Τα δίκτυα αισθητήρων είναι μια εξειδικευμένη κατηγορία κατανεμημένων δικτύων, η οποία τα τελευταία χρόνια έχει συγκεντρώσει το ενδιαφέρον της ερευνητικής κοινότητας, λόγω του ευρύτατου πεδίου εφαρμογών της. Τα δίκτυα αυτά αποτελούνται από συσκευές που διαθέτουν αισθητήρες (sensors) και ενδεχομένως μηχανισμούς δράσης (actuators) και είναι διασκορπισμένες στο χώρο, με δυνατότητα επικοινωνίας μεταξύ τους και επεξεργασίας σε ένα βαθμό της πληροφορίας που διακινούν στο δίκτυο. Στόχος των δικτύων αυτών είναι η παρακολούθηση της εξέλιξης ενός φαινόμενου, ή η ανίχνευση περιβαλλοντικών συνθηκών και η αποστολή των δεδομένων που συλλέγονται σε έναν κεντρικό κόμβο, το κέντρο ελέγχου. Οι δυνατότητες των συσκευών είναι κατά κανόνα περιορισμένες, λόγω του μικρού μεγέθους τους, του χαμηλού κόστους τους και ενίοτε του αναλώσιμου ρόλου τους. Οι εφαρμογές των δικτύων αυτών ποικίλουν, από εφαρμογές στην επιστήμη γεωργίας ακριβείας, στην πυρανίχνευση και την παρακολούθηση συνθηκών περιβάλλοντος σε κτιριακές εγκαταστάσεις, μέχρι εφαρμογές ανίχνευσης κίνησης των εχθρικών μονάδων σε πεδίο μάχης, ή παρακολούθησης φαινόμενου που εξελίσσεται σε δυσπρόσιτη περιοχή. Μερικές από τις βασικές προκλήσεις που προκύπτουν σε αυτά τα δίκτυα, λόγω της φύσης τους, είναι η βέλτιστη διαχείριση των ενεργειακών πόρων κάθε κόμβου, η αποδοτική συνδυαστική επεξεργασία των διακινούμενων μηνυμάτων και η αξιόπιστη δρομολόγηση της πληροφορίας που συλλέγεται προς το κέντρο ελέγχου, καθώς και η δυναμική και αυτόνομη οργάνωση του δικτύου. Η εξέλιξη των δικτύων αισθητήρων σε συνδυασμό με την επιθυμία υλοποίησης περίπλοκων και περισσότερο ολοκληρωμένων εφαρμογών, οδήγησε σε δίκτυα που περιέχουν ετερογενείς κόμβους, όπως για παράδειγμα κόμβους με διαφορετική αρχιτεκτονική, διαφορετικούς αισθητήρες, με διαφορετικές επεξεργαστικές και επικοινωνιακές ικανότητες ή και κόμβους με δυνατότητες κίνησης ή επιτέλεσης εργασιών (actuators) σε απόκριση εντολών που λαμβάνουν από το κέντρο ελέγχου. Επιπρόσθετα, σε πολλές εφαρμογές διαφαίνεται η ανάγκη για διασύνδεση πολλαπλών δικτύων αισθητήρων και διάδοση της πληροφορίας που συλλέγουν μέσω του διαδικτύου προς απομακρυσμένους εξυπηρετητές με αυξημένες επεξεργαστικές ικανότητες, προς βάσεις δεδομένων, συσκευές pda ή κινητά τηλέφωνα, σταθμούς εργασίας τελικών χρηστών και άλλες συσκευές. Δημιουργείται με αυτόν τον τρόπο ένα ευρύτερο ετερογενές δίκτυο επικάλυψης (overlay sensor network), η διαχείριση και αποδοτική χρήση του οποίου απαιτεί νέες αρχιτεκτονικές οργάνωσης των επιμέρους δικτύων, προσαρμοσμένα πρωτόκολλα διάδοσης πληροφορίας και πλατφόρμες που διευκολύνουν τον προγραμματισμό των δικτύων αυτών. Για το λόγο αυτό η επιστημονική κοινότητα επικεντρώνει το ενδιαφέρον της στο σχεδιασμό ειδικών περιβαλλόντων λογισμικού που μεσολαβούν ανάμεσα στον προγραμματιστή εφαρμογών και τα ετερογενή δίκτυα αισθητήρων, τα οποία ανήκουν στην κατηγορία των middleware. Τα περιβάλλοντα αυτά αναλαμβάνουν να διαχειριστούν θέματα χαμηλού επιπέδου ή και ανώτερων επιπέδων στα δίκτυα αισθητήρων, που δεν θα έπρεπε να απασχολούν τον προγραμματιστή κάθε φορά που επιθυμεί να υλοποιήσει μια εφαρμογή. Απώτερος σκοπός είναι να παρέχουν υπηρεσίες υψηλού επιπέδου και ομοιογενείς λογικές αφαιρέσεις πάνω στα ετερογενή δίκτυα, ενώ είναι επιθυμητή η αποδοτική λειτουργία τους σε παγκόσμια κλίμακα όπου πολλά γεωγραφικά διάσπαρτα δίκτυα συνεργάζονται για να παρέχουν τις υπηρεσίες τους με οργανωμένο και καλά ορισμένο τρόπο. Η δική μας συνεισφορά στην έρευνα του πεδίου αυτού, έγκειται πρώτα στη μελέτη ήδη διαθέσιμων προτάσεων middleware για τον προγραμματισμό και τη διασύνδεση πολλαπλών και ετερογενών δικτύων αισθητήρων, με σκοπό τον εντοπισμό των θεμάτων και προβλημάτων που αντιμετώπισαν κατά το σχεδιασμό τους, την ανάλυση της αρχιτεκτονικής τους και την αξιολόγηση της απόδοσής τους. Επιθυμώντας να δώσουμε τη δική μας πρόταση στο πεδίο των middleware για δίκτυα αισθητήρων και αξιοποιώντας τα συμπεράσματά μας από την μελέτη των άλλων προτάσεων, σχεδιάσαμε και υλοποιήσαμε το middleware σύστημα ShareSense II. Το σύστημα ShareSense II προέρχεται από τον επανασχεδιασμό τού αρχικού και απλούστερου ShareSense και ενσωματώνει το middleware jWebDust επεκτείνοντας κατά ένα τρόπο την αρχιτεκτονική του, ώστε να υποστηρίζει δίκτυα επικάλυψης (overlay sensor networks) μεγάλης κλίμακας. Η πλατφόρμα του ShareSense II σχεδιάστηκε για να παρέχει λογική αφαίρεση των δικτύων αισθητήρων, ώστε ο προγραμματιστής να μπορεί εύκολα να ρυθμίσει τις υπηρεσίες που παρέχει ένα δίκτυο επικάλυψης, να διαχειρίζεται τις λειτουργίες των επιμέρους δικτύων, να μπορεί να προγραμματίσει δυναμικά τη συμπεριφορά τους και να καθορίσει τον τρόπο παρουσίασης της χρήσιμης πληροφορίας που αποκομίζει από αυτά, στον τελικό χρήστη. Βασιζόμενοι στην ευέλικτη υποδομή των peer-to-peer δικτύων, προτείνουμε μια λύση για τη διασύνδεση πολλαπλών ετερογενών δικτύων αισθητήρων με συσκευές