We address the challenge of providing low-cost, universal access of useful information to people in different parts of the globe. We achieve this by following two strategies. First, we focus on the delivery of information through computerized devices and prototype new methods for making that delivery possible in a secure, low-cost, and universal manner. Second, we focus on the use of participatory media, such as blogs, in the context of news related content, and develop methods to recommend useful information that will be of interest to users. To achieve the first goal, we have designed a low-cost wireless system for Internet access in rural areas, and a smartphone-based system for the opportunistic use of WiFi connectivity to reduce the cost of data transfer on multi-NIC mobile devices. Included is a methodology for secure communication using identity based cryptography. For the second goal of identifying useful information, we make use of sociological theories regarding social networks in mass-media to develop a model of how participatory media can offer users effective news-related information. We then use this model to design a recommender system for participatory media content that pushes useful information to people in a personalized fashion. Our algorithms provide an order of magnitude better performance in terms of recommendation accuracy than other state-of-the-art recommender systems. Our work provides some fundamental insights into the design of low-cost communication systems and the provision of useful messages to users in participatory media through a multi-disciplinary approach. The result is a framework that efficiently and effectively delivers information to people in remote corners of the world.

We address the challenge of providing low-cost, universal access of useful information to people in different parts of the globe. We achieve this by following two strategies. First, we focus on the delivery of information through computerized devices and prototype new methods for making that delivery possible in a secure, low-cost, and universal manner. Second, we focus on the use of participatory media, such as blogs, in the context of news related content, and develop methods to recommend useful information that will be of interest to users. To achieve the first goal, we have designed a low-cost wireless system for Internet access in rural areas, and a smartphone-based system for the opportunistic use of WiFi connectivity to reduce the cost of data transfer on multi-NIC mobile devices. Included is a methodology for secure communication using identity based cryptography. For the second goal of identifying useful information, we make use of sociological theories regarding social networks in mass-media to develop a model of how participatory media can offer users effective news-related information. We then use this model to design a recommender system for participatory media content that pushes useful information to people in a personalized fashion. Our algorithms provide an order of magnitude better performance in terms of recommendation accuracy than other state-of-the-art recommender systems. Our work provides some fundamental insights into the design of low-cost communication systems and the provision of useful messages to users in participatory media through a multi-disciplinary approach. The result is a framework that efficiently and effectively delivers information to people in remote corners of the world.

As more and more wireless applications/services emerge in the market, the already heavily crowded radio spectrum becomes much scarcer. Meanwhile, however,as it is reported in the recent literature, there is a large amount of radio spectrum that is under-utilized. This motivates the concept of cognitive radio wireless networks that allow the unlicensed secondary-users (SUs) to dynamically use the vacant radio spectrum which is not being used by the licensed primary-users (PUs). In this dissertation, we investigate protocol design for both the synchronous and asynchronous cognitive radio networks with emphasis on the medium access control (MAC) layer. We propose various spectrum sharing schemes, opportunistic packet scheduling schemes, and spectrum sensing schemes in the MAC and physical (PHY) layers for different types of cognitive radio networks, allowing the SUs to opportunistically utilize the licensed spectrum while confining the level of interference to the range the PUs can tolerate. First, we propose the cross-layer based multi-channel MAC protocol, which integrates the cooperative spectrum sensing at PHY layer and the interweave-based spectrum access at MAC layer, for the synchronous cognitive radio networks. Second, we propose the channel-hopping based single-transceiver MAC protocol for the hardware-constrained synchronous cognitive radio networks, under which the SUs can identify and exploit the vacant channels by dynamically switching across the licensed channels with their distinct channel-hopping sequences. Third, we propose the opportunistic multi-channel MAC protocol with the two-threshold sequential spectrum sensing algorithm for asynchronous cognitive radio networks. Fourth, by combining the interweave and underlay spectrum sharing modes, we propose the adaptive spectrum sharing scheme for code division multiple access (CDMA) based cognitive MAC in the uplink communications over the asynchronous cognitive radio networks, where the PUs may have different types of channel usage patterns. Finally, we develop a packet scheduling scheme for the PU MAC protocol in the context of time division multiple access (TDMA)-based cognitive radio wireless networks, which is designed to operate friendly towards the SUs in terms of the vacant-channel probability. We also develop various analytical models, including the Markov chain models, M=GY =1 queuing models, cross-layer optimization models, etc., to rigorously analyze the performance of our proposed MAC protocols in terms of aggregate throughput, access delay, and packet drop rate for both the saturation network case and non-saturation network case. In addition, we conducted extensive simulations to validate our analytical models and evaluate our proposed MAC protocols/schemes. Both the numerical and simulation results show that our proposed MAC protocols/schemes can significantly improve the spectrum utilization efficiency of wireless networks.

