Este trabalho aborda a avaliação de impactos ambientais de empreendimentos rodoviários, no âmbito do licenciamento ambiental. As obras rodoviárias geram numerosos impactos ambientais e atualmente ainda existem falhas na gestão ambiental destes projetos, desde a pequena dimensão dada aos aspectos ambientais ainda na fase de planejamento da obra, perpassando por falhas nos estudos ambientais, dificuldades na previsão dos impactos e dimensionamento das medidas preventivas e mitigadoras, pelas rotinas controversas dos processos de licenciamento até o acompanhamento ambiental deficiente. Neste contexto, o presente trabalho visa propor diretrizes e procedimentos para o licenciamento ambiental de rodovias, tendo como base a análise de diferentes projetos rodoviários em licenciamento ambiental federal, localizados no Sul do país. Foram analisados os empreendimentos rodoviários BR 285 (Timbé do Sul/SC – São José dos Ausentes/RS) e BR 386 (Tabaí/RS – Estrela/RS), por meio de pesquisa qualitativa, com revisão teórica e documental. Ao final da análise foram apresentadas propostas de medidas preventivas e mitigadoras sistematizadas às etapas de instalação e operação de empreendimentos rodoviários, além dos estudos ambientais necessários ao licenciamento ambiental, de acordo com as tipologias pavimentação, implantação e duplicação de rodovias. Foram elaborados roteiros orientativos para o licenciamento de obras de apoio e para a escolha dos Programas Ambientais mais adequados às diferentes fases do projeto e diferentes tipologias de obras rodoviárias. Concluiu-se o trabalho com diretrizes básicas para os processos de licenciamento ambiental e de avaliação de impactos ambientais de rodovias. Para o processo de licenciamento: tramitação eletrônica do processo de licenciamento; licenciamento trifásico com possibilidade de fusão em duas ou uma etapa; criação de padrões para o estabelecimento de condicionantes para as licenças; participação popular em outros momentos do processo, além das audiências públicas; divulgação de impactos positivos e boas práticas adotadas; consulta aos órgãos intervenientes na fase de planejamento; exigência de manutenção de equipe de supervisão ambiental durante toda a fase de obras. Para a avaliação de impactos ambientais: criação de banco de dados nacional compartilhado com informações ambientais de empreendimentos já licenciados; elaboração de um manual de avaliação de impacto ambiental, com regras claras para a elaboração dos estudos ambientais; elaboração de manuais técnicos para temas relacionados ao licenciamento, passíveis de padronização de técnicas e metodologias; criação de roteiro metodológico com critérios para avaliação dos estudos pelos analistas ambientais; limitação do diagnóstico às variáveis ambientais com possibilidade de interagirem com o empreendimento e obrigatoriedade de um Programa de Controle Ambiental para execução durante a paralisação de obras. / This study discusses the environmental impact assessment of highways projects in the context of project licensing. Constructing highways create many environmental impacts and, nowadays, there are still flaws in environmental management of these projects, including the little importance given to environmental aspects in project planning, low quality of environmental impact statements, difficulties in impact prediction and mitigation design, common shortfalls in the project licensing process and, lastly, deficient environmental monitoring. In this context, this study aims to propose guidelines and procedures to improve the project licensing process, based on the analysis of different highways projects under government permitting process, located in southern Brazil. The following highways projects were selected: BR 285 (Timbé do Sul/SC – São José dos Ausentes/RS) and BR 386 (Tabaí/RS – Estrela/RS). The study was based on qualitative research with theoretical and documentary review. At the end of analysis, the proposals were focused on preventive and mitigating measures, considering installation and operation stages of highways projects, in addition to the main issues and statements to be considered in the licensing process, according to the different types of highways projects: paving, implementation and duplication. Some guidelines for the support project licensing were presented, as well as guidelines for the most appropriate environmental programs to be applied along different stages of the projects and to different types of highways projects. The study was completed with basic guidelines for environmental impact assessment and for project licensing of highways projects. Suggestions for project licensing: electronic processing, licensing processes in three phases with possibility of fusing into two or one, creation of standards for constraints imposed in the environmental permit, popular participation in all stages of the process, dissemination of positive impacts and best practices adopted, discussion with government agencies in highway planning moment, mandatory requirement of environmental supervision team throughout the construction phase. Suggestions for environmental impact assessment: creation of a national and shared database with environmental information from already licensed projects, development of environmental impact assessment guideline, with clear rules for the preparation of environmental impact statements, preparation of manuals on issues related to licensing with the possibility of standardization of methodologies and techniques, creation of methodological script with criteria for evaluation of studies by staff members at government agencies in charge of the licensing process, scoping on issues associated with the project (that truly matter), and mandatory requirement of a control program to run during the stoppage of works.