και σταθμούς εργασίας πάνω από το διαδίκτυο. Δώσαμε έμφαση στην επεκτασιμότητα της αρχιτεκτονικής ως προς τις υποστηριζόμενες υπηρεσίες και τύπους δικτύων, την αξιοποίηση και τη συνεργασία με υπάρχοντα middleware που διαχειρίζονται κάποια επιμέρους δίκτυα και την παροχή χρήσιμων διεπαφών για την εύκολη υλοποίηση πρακτικών εφαρμογών. Υλοποιήσαμε, τέλος, μια εφαρμογή η οποία στηρίζεται στην πλατφόρμα του ShareSense II για να τεκμηριώσουμε την επάρκεια της αρχιτεκτονικής του συστήματός μας και να εντοπίσουμε τα σημεία όπου απαιτείται βελτίωσή της. Η εφαρμογή χρησιμοποιεί το περιβάλλον του Google Earth για την παρακολούθηση των επιμέρους δικτύων που συμμετέχουν στο σύστημα, επιτρέποντας παράλληλα τη δυναμική υποβολή ερωτημάτων και την αντιστοίχιση των δικτύων σε τρισδιάστατα μοντέλα κτιρίων και άλλων περιοχών, ώστε να είναι άμεση και εύληπτη η παρουσίαση της πληροφορίας στον τελικό χρήστη. / Sensor networks are a special case of distributed networks, which in the recent years have become increasingly interesting to the scientific community, due to their wide range of applications. These networks are comprised of devices that have sensors attached to them and possibly even actuators, and are scattered in a field, being able to comminucate with each other and process -to a certain degree- information that they forward in the network. Among the goals of these networks are the monitoring of physical phenomena, the detection of special events or conditions and consequently the communication of the acquired information towards a control center. These devices usually have strict constraints on their capabilities due to their small size, their low production cost and quite often their expendable role. The applications of these networks vary, from applications in the precision agriculture field, fire detection and monitoring environmental conditions in buildings and offices, to applications for the detection of enemy units' movements in the battlefield or observing a physical phenomenon in a inaccessible location. Some of the important challeges that emerge for these networks are the optimal management of the power resources of each node, the efficient aggregation of the in-network messages and the reliable routing of information acquired towards the control center, as well as the autonomous and adaptive network operation. The evolution in the sensor netorks research in combination with the desire to implement even more sophisticated applications, has led to highly heterogeneous networks, where nodes belong to different architectures, they use various sensor models, and they have different processing and communicating capabilities. Additionally, in many applications there is the need to interconnect multiple sensor networks and to distribute the information collected locally towards remote servers, databases, pda devices or cell phones, workstations and other end user devices. Thus, a new type of networks, the overlay networks, emerges. The administration and effecient usage of these networks require new management architectures for the local networs, adaptive protocols for the distribution of information and new software platforms that simplify application programming. Following these developments, the scientific community has focused in designing middleware software for the sensor networks. Such software have the role of managing low level or intermediate level issues, that should not burden a programmer every time s/he needs to design and implement a new application. The main goal of middleware is to provide high level services and unified logical abstractions over heterogeneous sensor networks, and to perform well in a global scale where multiple geographically disparate networks cooperate to provide services in an organized and well defined manner. Our contribution to this field, is foremost to study the state of the art middleware projects for overlay sensor networks, in an effort to understand the issues and problems that were faced during their design, to analyze their architecure and evaluate their performance. We have used the results of this study to design and implement a new middleware architecture, which we have named ShareSense II. Our middleware comes from the redesign and expansion of its simpler predecessor, the original ShareSense middleware, and also integrates the jwebdust middleware, bringing the services of that middleware to the large scal overlay networks. The ShareSense II platfrom was designed to provide logical abstractions for sensor networks, so that the programmer is able to tweak their services, maange the resources of the local networks and build flexible applications. For our overlay netowrk we have embedded an efficient peer-to-peer infrastructure that performs well in networks with frequent and temporary node disconnections and large scale applications. Finally, we implemented an application that uses the ShareSense II middleware, in order to show the benefits of our design and also locate the parts of the architecture that need further optimization. Our application uses the Google Earth software to monitor geographically disparate networks that participate in ShareSense II, allowing the online issuing of queries, as well as matching 3d models of buildings (and other areas) to local networks, in order to display information to the end user in an interesting and exciting way.