An information society under constant development enables organizations to have access to a growing supply of information. Handled in an efficient manner, information can be a valuable, competitive resource. This can be achieved by investing in a Business Intelligence system (BI system). BI system's main function is to manage large amounts of unstructured data, convert it into useful information, which in turn will be used as a basis for performance management. The purpose of this study is that, through qualitative, semi-structured, in-depth interviews, to examine the perceived benefit of using BI systems to support business governance. This benefit is analyzed using theories such as traditional, bounded and flexible-bounded rationality, cognitive bias and theories of man's ability to think intuitively and reflective. The benefits of BI systems will also be analyzed using the theories of the communication process, conflicts in decision making and DIKW pyramid describing the process data, information, knowledge, wisdom. It also analyzes the benefits of BI systems using agency theory. The results show that users of BI systems are experiencing the benefits as follow: BI systems provide increased access to information in the organization, increasing the ability to handle large amounts of information, creating more fact-based decisions, freeing up time for analysis, reducing opportunistic behavior and facilitates internal communication. This creates flexibility in the bounded rationality, a more reflective decision-making process that improves the prospects to make rational decisions. Users go higher up in DIKW pyramid. BI systems reduce the information asymmetry between principal and agent. BI systems reduce uncertainty in decision reducing the risk of conflict. Training and practice are essential for BI systems to generate benefits. Unlike previous research, this study shows that BI systems are well integrated into organizations as well as live up to expectations. A new aspect of BI systems is that they reduce the risk of opportunistic behavior.

Cette thèse apporte des contributions à la modélisation, compréhension ainsi qu'à la communication efficace d'information dans les réseaux dynamiques peuplant la périphérie de l'Internet. Par réseaux dynamiques, nous signifions les réseaux pouvant être modélisés par des graphes dynamiques dans lesquels noeuds et liens évoluent temporellement. Dans la première partie de la thèse, nous proposons un nouveau modèle de mobilité - STEPS - qui permet de capturer un large spectre de comportement de mobilité humains. STEPS mets en oeuvre deux principes fondamentaux de la mobilité humaine : l'attachement préférentiel à une zone de prédilection et l'attraction vers une zone de prédilection. Nous proposons une modélisation markovienne de ce modèle de mobilité. Nous montrons que ce simple modèle paramétrique est capable de capturer les caractéristiques statistiques saillantes de la mobilité humaine comme la distribution des temps d'inter-contacts et de contacts. Dans la deuxième partie, en utilisant STEPS, nous analysons les propriétés comportementales et structurelles fondamentales des réseaux opportunistes. Nous redéfinissons dans le contexte des réseaux dynamiques la notion de structure petit monde et montrons comment une telle structure peut émerger. En particulier, nous montrons que les noeuds fortement dynamiques peuvent jouer le rôle de ponts entre les composants déconnectés, aident à réduire significativement la longueur du chemin caractéristique du réseau et contribuent à l'émergence du phénomène petit-monde dans les réseaux dynamiques. Nous proposons une façon de modéliser ce phénomène sous STEPS. À partir d'un réseau dynamique régulier dans lequel les noeuds limitent leur mobilité à leurs zones préférentielles respectives. Nous recablons ce réseau en injectant progressivement des noeuds nomades se déplaçant entre plusieurs zones. Nous montrons que le pourcentage de tels nœuds nomades est de 10%, le réseau possède une structure petit monde avec un fort taux de clusterisation et un faible longueur du chemin caractéristique. La troisième contribution de cette thèse porte sur l'étude de l'impact du désordre et de l'irrégularité des contacts sur la capacité de communication d'un réseau dynamique. Nous analysons le degré de désordre de réseaux opportunistes réels et montrons que si exploité correctement, celui-ci peut améliorer significativement les performances du routage. Nous introduisons ensuite un modèle permettant de capturer le niveau de désordre d'un réseau dynamique. Nous proposons deux algorithmes simples et efficaces qui exploitent la