Les circuits reconfigurables (Field Programmable Gate Arrays - FPGAs) sont largement utilisés dans divers domaines d'application en raison de leur flexibilité, de leur haute densité d'intégration, de leur niveau de performance et du faible coût de développement associé. Toutefois, leur grande sensibilité aux défauts dus aux rayonnements électromagnétiques tels que les "Single Event Effets" (SEE), est un défi qui doit être abordée pendant la conception du système. Ces SEE sont une préoccupation majeure dans la sécurité et pour les systèmes critiques tels que les systèmes de l'automobile et de l'avionique. En général, la plupart des FPGA d'aujourd'hui ne sont pas conçus pour fonctionner dans ces environnements difficiles, sauf pour les circuits spécifiques qui ont été durcies par construction au niveau du processus de fabrication. Ces circuits ont un surcoût très élevé et des performances moindres, ce qui les rend moins intéressant que leur équivalent non protégé. Le projet ARDyT vise à développer une architecture FPGA fiable à faible coût avec une suite d'outils de conception, offrant un environnement complet pour la conception d'un système tolérant aux fautes. Ce travail de thèse présente l'architecture du FPGA ARDyT, qui intègre des stratégies de prises en charge des fautes adaptées aux différents éléments de l'architecture. L'un des principaux objectifs du projet ARDyT est de gérer les changements de valeurs multiples (multi bit upsets (MBUs)) dans le flux binaire de configuration du FPGA. Ces stratégies de tolérance aux fautes pour protéger les ressources logiques et le flux binaire de configuration sont discutées en détail. Une architecture spécifique du bloc logique élémentaire configurable est proposée afin de simplifier la stratégie de prise en compte des fautes dans les ressources logiques. Un nouveau système de correction d'erreur intégrée (3-Dimensional Hamming - 3DH) est proposé pour gérer les MBU dans le flux binaire de configuration. L'ensemble de la stratégie de gestion des fautes est implémenté dans l'architecture au travers d'un manager de la fiabilité centralisée nommée R3M (Run-time Reconfigurable Resource Manager), et d'une suite d'outils adaptée. / Reconfigurable Field Programmable Gate Arrays (FPGAs) are extensively employed in various application domains due to their flexibility, high-density functionality, high performance and low-cost development compared to ASICs (Application Specific Integrated Circuits). However, the challenge that must be tackled during system design is their high susceptibility to the radiation induced faults such as Single Event Effects (SEEs). These radiation induced faults are a major concern in safety and mission critical systems such as automotive and avionics systems. In general, most of today’s COTS FPGAs are not designed to work under these harsh environments, except for specific circuits that have been radiation-hardened at the fabrication process level, but at a very high cost overhead, which makes them less interesting from an economic and performance point of view. The project ARDyT is aimed to develop a low-cost reliable FPGA architecture with supporting EDA tool-suite that offers a complete environment for a fault tolerant system design. This thesis work presents the proposed ARDyT FPGA architecture, which incorporates appropriate fault mitigation strategies at different levels. One of the main objectives of ARDyT project is to handle multi-bit upsets (MBUs) in the configuration bistream. Fault mitigation strategies to protect logic resources and configuration bitstream are discussed in detail. A fault-aware customized configurable logic block architecture is proposed to support logic resource fault mitigation strategy. A new built-in 3-Dimensional Hamming (3DH) error correcting scheme is proposed to handle MBUs in the configuration bitstream. The additional features introduced in this architecture ensure complete reliability with the help of centralized reliability manager named R3M (Run-time Reconfigurable Resource Manager), corresponding tool-suite and increased flexibility in the design.

