During the last decade, the average mobile wireless data usage per person has tremendously increased. An even faster growth of the traffic demand is expected for the incoming years, due to several factors such as the increasing global population, the spread of the Internet of things (IoT), and the development of advanced technologies that require a higher amount of data. While mobile communication technologies have rapidly evolved to meet this need in the most usual situations, it is expected that the sixth generation (6G) of mobile connectivity will be the first one paying considerable attention to under-connected environments such as low-income, remote, or disaster-struck regions. Many specialized researchers and entrepreneurs are trying to design and implement alternative network architectures specifically meant for enhancing the performances of the current telecommunication (telecom) infrastructure. In particular, the use of aerial base stations (ABSs) has received considerable attention due to the main advantages of easy deployability and low-cost that are typical of unmanned aerial vehicles (UAVs), which are available in several fashions depending on the application; moreover, UAVs are also eligible to carry reflective intelligent surfaces (RISs), which represent a promising technology that allows to reflect signals towards specific directions. Another possibility that we have investigated consists in integrating the transceivers inside or atop existing rural wind turbine (WT) towers, in order to increase the coverage radius while avoiding the cost of building a separate telecom infrastructure. A powerful mathematical tool for evaluating the performance metrics of either terrestrial, aerial, or vertical heterogeneous wireless networks is stochastic geometry (SG), since it can be used to model the locations of the base stations (BSs) according to tractable spatial distributions (with either a fixed or a random cardinality) in order to imitate the typical deployments of the nodes made in realistic scenarios; in particular, in this work we focus on rural and post-disaster situations. SG makes use of point processes to model networks' topologies. The developed spatial models, in turn, allow us to analyze the quality of service (QoS) experienced by the typical user served by the proposed networks. To this extent, we creatively and efficiently studied our inhomogeneous systems by making use of what we call the indicator method, meaning that we do not subdivide the ground plane in multiple homogeneous sub-regions, but we use indicator functions to provide general expressions that are valid over the entire ground plane. To prove the effectiveness of the novel architectures, insightful comparisons with the conventional ones are presented.

Orientadora: Profa. Dra. Margarethe Born Steinberger-Elias / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia da Informação, 2014. / Esta pesquisa integra um projeto interdisciplinar nas áreas da Comunicação, Linguística e Computação, voltado à Comunicação de Desastres em língua portuguesa. O objetivo é a exploração de aplicações de métodos de Processamento de Linguagem Natural para modelagem de redes comunicativas a fim de criar um modelo que possibilite o reconhecimento e a classificação automática dos perfis comunicacionais dos atores envolvidos em situações de desastre. Assumindo que o perfil dos atores pode ser detectado linguisticamente em textos jornalísticos, esta pesquisa explora a capacidade dos verbos de elocução (dicendi) funcionarem como marcadores discursivos. Utiliza-se, então, de ferramentas computacionais para identificar automaticamente marcadores de interlocução. Dessa forma, o problema da pesquisa recai sobre como identificar marcadores semânticos associados a modos de apropriação de conceitos (sistemas de categorização) adotados pelas comunidades de conhecimento a que pertençam os atores. A análise de frequência e probabilidade de certos itens lexicais vinculados aos atores envolvidos em desastres específicos permitirá detectar como eles se organizam em redes sócio discursivas. A geração automática destas redes contribui para aperfeiçoar a comunicação em cenários emergenciais. Com apoio de ferramentas de Processamento de Linguagem Natural, o estudo baseia-se em dados de um corpus de textos do jornal Folha de S. Paulo sobre desastres importantes ocorridos em 2010 e 2011 no Estado do Rio de Janeiro, que mataram milhares de pessoas e desencadearam muitos prejuízos sociais e econômicos. / This research is part of an interdisciplinary project in the areas of communication, Linguistics and computing, focused on disaster Communication in Portuguese language. The goal is an exploration of applications of Natural Language Processing methods for modeling communication networks, in order to create a conceptual model that allows recognition and categorization automatic of communicational profiles of actors involved in disaster situations. Assuming that the profile of actors can be detected linguistically in journalistic texts, this study explores the ability of verbs of elocution (dicendi) work as discursive markers. It is used, then of computational tools for automatically identifying markers of interlocution. In this way, the problem of research rests on how to identify semantic markers associated with modes of appropriation of concepts (categorization systems) adopted by the knowledge communities that belong to the actors. The frequency analysis and probability of certain lexical items linked to actors involved in specific disaster will detect how they organize themselves in socio-discursive networks. The automatic generation of these networks contributes to enhance communication in emergency scenarios. With the support of Natural Language Processing tools, the study is based on data from a text corpus of newspaper Folha de S. Paulo on major disasters occurring in 2010 and 2011 in the State of Rio de Janeiro, which killed thousands of people and triggered many social and economic losses.

