We have witnessed two main trends in recent years that have shaped the current state of communication networks. First, the Internet was designed with the initial idea to provide remote access to resources in the network; today it is overwhelmingly being used for content distribution. In addition, the community of content creators has evolved from a small group of professionals into a global community where every user can generate his contents and share it with other users. Second, the proliferation of personal mobile devices, such as smartphones and media tablets, has altered the way people access, create and share information, leading to a significant migration from wired to wireless networks and raising user expectations for ubiquitous connectivity. These trends have incited research on new communication modes and in this thesis we consider a specific mode, namely opportunistic networking. Opportunistic networking is a communication paradigm that utilizes intermittent connectivity between mobile devices to enable communication in infrastructure-less environments, and to provide complementary transport mechanisms in wireless networks where infrastructure is present. The thesis focuses on two main topics: understanding and modeling human mobility, and opportunistic content distribution. Mobility modeling is one of the key issues in opportunistic networking research. First, we discuss the structure of human mobility and introduce a framework to study mobility at different behavioural levels. We propose a queuing model, denoted by meeting-point model, for pedestrian mobility in smaller urban areas, such as city squares, parks, shops or at bus stops. The model is also a contribution to the second topic we address in the thesis, since we will use it to study characteristics of content distribution in smaller areas. We envision this model as a building block in a library of analytical models that would be used to study the performance of pedestrian content distribution in common scenarios of urban mobility. Furthermore, we show how the proposed model can be used to build larger, more complex models. In the area of opportunistic content distribution, we apply both analytical and simulation-based evaluation. We empirically study the performance of epidemic content distribution by using real-life mobility traces and investigate the fitness of a homogeneous stochastic model to capture the epidemic process. In addition, we present the design, implementation and evaluation of a mobile peer-to-peer system for opportunistic networking and discuss some promising application scenarios. / <p>QC 20131115</p>

Mobile devices are often expected to perform computational tasks that may be beyond their processing or battery capability. Cloud computing techniques have been proposed as a means to offload a mobile device's computation to more powerful resources. In this thesis, we consider the case where powerful computing resources are made available by utilizing vehicles. These vehicles can be repositioned in real time to receive computational tasks from user-carried devices. They can be either equipped with rugged high-performance computers to provide both computation and communication service, or they can be simple message ferries that facilitate communication with a more powerful computing resource. These scenarios find application in challenged environments and may be used in a military or disaster relief settings. It is further enabled by increasing feasibility of (i) constructing a Mobile High Performance Computer (MHPC) using rugged computer hardware with form factors that can be deployed in vehicles and (ii) Message Ferries (MF) that provide communication service in disruption tolerant networks. By analogy to prior work on message ferries and data mules, one can refer to the use of our first schema, MHPCs, as computational ferrying. After illustrating and motivating the computational ferrying concept, we turn our attention into the challenges facing such a deployment. These include the well known challenges of operating an opportunistic and intermittently connected network using message ferries -- such as devising an efficient mobility plan for MHPCs and developing techniques for proximity awareness. In this thesis, first we propose an architecture for the system components to be deployed on the mobile devices and the MHPCs. We then focus on defining and solving the MHPC movement scheduling problem with sufficient generality to describe a number of plausible deployment scenarios. After thorough examination of the MHPC concepts, we propose a scheme in which MHPCs are downgraded to be simple MFs that instead provide communication to a stationary HPC with powerful computing resources. Similar to the MPHCs, we provide a framework for this problem and then describe heuristics to solve it. We conduct a number of experiments that provide an understanding of how the performance of the system using MHPCs or MFs is affected by various parameters. We also provide a thorough comparison of the system in the dimensions of Computation on the Move and Controlling the Mobility.