A qualidade do serviço oferecido por Provedores do Serviço de Internet (Internet Service Provider - ISPs) depende diretamente da quantidade de recursos disponíveis naquele momento. Nas últimas décadas, essa qualidade tem sido afetada por frequentes e intensos ataques que consomem tais recursos, como é o caso dos ataques de Negação de Serviço Distribuídos (Distributed Denial of Service - DDoS). Com o objetivo de tornar a rede dos ISPs mais resiliente aos diferentes tipos de ataques DDoS, foram desenvolvidas técnicas contra tais ataques ao longo dos últimos anos. Com o objetivo de contribuir com a melhoria de tais mecanismos, esta dissertação apresenta um método autônomo reativo para detecção e mitigação de ataques DDoS, utilizando um sistema multiagentes (SMA), em redes de ISPs. A propriedade principal do método proposto é identificar padrões de tráfego característicos de um ataque, como um grande fluxo de pacotes direcionados para um serviço ou equipamento, dentro da rede do ISP. Com os agentes posicionados nas prováveis vítimas e nos pontos da rede com maior fluxo de pacotes, o processo de mitigação inicia-se automaticamente após uma quantidade de pacotes, excedente ao tráfego padrão, passar por qualquer um dos nós monitorados. Como o tráfego entrante na rede do ISP é dinâmico, seja ele legítimo ou malicioso, a utilização de agentes tende a facilitar o processo de definição da rota de ataque, conforme mostram os resultados experimentais obtido com o sistema proposto. / The quality of service offered by the Internet Service Provider (ISP) depends directly on the amount of resources available at that time. In recent decades, this quality has been affected by the frequent and intense attacks that consume these resources, such as the Distributed Denial of Service (DDoS) attacks. In order to make the ISPs network more resilient to different types of DDoS attacks, techniques have been developed against such attacks over the past few years. Aiming to contribute to the improvement of such mechanisms, this dissertation presents a reactive autonomous method for detecting and mitigating DDoS attacks using a Multi-Agent system (MAS), in networks of ISPs. The main property of the proposed method is to identify characteristic traffic patterns of an attack, such as a large stream of packets directed to a service or equipment within the ISP network. With agents positioned on likely victims and at points of the network with the highest packet stream, the mitigation process starts automatically after a number of packets exceeding the traffic pattern, go through any of the monitored nodes. Since the incoming traffic on the network of any ISP is dynamic, whether legitimate or malicious, the using of agents tends to facilitate the process of defining the route of attack, as shown by the experimental results obtained with the proposed system.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-18T18:54:16Z No. of bitstreams: 1 2012 - Abmael da Silva Cardoso.pdf: 1600160 bytes, checksum: 714351549deda5ed89c5e1ae3f665e30 (MD5) / Made available in DSpace on 2017-04-18T18:54:16Z (GMT). No. of bitstreams: 1 2012 - Abmael da Silva Cardoso.pdf: 1600160 bytes, checksum: 714351549deda5ed89c5e1ae3f665e30 (MD5) Previous issue date: 2012-01-27 / CAPES / The production of beef cattle in Brazil is responsible for much of the anthropogenic emission of greenhouse gases (GHG) emissions, especially methane from enteric fermentation and nitrous oxide from animal excretion. Changes in pasture management cattle diets may reflect a reduction in greenhouse gas emissions per unit of product produced. The objectives of this study were to simulate the effect of emission of greenhouse gases at different levels of intensification of beef production in Brazil, applying