Orientadora: Profa. Dra. Margarethe Born Steinberger-Elias / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia da Informação, 2014. / Esta é uma pesquisa interdisciplinar envolvendo Ciências da Comunicação, Linguística e Computação, aplicando métodos e técnicas de modelagem linguística à comunicação de desastres baseada em textos jornalísticos. O objetivo específico é recuperar informação relativa à causalidade em textos sobre desastres naturais nas regiões mais propensas do estado de São Paulo entre 1994 e 2012. A metodologia prevê a criação de um corpus de relatos noticiosos do qual se possam extrair indicadores linguísticos para reconhecimento automático das causas mais comumente atribuídas aos desastres. São três etapas: a) identificação de vocabulário específico associado a diferentes tipos de desastres naturais e a regiões do estado de São Paulo onde ocorreram; b) extração de informação sobre causalidade e cadeias causais vinculadas a tipos de desastres e a regiões referidas no corpus; c) criação de um modelo capaz de reconhecer o encadeamento entre expressões de causalidade e de representação dos efeitos associados. Para o desenvolvimento da pesquisa foi feita a coleta e organização de um corpus dos textos jornalísticos de referência; seleção e aplicação de ferramentas computacionais para tratamento de itens lexicais por critérios semânticos e estatísticos; construção de matrizes para visualização de redes léxico-semânticas; e um mapeamento da distribuição da informação sobre causalidade associada a desastres indexados por tipo e região. Os resultados obtidos indicam recursos de modelagem linguística que podem ser generalizados para uma recuperação automática de informação relevante sobre causalidade em textos jornalísticos. Tais resultados também permitem acesso rápido a informações estratégicas que ajudem a avaliar riscos e orientar medidas de prevenção de desastres. A modelagem baseada em língua portuguesa contribuiu para viabilizar o projeto futuro de um "banco de riscos" brasileiro contando com informação sobre causas de desastres em dimensão regional e nacional no Brasil. / This is an interdisciplinary research involving Communication, Language and Computation Sciences, applying methods and techniques of linguistic modeling to disaster communication in journalistic texts. Our goal is to retrieve information about causality in texts on natural disaster prone regions in the state of São Paulo between 1994 and 2012. The methodology includes the creation of a corpus of news reports with linguistic indicators to allow automatic recognition of most commonly attributed causation to disasters. Research methods followed three steps: a) identification of specific vocabulary associated with types of natural disasters and regions of the state of São Paulo where they mostly occurred, b) extraction of information about causation and causal chains linked to types of disaster and regions referred to in the corpus; c) development of a model to recognize the linkage between expressions of causality and lexical representation of associated effects. Adequate computational tools were necessary for collecting and organizing the corpus, treating lexical items by semantic and statistical criteria, viewing lexical-semantic networks, and mapping the distribution of information on causality associated to disasters indexed by type and region. Results indicated that linguistic modeling can be generalized to automatic retrieval of causal information in journalistic texts. Results extensions could provide quick access to strategic information on Brazilian most risky regions and relevant disaster prevention measures. Modeling in Portuguese language could also allow to build a wider and more ambitious "brazilian bank of risks" relying on regional and national scale information on causality.

L'objectif de cette thèse est de proposer des stratégies d'optimisation protocolaire et architecturale adaptées aux cas d'usages pour lesquels les communications entre les noeuds d'un réseau sont susceptibles d'être fortement perturbées par des conditions de déploiement défavorables, sans que les mécanismes standards de réparation de panne prévus pour ce réseau puissent convenablement traiter et résorber les effets de ces perturbations. Il peut s'agir de divers contextes applicatifs, comme celui des réseaux de communication d'urgence, mis en oeuvre suite à la survenue de désastres ou plus généralement d'incidents non planifiés capables de laisser les réseaux d'une zone affectée partiellement ou totalement endommagés. Les perturbations mentionnées peuvent être de différente nature : elles peuvent par exemple être provoquées par un dimensionnement du réseau défavorable (ex. nombre de noeuds trop faible, surface de dispersion des nœuds trop importante, portée des interfaces de communication sans fil trop réduites, . . . en regard des autres paramètres de déploiement considérés). Elles peuvent aussi être provoquées par des causes externes, comme par exemple la présence non anticipée d'obstacles ou la survenue de sources d'interférences extérieures au réseau considéré. De manière générale, on constate qu'en présence de telles perturbations, un réseau non conçu pour spécifiquement fonctionner dans de telles conditions peut voir ses performances et la qualité d'expérience de ses utilisateurs baisser significativement. Dans ce contexte, nous cherchons à comparer la perception que nous avons traditionnellement de la mobilité dans les réseaux sans fil, en particulier dans les réseaux ad hoc mobiles et les réseaux tolérants aux perturbations et aux délais, avec les principes de la mobilité contrôlée, selon lesquels un noeud est capable de participer directement à la détermination de sa trajectoire et à la réalisation de son déplacement. Nous définissons un système de forces virtuelles, comprenant diverses composantes répulsives, attractives, de frottement et d'alignement, pouvant être appliquées aux noeuds d'un réseau. Nous expliquons ensuite comment concrètement utiliser ces forces virtuelles dans un déploiement réseau, et nous spécifions une solution protocolaire utilisée selon diverses variations, que nous mettons en oeuvre à travers des stratégies de mobilité contrôlée adaptées à différents environnements réseau.Nous prenons tout d'abord appui sur