Next generation heterogeneous wireless networks are expected to interwork with Internet Protocol (IP)-based infrastructures. Conventional network services operate like silos in that a specific set of services are offered over a specific type of access network. As access networks evolve to provide IP-based packet access, it becomes attractive to break these “service silos” by offering a converged set of IP-based services to users who may access these services using a number of alternative access networks. This trend has started with third generation cellular mobile networks, which have standardized on the use of the IP Multimedia Subsystem (IMS) to manage user access to a wide variety of multimedia services over the mobile Internet, while facilitating interworking of heterogeneous wireless and landline access networks. The future users of communication systems will subscribe to both IP-based and Circuit Switched (CS) based services and in the foreseeable future a single database that handles user profiles across all domains will be required. Home Subscriber Server (HSS) as an evolved version of Home Location Register (HLR) is one of the key components of IMS. In deploying HSS as a central repository database, in a fully overlapped heterogeneous network setting, changes of access mode are very frequent and conveying this information to HSS imposes excessive signaling load and delay. In our proposed scheme we introduce an Interface Agent (IA) for each location area that caches the location and information about the access mode through which a user can be reached. This method results in significant amount of savings in signaling cost and better delay performance. The existing call delivery approaches in cellular networks may not be well suited for future communication systems because they suffer from unnecessary usage of network resources for call attempts that may fail which adds to excessive signaling delays and queuing costs. Reducing the number of queries and retrievals from the database will have a significant impact on the network performance. We present a new scheme based on Reverse Virtual Call setup (RVC) as a solution to the call delivery problem in heterogeneous wireless networks and evaluate the performance of this framework. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Les futurs réseaux sans fil devront être conçus pour répondre aux besoins hétérogènes de systèmes entièrement différents. De nouveaux services soumis à des contraintes variées coexisteront avec les utilisateurs actuels sur la même bande de fréquences. L'OFDM, la couche physique utilisée par les systèmes actuels, souffre d’un mauvais confinement spectral et ne permet pas cette coexistence. De nombreuses nouvelles formes d'onde avec une localisation spectrale améliorée ont donc été proposées. Nous étudions la coexistence de nouveaux systèmes basés sur ces formes d'onde avec des utilisateurs OFDM préexistant. Nous fournissons la première analyse théorique et expérimentale de l'interférence inter-système qui se produit dans ces scenarios. Nous appliquons ensuite cette analyse pour évaluer les performances de différentes formes d'ondes avancées et nous étudions finalement les performances d'un réseau où des utilisateurs cellulaires OFDM coexistent avec des paires D2D utilisant l'une des formes d'ondes améliorées étudiées. / Future wireless networks are envisioned to accommodate the heterogeneous needs of entirely different systems. New services obeying various constraints will coexist with legacy cellular users in the same frequency band. This coexistence is hardly achievable with OFDM, the physical layer used by current systems, because of its poor spectral containment. Thus, a myriad of multi-carrier waveforms with enhanced spectral localization have been proposed for future wireless devices. In this thesis, we investigate the coexistence of new systems based on these waveforms with legacy OFDM users. We provide the first theoretical and experimental analysis of the inter-system interference that arises in those scenarii. Then, we apply this analysis to evaluate the merits of different enhanced waveforms and we finally investigate the performance achievable by a network composed of legacy OFDM cellular users and D2D pairs using one of the studied enhanced waveforms.