appropriate emission factors, and to assess the effect of changes in soil carbon stocks on the carbon balance. Four scenarios were established: number 1 - animals spent the entire cycle in areas of degraded pastures and extensive system; 2 - the animals spent the entire cycle on improved pastures but under an extensive system; 3 - the animals were raised on extensive improved pastures and supplemented in growing and fattening systems; and 4 - the animals were raised on pastures with intensive finishing in feedlots. The estimates of the GHG emissions were based on Brazilian studies of the zootecnic characteristics for each scenario. Using the methodology of the IPCC Tier 2 in the Scenario 2, the annual amount of CO2 emitted per carcass produced was 35.47 % lower than scenario 1; less than 18.85% in scenario 3 compared to scenario 2; and 19.6% lower in scenario 4 compared to scenario 3. Thus the intensification of production systems reduced the carbon emission per unit of product. Among the different factors used to compute the GHG balance, the application of Brazilian originated factors showed lower emissions per kg of product, and the methodology that uses the level of detail 2 of IPCC the highest. When the carbon sequestered by the soil was included in the balance, the mitigation values increase to 83.92% when comparing scenario 1 with 4, pointing to an even greatest mitigation potential per unit of product. The association between intensification and pasture recovery with carbon sequestration by soil presented a mitigation potential from 14.91 to 83.92% of emissions per unit of product. / A produ??o de bovinos de corte ? respons?vel no Brasil por grande parte da emiss?o de gases de efeito estufa (GEE), especialmente metano pela fermenta??o ent?rica dos animais e ?xido nitroso pela excre??o. Mudan?as no manejo e alimenta??o de animais bovinos podem repercutir numa redu??o das emiss?es destes gases por unidade de produto produzida. O objetivo deste trabalho foi verificar o efeito da emiss?o de gases de efeito estufa em diferentes n?veis de intensifica??o da pecu?ria de corte no Brasil aplicando diferentes fatores de emiss?o, bem como avaliar o efeito do sequestro de carbono sobre o balan?o de carbono. Quatro cen?rios foram estabelecidos: no primeiro os animais passavam todo o ciclo em ?reas com pastagens degradadas e sistema extensivo; no segundo os animais tinham o ciclo completo em pastagens resolutivas e sistema extensivo; no terceiro os animais eram criados em sistema extensivo em pastagens melhoras e com suplementa??o na recria e engorda; e no quarto sistema os animais eram criados em pastagens manejadas intensivamente com engorda em confinamento. A emiss?o de GEE para cada cen?rio foi calculada em fun??o das caracter?sticas zoot?cnicas e com base em estudos nacionais. Foi utilizada a metodologia do IPCC Tier 2 para o Cen?rio 2, a quantidade anual de CO2 emitido por carca?a produzida foi 35,47% menos em rela??o ao cen?rio 1, menos 18,85% no cen?rio 3 em rela??o ao cen?rio 2, e 19,6% menos no cen?rio 4 em rela??o ao cen?rio 3. Portanto a intensifica??o da bovinocultura de corte reduz a pegada de carbono da carne bovina. Entre os diferentes fatores usados para o balan?o de GEE o com fatores nacionais apresentou menor emiss?o por quilo de produto, e o m?todo com o n?vel de detalhamento 2 do IPCC a maior emiss?o. Quando inclusos os valores de carbono sequestrado pelo solo no balan?o, os valores de mitiga??o aumentaram para 83,92% entre o cen?rio 1 e 4, apontando para um potencial de mitiga??o ainda maior por unidade de produto. A associa??o entre intensifica??o e recupera??o das pastagens com sequestro de carbono pelo solo apresentou potencial de mitiga??o entre 14,91 e 83,92% das emiss?es por unidade de produto.

