Made available in DSpace on 2016-04-25T20:20:57Z (GMT). No. of bitstreams: 1 Pedro Malina.pdf: 1037064 bytes, checksum: 35f53cc3c16eee2d1571a091d7c1965f (MD5) Previous issue date: 2013-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation establishes as an exploratory study, trying to bring new elements to Wikipedia s analysis within the political science field. This work analysis Wikipedia as a distributed network, a way of functioning that brings many elements from control society. In order to achieve that, it initially puts the main rules of Wikipedia and how they establish a play of forces, where consensus, verifiability, and neutrality are main elements. Besides that, through the genealogical method, presents the forces relations implied in the articles elaboration procedures based on the presentation of three talk pages from Wikipedia / Esta dissertação estabelece-se como um estudo exploratório, tentando trazer novos elementos para a análise da Wikipedia dentro do campo da ciência politica. Este trabalho analisa a Wikipedia como uma rede distribuída, um modo de funcionamento que traz diversos elementos da sociedade de controle. Para isso, coloca inicialmente as regras centrais da Wikipedia e como estas estabelecem um jogo de forças, onde consenso, verificabilidade e neutralidade são elementos centrais. Além disso, através do método genealógico, apresenta as relações de força implicadas nos procedimentos de elaboração dos verbetes a partir da apresentação de três talk pages da Wikipedia

Made available in DSpace on 2016-04-26T14:54:06Z (GMT). No. of bitstreams: 1 Pedro Malina.pdf: 1037064 bytes, checksum: 35f53cc3c16eee2d1571a091d7c1965f (MD5) Previous issue date: 2013-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation establishes as an exploratory study, trying to bring new elements to Wikipedia s analysis within the political science field. This work analysis Wikipedia as a distributed network, a way of functioning that brings many elements from control society. In order to achieve that, it initially puts the main rules of Wikipedia and how they establish a play of forces, where consensus, verifiability, and neutrality are main elements. Besides that, through the genealogical method, presents the forces relations implied in the articles elaboration procedures based on the presentation of three talk pages from Wikipedia / Esta dissertação estabelece-se como um estudo exploratório, tentando trazer novos elementos para a análise da Wikipedia dentro do campo da ciência politica. Este trabalho analisa a Wikipedia como uma rede distribuída, um modo de funcionamento que traz diversos elementos da sociedade de controle. Para isso, coloca inicialmente as regras centrais da Wikipedia e como estas estabelecem um jogo de forças, onde consenso, verificabilidade e neutralidade são elementos centrais. Além disso, através do método genealógico, apresenta as relações de força implicadas nos procedimentos de elaboração dos verbetes a partir da apresentação de três talk pages da Wikipedia

This thesis investigates the average consensus of multi-agent systems with linear dynamics whose interconnections are modelled by balanced digraphs with matrix- weights. The thesis first introduces the notion of balanced digraphs and mirror graphs for matrix weights. Then it proves that the matrix-weight-balanced con- sensus controller is indeed globally asymptotically stable. The Lyapunov stability analysis exploits the properties of the mirror graph of a balanced digraph. Further, the necessary and sufficient condition for the system to achieve average consensus is shown to be positive definiteness of the matrix weights of its balanced digraph. Simulations with robots in SIMULINK verify that positive definite matrix weights on balanced graphs are indeed necessary and sufficient for average consensus. Fi- nally formation control of a multi-robot system is shown to be an application of the matrix-weight-balanced consensus algorithm using real time simulation of Clearpath Ridgeback robots in Gazebo and ROS. / Graduate

