Les études de Sûreté de Fonctionnement (SdF) sur les barrières instrumentées de sécurité représentent un enjeu important dans de nombreux domaines industriels. Afin de pouvoir réaliser ce type d'études, TOTAL développe depuis les années 80 le logiciel GRIF. Pour prendre en compte la complexité croissante du contexte opératoire de ses équipements de sécurité, TOTAL est de plus en plus fréquemment amené à utiliser le moteur de calcul MOCA-RP du package Simulation. MOCA-RP permet d'analyser grâce à la simulation de Monte-Carlo (MC) les performances d'équipements complexes modélisés à l'aide de Réseaux de Petri (RP). Néanmoins, obtenir des estimateurs précis avec MC sur des équipements très fiables, tels que l'indisponibilité, revient à faire de la simulation d'événements rares, ce qui peut s'avérer être coûteux en temps de calcul. Les méthodes standard d'accélération de la simulation de Monte-Carlo, initialement développées pour répondre à cette problématique, ne semblent pas adaptées à notre contexte. La majorité d'entre elles ont été définies pour améliorer l'estimation de la défiabilité et/ou pour les processus de Markov. Par conséquent, le travail accompli dans cette thèse se rapporte au développement de méthodes d'accélération de MC adaptées à la problématique des études de sécurité se modélisant en RP et estimant notamment l'indisponibilité. D'une part, nous proposons l'Extension de la Méthode de Conditionnement Temporel visant à accélérer la défaillance individuelle des composants. D'autre part, la méthode de Dissociation ainsi que la méthode de ``Truncated Fixed Effort'' ont été introduites pour accroitre l'occurrence de leurs défaillances simultanées. Ensuite, nous combinons la première technique avec les deux autres, et nous les associons à la méthode de Quasi-Monte-Carlo randomisée. Au travers de diverses études de sensibilité et expériences numériques, nous évaluons leur performance, et observons une amélioration significative des résultats par rapport à MC. Par ailleurs, nous discutons d'un sujet peu familier à la SdF, à savoir le choix de la méthode à utiliser pour déterminer les intervalles de confiance dans le cas de la simulation d'événements rares. Enfin, nous illustrons la faisabilité et le potentiel de nos méthodes sur la base d'une application à un cas industriel. / The dependability analysis of safety instrumented systems is an important industrial concern. To be able to carry out such safety studies, TOTAL develops since the eighties the dependability software GRIF. To take into account the increasing complexity of the operating context of its safety equipment, TOTAL is more frequently led to use the engine MOCA-RP of the GRIF Simulation package. Indeed, MOCA-RP allows to estimate quantities associated with complex aging systems modeled in Petri nets thanks to the standard Monte Carlo (MC) simulation. Nevertheless, deriving accurate estimators, such as the system unavailability, on very reliable systems involves rare event simulation, which requires very long computing times with MC. In order to address this issue, the common fast Monte Carlo methods do not seem to be appropriate. Many of them are originally defined to improve only the estimate of the unreliability and/or well-suited for Markovian processes. Therefore, the work accomplished in this thesis pertains to the development of acceleration methods adapted to the problematic of performing safety studies modeled in Petri nets and estimating in particular the unavailability. More specifically, we propose the Extension of the "Méthode de Conditionnement Temporel" to accelerate the individual failure of the components, and we introduce the Dissociation Method as well as the Truncated Fixed Effort Method to increase the occurrence of their simultaneous failures. Then, we combine the first technique with the two other ones, and we also associate them with the Randomized Quasi-Monte Carlo method. Through different sensitivities studies and benchmark experiments, we assess the performance of the acceleration methods and observe a significant improvement of the results compared with MC. Furthermore, we discuss the choice of the confidence interval method to be used when considering rare event simulation, which is an unfamiliar topic in the field of dependability. Last, an application to an industrial case permits the illustration of the potential of our solution methodology.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / High concentrations of nitrate have been found in water samples from irrigation wells north of the Tucson Arizona sewage treatment plant. The plant, which had primary treatment prior to 1951, produced 2,800 acre-feet of effluent in 1940, 4,600 acre-feet in 1950, 16,300 acre-feet in 1960, and 33,000 acre-feet in 1970. Large amounts of treated effluent recharge the groundwater system north of the plant. Sources of nitrate contamination beside sewage effluent may be sewage lagoons, sanitary landfills, meat packing and dairy effluent, septic tanks, and agricultural runoff. Sewage effluent is considered to be the primary source of nitrate contamination in the area. Geologic and flow net analysis indicate that aquifer conditions minimize the effects of sewage effluent contamination. Chloride and nitrate migration appears to be similar in the aquifer. Large-capacity wells were sampled to reflect regional conditions, and chemical hydrographs of chloride and nitrate were analyzed. The seasonal nature of these hydrographs patterns depend on total nitrogen in sewage effluent. Management alternatives are suggested to decrease nitrate pollution by sewage effluent.