La présente thèse s’intéresse aux communications descendantes, plus spécifiquement aux canaux de multidiffusion, pour lesquels un émetteur diffuse un message commun destiné à tous les utilisateurs d’un groupe. Pour que le débit ne soit pas limité par le plus faible utilisateur en terme de qualité de canal, différentes solutions reposant sur des techniques entrées multiples sorties multiples massives ou multi-débit ont été proposées dans la littérature. Cependant, si tous les utilisateurs souhaitaient obtenir le même niveau de qualité, le plus faible utilisateur établirait le débit et/ou nécessiterait une quantité de ressources démesurée, ce qui impacterait tout le groupe. Les études récentes portant sur les communications d’appareil à appareil ouvrent la voie à la coopération entre utilisateurs proches, ce qui pourrait bénéficier à tous les utilisateurs, en garantissant le même niveau de qualité tout en maintenant un faible coût en ressource et en énergie. C’est pour ces raisons que cette thèse s’intéresse aux canaux de multidiffusion avec coopération entre récepteurs. La théorie de l’information formalise l’étude de ces réseaux et fournit des bornes universelles portant sur le débit transmissible. Le schéma de coopération proposé se base sur une superposition appropriée d’opérations de compresse-relaie (CF) et décode-relaie (DF), et il est prouvé que ses performances surpasse celles des schémas de coopérations non-interactifs pour le scénario à deux récepteurs. Les propriétés de la coopération interactive émergent de l’asymétrie de construction du schéma de coopération, ce qui permet d’adapter l’ordre des CFs et DFs en fonction de la qualité du canal. L’idée derrière cette interaction, les intuitions concernant les points clés de la construction, et des résultats numériques sont donnés pour des réseaux de petites tailles. Des simulations au niveau du système illustrent le gain potentiel que la coopération entre récepteurs pourrait apporter pour des réseaux de plus grandes tailles. / The present thesis concentrates on downlink communications. In order to tackle one part of this challenging problem, we focus on the multicast channel in which one transmitter broadcasts a common message intended to a whole group of users. To ensure that the transmission rate is not limited by the weakest user in terms of channel quality, different solutions using massive multiple-input multiple-output or multirate strategies have been proposed in the literature. However, if all users wish to obtain the same content quality, the weakest user would set the rate and/or require a disproportionate amount of resource, and thus impact the whole group. With the recent study of device-to-device mechanisms, user cooperation in close proximity becomes possible and would benefit to all users by ensuring the same content quality while maintaining a low cost in terms of amount of resource and energy. Consequently, this thesis is centered around the multicast network with receiver cooperation. Information-theoretic tools formalize the study of the network considered and provide general bounds on the achievable transmission rate. The proposed cooperation scheme is based on an appropriate superposition of compress-forward (CF) and decode-forward (DF) operations, and provenly outperform non-interactive schemes in the two-receiver scenario. Properties of the interactive cooperation emerge from the asymmetric construction of the scheme which permits to adapt the order of CFs and DFs according to the channel condition. The core idea of the interaction, some insights on key construction points, and numerical results are given for small size networks. System level simulations illustrate the potential gain of receiver cooperation for larger networks.

No description available.