Este trabalho relata observações e analises sobre como os detectores de defeitos influenciam as operação de consenso. O conceito dos detectores de defeitos é essencial para as operações de consenso em sistemas distribuídos assíncronos, uma vez que esses representam uma das (micas formas de sobrepujar as limitações impostas pela chamada Impossibilidade FLP (impossibilidade de diferenciar um processo falho de um processo mais lento). Enquanto os detectores de defeitos tem seu funcionamento bem definido através de duas propriedades, completeness e accuracy, Não há nenhuma restrição quanto a forma de implementá-los. Na literatura são encontrados vários modelos de detectores de defeitos, construídos com as mais variadas estratégias, mecanismos de comunicação e de detecção. No entanto, estes modelos não costumam ser acompanhados de uma comparação com os detectores já existentes; os autores limitam-se a apresentar as inovações dos mecanismos sugeridos. De toda literatura pesquisada, apenas um trabalho procurou comparar diferentes modelos de detectores de defeitos, e através de simulações, avaliou o impacto destes detectores sobre o tempo de terminação das operações de consenso. Entretanto, aquele trabalho era bem limitado, tanto nos modelos de detectores analisados quanto nos objetivos das observações. O presente trabalho procurou estender aquele experimento, incluindo mais modelos de detectores, e transportando-os para um ambiente prático de execução. As observações realizadas não ficaram limitadas as avaliações já realizadas por aquele trabalho, de tal forma que os modelos de detectores testados foram analisados sob diversas métricas, situações e parâmetros de operação. Essas avaliações possibilitaram verificar o comportamento dos detectores frente aos padrões de falhas mais significativos, avaliar o impacto de cada detector sobre as operações de consenso e a sua interação com os elementos do ambiente de execução. Essas avaliações permitiram fazer uma comparação dos detectores, possibilitando a identificação de suas limitações, suas situações de melhor desempenho e possíveis otimizações para serem realizadas em trabalhos futuros. / This work presents our observations and analysis on the influence of the failure detectors on the consensus algorithm. Failure detectors are essential to the consensus over an asynchronous distributed system, as they represent one of the few techniques that are able to circumvent the limitation imposed by the FLP Impossibility (the impossibility to distinguish a crashed process from a slow one, in asynchronous systems). While failure detectors are well defined through two properties, completeness and accuracy, there's no rule about their implementation. Thus, in the literature there are many models of failure detectors, each one implemented using different approaches to the communication and detection strategies. However, these detectors seldom compare themselves to the existing ones; their authors usually present only the advantages and innovations of the new model. Indeed, we only found one work that tried to compare different failure detectors. Using simulation techniques, that work evaluated the impact of the failure detectors on the consensus termination time. However, that research was very limited in the number of detectors analyzed and in the evaluation goals. The present work extended that experience, including more detectors in the analysis and evaluating them in a practical environment. Also, the observations were not restricted to those from the original paper, and the detectors were analyzed with more metrics, failure patterns and operational parameters. The evaluation allowed us to identify the behavior from the detectors in face of the most significant failure patterns, their influence on the consensus operation and their interaction with the execution environment. These evaluation also enabled us to compare the detectors, identifying their limitations, their best employment situations and possible optimizations to future developments.

Power grid is an interconnected system of supplying electricity from the supplier to the consumer, consisting of electricity generating plant, high voltage transmission lines- to carry electricity from the generating plant to the load center, and distribution lines- to carry electricity from load centers to individual consumers. A lot of research is being pursued to develop technologies for improving the next generation of power grid called the Smart Power Grid. The Smart Power Grid will have sophisticated communication infrastructure to improve the efficiency of electricity generation using renewable energy sources like the sun, water, etc and also to inform consumers of their electricity usage pattern. Also, the electricity market is now divided into three sections- generation, transmission and distribution. Private companies are competing with each other to provide electricity at the most competitive market price. We have developed two algorithms to help generating companies achieve their goal of meeting the hourly electricity need of the consumers and to do so at a minimum total cost.

After more than twenty years of increasing understanding of the human immunodeficiency virus known as HIV, the virus continues to spread throughout the world, manifesting itself lethally in the form of the Acquired Immune Deficiency Syndrome (AIDS). With no cure or affordable treatment presently available for the majority of the people of sub-Saharan Africa and the African nation of Malawi, work aimed at preventing the spread of the virus continues to be the best strategy for lessening its impact, both at a personal level and across populations. Most people and communities in this part of the world demonstrate some understanding of HIV and its impact, and strategies such as condom use and abstinence education are familiar program interventions. However, less is known about how social and cultural processes influence personal risk taking and decision making related to HIV/AIDS. In this research, participatory research activities involving planning and producing dramas provide a venue for exploration of how rural Malawian communities can investigate and confront HIV/AIDS social causality through analyzing, planning and acting, presenting, and critiquing research. This research studies the role that shared agreement or consensus plays in developing a community's AIDS-related knowledge and in creating community-specific priorities for AIDS prevention activities. This aspect of the research is significant for applications of participatory research in community AIDS work. The research was designed so that information was collected from individuals participating in the interventions both before and after the interventions. This was intended to facilitate a better understanding of how participatory research affected group knowledge. The analytical process of Cultural Domain Analysis was used in conjunction with the non-probabilistic analytical technique of consensus modeling to gauge whether changes in agreement or consensus occurred as a result of participatory activities among intervention groups.