structure temporelle d'un réseau dynamique pour délivrer les messages avec un bon compromis entre l'usage des ressources et les performances. Les résultats de simulations et analytiques montrent que ce type d'algorithme est plus performant que les approches classiques. Nous mettons également en évidence aussi la structure de réseau pour laquelle ce type d'algorithme atteint ses performances optimum. Basé sur ce résultat théorique nous proposons un nouveau protocole de routage efficace pour les réseaux opportunistes centré sur le contenu. Dans ce protocole, les noeuds maintiennent, via leurs contacts opportunistes, une fonction d'utilité qui résume leur proximité spatio-temporelle par rapport aux autres noeuds. En conséquence, router dans un tel contexte se résume à suivre le gradient de plus grande pente conduisant vers le noeud destination. Cette propriété induit un algorithme de routage simple et efficace qui peut être utilisé aussi bien dans un contexte d'adressage IP que de réseau centré sur les contenus. Les résultats de simulation montrent que ce protocole superforme les protocoles de routage classiques déjà définis pour les réseaux opportunistes. La dernière contribution de cette thèse consiste à mettre en évidence une application potentielle des réseaux dynamiques dans le contexte du " mobile cloud computing ". En utilisant les techniques d'optimisation particulaires, nous montrons que la mobilité peut augmenter considérablement la capacité de calcul des réseaux dynamiques. De plus, nous montrons que la structure dynamique du réseau a un fort impact sur sa capacité de calcul.

I tidigare studier har det framkommit att amerikanska företag manipulerar sina finansiella räkenskaper inför en nyemission med hjälp av Earnings Management genom oförklarliga periodiseringar. Detta görs i syfte att reflektera en bättre bild av företagets finansiella ställning gentemot hur det i verkligheten ser ut. Företeelsen tillämpas med avsikt att erhålla ett större finansiellt riskkapital då företaget utfärdar nyemission. Denna studie undersöker om svenska företag agerar likt amerikanska företag vid en nyemission och därför är syftet i studien att undersöka om svenska företag tillämpar Earnings Management genom oförklarliga periodiseringar vid perioden då de utfärdar nyemission. Svenska företag har varit av intresse i följande studie då svenska företag verkar under ett annorlunda redovisnings- och skattesystem än amerikanska företag gör, varpå vi vill testa om teorin Earnings Management genom oförklarliga periodiseringar är tillämpbar på även svenska företag, trots de skillnader som föreligger mellan ländernas lagsystem. Studien har genomförts med hjälp av en kvantitativ metod som vi presenterat med hjälp av en deskriptiv statistisk analys. De resultat som framkommit i studien är att även svenska, såväl som amerikanska, företag tillämpar Earnings Management genom oförklarliga periodiseringar vid de kvartal då ska utfärda nyemission, trots de olikheter i redovisnings- och skattesystem som råder länderna emellan. Förutom detta visar studien på att svenska företag även tillämpar en extrem form av Earnings Management samt att olika branscher tillämpar Earnings Management genom oförklarliga periodiseringar i olika grad då de ska utfärda nyemission. De resultat som framkommer i följande studie visar att det är av stor betydelse att investerare har en medvetenhet om att Earnings Management genom oförklarliga periodiseringar förekommer när svenska företag ska utfärda nyemission. Detta är av vikt då tidigare studier har påvisat att många investerare som förvärvat aktier i företagen som tillämpat Earnings Management genom oförklarliga periodiseringar har känt en besvikelse samt upplevt att de blivit missledda av företagens publicerade finansiella rapporter efter nyemissionen. Besvikelsen grundar sig i att det rapporterade resultatet vanligtvis kraftigt sjunker kvartalen efter nyemission då företagen tillämpat Earnings management genom oförklarliga periodiseringar. / In previous studies, it has been found that US companies manipulate their financial statements before issuing Seasoned Equity Offerings (SEO) using Accrual-based Earnings Management. This is done by the company in order to reflect a better financial position compared to their true underlying financial performance. Accrual-based Earnings Management is applied with the intention of obtaining larger financial capital when issuing SEOs. This study examines whether Swedish companies, consistent with US companies, apply the phenomenon in a similar way while issuing SEOs and the purpose of our study is therefore to investigate whether Swedish companies