Made available in DSpace on 2016-04-29T13:30:58Z (GMT). No. of bitstreams: 1 Jacy Correa Curado.pdf: 1878864 bytes, checksum: 30c8d5cefd3066c88698e38bd8dced21 (MD5) Previous issue date: 2012-07-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation addresses poverty as a multiple and complex phenomenon performed by a network of heterogeneous materials from contemporary public policies. To delimit these assumptions, theoretical and epistemological dialogues based on Discursive Social Psychology were articulated, addressing aspects such as the historical construction of poverty, importance of language in this construction, polysemy of meanings, and corresponding linguistic repertoires. Poverty was interpreted as a manifestation of the governmentalization of the Modern State that allowed the pursuit of a specific and complex form of government targeting the poor. Strategies for combating poverty also underwent resignifications accompanying the processes of metamorphosis and reconversion of social issues, bringing about changes in the framework of contemporary social policies, ultimately taking on the form of income transfer. To understand how the Public Policy for Combating Poverty is performed by a heterogeneous network of human and nonhuman actors through the Bolsa Família Income Allowance Program, a dialogue was articulated with selected inputs from the Actor-Network Theory and epistemological references questioning the ontological bases of truth and reality through the notions of multiplicity and performativity. Drawing on observations, interviews, conversations, and readings of public documents addressing actions of the Bolsa Família Program, three versions of "poverty" emerged: calculated, officially recorded, and controlled. These versions coexist and should not be interpreted in isolation, since taken together they would yield a joint entity or comprise a portrait of poverty that is homogeneous, stable, and permanent, understood from diverse viewpoints and perspectives. By contrast, a focus on a multiplicity of poverties is proposed in the present study. Connections between and bifurcations from versions of poverty produced by the materialities and socialities of the heterogeneous network of public policies for combating poverty are also highlighted, in a bid to destabilize, deterritorialize, and impart flexibility to the traditional notions of poor and poverty" / Esta tese apresenta a pobreza como múltipla e complexa, performada por uma rede de materiais heterogêneos nas políticas públicas contemporâneas. Para chegarmos a esses pressupostos construímos diálogos teóricos e epistemológicos com a abordagem da Psicologia Social Discursiva, tais como a construção histórica da pobreza, a importância da linguagem nessa construção, a polissemia de sentidos e seus repertórios linguísticos. Procurou-se entendê-la como manifestação de governamentalização do Estado Moderno, que permitiram o exercício de uma de forma específica e complexa de governo, que tem por alvo a população pobre. O enfrentamento à pobreza também passou por ressignificações trazidas pelos processos de metamorfose e reconversão da questão social, produzindo mudanças no marco das políticas sociais contemporâneas, assumindo o formato da transferência de renda. Para compreender como a Política Pública de Enfrentamento à Pobreza é performada por uma rede heterogênea de atores humanos e não humanos via o Programa Bolsa Família, articulou-se ainda um diálogo com algumas pontuações da Teoria Ator-rede e referenciais epistemológicos que questionam os fundamentos ontológicos de verdade e realidade por meio das noções de multiplicidade e performatividade. A partir das observações, entrevistas, conversas e leitura de documentos públicos das ações do Programa Bolsa Família, descrevemos três versões de pobrezas : a pobreza calculada, a cadastrada e a controlada. Essas versões coexistem entre si, e não devem ser entendidas de forma isoladas de tal modo que somadas produziriam um todo ou comporiam um retrato da pobreza homogênea, estável e permanente, apreendida por uma diversidade de olhares e perspectivas. Ao contrário, propomos aqui se trate de uma multiplicidade de pobrezas . Pontuamos também as conexões e bifurcações entre as versões de pobrezas produzidas pelas materialidades e socialidades da rede heterogênea das políticas públicas de enfrentamento à pobreza, como forma de desestabilizar, desterritorializar e flexibilizar as noções tradicionais de pobre e pobreza

Made available in DSpace on 2016-04-29T13:31:20Z (GMT). No. of bitstreams: 1 George Moraes De Luiz.pdf: 5186035 bytes, checksum: 3b435105f641786fe4bc92c797215ff4 (MD5) Previous issue date: 2015-11-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This research looks into the co-inhabitance of the population native to the Pantanal region in the center-west region of Brazil, state of Mato Grosso, with the cycle of full tide of the swamps surrounding the rural areas of three cities. We have selected the water cycle as our subject because they dictate the course all forms of life in the Pantanal. The basis of our discussion is formed by an interdisciplinary perspective, which allows for theoretical and methodological approximations with different areas of the social sciences and human sciences, notably the theoretical and epistemological notions of the Actor-Network theory. This has provided us with the understanding of the swamps as heterogeneous networks, establishing a debate with authors of the field of Environmental Education. We have assigned ourselves the task of writing a thesis in which both style and content question the "canons" of the academy, thus opening ourselves to reflections upon new manners of doing social research. In this challenge, we have given a poetic note to the text, valuing the traditional knowledge of the Pantanal region without losing sight of scientific knowledge. This thesis is the result of experiences lived by the researcher as an inhabitant of the Pantanal region, as wells as a result of formal and informal conversations with 42 people who are directly associated with the activities conducted in the swamps, among whom those who live on the river banks. Anchored in the notions of Everyday Conversation, with semi-structured script and field annotations, we have systematized the