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / The geohydrology of a portion of the Santa Catalina Mountains including the definition of aquifer systems in the foothills was studied in order to calculate groundwater recharge to the Tucson basin. This underlying groundwater aquifer is the only source of Tucson, Arizona's water supply. A well network, well logs, geologic profiles, and a water level contour map were used as source information. Recharge was found to occur in some sections of washes and close to the mountains where washes cross or coincide with faults. Significant recharge to sand and gravel aquifers occurs directly through faults and joints. Little of the surface runoff is thought to recharge local aquifers because of low permeability layers beneath the alluvium and the short duration of the flows. Recharge calculation using the Darcy equation was subject to considerable error; but flow net analysis showed the total recharge to be 336 acre-feet per year representing about 50 acre feet per mile of mountain front per year.

No description available.

Cette thèse comporte trois essais en macroéconomie en économie ouverte et commerce international. Je considère tour à tour les questions suivantes: sous quelles conditions est-il optimal pour un pays de former une union économique? (essai 1); l'augmentation de la dispersion transversale des avoirs extérieurs nets des pays est-elle compatible avec une dispersion relativement stable des taux d'investissement? (essai 2); le risque de perte de marché à l'exportation du fait de l'existence des zones de commerce préférentiel joue t-il un rôle dans la décision des pays exclus de négocier des accords commerciaux à leur tour? (essai 3). Le premier essai examine les conditions d'optimalité d'une union économique. Il s'intéresse à une motivation particulière: le partage du risque lié aux fluctuations du revenu. Dans la situation initiale, les pays ont très peu d'opportunités pour partager le risque à cause des frictions: les marchés financiers internationaux sont incomplets et il n'y pas de mécanisme pour faire respecter les contrats de crédit entre pays. Dans ce contexte, une union économique apparait comme un arrangement qui pallie à ces frictions entre les pays membres seulement. Cependant, l'union dans son ensemble continue de faire face à ces frictions lorsqu'elle échange avec le reste du monde. L'arbitrage clé dans le modèle est le suivant. D'un coté, l'intégration économique permet un meilleur partage du risque entre pays membres et la possibilité pour le partenaire pauvre d'utiliser la ligne de crédit du partenaire riche en cas de besoin. De l'autre coté, l'union peut faire face à une limite de crédit plus restrictive parce que résilier la dette extérieure est moins coûteux pour les membres l'union. De plus, le fait que le partenaire pauvre peut utiliser la limite de crédit du partenaire riche génère une externalité négative pour ce dernier qui se retrouve plus fréquemment contraint au niveau des marchés internationaux des capitaux. En conformité avec les faits observés sur l'intégration économique, le modèle prédit que les unions économiques sont relativement peu fréquentes, sont plus susceptibles d'être créées parmi des pays homogènes, et généralement riches. Le deuxième essai porte sur la dispersion des avoirs extérieurs nets et la relation avec la dispersion des taux d'investissement. Au cours des récentes décennies, la dispersion croissante des déséquilibres extérieurs et les niveaux record atteints par certaines grandes économies ont reçu une attention considérable. On pourrait attribuer ce phénomène à une réduction des barrières aux mouvements internationaux des capitaux. Mais dans ce cas, il est légitime de s'attendre à une augmentation de la dispersion au niveau des taux d'investissement; ceci, parce que le financement des besoins en investissements constitue une raison fondamentale pour laquelle les pays échangent les capitaux. Les données indiquent cependant que la dispersion des taux d'investissement est restée relativement stable au cours des récentes décennies. Pour réconcilier ces faits, je construis un modèle d'équilibre général dynamique et stochastique où les pays sont hétérogènes en raison des chocs idiosyncratiques à leurs niveaux de productivité totale des facteurs. Au niveau des marchés internationaux des capitaux, le menu des actifs disponibles est restreint à une obligation sans risque et il n'y a pas de mécanisme pour faire respecter les contrats de crédit entre pays. A tout moment, un pays peut choisir de résilier sa dette extérieure sous peine d'exclusion financière et d'un coût direct. Ce coût direct reflète les canaux autres que l'exclusion financière à travers lesquels les pays en défaut sont pénalisés. Lorsque le modèle est calibré pour reproduire l'évolution de la dispersion transversale des avoirs extérieurs nets, il produit une dispersion relativement stable des taux d'investissement. La raison principale est que les incitations que les pays ont à investir sont liées à la productivité. Avec l'intégration financière, même si les opportunités d'emprunt se sont multipliées, les incitations à investir n'ont pas beaucoup