In this thesis we study Boolean functions from three different perspectives. First, we study the complex- ity of Boolean minimization for several classes of formulas with polynomially solvable SAT, and formulate sufficient conditions for a class which cause the minimization problem to drop at least one level in the polyno- mial hierarchy. Second, we study a class of matched CNFs for which SAT is trivial but minimization remains Σp 2 complete. We prove that every matched CNF has at least one equivalent prime and irredundant CNF that is also matched. We use this fact to prove the main result of this part, namely that for every matched CNF all clause minimal equivalent CNFs are also matched. Third, we look at propagation completeness - the property of a CNF that says that for every partial assignment all entailed literals can be discovered by unit propagation. We can extend every CNF to be propagation complete by adding empowering impli- cates to it. The main result of this section is a the proof of coNP completeness of the recognition problem for propagation complete CNFs. We also show that there exist CNFs to which an exponential number of empowering implicates have to be added to make them propagation complete.

Submitted by infopei ufba (infopei@ufba.br) on 2016-09-30T14:56:36Z No. of bitstreams: 1 dis_gardenia_o_d_de_azevedo.pdf: 1013545 bytes, checksum: 82f19fc8799e3ed10e5a2c222567863f (MD5) / Approved for entry into archive by Escola Politécnica Biblioteca (biengproc@ufba.br) on 2017-03-20T15:49:38Z (GMT) No. of bitstreams: 1 dis_gardenia_o_d_de_azevedo.pdf: 1013545 bytes, checksum: 82f19fc8799e3ed10e5a2c222567863f (MD5) / Made available in DSpace on 2017-03-20T15:49:38Z (GMT). No. of bitstreams: 1 dis_gardenia_o_d_de_azevedo.pdf: 1013545 bytes, checksum: 82f19fc8799e3ed10e5a2c222567863f (MD5) / CONDER, PUC/PR, CAPES, PROCAD, COMEC, LIMPURB, / Esta dissertação busca alternativas para a gestão dos resíduos sólidos urbanos da cidade do Salvador, objetivando a redução da geração de resíduos na unidade habitacional à luz de uma visão de sustentabilidade ambiental. Para tanto, foi investigado o conceito sobre prevenção da poluição e a hierarquia de técnicas para a redução dos resíduos, buscando sua aplicabilidade para a minimização dos resíduos sólidos urbanos. Foram também analisadas algumas experiências internacionais e feita uma avaliação mais detalhada da experiência de Curitiba, considerada pioneira na reciclagem de resíduos urbanos, comparando-a, então, com a gestão no município do Salvador. A partir desses estudos, sugerem-se medidas possíveis para Salvador, esboçando-se modelos de fluxo para os resíduos domiciliares e procedimentos para atuação junto à população, no sentido de sensibilizá-la para a redução da geração de resíduos. Verifica-se, com base nesse modelo, que existe possibilidade de reduzir o resíduo domiciliar de forma significativa e de melhorar a gestão do sistema de resíduos sólidos urbanos da cidade, contribuindo para a redução de impactos ambientais, provocados pelo intenso consumo de matéria-prima, geração de resíduos e disposição inadequada, bem como ampliar a vida útil do aterro sanitário em operação, com ganhos econômicos, sociais e ambientais para a população. / This research seeks for alternatives to the urban solid waste management of Salvador/Brazil, aiming the reduction of waste generation from residential units in an environmental sustainability perspective. The concept on pollution prevention was investigated, as well as the hierarchy of techniques used to reduce pollution, searching for its applicability on municipal solid waste minimization. Some international experiences were also analyzed; and a detailed assessment on Curitiba´s (pioneer on urban waste recycling in Brazil) experience was done, and compared with Salvador´s system. Based on these studies, suggestions of possible measures for Salvador were made, drafting models for household waste streams and for procedures to increase community awareness about waste generation reduction. Results confirmed the possibility of reduction of household waste in a significant way and of improvement of urban solid waste management in the city. This contributes with the reduction of environmental impacts, caused by waste generation and inadequate disposal, the growth of the useful life of landfill, with economics, social and environmental benefits, as well the extraction of raw materials from nature.

Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-10T19:28:17Z No. of bitstreams: 1 Gardênia.pdf: 2164691 bytes, checksum: b1700a2c5f0f7830fcebab9bedd3db72 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-13T20:05:05Z (GMT) No. of bitstreams: 1 Gardênia.pdf: 2164691 bytes, checksum: b1700a2c5f0f7830fcebab9bedd3db72 (MD5) / Made available in DSpace on 2013-04-13T20:05:05Z (GMT). No. of bitstreams: 1 Gardênia.pdf: 2164691 bytes, checksum: b1700a2c5f0f7830fcebab9bedd3db72 (MD5) Previous issue date: 2004 / Esta dissertação busca alternativas para a gestão dos resíduos sólidos urbanos da cidade do Salvador, objetivando a redução da geração de resíduos na unidade habitacional à luz de uma visão de sustentabilidade ambiental. Para tanto, foi investigado o conceito sobre prevenção da poluição e a hierarquia de técnicas para a redução dos resíduos, buscando sua aplicabilidade para a minimização dos resíduos sólidos urbanos. Foram também analisadas algumas experiências internacionais e feita uma avaliação mais detalhada da experiência de Curitiba, considerada pioneira na reciclagem de resíduos urbanos, comparando-a, então, com a gestão no município do Salvador. A partir desses estudos, sugerem-se medidas possíveis para Salvador, esboçando-se modelos de fluxo para os resíduos domiciliares e procedimentos para atuação junto à população, no sentido de sensibilizá-la para a redução da geração de resíduos. Verifica-se, com base nesse modelo, que existe possibilidade de reduzir o resíduo domiciliar de forma significativa e de melhorar a gestão do sistema de resíduos sólidos urbanos da cidade, contribuindo para a redução de impactos ambientais, provocados pelo intenso consumo de matéria-prima, geração de resíduos e disposição inadequada, bem como ampliar a vida útil do aterro sanitário em operação, com ganhos econômicos, sociais e ambientais para a população. / Salvador

FARIAS, Pablo Mayckon Silva. O problema de ordenação de rodadas e problemas de otimização associados. 2013. 127 f. Tese (Doutorado em ciência da computação)- Universidade Federal do Ceará, Fortaleza-CE, 2013. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-20T12:44:36Z No. of bitstreams: 1 2013_tese_pmsfarias.pdf: 1600516 bytes, checksum: afaccc349ce6f2d065494cd2601913c0 (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2016-07-25T12:05:15Z (GMT) No. of bitstreams: 1 2013_tese_pmsfarias.pdf: 1600516 bytes, checksum: afaccc349ce6f2d065494cd2601913c0 (MD5) / Made available in DSpace on 2016-07-25T12:05:15Z (GMT). No. of bitstreams: 1 2013_tese_pmsfarias.pdf: 1600516 bytes, checksum: afaccc349ce6f2d065494cd2601913c0 (MD5) Previous issue date: 2013 / This thesis is composed of three well-delineated parts. In the first part, we introduce the round sorting problem (RSP), which models the minimization of the usage of buffer for the temporary storage of packets to be forwarded in TDMA communications of wireless mesh networks. We present a complete foundation for the definition of the RSP, and show that the problem is NP-hard for two theoretical models of radio interference known in the literature. A mixed integer programming formulation is also presented for a purely combinatorial and applicationindependent generalization of the RSP, the SMSP problem. In the second part of the work, we deal with problems about queries on insertions into sequences of numbers. Our main result in this part of the thesis is to show how, after a preprocessing step which runs in linear time on a sequence A of arbitrary real numbers, it is possible to compute in constant time the greatest sum of a (circular or not) contiguous subsequence of the sequence which results from the insertion of a given real number x into a given position p of A. In the third part of the thesis, we use the query algorithms from the second part to obtain an efficient implementation of the GRASP metaheuristic applied to the SMSP problem. An experimental analysis of this implementation is described, in which the values of the solutions returned by the metaheuristic are compared with those of the solutions obtained through the mixed integer formulation, in the case of small instances, and with the available lower bound, in the case of larger instances. / Esta tese é composta de três partes bem-delineadas. Na primeira parte, nós introduzimos o "problema de ordenação de rodadas" (POR), que modela a minimização do uso de memória ("buffer") para o armazenamento temporário de pacotes a serem repassados em comunicações TDMA de redes de rádio em malha. Nós apresentamos uma fundamentação completa para a definição do POR, e mostramos que o problema é NP-difícil para dois modelos teóricos de interferência de rádio conhecidos na literatura. Uma formulação de programação inteira mista é também apresentada para uma generalização puramente combinatória e independente de aplicação do POR, o problema SMSP. Na segunda parte do trabalho, nós abordamos problemas de consulta sobre inserções em sequências de números. O nosso principal resultado nesta parte da tese é mostrar como, após um passo de pré-processamento que executa em tempo linear sobre uma sequência "A" de números reais quaisquer, é possível computar em tempo constante a maior soma de uma subsequência contígua (circular ou não) da sequência que resulta da inserção de dado um número real "x" numa dada posição "p" de "A". Na terceira parte da tese, nós utilizamos os algoritmos de consulta da segunda parte para obter uma implementação eficiente da meta-heurística GRASP aplicada ao problema SMSP. Uma análise experimental dessa implementação é descrita, onde os valores das soluções retornadas pela meta-heurística são comparados com os das soluções obtidas pela formulação inteira mista, no caso de instâncias pequenas, e com o limite inferior disponível, no caso de instâncias maiores.