information by the means of fluctuating readings, generating themes which comprise the corpus of the thesis in the form descriptive narratives. The focus of our analysis is on the manner in which traditional populations predict, prepare themselves for, and live with the cycle of full tide, prioritizing the association between humans and non-humans as a possibility for survival in a flooded territory. The co-inhabitance of people with the full tides is described here in three different themes: birth-giving, housing, and means of transportation. This way of life, intertwined with nature, is commonly described in classic literature as the culture and tradition of the Pantanal populations. However, what we indicate here is that new actors, such as the construction of river dams, park roads and industrial plants, interfere in the Pantanal, altering the cycle of full tide. Due to this interference, it becomes unviable to understand the ways of life of the local populations as crystallized, which makes us argue in favor of the processuality of relations between people and nature, while rethinking the very notion of what the swamps come to be after constant socio-environmental interventions / O foco desta pesquisa é a convivência da população pantaneira com o ciclo de cheia nos pantanais mato-grossenses da região rural dos municípios de Barão de Melgaço, Poconé e Nossa Senhora do Livramento. Elegemos o ciclo das águas como fio condutor deste trabalho por ele ditar o ritmo de todas as formas de vida no Pantanal. Para sustentar nossa discussão, adotamos uma postura interdisciplinar, o que permite aproximações teórico-metodológicas com diferentes áreas das ciências sociais e humanas, notadamente os pressupostos teórico-epistemológicos da teoria ator-rede, o que permitiu compreender os pantanais como redes heterogêneas, em diálogo com autores da educação ambiental. Demo-nos a tarefa de escrever uma tese cujo estilo e conteúdo questionam os cânones da academia, abrindo-nos, assim, para reflexões sobre novas formas de fazer pesquisa social. Nesse desafio, demos tons poéticos ao texto, valorizando o saber tradicional pantaneiro sem abrir mão do conhecimento científico. Esta tese resulta das experiências vivenciadas pelo pesquisador enquanto morador da região pantaneira de Poconé, assim como da convivência e de conversas formais e informais com 42 pessoas ligadas diretamente às atividades nos pantanais, com destaque para os(as) pantaneiros(as) e ribeirinhos(as). Ancorados nas noções de conversas no cotidiano, com roteiro semiestruturado e anotações de diário de campo, sistematizamos as informações por meio de leituras flutuantes, gerando temas que compuseram o corpus da tese em forma de narrativas descritivas. O enfoque de nossa análise está na maneira como os povos tradicionais preveem, se preparam e convivem com o ciclo de cheias, privilegiando a associação entre humanos e não humanos como possibilidade de sobrevivência em um território de inundação. A convivência das pessoas com as cheias está descrita a partir de três temas: os partos, as moradias e os meios de transportes. Comumente, esse modo de vida que se atrela aos elementos da natureza é descrito pela literatura clássica como cultura e tradição pantaneira. Entretanto, sinalizamos aqui que novos atores, como a construção de diques, estradas-parque, aterros e usinas, interferem nos pantanais, alterando o ciclo de cheias. Considerando esse pressuposto, apontamos a inviabilidade de compreender os modos de vida pantaneiros de forma cristalizada, argumentando a favor da processualidade das relações entre os povos pantaneiros com a natureza, e repensando a própria noção do que vêm a ser os pantanais após constantes intervenções socioambientais

Cette thèse porte sur le paradigme « Mobile Edge cloud» qui rapproche le cloud des utilisateurs mobiles et qui déploie une architecture de clouds locaux dans les terminaisons du réseau. Les utilisateurs mobiles peuvent désormais décharger leurs tâches de calcul pour qu’elles soient exécutées par les femto-cellules (FCs) dotées de capacités de calcul et de stockage. Nous proposons ainsi un concept de regroupement de FCs dans des clusters de calculs qui participeront aux calculs des tâches déchargées. A cet effet, nous proposons, dans un premier temps, un algorithme de décision de déportation de tâches vers le cloud, nommé SM-POD. Cet algorithme prend en compte les caractéristiques des tâches de calculs, des ressources de l’équipement mobile, et de la qualité des liens de transmission. SM-POD consiste en une série de classifications successives aboutissant à une décision de calcul local, ou de déportation de l’exécution dans le cloud.Dans un deuxième temps, nous abordons le problème de formation de clusters de calcul à mono-utilisateur et à utilisateurs multiples. Nous formulons le problème d’optimisation relatif qui considère l’allocation conjointe des ressources de calculs et de communication, et la distribution de la charge de calcul sur les FCs participant au cluster. Nous proposons également une stratégie d’éparpillement, dans laquelle l’efficacité énergétique du système est améliorée au prix de la latence de calcul. Dans le cas d’utilisateurs multiples, le problème d’optimisation d’allocation conjointe de ressources n’est pas convexe. Afin de le résoudre, nous proposons une reformulation convexe du problème équivalente à la première puis nous proposons deux algorithmes heuristiques dans le but d’avoir un algorithme de formation de cluster à complexité réduite. L’idée principale du premier est l’ordonnancement des tâches de calculs sur les FCs qui les reçoivent. Les ressources de calculs sont ainsi allouées localement au niveau de la FC. Les tâches ne pouvant pas être exécutées sont, quant à elles, envoyées à une unité de contrôle (SCM) responsable de la formation des clusters de calculs et de leur exécution. Le second algorithme proposé est itératif et consiste en une formation de cluster au niveau des FCs ne tenant pas compte de la présence d’autres demandes de calculs dans le réseau. Les propositions de cluster sont envoyées au SCM qui évalue la distribution des charges sur les différentes FCs. Le SCM signale tout abus de charges pour que les FCs redistribuent leur excès dans des cellules moins chargées.Dans la dernière partie de la thèse, nous proposons