Made available in DSpace on 2017-07-10T19:24:33Z (GMT). No. of bitstreams: 1 Elisabete Ferro Mendonca.pdf: 1930052 bytes, checksum: 772f421efdecf47a02c45460b7957433 (MD5) Previous issue date: 2009-07-13 / The wastewater resulting from milk production processes with animals at free stall barns has huge organic matter concentration and requires treatment before being disposed at the environment. At this study, the dairy cattle wastewater from free stall barns was treated in horizontal tubular anaerobic reactors with continuous flow and 9.6 liters volume each, made with polyvinyl chloride (PVC). The material was collected at Iguaçu Farm, with geographic coordinates latitude 25°02'43.07" south, longitude 53°46'51.85" west and 641 meters altitude, sieved at 2 mm mesh and stored at -18 °C, conditioned in polyethylene terephthalate (PET) packs. The material was put in room temperature before being added to the reactor each day. Different loads were used, resulting in retention times equals to were 8, 10, 15 and 20 days. Two temperatures were used: 30 and 35 °C; with 4 replications. Statistical data were evaluated by factorial crossover design 4 x 2 x 4, 4 factors of hydraulic retention time (HRT), 2 temperature factors and 4 replicates, with the average calculated by the Tukey method. They were evaluated the chemical oxygen demand (COD) removal, by colorimetric method, total solids (TS) and volatile solids (VS), by gravimetric methods. The best treatments were met with 20 days HRT and 30 °C, with average 83.30% 76.16% and 86.23% of COD, TS and VS removed. The biogas production was measured relatively to COD, TS and VS removals, resulting in 1.32 m³ of biogas kg-¹ DQO at 5 days of HRT and 35 ° C. At the 8 days HRT and 30 ° C, they resulted in 1.05 and 1.01 m³ of biogas · kg-¹ of TS and VS removed from the system, respectively. / A água residuária resultante dos processos das atividades de produção intensiva de leite com animais em regime de estabulação completa possui elevada concentração de matéria orgânica e necessita de tratamento antes de ser disposta no ambiente. Neste estudo, a água residuária da criação e produção de bovinos leiteiros em regime de estabulação completa foi tratada em reatores anaeróbios tubulares horizontais de fluxo contínuo, em escala laboratorial, de volume útil de 9,6 litros cada, construídos em cloreto de polivinila (PVC). O material foi coletado na Fazenda Iguaçu, com coordenadas geográficas latitude 25°02 43,07 sul, longitude 53°46 51,85 oeste e altitude 641 metros, sendo peneirado em malha de 2 milímetros e armazenado a 18 °C abaixo de zero, em embalagens de polietileno tereftalato (PET). O material foi levado à temperatura ambiente antes de ser acrescentado aos reatores a cada dia. Foram utilizadas diferentes cargas, de forma que os tempos de retenção do efluente foram de 8, 10, 15 e 20 dias. Foram empregadas 2 temperaturas: 30 e 35 °C; com 4 repetições. Os dados estatísticos foram avaliados através de delineamento fatorial cruzado 4 x 2 x 4, sendo 4 fatores de tempo de retenção hidráulica (TRH), 2 fatores temperatura e 4 repetições; com as médias calculadas pelo método de Tukey. Foram avaliados a remoção de demanda química de oxigênio (DQO), a partir da metodologia colorimétrica, sólidos totais (ST) e sólidos voláteis (SV), com métodos gravimétricos. Os melhores tratamentos ocorreram com 20 dias de TRH e 30 °C com médias de 83,30%, 76,16% e 86,23% de DQO, ST e SV removidos, respectivamente. A produção de biogás foi avaliada em relação à DQO removida e aos ST e SV retirados do sistema, com 1,32 m³ de biogás·kg-¹ DQO em 15 dias de TRH a 35 °C e 8 dias com 30 °C, 1,05 e 1,01 m³ de biogás·kg-¹de ST e SV retirados do sistema, respectivamente.