changé. Ce qui permet de générer une dispersion accrue de la position des avoirs extérieurs nets des pays avec une dispersion relativement stable des taux d'investissement. Le troisième essai analyse un aspect de l'interdépendance dans la formation des accords commerciaux préférentiels: j'examine empiriquement si le risque de diversion des exportations en faveur des pays membres des zones de commerce préférentiel est un facteur déterminant dans la décision des pays exclus de ces accords de négocier un accord à leur tour. Je construis un indicateur qui mesure le potentiel de diversion des exportations auquel font face les pays et estime un modèle probit de formation des zones de commerce préférentiel créées entre 1961 et 2005. Les résultats confirment que les pays confrontés à un plus grand potentiel de détournement des échanges sont plus susceptibles de former une zone de commerce préférentiel à leur tour. / This thesis consists of three essays in open economic macroeconomics and international trade. I consider the following questions: Which countries find it individually optimal to form an economic union? (essay 1); is the rising cross-sectional dispersion in net foreign asset positions consistent with a relatively stable dispersion in investment rates? (essay 2); is the risk of trade diversion due to existing preferential trade areas an important factor in excluded countries decision to seek one? (essay 3). The first essay studies the individual optimality of economic integration. It emphasizes the risk-sharing benefits of economic integration. In an initial situation, countries have very limited possibilities to share idiosyncratic endowment risk because of financial frictions: international financial markets are incomplete and contracts not enforceable. A union is an arrangement that solves both the market incompleteness and the lack of enforcement problems among member countries. The union as a whole still faces these frictions when trading in the world economy. The model emphasizes the following key trade-off. There are two benefits from economic integration: better risk-sharing among member countries and the possibility for poor partners to use the rich partners' credit lines. The costs are the following: borrowing limits become tighter because defaulting on international debt becomes less costly for union partners. Since poor partners may benefit from the rich partner's credit limit, this generates a negative externality: rich partners will find themselves more often borrowing-constrained in a union compared to standing alone in the world economy. Consistently with evidence on economic integration, the model predicts that economic unions occur relatively infrequently and are more likely to emerge among homogeneous and rich countries. The rising dispersion of external imbalances over the recent decades and the record-high levels reached by some major economies has received considerable attention during the recent years. The second essay focuses on one of such imbalances: the net foreign asset positions (NFA). One can view this rising dispersion as a consequence of the reduction in barriers to capital flows. But in such case, one would expect the dispersion in investment rates to go up as well because one fundamental reason countries borrow and lend internationally is to finance their investments needs. Instead, the dispersion in investment rates was relatively stable. To explain this puzzling fact, I undertake a quantitative analysis of the global dispersion of net foreign asset positions and investment rates. The framework is an integrated model of world economy where countries differences arise from idiosyncratic shocks to their total factor productivity levels. International capital flows is restricted: the menu of assets traded is exogenously restricted to a risk-free bond, and international lending contracts are not legally enforceable. At any time, a country may choose to repudiate its foreign debt subject to financial exclusion and an output cost. The output cost captures margins other than financial exclusion through which defaulting countries can be punished. When calibrated to match the evolution of the cross-sectional dispersion in net foreign asset positions, the model produces a relatively stable dispersion in investment rates. The reason is because the incentives to invest are related to the productivity, not to the borrowing and lending opportunities. Although the opportunities to borrow and lend internationally have increased, the incentives to invest have not changed much, thereby generating a large cross-sectional dispersion in NFA positions with a relatively stable dispersion in investment rates. The third essay investigates empirically whether the risk of trade diversion faced by countries excluded from preferential trade areas (PTA) is determinant in their decision to seek a preferential trade agreement. Using the trade complementarity index, I derive a measure of the potential of trade diversion and estimate a probit model of the formation of PTAs between 1961 and 2005. The results show that country-pairs facing a larger potential of trade diversion are more likely to form a PTA in the future.