un nouveau concept de mise en cache des calculs dans l’Edge cloud. Afin de réduire la latence et la consommation énergétique des clusters de calculs, nous proposons la mise en cache de calculs populaires pour empêcher leur réexécution. Ici, notre contribution est double : d’abord, nous proposons un algorithme de mise en cache basé, non seulement sur la popularité des tâches de calculs, mais aussi sur les tailles et les capacités de calculs demandés, et la connectivité des FCs dans le réseau. L’algorithme proposé identifie les tâches aboutissant à des économies d’énergie et de temps plus importantes lorsqu’elles sont téléchargées d’un cache au lieu d’être recalculées. Nous proposons ensuite d’exploiter la relation entre la popularité des tâches et la probabilité de leur mise en cache, pour localiser les emplacements potentiels de leurs copies. La méthode proposée est basée sur ces emplacements, et permet de former des clusters de recherche de taille réduite tout en garantissant de retrouver une copie en cache. / Mobile Edge Cloud brings the cloud closer to mobile users by moving the cloud computational efforts from the internet to the mobile edge. We adopt a local mobile edge cloud computing architecture, where small cells are empowered with computational and storage capacities. Mobile users’ offloaded computational tasks are executed at the cloud-enabled small cells. We propose the concept of small cells clustering for mobile edge computing, where small cells cooperate in order to execute offloaded computational tasks. A first contribution of this thesis is the design of a multi-parameter computation offloading decision algorithm, SM-POD. The proposed algorithm consists of a series of low complexity successive and nested classifications of computational tasks at the mobile side, leading to local computation, or offloading to the cloud. To reach the offloading decision, SM-POD jointly considers computational tasks, handsets, and communication channel parameters. In the second part of this thesis, we tackle the problem of small cell clusters set up for mobile edge cloud computing for both single-user and multi-user cases. The clustering problem is formulated as an optimization that jointly optimizes the computational and communication resource allocation, and the computational load distribution on the small cells participating in the computation cluster. We propose a cluster sparsification strategy, where we trade cluster latency for higher system energy efficiency. In the multi-user case, the optimization problem is not convex. In order to compute a clustering solution, we propose a convex reformulation of the problem, and we prove that both problems are equivalent. With the goal of finding a lower complexity clustering solution, we propose two heuristic small cells clustering algorithms. The first algorithm is based on resource allocation on the serving small cells where tasks are received, as a first step. Then, in a second step, unserved tasks are sent to a small cell managing unit (SCM) that sets up computational clusters for the execution of these tasks. The main idea of this algorithm is task scheduling at both serving small cells, and SCM sides for higher resource allocation efficiency. The second proposed heuristic is an iterative approach in which serving small cells compute their desired clusters, without considering the presence of other users, and send their cluster parameters to the SCM. SCM then checks for excess of resource allocation at any of the network small cells. SCM reports any load excess to serving small cells that re-distribute this load on less loaded small cells. In the final part of this thesis, we propose the concept of computation caching for edge cloud computing. With the aim of reducing the edge cloud computing latency and energy consumption, we propose caching popular computational tasks for preventing their re-execution. Our contribution here is two-fold: first, we propose a caching algorithm that is based on requests popularity, computation size, required computational capacity, and small cells connectivity. This algorithm identifies requests that, if cached and downloaded instead of being re-computed, will increase the computation caching energy and latency savings. Second, we propose a method for setting up a search small cells cluster for finding a cached copy of the requests computation. The clustering policy exploits the relationship between tasks popularity and their probability of being cached, in order to identify possible locations of the cached copy. The proposed method reduces the search cluster size while guaranteeing a minimum cache hit probability.

Fifth Generation (5G) cellular networks will experience a thousand-fold increase in data traffic with over 100 billion connected devices by 2020. In order to support this skyrocketing traffic demand, smaller base stations (BSs) are deployed to increase capacity. However, more BSs increase energy consumption which contributes to operational expenditure (OPEX) and CO2 emissions. Also, an introduction of a plethora of 5G applications running in the mobile devices cause a significant amount of energy consumption in the mobile devices. This thesis presents a novel framework for energy efficiency in 5G cloud radio access networks (C-RAN) by leveraging cloud computing technology. Energy efficiency is achieved in three ways; (i) at the radio side of H-C-RAN (Heterogeneous C-RAN), a dynamic BS switching off algorithm is proposed to minimise energy consumption while maintaining Quality of Service (QoS), (ii) in the BS cloud, baseband workload consolidation schemes are proposed based on simulated annealing and genetic algorithms to minimise energy consumption in the cloud, where also advanced fuzzy based admission control with pre-emption is implemented to improve QoS and resource utilisation (iii) at the mobile device side, Mobile Edge Computing (MEC) is used where computer intensive tasks from the mobile device are executed in the MEC server in the cloud. The simulation results show that the proposed framework effectively reduced energy consumption by up to 48% within RAN and 57% in the mobile devices, and improved network energy efficiency by a factor of 10, network throughput by a factor of 2.7 and resource utilisation by 54% while maintaining QoS.