Com a reestruturação do modelo do setor elétrico brasileiro, a partir do Projeto RE-SEB, as empresas de distribuição de energia elétrica no Brasil tiveram que se adequar às novas regras de mercado, bem como alterar a sua maneira de administrar a empresa. Com o conceito de regulação por incentivos e competição por mercado, e não competição no mercado, novos mecanismos de mitigação de riscos de mercado foram introduzidos no modelo do setor elétrico, de tal forma que as empresas de distribuição de energia elétrica sejam ressarcidas de maneira justa pelo serviço prestado à sociedade. Diante desse contexto, a gestão eficiente da empresa e, conseqüentemente, o fato de atingir as metas de desempenho pré-estabelecidas pela alta administração de cada distribuidora depende cada vez mais do conhecimento das regras de mercado por seus colaboradores, bem como da utilização dos mecanismos de mitigação de riscos de mercado das distribuidoras. Assim, esse trabalho pretende analisar os principais mecanismos de mitigação de riscos de mercado das distribuidoras envolvidos no processo de repasse dos custos de aquisição de energia elétrica às tarifas dos consumidores finais, bem como avaliar os dispositivos previstos na regulamentação legal, inserindo um estudo de caso que analisa o portfólio de contratação de uma empresa de distribuição de energia elétrica fictícia, simulando variações nos níveis de contratação da mesma bem como no portfólio, avaliando a utilização dos mecanismos de mitigação de riscos de mercado e as alternativas simuladas, como também identificando os pontos de sucesso e os pontos a serem melhorados na gestão e contratação da distribuidora. / As the restructuring of the model of the Brazilian electric sector, with the Project RE-SEB, the electric energy distribution companies in Brazil had to adjust themselves to the new rules of the market, as well as modify their way of manage the company. As the concept of regulation for incentives (price cap model) and competition by market, and not competition in the market, new mechanisms to reduce the risks of the market had been introduced in the model of the electric sector, in such a way that the electric energy distribution companies receive a fair revenue for the service delivered to the society. In this perspective, the efficient management of the company and, consequently, the fact of reaching the goals in the performance targets established by the high administration, depends on the deep knowledge of the rules of market by its technical team , as well as the use of the mechanisms to reduce the risks of the market of the distribution utilities. In this way, this work intends to analyze (i) the main mechanisms available to the distribution companies in order to mitigate the market risks in the process of contract energy supply and to pass-though such costs to the final consumers, as well as (ii) evaluate the rules implemented in the legal regulation framework. Furthermore, to illustrate the analysis, a case study was developed focusing the contract portfolio of a fictitious distribution company, simulating variations in the contracted energy volume as well as in the portfolio composition, evaluating the uses of the mitigation mechanisms of the market risks and solution alternatives to minimize such risks, searching for improvements that could be made in the management strategy of energy supply contracting.

Made available in DSpace on 2017-05-12T14:47:55Z (GMT). No. of bitstreams: 1 Elisabete Ferro Mendonca.pdf: 1930052 bytes, checksum: 772f421efdecf47a02c45460b7957433 (MD5) Previous issue date: 2009-07-13 / The wastewater resulting from milk production processes with animals at free stall barns has huge organic matter concentration and requires treatment before being disposed at the environment. At this study, the dairy cattle wastewater from free stall barns was treated in horizontal tubular anaerobic reactors with continuous flow and 9.6 liters volume each, made with polyvinyl chloride (PVC). The material was collected at Iguaçu Farm, with geographic coordinates latitude 25°02'43.07" south, longitude 53°46'51.85" west and 641 meters altitude, sieved at 2 mm mesh and stored at -18 °C, conditioned in polyethylene terephthalate (PET) packs. The material was put in room temperature before being added to the reactor each day. Different loads were used, resulting in retention times equals to were 8, 10, 15 and 20 days. Two temperatures were used: 30 and 35 °C; with 4 replications. Statistical data were evaluated by factorial crossover design 4 x 2 x 4, 4 factors of hydraulic retention time (HRT), 2 temperature factors and 4 replicates, with the average calculated by the Tukey method. They were evaluated the chemical oxygen demand (COD) removal, by colorimetric method, total solids (TS) and volatile solids (VS), by gravimetric methods. The best treatments were met with 20 days HRT and 30 °C, with average 83.30% 76.16% and 86.23% of COD, TS and VS removed. The biogas production