Cidades Inteligentes são sistemas urbanos que usam as Tecnologias da Informação e Comunicação (TICs) para tornar a infraestrutura e os serviços públicos de uma cidade mais interativos, acessíveis e eficientes aos seus habitantes. Com isso, surge a necessidade de proporcionar novos tipos de serviços que busquem auxiliar na organização da cidade, no bem-estar das pessoas e auxiliem a melhorar a governança da cidade. Nesse contexto, o Sensoriamento Urbano é um paradigma emergente, situado no escopo de Cidades Inteligentes, que combina a ubiquidade de smartphones e de diferentes tipos de sensores para coletar dados que retratam diferentes aspectos da cidade. Um aspecto importante nesse processo de sensoriamento é a transmissão dos dados coletados para serem processados por um sistema centralizado remoto. Isso demanda uma ampla e constante cobertura de infraestrutura de rede de comunicação, fato que nem sempre é possível. As Redes Oportunistas surgem como uma alternativa complementar e inovadora para situações como essa, onde as aplicações precisam transmitir dados porém a infraestrutura de rede é intermitente ou mesmo inexistente. Entretanto, com o uso de Redes Oportunistas, as aplicações além de herdarem os seus benefícios também herdam os desafios existentes na área relacionados à tomada de decisão de encaminhamento das mensagens. Dessa forma, a presente tese busca responder ao questionamento de como intensificar a disseminação de conteúdo e o encaminhamento de mensagens em aplicações de Sensoriamento Urbano que fazem uso de Redes Oportunistas como paradigma complementar de comunicação. Para isso é proposto o Situs, um componente de software baseado em Redes Oportunistas que utiliza Sensibilidade à Situação com vistas à proatividade nas tomadas de decisões de roteamento para com isso intensificar a entrega de mensagens. Ele emprega Lógica Fuzzy para a compreensão da situação e uma rede neural chamada Echo State Network (ESN) para efetuar a projeção de situações. Os resultados experimentais demonstraram que a sua performance supera algumas das principais iniciativas existentes na literatura. Por fim, pode-se concluir que ele é capaz de preencher as lacunas do estado da arte apresentadas durante o desenvolvimento da tese sendo capaz de proporcionar um comportamento proativo com o uso de Sensibilidade à Situação. / Smart cities are urban systems that uses Information and Communication Technologies (ICTs) to make infrastructure and public services in a more interactive, accessible and efficient city to its inhabitants. With this comes the need to provide new types of services that seeks to assist in the organization of the city, the well-being of people and assist to improve the governance of the city. In this context, urban sensing is an emerging paradigm, sited in the Smart Cities scope, combining the ubiquity of smartphones with the capability of measuring o sensors to collect data that depict different aspects of the city. This ecosystem consists of different types of mobile and fixed devices orchestrated by a computational architecture that encompass the full sensing process. An important aspect of this process is the transmission of data collected for processing by a remote central system. This requires a broad and constant coverage of communication network infrastructure, a fact that is not always possible. The Opportunistic Networks emerge as an innovative and complementary alternative for situations like this where the applications needs to transmit data but the network infrastructure is intermittent or unavailable. However, using Opportunistic Networks, applications as well as inherit its benefits also inherit the existing challenges in the area related to decision-making of messages forwarding. Thus, this thesis seeks to answer the question of how to improve the dissemination of content and message routing of urban sensing applications that makes use of Opportunistic networks as complementary communication paradigm. Therefore, it proposes Situs, a software component based on Opportunistic Networks that uses Situation Awareness towards a proactivity in making routing decisions. For such task, it applies fuzzy logic for situation comprehension and a king of neural network called Echo State Network (ESN) for situation projection. The results of the experiments showed that their performance outperforms some existent initiatives in literature. Finally, we argue it fullfills the gaps of state of art presented in this thesis and could provide a proactive behaviour with usage of situation awareness.