Η διπλωματική εργασία διαπραγματεύεται την εφαρμοσιμότητα του peer-to-peer υπολογισμού και τεχνικών στα ασύρματα κινητά ad-hoc δίκτυα και στα δίκτυα αισθητήρων. Παρουσιάζεται μια παραλλαγή ενός νέου P2P πρωτοκόλλου (Energy Level Distributed Tree) που σαν κύρια λειτουργία του έχει την αύξηση του προσδόκιμου λειτουργίας ενός δικτύου αισθητήρων. Επίσης, γίνεται αναφορά στα πιο δημοφιλή εργαλεία προσομοίωσης για P2P πρωτόκολλα δρομολόγησης και παρουσιάζεται ένα νέο εργαλείο, d-p2p-sim, με δυνατότητα προσομοίωσης εκατομμυρίων κόμβων. Τέλος, εξετάζουμε την απόδοση ενός νέου P2P πρωτοκόλλου δρομολόγησης, του Nested Balanced Distributed Tree, που απαντά με βέλτιστο τρόπο ερωτήμα ακριβούς ταιριάσματος και ερωτήματα διαστήματος παρουσιάζοντας παράλληλα δύο νέους αλγορίθμους αναζήτησης για αυτό. / In this master thesis we study the applicability of the peer-to-peer computing and techniques on wireless ad-hoc networks and sensor-nets. We propose a simplified mapping of an optimal P2P protocol (NBDT) onto sensor-nets, the so called Energy Level Distributed Tree (ELDT), which has one main operation: the life expectancy of a sensor-net. Furthermore, are examined the most popular Peer-to-Peer simulators and is presented a new distributed simulator for P2P routing algorithms. The key feature of the proposed simulator is the ability to simulate millions of peers. Finally, is presented a revised version of the NBDT protocol which is hot-spot free and achieves a better load distribution introducing a negligible routing overhead.

Neste trabalho, foram utilizadas técnicas e conceitos tipicamente encontrados em estudos de Redes Complexas, uma sub-área da Física Estatística, para caracterizar a Internet e sua evolução em uma década, de 1998 a 2007. Foi considerada como unidade básica de análise, a estrutura Sistema Autônomo. Nesta caracterização, foram utilizadas várias ferramentas computacionais desenvolvidas em linguagem C/C++, que permitiram classificar, simular e modelar propriedades dinâmicas. Dentre estas propriedades podemos destacar o coeficiente de conectividade, fundamental para os estudos topológicos, e o parâmetro menor caminho médio, ambos baseados nas propriedades da matriz adjacência. Os dados experimentais foram inicialmente obtidos nos roteadores de borda da RedeRio de Computadores - FAPERJ e posteriormente, os dados relativos ao intervalo de estudo, foram retirados da base de dados disponibilizada pela Universidade de Oregon. Foi proposto um modelo de crescimento de uma rede complexa baseado nas premissas de crescimento contínuo e conexão preferencial não linear com suporte aos mecanismos de rearranjo e novas conexões entre nós já existentes. Este modelo se mostrou bastante adequado no estudo das propriedades consideradas. Foi desenvolvido um método para cálculo do menor caminho médio que apresentou performance superior àqueles normalmente utilizados pela comunidade acadêmica. O comportamento da topologia sob o ponto de vista da distribuição de probabilidades de conexão e do ranque de conectividade, apresentaram comportamento linear constante no período estudado com coeficientes médios iguais a -2,0 e -0,93, respectivamente. O parâmetro menor caminho médio global da Internet permaneceu praticamente inalterado e igual a 4, 2 ao longo da década estudada. / Connection networks are observed in many areas of human knowledge. The characterization and topological studies of these networks may be performed through distribution of connectivity degrees, rank properties, shortest path length between nodes, adjacency matrix etc, typical concepts from Complex networks, a filed of study of Statistical Physics domain. In this thesis we characterize the Internet connections evolution from 1998 to 2007. The Internet may be seen under several levels of reach and complexity considering different basic units. A wide vision is to consider the Internet basic element as an Autonomous System - AS, which is defined as a cluster of LANs or routers submitted to the same policy of usage, connectivity and technically administrated by the same network management group. The complex network considered in this work is composed by Autonomous Systems (vertices) and the established tra connection (edges) between them obtained from the BGP routing table. Many interesting property of this networks is analyzed, e.g. degree distribution (the rank and outdegree exponents) from 1998 to 2007 and the shortest path length (L), obtained by a proposed computational method (Friburgo algorithm) among each pair of ASs represented in the adjacency matrix. Finally, we present the behavior of the power law function and the shortest path length of the Internet for each year. Simulations of the connections network were carried out by a proposed model developed from continuous growth premises, possibilities of new and rearranging connections. This model was based on the concept of potential preferable connection showing a stable exponential factor that reproduces the true shortest path parameter over the decade.