was measured relatively to COD, TS and VS removals, resulting in 1.32 m³ of biogas kg-¹ DQO at 5 days of HRT and 35 ° C. At the 8 days HRT and 30 ° C, they resulted in 1.05 and 1.01 m³ of biogas · kg-¹ of TS and VS removed from the system, respectively. / A água residuária resultante dos processos das atividades de produção intensiva de leite com animais em regime de estabulação completa possui elevada concentração de matéria orgânica e necessita de tratamento antes de ser disposta no ambiente. Neste estudo, a água residuária da criação e produção de bovinos leiteiros em regime de estabulação completa foi tratada em reatores anaeróbios tubulares horizontais de fluxo contínuo, em escala laboratorial, de volume útil de 9,6 litros cada, construídos em cloreto de polivinila (PVC). O material foi coletado na Fazenda Iguaçu, com coordenadas geográficas latitude 25°02 43,07 sul, longitude 53°46 51,85 oeste e altitude 641 metros, sendo peneirado em malha de 2 milímetros e armazenado a 18 °C abaixo de zero, em embalagens de polietileno tereftalato (PET). O material foi levado à temperatura ambiente antes de ser acrescentado aos reatores a cada dia. Foram utilizadas diferentes cargas, de forma que os tempos de retenção do efluente foram de 8, 10, 15 e 20 dias. Foram empregadas 2 temperaturas: 30 e 35 °C; com 4 repetições. Os dados estatísticos foram avaliados através de delineamento fatorial cruzado 4 x 2 x 4, sendo 4 fatores de tempo de retenção hidráulica (TRH), 2 fatores temperatura e 4 repetições; com as médias calculadas pelo método de Tukey. Foram avaliados a remoção de demanda química de oxigênio (DQO), a partir da metodologia colorimétrica, sólidos totais (ST) e sólidos voláteis (SV), com métodos gravimétricos. Os melhores tratamentos ocorreram com 20 dias de TRH e 30 °C com médias de 83,30%, 76,16% e 86,23% de DQO, ST e SV removidos, respectivamente. A produção de biogás foi avaliada em relação à DQO removida e aos ST e SV retirados do sistema, com 1,32 m³ de biogás·kg-¹ DQO em 15 dias de TRH a 35 °C e 8 dias com 30 °C, 1,05 e 1,01 m³ de biogás·kg-¹de ST e SV retirados do sistema, respectivamente.

A qualidade do serviço oferecido por Provedores do Serviço de Internet (Internet Service Provider - ISPs) depende diretamente da quantidade de recursos disponíveis naquele momento. Nas últimas décadas, essa qualidade tem sido afetada por frequentes e intensos ataques que consomem tais recursos, como é o caso dos ataques de Negação de Serviço Distribuídos (Distributed Denial of Service - DDoS). Com o objetivo de tornar a rede dos ISPs mais resiliente aos diferentes tipos de ataques DDoS, foram desenvolvidas técnicas contra tais ataques ao longo dos últimos anos. Com o objetivo de contribuir com a melhoria de tais mecanismos, esta dissertação apresenta um método autônomo reativo para detecção e mitigação de ataques DDoS, utilizando um sistema multiagentes (SMA), em redes de ISPs. A propriedade principal do método proposto é identificar padrões de tráfego característicos de um ataque, como um grande fluxo de pacotes direcionados para um serviço ou equipamento, dentro da rede do ISP. Com os agentes posicionados nas prováveis vítimas e nos pontos da rede com maior fluxo de pacotes, o processo de mitigação inicia-se automaticamente após uma quantidade de pacotes, excedente ao tráfego padrão, passar por qualquer um dos nós monitorados. Como o tráfego entrante na rede do ISP é dinâmico, seja ele legítimo ou malicioso, a utilização de agentes tende a facilitar o processo de definição da rota de ataque, conforme mostram os resultados experimentais obtido com o sistema proposto. / The quality of service offered by the Internet Service Provider (ISP) depends directly on the amount of resources available at that time. In recent decades, this quality has been affected by the frequent and intense attacks that consume these resources, such as the Distributed Denial of Service (DDoS) attacks. In order to make the ISPs network more resilient to different types of DDoS attacks, techniques have been developed against such attacks over the past few years. Aiming to contribute to the improvement of such mechanisms, this dissertation presents a reactive autonomous method for detecting and mitigating DDoS attacks using a Multi-Agent system (MAS), in networks of ISPs. The main property of the proposed method is to identify characteristic traffic patterns of an attack, such as a large stream of packets directed to a service or equipment within the ISP network. With agents positioned on likely victims and at points of the network with the highest packet stream, the mitigation process starts automatically after a number of packets exceeding the traffic pattern, go through any of the monitored nodes. Since the incoming traffic on the network of any ISP is dynamic, whether legitimate or malicious, the using of agents tends to facilitate the process of defining the route of attack, as shown by the experimental results obtained with the proposed system.