Thanks to their increasing sophistication and popularity, mobile devices, in the form of smartphones and tablets, have become the fastest growing contributors to Internet traffic. Indeed, smartphones are projected to account for 50% of global Internet traffic by 2017, with the share of mobile video increasing to about 40% of total Internet traffic. As users embrace Internet streaming of video, several studies have found that a small decrease in video quality leads to a substantial increase in viewer abandonment and disengagement rates. To handle the explosive growth in video traffic, Adaptive HTTP streaming, which exploits the prevalence of commodity web servers and content distribution networks, has emerged as the key technology for delivering video to end users. Although a number of systems have been proposed for HTTP video streaming in traditional environments and for fixed clients, existing platforms for video streaming on mobile devices are still in their infancy and do not address the additional challenges often experienced by mobile clients: high fluctuations in network conditions, heterogeneous networking interfaces, multiple form-factors, and limited battery life. In this dissertation, we propose a number of solutions for improving the Quality of Experience of HTTP video streaming on mobile devices. We begin by evaluating the performance of several existing video quality adaptation schemes when deployed on mobile platforms. Through experiments with smartphones in wide-area environments, we assemble several key findings. First, we show that the high fluctuations in network throughput on cellular and Wi-Fi networks impose significant challenges for efficiently architecting the video adaptation scheme. Second, we find significant differences between the performance of the current state-of-the-art schemes in controlled experimental settings and their performance in mobile settings on key quality metrics such as inefficiency, instability, rebuffering ratio, and startup latency. We also find noticeable differences in the behavior of the schemes under Wi-Fi and cellular network access, with most of the schemes performing worse when the network access is cellular. Given these observations, we hypothesize on the possible causes of these inefficiencies. We also identify the best practices of existing schemes and key insights from experimental results that can serve as foundations for addressing many of the limitations. Armed with these measurement-driven insights, we propose a novel video quality adaptation scheme, called MASS, which is more robust to the vagaries of the wireless networking conditions. We implement and evaluate our solution on commodity Android smartphones, and demonstrate significant performance gains over existing schemes. To further improve the streaming experience, we introduce an extension to HTTP video streaming that leverages the synergy between social network participation and video streaming to optimize end-user Quality of Experience. Our system, called SDASH, integrates and applies well-known concepts such as cooperative caching, prefetching, and P2P streaming for reducing bitrate fluctuations and optimizing the viewing experience. Finally, we develop a general infrastructure for constructing temporally and spatially localized P2P communities of mobile devices sharing similar interests. The platform enables on-demand cooperation among mobile clients based on device context and client preferences. We use a concrete implementation of the mobile P2P infrastructure for evaluating the performance of SDASH. This dissertation addresses the challenges facing Adaptive HTTP Streaming under mobile networking conditions. Through experimentation with commodity mobile devices, we show that the proposed techniques for bitrate adaptation and cooperative streaming can significantly improve the video viewing experience.

With the growth of Internet, the underlying protocols are increasingly challenged by new technologies and applications. The original Internet protocols were, however, not designed for wireless communication, mobility, long disconnection times, and varying bandwidths. In this thesis, we study challenged networking, and how well old and new protocols operate under such constraints. Our study is experimental. We build network testbeds and measure the performance of alternative protocols and architectures. We develop novel methodologies for repeatable experiments that combine emulations, simulations and real world experiments. Based on our results we suggest modifications to existing protocols, and we also develop a new network architecture that matches the constraints of a challenged network, in our case, an opportunistic network. One of our most important contributions is an Ad hoc Protocol Evaluation (APE) testbed. It has been successfully used worldwide. The key to its success is that it significantly lowers the barrier to repeatable experiments involving wireless and mobile computing devices. Using APE, we present side-by-side performance comparisons of IETF MANET routing protocols. A somewhat surprising result is that some ad hoc routing protocols perform a factor 10 worse in the testbed than predicted by a common simulation tool (ns-2). We find that this discrepancy is mainly related to the protocols’ sensing abilities, e.g., how accurately they can infer their neighborhood in a real radio environment. We propose and implement improvements to these protocols based on the results. Our novel network architecture Haggle is another important contribution. It is based on content addressing and searching. Mobile devices in opportunistic networks exchange content whenever they detect each other. We suggest that the exchange should be based on interests and searches, rather than on destination names and addresses. We argue that content binding should be done late in challenged networks, something which our search approach supports well.