Made available in DSpace on 2016-12-01T19:18:47Z (GMT). No. of bitstreams: 1 elaine1.pdf: 68069 bytes, checksum: cd260d38deaa4ba74891474ac9c74d01 (MD5) Previous issue date: 2009-05-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present dissertation reports a study performed in the Social Organizations of Itajaí Region, Santa Catarina, aiming to identify these entities contributions in the implementation of Working and Income Policies. The Third Sector Organizations have broaden their acting in modern societies. First, through the overture given by the State to formalize these actions, that have being executed since long ago by individuals around a common cause. Second, by the human being's need of giving sense to its work; by its incessant search for happiness through collectivity. However, there is not sedimented management way in this ambient. The knowledgement in these fields are built and rebuilt each day, characterizing into constant dilemma to the researchers' eyes. Allied to this conjuncture is the growing worry of the public managers in visualizing the public policies as a cycle whose effectivity depends on a range of distinct actors. For that, the predominant values in the Public Administration need new delineation. The New Public Service appears then as a theoretical framework in construction, based on values of citizenship, dialogue, citizen participation, spirit and public interest. From an understanding about the Social Organizations, the Third Sector, the Public Policies, the Social Nets and the Co-production of Public Services; it is defined the conceptual map that guides the research application. It is a descriptive research, with a qualitative/quantitative approach, performed in eight social organizations of Itajaí Region, which execute actions vinculated to the Working and Income Policies. The data was collected through a questionnaire and, when needed, a complementary interview, within the period of November, 2008 January, 2009. The data was treated and analysed from the conceptual map, integrated to the emergent variables along the research application. The organizations were analysed concerning to the Accountability, Citizenship, Dialogue, Public Spirit, Citizen Participation, Decentralization, Shared Leadership, Motivation, Roles Definition, Shared Objectives, Trust and Continued Learning. It is verifyed that the researched social organizations' contributions are directly related to the space they provide to the citizens to co-produce actions turned to specific demands in their communities, constituting favourable arranges to the essential elements for the construction of new management ways based in the New Public Service. However, the analyzed net presents embryonic characteristics related to the broaden perspectives of actuation that the arrange of net offers. It is the Public Administrators' concern to act in this ambient in a way to potentiate the social capital available, aiming to reach better results in the public policies implementation / A presente dissertação relata um estudo aplicado nas organizações sociais da Região de Itajaí, Santa Catarina, visando identificar as contribuições dessas entidades na implementação de políticas de Trabalho e Renda. As organizações do Terceiro Setor têm ampliado sua atuação nas sociedades modernas. Primeiro, pela abertura dada pelo Estado para a formalização dessas ações, que há muito são executadas por indivíduos reunidos em torno de uma causa comum. Segundo, pela necessidade do ser humano dar sentido ao seu trabalho; pela sua incessante busca pela felicidade por meio da coletividade. Entretanto, não há forma de gestão sedimentada nesse ambiente. A cada dia, os saberes nesse campo são construídos e reconstruídos, caracterizando-se em consta tes dilemas aos olhos dos pesquisadores. Aliada a essa conjuntura, está a crescente preocupação dos gestores públicos em visualizar a política pública como um ciclo, cuja efetividade depende de uma gama de atores distintos. Para isso, os valores predominantes na Administração Pública necessitam de novas delineações. O Novo Serviço Público surge, então, como um arcabouço teórico em construção pautado em valores de cidadania, diálogo, participação cidadã, espírito e interesse público. Partindo de um entendimento sobre as Organizações Sociais, o Terceiro Setor, as Políticas Públicas, as Redes Sociais e a Coprodução dos Serviços Públicos; é definido o mapa conceitual que norteia a aplicação da pesquisa. Trata-se de uma pesquisa descritiva, com abordagem qualiquantitativa, realizada em oito organizações sociais da Região de Itajaí que executam ações vinculadas às políticas de Trabalho e Renda. Os dados foram coletados por meio de aplicação de questionário