Maritime surveillance radars are critical in commerce, transportation, navigation, and defense. However, the sea environment is perhaps the most challenging of natural radar backdrops because maritime radars must contend with electromagnetic backscatter from the sea surface, or sea clutter. Sea clutter poses unique challenges in very low grazing angle geometries, where typical statistical assumptions regarding sea clutter backscatter do not hold. As a result, traditional constant false alarm rate (CFAR) detection schemes may yield a large number of false alarms while objects of interest may be challenging to detect. Solutions posed in the literature to date have been either computationally impractical or lacked robustness. This dissertation explores whether fully polarimetric radar offers a means of enhancing detection performance in low grazing angle sea clutter. To this end, MIT Lincoln Laboratory funded an experimental data collection using a fully polarimetric X-band radar assembled largely from commercial off-the-shelf components. The Point de Chene Dataset, collected on the Atlantic coast of Massachusetts’ Cape Ann in October 2015, comprises multiple sea states, bandwidths, and various objects of opportunity. The dataset also comprises three different polarimetric transmit schemes. In addition to discussing the radar, the dataset, and associated post-processing, this dissertation presents a derivation showing that an established multiple input, multiple output radar technique provides a novel means of simultaneous polarimetric scattering matrix measurement. A novel scheme for polarimetric radar calibration using a single active calibration target is also presented. Subsequent research leveraged this dataset to develop Polarimetric Co-location Layering (PCL), a practical algorithm for mitigation of low grazing angle sea clutter, which is the most significant contribution of this dissertation. PCL routinely achieves a significant reduction in the standard CFAR false alarm rate while maintaining detections on objects of interest. Moreover, PCL is elegant: It exploits fundamental characteristics of both sea clutter and object returns to determine which CFAR detections are due to sea clutter. We demonstrate that PCL is robust across a range of bandwidths, pulse repetition frequencies, and object types. Finally, we show that PCL integrates in parallel into the standard radar signal processing chain without incurring a computational time penalty.

Soft robots and particularly inflatable robots are of interest because they are lightweight, compact, robust to impact, and can interact with humans and their environment relatively safely compared to rigid and heavy traditional robots. Improved safety is due to their low mass that results in low-energy collisions and their compliant, soft construction. Inflatable robots (which are a type of soft robot) are also robust to impact and have a high torque to weight ratio. As a result inflatable robots may be used for many applications such as space exploration, search and rescue, and human-robot interaction. One of the potential problems with inflatable or pneumatically actuated robots is air leaking from the structural or actuation chambers. In this thesis methods are demonstrated to detect leaks in the structural and actuation chambers of inflatable and pneumatically actuated robots. It is then demonstrated that leaks can be slowed by lowering a target pressure which affects joint stiffness to prolong the life of the system. To demonstrate the effects of lowering the target pressure it is first shown that there exists a trade-off between the commanded target pressures at steady-state and the steady-state error at the robot end effector under normal operation. It is then shown that lowering the target pressure (which is related to stiffness) can extend the operational life of the system when compressed air is a limited resource. For actuator leaks a lower target pressure for the leaking joint is used to demonstrate the trade-off between slowing the leak rate and system performance. For structural leaks a novel control algorithm is demonstrated to lower target pressure as much as possible to slow the leak while maintaining a user specified level of accuracy. The method developed for structural leaks extends the operational life of the robot. Long-term error during operation is decreased by as much as 50% of the steady-state error at the end effector when compared to performance during a leak without the control algorithm. For actuation leaks in a joint with a high-torque load the possibility of a 30% increase in operation time while only increasing steady-state error by 2 cm on average is demonstrated. For a joint with a low-torque load it is shown that up to a 300% increase in operation time with less than 1 cm increased steady-state error is possible. The work presented in this thesis demonstrates that varying stiffness may be used to extend the operational life of a robot when a leak has occurred. The work discussed here could be used to extend the available operation time of pneumatic robots. The methods and principles presented here could also be adapted for use on other types of robots to preserve limited system resources (e.g., electrical power) and extend their operation time.