The networking paradigm uses new information vectors consisting of human carried devices is known as disruption-tolerant networks (DTN) or opportunistic networks. We identify the binary assertion issue in DTN. We notice how most DTNs mainly analyze nodes that are in contact. So all nodes that are not in contact are in intercontact. Nevertheless, when two nodes are not in contact, this does not mean that they are topologically far away from one another. We propose a formal definition of vicinities in DTNs and study the new resulting contact/intercontact temporal characterization. Then, we examine the internal organization of vicinities using the Vicinity Motion framework. We highlight movement types such as birth, death, and sequential moves. We analyze a number of their characteristics and extract vicinity usage directions for mobile networks. Based on the vicinity motion outputs and extracted directions, we build the TiGeR that simulates how pairs of nodes interact within their vicinities. Finally, we inquire about the possibilities of vicinity movement prediction in opportunistic networks. We expose a Vicinity Motion-based heuristic for pairwise shortest distance forecasting. We use two Vicinity Motion variants called AVM and SVM to collect vicinity information. We find that both heuristics perform quite well with performances up to 99% for SVM and around 40% for AVM.

Cidades Inteligentes são sistemas urbanos que usam as Tecnologias da Informação e Comunicação (TICs) para tornar a infraestrutura e os serviços públicos de uma cidade mais interativos, acessíveis e eficientes aos seus habitantes. Com isso, surge a necessidade de proporcionar novos tipos de serviços que busquem auxiliar na organização da cidade, no bem-estar das pessoas e auxiliem a melhorar a governança da cidade. Nesse contexto, o Sensoriamento Urbano é um paradigma emergente, situado no escopo de Cidades Inteligentes, que combina a ubiquidade de smartphones e de diferentes tipos de sensores para coletar dados que retratam diferentes aspectos da cidade. Um aspecto importante nesse processo de sensoriamento é a transmissão dos dados coletados para serem processados por um sistema centralizado remoto. Isso demanda uma ampla e constante cobertura de infraestrutura de rede de comunicação, fato que nem sempre é possível. As Redes Oportunistas surgem como uma alternativa complementar e inovadora para situações como essa, onde as aplicações precisam transmitir dados porém a infraestrutura de rede é intermitente ou mesmo inexistente. Entretanto, com o uso de Redes Oportunistas, as aplicações além de herdarem os seus benefícios também herdam os desafios existentes na área relacionados à tomada de decisão de encaminhamento das mensagens. Dessa forma, a presente tese busca responder ao questionamento de como intensificar a disseminação de conteúdo e o encaminhamento de mensagens em aplicações de Sensoriamento Urbano que fazem uso de Redes Oportunistas como paradigma complementar de comunicação. Para isso é proposto o Situs, um componente de software baseado em Redes Oportunistas que utiliza Sensibilidade à Situação com vistas à proatividade nas tomadas de decisões de roteamento para com isso intensificar a entrega de mensagens. Ele emprega Lógica Fuzzy para a compreensão da situação e uma rede neural chamada Echo State Network (ESN) para efetuar a projeção de situações. Os resultados experimentais demonstraram que a sua performance supera algumas das principais iniciativas existentes na literatura. Por fim, pode-se concluir que ele é capaz de preencher as lacunas do estado da arte apresentadas durante o desenvolvimento da tese sendo capaz de proporcionar um comportamento proativo com o uso de Sensibilidade à Situação. / Smart cities are urban systems that uses Information and Communication Technologies (ICTs) to make infrastructure and public services in a more interactive, accessible and efficient city to its inhabitants. With this comes the need to provide new types of services that seeks to assist in the organization of the city, the well-being of people and assist to improve the governance of the city. In this context, urban sensing is an emerging paradigm, sited in the Smart Cities scope, combining the ubiquity of smartphones with the capability of measuring o sensors to collect data that depict different aspects of the city. This ecosystem consists of different types of mobile and fixed devices orchestrated by a computational architecture that encompass the full sensing process. An important aspect of this process is the transmission of data