success of such operations. ORWAR has been implemented and simulated on a high-level simulator, with promising results. To make a better assessment about what ORWARs performance would be in a real world network, more realistic and detailed simulations are needed. This Master's Thesis describes the design, implementation and evaluation of ORWAR in the network simulator ns-3, which simulates networks down to physical layer. The contributions of this thesis is a extension to ns-3 giving it an framework with support for the bundle protocol and delay-tolerant routing protocols and an evaluation of the ORWAR performance using more detailed simulations. The simulations represent a city scenario in down-town Helsinki city, Finland, were pedestrians, cars and trams form a network to communicate. The simulations with a higher level of detail has added to insight about the protocol. The obtained results showed that the high-level simulation may be overly optimistic and hides implementation details. On the other hand, some assumptions were found to be too pessimistic. For example we have shown that ORWAR actually performs better than the high level simulations, with regard to partial transmissions and that the high-level simulations have rather optimistic assumptions regarding the latency.

The Aim of this thesis is to implement the "Opportunistic DTN Routing with Window-aware Adaptive Replication" (ORWAR) protocol on the Android platform.Delay-Tolerant Networks (DTNs) are particular mobile ad-hoc network (MANET) architectures that try to solve the issues related to the lack of point to point connectivity between the nodes of the network or between its sub-networks (partitions). The general approach is based on techniques of store-carry-forward of the messages whereby delivery can be achieved even in partitioned networks, though with mobility-dependent delays. DTNs can be considered as a means of communication for scenarios where infrastructure-based networks cannot be deployed or get dysfunctional for some reasons, such as in the case of a natural disaster or highly overloaded infrastructure. ORWAR is a DTN protocol that tries to exploit knowledge about the context of mobile nodes (speed, direction of movement and radio range) to estimate the size of a contact window in order to avoid the energy waste deriving from partial transmissions. This report presents the design and the implementation of the protocol on the Android platform. It then describes some functional tests together with an analysis of the energy consumption and the performance reachable on our test device Android Development Phone 1.

The reduction of noise generated by new and existing engineering products is of increasing importance commercially, socially and environmentally. Commercially, the noise emission of vehicles, such as cars and aircraft, may often be considered a selling point and the effects of noise pollution on human health and the environment has led to legislation restricting the noise emissions of many engineering products. Noise prediction schemes are important tools to help us understand and develop a means of controlling noise. Acoustic problems present numerous challenges to traditional CFD-type numerical methods rendering all but the most trivial problems unsuitable. Difficulties relate to the length scale discrepancies which arise due to the relatively tiny pressure and density fluctuations of an acoustic wave propagating over large distancesto the point of interest; the result being large computational domains to capture wave behaviour accurately between source and observer. Noise prediction may be performed using a hybrid Computational Aero-Acoustics (CAA) scheme, an approach to noise prediction which alleviates many issues associated with exclusively numerical or analytical approaches. Hybrid schemes often rely on knowledge of a Green’s function, representing the scattering of the geometry, to propagate source fluctuations to the far-field. Presently, these functions only exist in analytical form for relatively simple geometries. This research develops principles for the robust calculation of Green’s functions for general situations. In order to achieve this, three techniques to computeGreen’s functions for the Helmholtz equation within an extended class of 2D geometries are developed, evaluated and compared. Where appropriate, their extension to 3D is described. Guidance is provided on the selection of a suitable numerical method in practice given knowledge of the geometry of interest. Through inclusion of the numerical methods for the construction of Green’s functions presented here, the applicability of existing hybrid schemes will be significantly extended. Thus, it is expected that noise predictions may be performed on a more general range of geometries while exploiting the computational efficiency of hybrid prediction schemes.