e entrevista complementar, quando necessário, no período entre Novembro/2008 a Janeiro/2009. Os dados foram tratados e analisados a partir do mapa conceitual, integrado às variáveis emergentes no decorrer da aplicação da pesquisa. As organizações foram analisadas quanto às variáveis de Accoutability, Cidadania, Diálogo, Espírito Público, Interesse Público, Participação Cidadão, Descentralização, Liderança Compartilhada, Motivação, Definição de Papéis, Objetivos Compartilhados, Confiança e Aprendizagem Continuada. Verifica-se que as contribuições das organizações sociais pesquisadas estão diretamente relacionadas ao espaço que elas proporcionam aos cidadãos para co-produzirem ações voltadas às demandas específicas de suas comunidades, constituindo-se em arranjos favoráveis aos elementos essenciais para a construção de novas formas de gestão fundamentadas no Novo Serviço Público. No entanto, a rede analisada apresenta características embrionárias relacionadas às amplas perspectivas de atuação que o arranjo de rede oferece. Cabe aos Administradores Públicos atuarem nesse ambiente de forma a potencializar o capital social disponível, visando o alcance de melhores resultados na implementação de políticas públicas

Neste trabalho, foram utilizadas técnicas e conceitos tipicamente encontrados em estudos de Redes Complexas, uma sub-área da Física Estatística, para caracterizar a Internet e sua evolução em uma década, de 1998 a 2007. Foi considerada como unidade básica de análise, a estrutura Sistema Autônomo. Nesta caracterização, foram utilizadas várias ferramentas computacionais desenvolvidas em linguagem C/C++, que permitiram classificar, simular e modelar propriedades dinâmicas. Dentre estas propriedades podemos destacar o coeficiente de conectividade, fundamental para os estudos topológicos, e o parâmetro menor caminho médio, ambos baseados nas propriedades da matriz adjacência. Os dados experimentais foram inicialmente obtidos nos roteadores de borda da RedeRio de Computadores - FAPERJ e posteriormente, os dados relativos ao intervalo de estudo, foram retirados da base de dados disponibilizada pela Universidade de Oregon. Foi proposto um modelo de crescimento de uma rede complexa baseado nas premissas de crescimento contínuo e conexão preferencial não linear com suporte aos mecanismos de rearranjo e novas conexões entre nós já existentes. Este modelo se mostrou bastante adequado no estudo das propriedades consideradas. Foi desenvolvido um método para cálculo do menor caminho médio que apresentou performance superior àqueles normalmente utilizados pela comunidade acadêmica. O comportamento da topologia sob o ponto de vista da distribuição de probabilidades de conexão e do ranque de conectividade, apresentaram comportamento linear constante no período estudado com coeficientes médios iguais a -2,0 e -0,93, respectivamente. O parâmetro menor caminho médio global da Internet permaneceu praticamente inalterado e igual a 4, 2 ao longo da década estudada. / Connection networks are observed in many areas of human knowledge. The characterization and topological studies of these networks may be performed through distribution of connectivity degrees, rank properties, shortest path length between nodes, adjacency matrix etc, typical concepts from Complex networks, a filed of study of Statistical Physics domain. In this thesis we characterize the Internet connections evolution from 1998 to 2007. The Internet may be seen under several levels of reach and complexity considering different basic units. A wide vision is to consider the Internet basic element as an Autonomous System - AS, which is defined as a cluster of LANs or routers submitted to the same policy of usage, connectivity and technically administrated by the same network management group. The complex network considered in this work is composed by Autonomous Systems (vertices) and the established tra connection (edges) between them obtained from the BGP routing table. Many interesting property of this networks is analyzed, e.g. degree distribution (the rank and outdegree exponents) from 1998 to 2007 and the shortest path length (L), obtained by a proposed computational method (Friburgo algorithm) among each pair of ASs represented in the adjacency matrix. Finally, we present the behavior of the power law function and the shortest path length of the Internet for each year. Simulations of the connections network were carried out by a proposed model developed from continuous growth premises, possibilities of new and rearranging connections. This model was based on the concept of potential preferable connection showing a stable exponential factor that reproduces the true shortest path parameter over the decade.