collected for processing by a remote central system. This requires a broad and constant coverage of communication network infrastructure, a fact that is not always possible. The Opportunistic Networks emerge as an innovative and complementary alternative for situations like this where the applications needs to transmit data but the network infrastructure is intermittent or unavailable. However, using Opportunistic Networks, applications as well as inherit its benefits also inherit the existing challenges in the area related to decision-making of messages forwarding. Thus, this thesis seeks to answer the question of how to improve the dissemination of content and message routing of urban sensing applications that makes use of Opportunistic networks as complementary communication paradigm. Therefore, it proposes Situs, a software component based on Opportunistic Networks that uses Situation Awareness towards a proactivity in making routing decisions. For such task, it applies fuzzy logic for situation comprehension and a king of neural network called Echo State Network (ESN) for situation projection. The results of the experiments showed that their performance outperforms some existent initiatives in literature. Finally, we argue it fullfills the gaps of state of art presented in this thesis and could provide a proactive behaviour with usage of situation awareness.

Cidades Inteligentes são sistemas urbanos que usam as Tecnologias da Informação e Comunicação (TICs) para tornar a infraestrutura e os serviços públicos de uma cidade mais interativos, acessíveis e eficientes aos seus habitantes. Com isso, surge a necessidade de proporcionar novos tipos de serviços que busquem auxiliar na organização da cidade, no bem-estar das pessoas e auxiliem a melhorar a governança da cidade. Nesse contexto, o Sensoriamento Urbano é um paradigma emergente, situado no escopo de Cidades Inteligentes, que combina a ubiquidade de smartphones e de diferentes tipos de sensores para coletar dados que retratam diferentes aspectos da cidade. Um aspecto importante nesse processo de sensoriamento é a transmissão dos dados coletados para serem processados por um sistema centralizado remoto. Isso demanda uma ampla e constante cobertura de infraestrutura de rede de comunicação, fato que nem sempre é possível. As Redes Oportunistas surgem como uma alternativa complementar e inovadora para situações como essa, onde as aplicações precisam transmitir dados porém a infraestrutura de rede é intermitente ou mesmo inexistente. Entretanto, com o uso de Redes Oportunistas, as aplicações além de herdarem os seus benefícios também herdam os desafios existentes na área relacionados à tomada de decisão de encaminhamento das mensagens. Dessa forma, a presente tese busca responder ao questionamento de como intensificar a disseminação de conteúdo e o encaminhamento de mensagens em aplicações de Sensoriamento Urbano que fazem uso de Redes Oportunistas como paradigma complementar de comunicação. Para isso é proposto o Situs, um componente de software baseado em Redes Oportunistas que utiliza Sensibilidade à Situação com vistas à proatividade nas tomadas de decisões de roteamento para com isso intensificar a entrega de mensagens. Ele emprega Lógica Fuzzy para a compreensão da situação e uma rede neural chamada Echo State Network (ESN) para efetuar a projeção de situações. Os resultados experimentais demonstraram que a sua performance supera algumas das principais iniciativas existentes na literatura. Por fim, pode-se concluir que ele é capaz de preencher as lacunas do estado da arte apresentadas durante o desenvolvimento da tese sendo capaz de proporcionar um comportamento proativo com o uso de Sensibilidade à Situação. / Smart cities are urban systems that uses Information and Communication Technologies (ICTs) to make infrastructure and public services in a more interactive, accessible and efficient city to its inhabitants. With this comes the need to provide new types of services that seeks to assist in the organization of the city, the well-being of people and assist to improve the governance of the city. In this context, urban sensing is an emerging paradigm, sited in the Smart Cities scope, combining the ubiquity of smartphones with the capability of measuring o sensors to collect data that depict different aspects of the city. This ecosystem consists of different types of mobile and fixed devices orchestrated by a computational architecture that encompass the full sensing process. An important aspect of this process is the transmission of data collected