un scénario applicatif relatif à la lutte contre la progression d'une espèce invasive, le frelon asiatique, et décrivons un déploiement sur un réseau ad hoc sans fil reposant sur un ensemble de véhicules mobiles aériens qui exécutent une première stratégie de mobilité contrôlée. Nous cherchons à identifier les plages de valeurs pour les paramètres-clés de notre protocole à base de forces virtuelles aboutissant aux meilleures performances du réseau constitué par l'ensemble des noeuds considérés. Par la suite, nous introduisons également un scénario de déploiement de réseau temporaire de secours en situation de désastre, toujours de type ad hoc sans fil, puis nous présentons une analyse de la performance d'une seconde stratégie de mobilité contrôlée adaptée à cet environnement. Nous montrons en particulier comment cette stratégie se comporte lorsque le nombre de noeuds du réseau augmente. Nous abordons ensuite le contexte des réseaux utilisés en conditions défavorables et des mécanismes de tolérance aux perturbations. Nous cherchons ici à concevoir un troisième type de stratégie de mobilité contrôlée utilisant conjointement des mécanismes de tolérance aux perturbations et aux délais et les principes de mobilité contrôlée afin d'augmenter significativement les performances du réseau / Throughout this thesis, we seek to propose and design optimized strategies that are adapted to a widespread class of use cases in which communications between network nodes may be disrupted by adverse deployment conditions, assuming that standard fault repair mechanisms are unable to address and mitigate the effects created by these disruptions. Such use cases include the applicative context of emergency communication networks, which are often met in the wake of disasters, or more generally after the occurrence of any unexpected event which may leave the existing networks of an affected area partially or even totally damaged. The aforementioned disruptions can be of different nature: they may result from a detrimental network dimensioning (e.g. low number of network nodes, excessive node scattering surface, insufficient radio communication range, . . . with respect to the other considered deployment parameter values). They may also stem from external causes, e.g. the unexpected presence of obstacles on the area of interest, or the existence of extrinsic interference sources that may disturb the considered network. In general, it can be observed that given such disruptions, a network which is not inherently designed to operate in these conditions is likely to under-perform and, as a result, to offer a significantly decreased quality of experience to its users. In this regard, we seek to compare our perception of the traditional concept of mobility as seen in common infrastructure, ad hoc or disruption- and delay-tolerant wireless networks with the principles of controlled mobility, according to which a network node may directly control its own movement and affect its trajectory accordingly. More precisely, we investigate the means to define a virtual force system which encompasses multiple repulsive, attractive, friction and alignment forces, all of which may be applied to network nodes in order to enforce this principle of controlled mobility.We then explain how virtual forces can concretely be implemented and used in a realistic network deployment, and we specify a protocol solution and its variations, which we enforce within controlled mobility strategies with the prospect that those prove best suited to the considered network environments. We first take as an applicative background a scenario aiming to fight the spread of an invasive species, the Asian hornet, and we outline a practical deployment relying on a wireless ad hoc network formed with unmanned aerial nodes which all enforce our first proposed controlled mobility strategy. We then seek to identify the best value intervals for the key parameters of our virtual force-based protocol, anticipating that configured with these values, the deployed network will yield its best performance in terms of delays and packet delivery. Later, we introduce a scenario related to the deployment of an emergency communication network, still on the basis of wireless ad hoc network principles. We then present an analysis of how a second proposed controlled mobility strategy performs in this applicative environment. In particular, we show how this strategy behaves when the number of network nodes increases. At that point, we address the context of networks deployed in challenging conditions, and of the use of disruption- and delaytolerant mechanisms. We aim here at designing a third type of strategy that jointly uses disruption- and delay-tolerant mechanisms as well as controlled mobility principles, in order to significantly increase the overall network performance. We then investigate and explain how this strategy allows transmitting a fraction of the user traffic with short delays, when an end-to-end route is available along a communication chain, while the other fraction of the traffic is delivered with longer delays, with the support of delay-tolerant routing mechanisms

Disaster victims and vulnerable populations are audiences that communications professionals and scholars have ignored. Public relation practices dominate current disaster communication policy. This study examines the disaster communication network, including policy and practice, of the Thai Red Cross, before, during, and after the Asian tsunami. Disaster communication(s) is defined as the sharing and exchange of information with the victims immediately affected by a disaster. This definition focuses specifically on the vulnerable audience and allows response efforts to emerge from multiple disciplines. Focusing response efforts on victims' assessed needs and abilities allows for a multi-disciplinary approach to mitigate further suffering. The disciplines of health, development, and communications converge for efficient disaster management. This case study gives great insight into the cultural chasm between policy making and practical application and also reveals the value of personal initiative. A proposed model of disaster communication is offered. Significantly more research is needed in the area of disaster communications.