apply Accrual-based Earnings Management in the period they issue SEOs. Swedish companies have been of interest in the following study, as Swedish companies operate under a different accounting and tax law compared to that of American companies. As a result, we want to test the theory of Accrual-based Earnings Management to see if it is applicable to Swedish companies, despite the differences in tax law that exists between the countries. The study has been conducted using a quantitative methodology which has been presented through a descriptive statistical analysis. Our results imply that Swedish- as well as American companies, apply Accrual-based Earnings Management in the period they issue SEOs. This is found despite differences in accounting and tax law between the two countries. In addition to this, the study also shows that Swedish companies apply an extreme form of Accrual-based Earnings Management, and that it exist industrial differences in the level of Accrual-based Earnings Management that is applied when issuing SEOs. The results found in the following study show that it is of the utmost importance that investors have an awareness regarding Accrual-based Earnings Management and that it occurs when Swedish companies issue a SEO. This is important as previous studies have shown that many investors who acquired shares in the companies who applied Accrual-based Earnings Management when issuing SEOs, have felt disappointed and have found that they have been misled by the companies published financial reports following the SEO. The disappointment is based on the fact that as companies apply Accrual-based Earnings Management, the companies reported earnings usually fall in the period after issuing a SEO.

This study investigates whether the HIV/AIDS and Life Skills Education Programme for schools was implemented in accordance with the Ministry's directives. It also seeks to establish whether the programme was effective or not by identifying and examining different implementation strategies and methodologies. Fieldwork was undertaken in the Lupane Area Development Programme where nine schools were randomly selected from sixteen primary schools. A total of nine head-teachers responded to the heads' questionnaire and fifty-eight Grade 4 to 7 teachers responded to the teachers' questionnaire. The study reveals that to a very large extent the HIV/AIDS and Life-skills Education Programme was implemented from Grades 4 to 7 in the primary schools. However, substantial improvements still need to be made in mobilising reading and financial resources. More training and the introduction of more participatory methodologies need to be stepped up for the children to realise more benefits from this life skills education programme. / Development Studies / M.A. (Development Studies)

A colonização nasal por Staphylococcus aureus e a infecção pelo HIV representam problemas de saúde pública de preocupação mundial. O objetivo geral foi identificar os fatores de risco para a colonização nasal por Staphylococcus aureus em pessoas vivendo com HIV/aids. Para tanto, foi realizado um estudo tipo caso-controle, com pessoas vivendo com HIV/aids internadas nas unidades especializadas na assistência às doenças infecciosas de um hospital de ensino no interior paulista. A coleta de dados ocorreu de janeiro/2013 a fevereiro/2015, por meio de entrevista individual contemplando dados sociodemográficos e clínicos, além da coleta da secreção nasal com auxílio do swab em meio Stuart, ambos nas primeiras 24 horas de internação. As amostras foram encaminhadas e processadas pelo Laboratório de Microbiologia da própria instituição. Os critérios de inclusão foram: ter idade acima de 18 anos, ser soropositivo ao HIV, estar internado. Nas análises estatísticas foram realizados os testes qui-quadrado de Pearson, Exato de Fisher, t-Student, Wilcoxon e Regressão Logística Univariada e Multivariada, por meio do software SAS®. Os dados estão apresentados em tabelas e figuras. O presente estudo foi aprovado pelo Comitê de Ética em Pesquisa da Escola de Enfermagem de Ribeirão Preto (No CAAE 38990114.5.0000.5393) e pela instituição co-participante (No CAAE 38990114.5.3001.5440). Participaram do estudo 240 pessoas vivendo com HIV/aids, sendo 120 Casos e 120 Controles, houve predominância do sexo masculino em 65,0% dos Casos e 55,0% dos Controles, 35,8% dos Casos estavam na faixa etária de 30 a 39 anos e 45,8% dos Controles tinham idade de 40 a 49 anos, a etnia predominante foi a branca para Casos e Controles, 74,2% e 64,2%, respectivamente. Os grupos foram homogêneos entre si em relação ao sexo, etnia e escolaridade. A média do tempo