for processing by a remote central system. This requires a broad and constant coverage of communication network infrastructure, a fact that is not always possible. The Opportunistic Networks emerge as an innovative and complementary alternative for situations like this where the applications needs to transmit data but the network infrastructure is intermittent or unavailable. However, using Opportunistic Networks, applications as well as inherit its benefits also inherit the existing challenges in the area related to decision-making of messages forwarding. Thus, this thesis seeks to answer the question of how to improve the dissemination of content and message routing of urban sensing applications that makes use of Opportunistic networks as complementary communication paradigm. Therefore, it proposes Situs, a software component based on Opportunistic Networks that uses Situation Awareness towards a proactivity in making routing decisions. For such task, it applies fuzzy logic for situation comprehension and a king of neural network called Echo State Network (ESN) for situation projection. The results of the experiments showed that their performance outperforms some existent initiatives in literature. Finally, we argue it fullfills the gaps of state of art presented in this thesis and could provide a proactive behaviour with usage of situation awareness.

Les réseaux mobiles opportunistes (ou OppNets, pour Opportunistic Networks) constituent une solution séduisante pour compléter les réseaux fixes d’infrastructure, voire compenser leur absence dans des zones sinistrées ou défavorisées. Les recherches menées ces dernières années ont principalement visé à permettre les transmissions dans les OppNets, mais ceci ne peut être qu’un premier pas vers une réelle exploitation de tels environnements contraints. L’informatique opportuniste (Opportunistic Computing) dépasse le cadre des seules transmissions, et introduit un nouveau paradigme d’exécution de tâches collaboratives dans de tels environnements. Dans ce domaine qu’est l’informatique opportuniste, la conception, la mise en œuvre et le déploiement d’applications distribuées sont des objectifs majeurs. Une application pour OppNet doit pouvoir fonctionner et assurer un niveau de service satisfaisant, tout en supportant les diverses contraintes propres aux OppNets, telles qu’une connectivité fluctuante, un partitionnement chronique du réseau, de longs délais de transmissions, de fréquents échecs de transmission, et des équipements hétérogènes offrant des ressources limitées. La complexité et le coût du développement d’applications pour OppNets peuvent être réduits de manière significative en utilisant des modèles de programmation appropriés. De tels modèles peuvent être fournis par des systèmes intergiciels capables de supporter de manière transparente les contraintes évoquées plus haut. Le travail rapporté dans ce mémoire a porté sur l’étude des contraintes inhérentes aux OppNets, et sur la proposition de solutions appropriées. Parmi les modèles de programmation usuels, certains ont été identifiés comme pouvant être utilisés dans le cadre des OppNets. Sur la base de ces divers modèles de programmation, des systèmes intergiciels opportunistes ont été mis en oeuvre. Ces systèmes supportent respectivement le modèle de messagerie distribuée (sur la base de files d’attentes et de "topics"), le modèle du tuple-space, et la résolution de consensus. Des implémentations complètes ont été réalisées, et le code source est distribué sous licence GPL (GNU General Public License). Ces systèmes ont été évalués par le biais d’expérimentations menées en conditions réelles et par simulation. / Opportunistic networks (OppNets) constitute an appealing solution to complement fixed network infrastructures –or make up for the lack thereof– in challenged areas. Researches in the last few years have mostly addressed the problem of supporting networking in OppNets, yet this can only be a first step towards getting real benefit from these networks. Opportunistic computing goes beyond the concept of opportunistic networking, and provides a new paradigm to enable collaborative computing tasks in such environments. In the realm of opportunistic computing, properly designing, implementing and deploying distributed applications are important tasks. An OppNet-dedicated application must be able to operate and maintain an acceptable level of service while addressing the many problems that can occur in these networks, such as disconnections, partitioning, long transmission delays, transmission