Made available in DSpace on 2014-07-29T15:32:07Z (GMT). No. of bitstreams: 1 Dissertacao_Cristiana_Fernandes.pdf: 817648 bytes, checksum: a119839915c6670e7217c4e7ce3d5cc3 (MD5) Previous issue date: 2008-06-06 / In these work is considered that Craftworks are pieces made with manual techniques that presuppose lack or a few utilization of industrial machines help. The consumption s acceleration provided by the globalization, the constant technology s breakthrough, the cultural industry and the tourism are some of the factors that alter the craftwork in so far as that appear risks of objects padronization and consequent change on its meaning and sense. Considering those suppositions, the market and production analisation, in other words, the craftwork in the and for the market having as focus what was showed on the Hippie and Cerrado markets in Goiânia, recovering its organizational net. The craftwork on the markets, besides being a way to survive for the many merchant, has peculiarities and particularities that strick out in Goiânia s city. It s emphasized that so the production as the comercialization are parts of economy s inferior circuit, for owning characteristics like informality, whether on the production system characterized by being familiar, or in the way of comercialization on the own market. The pieces production is constantly influenced by the television and by the fashion s tendency. But due to specifics contexts, as comercialization s place and public that buy the pieces, we notice that the crafwork brings up some modifications in each market studied. The research is justified by the need of geographic production that are about these activity, in spite of its relevance, seeing that, ordinarily, even in the short distance s trips, there are no one that don t buy a little present or don t admire the skill of someone who produces such or what object when go around the markets. Methodologically, we drew on the techniques of observation and interview with structured and semi structured questionnaires applied in fieldworks, besides the documental and bibliographic analysis / Considera-se neste trabalho que artesanato são peças feitas com técnicas manuais e que pressupõem ausência ou pouca utilização de auxílio de máquinas industriais. A aceleração do consumo propiciada pela globalização, o constante avanço da tecnologia, a indústria cultural e o turismo são alguns fatores que alteram o artesanato na medida em que há o risco de padronização dos objetos e conseqüente modificação no seu significado e sentido. Considerando-se tais pressupostos, analisa-se o comércio e a produção, ou seja, o artesanato no e para o mercado, tendo como foco aquele exposto nas feiras Hippie e do Cerrado em Goiânia, recuperando-se sua rede organizacional. O artesanato nas feiras, além de ser um meio de sobrevivência para os diversos feirantes, possui singularidades e particularidades que se destacam na cidade de Goiânia. Ressalta-se que tanto a produção quanto a comercialização são parte do circuito inferior da economia, por possuírem características como informalidade, seja no sistema de produção caracterizado por ser familiar, seja no modo de comercialização nas próprias feiras. A produção das peças é constantemente influenciada pela televisão e pelas tendências da moda. Mas devido a contextos específicos, como local de comercialização e público que compra as peças, notamos que o artesanato apresenta algumas modificações em cada uma das feiras estudadas. A pesquisa justifica-se pela carência de produção geográfica versando sobre esta atividade, apesar de sua relevância, já que comumente, mesmo nas viagens de curta distância, não há quem não compre uma lembrancinha ou não se admire com a habilidade de alguém para produzir tal ou qual objeto, ao circular por uma feira. Metodologicamente, recorrem-se às técnicas de observação, entrevistas e questionários estruturados e semi-estruturados aplicados em trabalhos de campo, além das análises documental e bibliográfica