Abstract Substantially growing data traffic over wireless networks poses increased challenges for mobile network operators in deploying sufficient network resources and managing user mobility. This dissertation considers these challenges to providing satisfactory Quality of Service (QoS) for end-users and studies solutions for better utilization of the heterogeneous network environment. First, the dissertation examines what solutions mobile devices and network management entities can use to dynamically collect valid cross-layer information from different network entities. Cross-layer information allows monitoring of the condition of the network in multiple layers on a user and application basis. The second research topic considers the techniques the network management entities can use to improve resource usage in wireless networks based on the collected cross-layer information. The IEEE 802.21 standard, specified to facilitate handovers between heterogeneous networks, is used as the basis for cross-layer information delivery. This dissertation also focuses on utilization of the standard beyond the inter-access technology handovers. In order to improve resource usage in wireless networks dynamically, event delivery enhancements are proposed for the standard so that it better applies to the requirements of different techniques. Such techniques are traffic priority adjustment, traffic adaptation, packet aggregation, and network protocol header compression. The results show that when a handover is not feasible, these techniques effectively allow sharing of the limited radio resources for the user data according to applications’ importance and type. Mobility management is studied in terms of network information service, one of the main services of IEEE 802.21. The thesis proposes enhancing the information service with a base station cell coverage area database. The database provides significant improvements for the selection of a handover target in a dense base station environment. With all the results taken together, the dissertation provides mobile network operators various means to improve the usage of wireless networks on the basis of applications’ varying QoS requirements. / Tiivistelmä Voimakkaasti kasvava langattomien tietoverkkojen dataliikenne aiheuttaa verkko-operaattoreille haasteita tarjota riittävät verkkoresurssit ja hallita käyttäjien liikkuvuutta. Väitöskirja huomioi nämä haasteet tarjota loppukäyttäjille tyydyttävä palvelunlaatu (QoS) ja tutkii ratkaisuja, joilla heterogeenistä verkkoympäristöä voidaan hyödyntää tehokkaammin. Aluksi väitöskirja tutkii, mitä ratkaisuja päätelaitteet ja verkkohallintatoimijat voivat käyttää keräämään protokollakerrosten välistä (cross-layer) tietoa eri verkkotoimijoilta. Protokollakerrosten välinen tieto mahdollistaa verkon tilan seuraamisen usealla eri kerroksella käyttäjä- ja sovelluskohtaisesti. Toinen tutkimusaihe tarkastelee protokollakerrosten välistä tietoa hyödyntäviä tekniikoita, joita verkonhallintatoimijat voivat käyttää tehostamaan resurssien käyttöä langattomissa verkoissa. IEEE 802.21-standardia, joka on määritetty helpottamaan verkonvaihtoja heterogeenisten verkkojen välillä, käytetään pohjana protokollakerrosten välisen tiedon jakelulle. Väitöskirjassa keskitytään standardin hyödyntämiseen myös muussa kuin verkkoteknologioiden välisen verkonvaihdon yhteydessä. Väitöskirja ehdottaa parannuksia standardin tapahtumatietovälitykseen, jotta se täyttäisi paremmin eri tekniikoiden asettamat vaatimukset dynaamisesti toteutettavista toimista langattomien verkkojen resurssikäytön tehostamiseksi. Nämä tekniikat ovat liikenteen prioriteetin muutokset, liikenteen adaptointi, pakettien yhdistäminen ja verkkoprotokollaotsikoiden pakkaus. Tulokset osoittavat, että kun tukiasema- tai verkonvaihto ei ole mahdollinen, nämä tekniikat mahdollistavat rajattujen verkkoresurssien jakamisen tehokkaasti sovellusten tärkeyden ja tyypin mukaan. Liikkuvuudenhallintaa tutkitaan verkkoinformaatiopalvelun, joka on myös yksi IEEE 802.21-standardin pääpalveluista, kautta. Väitöskirja ehdottaa, että informaatiopalvelua tehostetaan liittämällä siihen tietokanta tukiasemasolujen peittoalueista. Tietokanta tehostaa huomattavasti verkonvaihdon kohteen valintaa tiheissä tukiasemaympäristöissä. Kun väitöskirjan tulokset huomioidaan kokonaisuutena, väitöskirja tarjoaa verkko-operaattoreille useita tapoja tehostaa langattomien verkkojen käyttöä sovellusten vaihtelevien palvelunlaatuvaatimusten perusteella.