This project describes and analyzes explanatory models of Chagas disease among people in a highly endemic area of eastern Bolivia, and examines the role that cultural and structural factors play in shaping explanatory models of this disease. Dressler (2001) characterizes medical anthropology as divided between two poles; the constructivist, which focuses on the "meaning and significance that events have for people," and the structuralist, which emphasizes the relationships between the components of a given society. This project endeavors to synthesize structuralist and constructivist perspectives by understanding the interaction between structural processes and explanatory models of Chagas disease. The research took place in the spring of 2013, in collaboration with the Centro Medico Humberto Parra, a non-profit clinic servicing low income populations in Palacios, Bolivia and surrounding communities. Semistructured interviews (n=68) and consensus analysis questionnaires (n=48) were administered to people dealing with Chagas disease, and free lists of possible treatments were collected. Overall, participants largely accepted the biomedical model, but also emphasized the emotional and social aspects of Chagas disease. The consensus analysis procedure indicated a clear shared model of Chagas disease, with coherent social, vector, symptoms, and ethnomedical domains. Furthermore, the model differed between groups based on ethnicity, gender, income and occupation. Significant differences were found in cultural knowledge of the disease based on community of residence and occupation status, two clear markers of how people are tied into the global economy. In the interviews, participants associate their Chagas disease with structural factors including poverty, rural living and traditional housing. They describe substantial barriers to getting biomedical care for their disease despite the existence of a free treatment program in Bolivia. However, participants reported numerous ethnomedical treatments; the study identified 39 ethnomedical treatments for Chagas disease and 66 for its cardiac symptoms. In sum, explanatory models include structural processes that shape disease, and are in turn influenced by these processes. In Bolivia, although structural constraints limit the scope of biomedical treatment, ethnomedical approaches to the disease are in a process of dynamic growth. The methods used here for assessing the structural component of the explanatory model of Chagas disease can be replicated in future research on explanatory models or political economy of health.

In the U.S., individuals of Afro-Caribbean and Latino descent are two to three times more likely to develop type 2 diabetes than non-Hispanic whites. Caribbean and Latin America migrants, particularly minority women bear a disproportionate burden of type 2 diabetes and its risk factors. The purpose of this research is to investigate if Afro-Caribbean women share a cultural belief model about type 2 diabetes and how this belief model, along with structural barriers to health care, influence disease risk and management. A sample of 40 women, primarily Jamaican and Trinidadian, 35 to 90 years of age previously diagnosed with type 2 diabetes were recruited in southwest Florida. Socio-demographic, medical history, and self-reported height and weight data were collected from women. A 53 item yes/no cultural beliefs questionnaire about type 2 diabetes' etiology, treatment, and symptoms was administered to 30 women. Semi-structured interviews about diet and lifestyle type 2 diabetes management were conducted with 38 women, 24 interviews were conducted over the telephone. The cultural consensus analysis used to analyze the cultural beliefs questionnaire found that the women shared a single cultural belief model (.72 ±.081 SD) about type 2 diabetes. Body mass index was calculated from self-reported height and weight data, and correlated with socio-demographic and cultural belief variables. The age-adjusted prevalence of obesity was 40.39 percent. The spearman correlation found that women with higher BMI (rs = -0.42993, p = .0125) and individual cultural knowledge scores (rs = -0.41730, p = .0218) were significantly younger at age of type 2 diabetes diagnosis than women with lower BMI and individual cultural knowledge scores. The women's cultural belief model about type 2 diabetes was similar to the biomedical model. Women struggled to modify their traditional Caribbean diet and failed to engage in regular leisure physical activity which may have contributed to their high BMI. Inadequate health insurance and transnational migration prevented women from accessing regular medical care and effectively managing the disease. Afro-Caribbean women face an ongoing struggle to control their glucose levels and BMI to prevent the onset of type 2 diabetes complications.