de diagnóstico foi de 9 anos para Casos e 8,8 anos para Controles. O modelo final de regressão logística evidenciou como fatores de risco associados à colonização nasal por Staphylococcus aureus em pessoas vivendo com HIV/aids, ser da etnia branca, p=0,05 (OR:1,85; IC95% 1,00 - 3,57); ter carga viral >40 cópias/mL, p= 0,03 (OR: 2,90; IC95% 1,15 - 7,30); estar com contagem de LT-CD4+ <200 células/mm3 p=0,001 (OR: 2,71; IC95% 1,53 - 4,81); e apresentar doença oportunista p=0,014 (OR: 2,09; IC95% 1,20 - 3,67). Além disso, foi evidenciado como fator de proteção para a colonização nasal pelo Staphylococcus aureus em pessoas vivendo com HIV/aids o uso de antirretroviral p=0,008 (OR: 0,45; IC95% 0,25 - 0,81). Concluímos que a colonização nasal por Staphylococcus aureus nas pessoas vivendo com HIV/aids foi associada aos fatores: etnia, carga viral, contagem de LT-CD4+ , infecção oportunista e uso de antirretroviral / Staphylococcus aureus nasal colonization and HIV infection represent public health problems of global concern. The overall objective was to identify the risk factors for nasal colonization by Staphylococcus aureus in people living with HIV / AIDS. Therefore, a case-control study was conducted, with people living with HIV / AIDS hospitalized at the units specialized in infectious disease care at a teaching hospital in the interior of São Paulo. Data were collected from January / 2013 to February / 2015 by means of an individual interview, including sociodemographic and clinical data, as well as the collection of nasal secretions with the aid of swab in Stuart\'s medium, both during the first 24 hours of hospitalization. The samples were sent and processed by the Laboratory of Microbiology of the institution itself. The inclusion criteria were: to be over 18 years of age, to be known as infected HIV, to be hospitalized. Statistical analyzes were performed using the Pearson chi-square test, Fisher\'s exact test, Student t-test, Wilcoxon test, and Univariate and Multivariate logistic regression using the SAS® software. The data are presented in tables and figures. The present study was approved by the Research Ethics Committee of the Ribeirão Preto College of Nursing (CAAE 38990114.5.0000.5393) and by the co- participating institution (CAAE 38990114.5.3001.5440). A total of 240 people living with HIV / AIDS participated in the study, of which 120 were Cases and 120 Controls; 65.0% of Cases and 55.0% of Controls were male: 35.8% of Cases were in the age group of 30 at 39 years and 45.8% of the Controls were aged from 40 to 49 years, the predominant ethnicity was white for Cases and Controls, 74.2% and 64.2%, respectively. The groups were homogeneous among themselves in relation to gender, ethnicity and schooling. The mean time of diagnosis was 9 years for Cases and 8.8 years for Controls. The final logistic regression model showed that the risk factors associated with Staphylococcus aureus nasal colonization in people living with HIV / AIDS were white, p = 0.05 (OR: 1.85, 95% CI: 1.00 - 3.57); having viral load> 40 copies / mL, p = 0.03 (OR: 2.90; IC95% 1.15 - 7.30); being with LT-CD4+ <200 cells / mm3 p = 0.001 (OR: 2.71; IC95% 1.53 - 4.81); and present opportunistic disease p = 0.014 (OR: 2,09; IC95% 1,20 - 3,67). In addition, it was also obtained by the final regression final model that the use of antiretroviral therapy is a protection factor of p = 0.008 (OR: 0.45; 95% CI 0.25 - 0.81) for nasal colonization by Staphylococcus aureus. We conclude that nasal colonization by Staphylococcus aureus in people living with HIV/AIDS was associated with factors: ethnicity, viral load, LT-CD4+ count, opportunistic infection, and antiretroviral use

[pt] A estrutura de contratos de Parcerias Público-Privadas (PPP) tem como característica o compartilhamento de riscos do projeto entre o governo e investidor. PPPs têm longo prazo de maturação, volumes elevados de investimentos iniciais e incerteza quanto às receitas. O comportamento futuro de agentes públicos e privados pode transmitir um risco adicional, tornando projetos pouco atrativos quando informações relevantes não ficam evidentes em um contrato. A teoria dos jogos tem sido um instrumento amplamente utilizado para trazer soluções analíticas quando o problema de assimetria de informação está presente. Portanto, este trabalho utiliza os conceitos de teóricos de mecanismos compatíveis com incentivos para PPPs objetivando: (i) aprimoramento de falhas contratuais ex-post via condições ex-ante ; (ii) aprimorar um modelo de jogo de renegociação de PPPs, mostrando como o comportamento oportunista pode ser evitado. Analisa-se o processo de