failures, resource constraints, frequent changes in topology, and heterogeneous devices. Much of the complexity and cost of building OppNet-dedicated applications can be alleviated by the use of high-level programming models. Such models can be supported by middleware systems capable of transparently addressing all the above-mentioned problems. The work reported in this dissertation focused on providing insight into the fundamental problems posed by OppNets, so as to analyze and solve the problems faced by application developers while dealing with these environments. The research focused on identifying well-known high-level programming models that can be satisfactorily implemented for OppNets, and that can prove useful for application developers. In order to demonstrate the feasibility of application development for OppNets, while assessing the benefits brought about by carefully designed middleware systems, a couple of such systems have been designed, implemented, and evaluated as part of this work. These middleware systems respectively support distributed messaging (through message queues and topics), the tuple-space model, and consensus solving in OppNets. They are supplemented with fully-functional implementations, that can be used in real settings, and that are all distributed under the terms of the GNU General Public License (GPL). Real-life experiments and simulations have been realized so as to evaluate the effectiveness and efficiency of these systems in real conditions.

Cette thèse s’inscrit dans le domaine de l’informatique ambiante et del’Internet des objets, et considère des réseaux qui peuvent se formerspontanément et qui sont composés d’équipements fixes ou mobiles. Ceséquipements peuvent communiquer à travers une infrastructure, ou de gré-à-gré en mode ad hoc. Des ruptures de connectivité peuvent apparaître dans le réseau d’unemanière fréquente et imprévisible. Ces ruptures de connectivité peuvents’avérer problématiques dès lors que ces équipements souhaitent accéder àdes ressources offertes par d’autres équipements.L’informatique opportuniste étend le principe des communicationsopportunistes en proposant d’exposer les ressources à travers des serviceset d’accéder à ces services par des techniques et des protocoles decommunication opportunistes qui mettent en œuvre le principe du “store,carry and forward”.Dans cette thèse, nous nous intéressons à la composition de services afin depouvoir combiner les services élémentaires offerts par les équipementsprésents dans le réseau et ainsi proposer aux utilisateurs des services deplus haut niveau et plus riches. La composition de services représente unetâche complexe dans l’informatique opportuniste du fait des ruptures deconnexion.Dans cette thèse, nous proposons une solution pour composer les servicesen utilisant deux stratégies, à savoir la chorégraphie et l’orchestration. Cettesolution repose en outre sur une fonction d’utilité qui permet de sélectionnerles fournisseurs de services. Nous proposons également une versionaméliorée exploitant un cache distribué de données et un mécanismeproactif de composition de services exploitant les profils d’intérêt desutilisateurs. / This thesis is related to the domain of Ubiquitous computing and Internet ofThings (IoT), and focuses on networks that can be formed spontaneously bymobile or fixed devices. These devices can be connected using aninfrastructure, or in a peer-to-peer mode using ad hoc communications.Connection disruptions may occur in the network frequently andunpredictably. These connection disruptions can be problematic when a givendevice tries to access remote resources provided by other devices, or when ittries to offer its own resources to these ones.Opportunistic computing extends the paradigm of opportunistic networkingby abstracting local resources as services accessible remotely using theprotocols of opportunistic networking that implement the "store, carry andforward" principle.In this thesis, we focus on service composition in order to combineelementary services and offer new, rich and high level composite services tousers. Service composition can be a very difficult task to perform inopportunistic networks due to connection disruptions. In this thesis, we propose a solution to compose services using twostrategies: orchestration and choreography. This solution also relies on autility function that selects service providers. We also propose an optimizedversion of our solution that exploits a distributed cache of data and aproactive service composition mechanism based on the user interest profile.