Escherichia coli 5'-nucleotidase is a periplasmically localised enzyme capable of hydrolysing a broad range of substrates, including all 5'-ribo- and 5'-deoxyribonucleotides, uridine diphosphate sugars, and a number of synthetic substrates such as bis (r-nitrophenyl) phosphate. The enzyme has been shown to contain at least one zinc ion following purification, and to have two metal binding sites in the catalytic cleft. 5'-Nucleotidase activity is significantly stimulated by the addition of particular divalent metal ions, most notably cobalt which results in a 30-50 fold increase in activity. Significant sequence homology between the E. coli 5'-nucleotidase and members of the Ser/Thr protein phosphatase family in the catalytic site has lead to 5'-nucleotidase being included in this protein family. This thesis describes the development of a rapid purification methodology for milligram quantities of 5'-nucleotidase, and the investigation of a number of physical and biochemical properties of the enzyme with the aim of comparing these properties to those of certain catalytic site mutants. The molecular weight of the mature protein was estimated as 58219 daltons, with a specific activity for 5'-AMP, in the presence of 4 mM Co2+ and 13 mM Ca2+ at pH 6.0, of 730 mmol/min/mg. The presence of up to two zinc ions associated with the purified enzyme was observed using ICP-ES analysis, suggesting both metal ion binding sites are occupied by zinc in vivo, and some degree of displacement of zinc by cobalt could be observed. Mass spectrometry data, gathered at 60 and 70 mS orifice potential, suggested the presence of a small proportion of material with a mass 118 to 130 daltons greater than the main 5'-nucleotidase mass estimation. This study suggests that this mass difference, only evident at the lower orificepotential, is due to the presence of two zinc ions closely associated with 5'-nucleotidase. To account for the observed high level of activation of 5'-nucleotidase activity by particular divalent metal ions, this thesis describes a proposed model in which these divalent ions may displace the zinc ion at one of the metal ion binding sites. This displacement only occurs at one of the two metal ion binding sites, with the other metal binding site retaining the zinc ion already present. Studies with purified enzyme, each with a single amino acid substitution, lend support to this hypothesis and suggest the identity of the metal ion binding site at which displacement occurs. Seven key catalytic site residues (Asp-41, His-43, Asp-84, His-117, Glu-118, His-217 and His-252) were selected on the basis of sequence conservation within the Ser/Thr protein phosphatases and 5'-nucleotidases. X-ray crystallographic data published by others during this study implicated five of the selected residues (Asp-41, His-43, Asp-84, His-217 and His-252) directly in metal ion binding, including two residues from each metal ion binding site and one directly involved in both sites (Asp-84). The remaining two residues (His-117 and Glu-118) are highly conserved but were not thought to play direct roles in metal ion binding. The seven selected residues were modified by site-directed mutagenesis, and the effect of the amino acid substitutions upon the kinetic properties of 5'-nucleotidase activity was determined. Residues hypothesised to be involved in metal ion displacement, and subsequent activation of 5'-nucleotidase activity, were identified by reductions in metal ion affinity and increased levels of activation by cobalt compared to the wild type 5'-nucleotidase. This study suggests that the metal binding site, M2, that includes residues Asp-84, His-217 and His-252, is involved in metal ion displacement, while the other metal binding site, M1, is not. This, in turn, suggests the metal binding sites are functionally non-equivalent and kinetically distinct. No residues were identified in this study as playing significant roles in substrate binding, as there was no significant reduction observed in affinity for 5'-AMP observed in any of the catalytic site mutants.

Le problème du Consensus est reconnu comme un paradigme important pour concevoir des systèmes répartis tolérants aux défaillances. Dans un système asynchrone pure, le consensus est impossible à résoudre de manière déterministe. En enrichissant le système avec des hypothèses de synchronie, plusieurs solutions (dont le protocole Paxos) ont été proposées pour contourner ce résultat d'impossibilité. Ce travail contribue à la conception de protocoles de consensus efficaces dans un système réparti asynchrone. La proposition d'un protocole efficace appelé Paxos-MIC, qui suit l'approche Paxos et intègre deux optimisations connues, est la contribution algorithmique de cette thèse. Paxos-MIC gère une séquence d'instances de consensus et garantie la persistance de toutes les décisions. L'adaptabilité est la principale qualité de ce protocole. Etant donné que l'une des optimisations peut être néfaste, Paxos-MIC intègre un mécanisme de déclenchement qui peut activer dynamiquement l'optimisation. Différents critères de déclenchement sont proposés pour prédire si l'utilisation de l'optimisation va être bénéfique. De nombreuses expérimentations ont été conduites sur la grille GRID'5000 afin d'évaluer le protocole et ces critères. Une seconde partie du travail se focalise sur l'utilisation du consensus comme une brique de base. Dans le contexte particulier des agents mobiles transactionnels, nous proposons une solution pour supporter l'exécution de transactions dans un réseaux ad-hoc. La solution repose sur une séquence de décisions construite de façon durable en invoquant des consensus. Ce service est fourni par le protocole Paxos-MIC.