concessão do Complexo Maracanã, como caso ilustrativo via uso de proposições, lemas e teoremas, mostrando que o edital do Governo do Estado do Rio de Janeiro é sub-ótimo do ponto de vista da Teoria de Desenho de Mecanismos. / [en] The Public-Private Partnerships (PPP) contract structure is characterized by the sharing of project risks between the government and the investor. PPPs have long maturation maturities, high initial investment volumes and revenue uncertainty. The future behavior of public and private agents may carry an additional risk, making projects unattractive when relevant information is not evident in a contract. Game theory has been a widely used instrument to provide analytical solutions when the problem of information asymmetry is present. Therefore, this thesis uses the concepts of mechanism theorists compatible with incentives for PPPs, aiming: (i) improvement of ex-ante and ex-post contractual failures; (ii) to improve a PPP renegotiation game model, showing how opportunistic behavior can be avoided. It analyzes the concession process of the Maracanã Complex as illustrative case via use of propositions, lemmas and theorems, showing that the State Government s announcement of Rio de Janeiro is sub-optimal from the point of view of the mechanisms of Design Theory.

Made available in DSpace on 2016-06-02T19:05:42Z (GMT). No. of bitstreams: 1 3072.pdf: 1703350 bytes, checksum: 5213111edf7f7c40880a68e93c0462c0 (MD5) Previous issue date: 2010-02-18 / Universidade Federal de Sao Carlos / Mobile computing devices often present high processing power and include several wireless network interfaces. 4G networks promise to provide a unified IP based infrastructure with QoS and security support for the communications using such devices. Transmission delays, and network disruptions, however, are often common when considering the current transmissions of mobile users. This work presents a software communications architecture which is tolerant to transmission delays and intermittent connectivity by exploring a hop-by-hop forwarding mode in DTNs. The proposed architecture is organized as a set of functional layers, which allow the use of different forwarding policies and network technologies. By providing the forwarding of objects, named bundles, an unlimited number of high level communication applications can be implemented on top of the architecture. Security aspects concerning the proper identification of users and transmission bundles, as well as the confidentiality and authentication of the received information are considered in the project of the developed architecture. Log keeping of the bundle forwarding activities performed by the architecture, including the interactions among users and the data passing operations, may be further investigated for use in different context aware forwarding and social organization algorithms. A partial implementation of the developed architecture was made and the results demonstrate the viability of its operation. / Dispositivos computacionais móveis comumente apresentam elevada capacidade de processamento e disponibilidade de múltiplas interfaces de comunicação em rede. Sob o ponto de vista da transmissão de dados, redes 4G deverão prover uma infraestrutura unificada baseada no uso do protocolo IP, com suporte a segurança e QoS para esses dispositivos. Atrasos de propagação, rupturas e perdas de conectividade, contudo, ainda são comuns quando se considera a mobilidade dos usuários. Este trabalho apresenta uma arquitetura de comunicação tolerante a atrasos e conectividade intermitente, que explora o modo de encaminhamento ponto a ponto para prover transmissões em redes DTNs. A arquitetura é organizada em camadas, possibilitando o uso de diferentes políticas de encaminhamento e de diferentes tecnologias de transmissão. Ao prover o encaminhamento de objetos de transmissão, chamados bundles, um número ilimitado de serviços de comunicação em alto nível pode ser implementado sobre a arquitetura desenvolvida. Questões de segurança na identificação dos usuários e dos bundles transmitidos, bem como a confidencialidade e a autenticação das informações são considerados no projeto da arquitetura desenvolvida. O registro de operações realizadas durante os encaminhamentos, incluindo contatos entre usuários e eventos de transmissão, pode ainda servir para alimentar uma base de dados a ser explorada por diferentes algoritmos relacionados a organizações sociais e políticas de encaminhamento cientes de contexto. Uma implementação parcial das funcionalidades previstas pela arquitetura foi realizada e os resultados obtidos mostram a viabilidade de sua operação.