Growing municipal waste mismanagement and associated environmental impacts is an enormous environmental concern in developing countries such as South Africa. Hence, this study explored current waste management and minimisation patterns and practices in the Ekurhuleni Metropolitan Municipality (EMM), located east of the Gauteng province. The study was undertaken using a mixed method design, particularly the concurrent triangulated design where the quantitative and qualitative data were collected at the same time. The methods employed were desktop surveys, interviews with the participants and use of questionnaires which were designed based on the objectives of the study. The questionnaires were designed for different types of participants (namely, households, informal reclaimers, municipal officials and landfill officials). All the data collected were stored in Microsoft Excel (2010) spread sheet for statistical analyses. The study has revealed some patterns, practices as well as trends regarding waste management and minimisation within the EMM municipality. At household level, there was some environmental awareness on waste management practices provided by the municipality as well as local recycling options although there are numerous challenges to be resolved before these functions can become effective. With informal recycling, a number of waste materials are being reclaimed at various landfill sites. However, current informal waste picking activities by the so-called scavengers are not sustainable as waste is not separated prior to disposal at various point sources. In addition, informal reclaimers have to travel long distances to reach waste sources. Another concerning constraint hampering the effectiveness of informal waste recovery, has to do with their daily exposure to several environmental and health risks. Furthermore, the study has found out that the EMM is predominantly focused on providing better waste management services rather than balancing this activity with waste minimisation through reclaiming and recycling operations. Thus, the municipality lacks adequate infrastructure to undertake waste minimisation effectively. Also, waste minimisation and awareness campaigns were found to be inadequate and at an infant stage, unlike those carried out by private companies. In view of these findings, a number of recommendations have been made. / Environmental Sciences / M. Sc. (Environmental Science)

Les principaux critères de comparaison des convertisseurs sont le rendement, la masse, le volume, le coût et la fiabilité. Le contexte environnemental et économique et le développement des applications nomades ouvrent à l’électronique de puissance un domaine d’application de plus en plus vaste. Mais pour imposer cette technologie, il faut sans cesse améliorer ces performances et les compromis entre celles qui sont antagonistes (augmentation du rendement et diminution de la masse par exemple…) ce qui amène naturellement à la problématique de conception et d’optimisation. Le cas spécifique de l’aéronautique n’échappe pas à la règle et les contraintes y semblent encore plus fortes. La réduction de la masse, du volume et l’augmentation du rendement et de la fiabilité sont parmi les défis principaux actuels, et la transition de systèmes hydrauliques ou pneumatique vers des systèmes électriques laisse espérer à une amélioration des performances globales de l’avion. Les architectures des convertisseurs sont un moyen efficace d’améliorer les convertisseurs parce qu’ils permettent de réduire les contraintes au sein des convertisseurs tout en améliorant les formes d’onde en entrée et/ou en sortie. Parallèlement, les composants classiques en silicium ont bénéficié de larges avancés au cours de ces dernières décennies et approchent de leurs limites théoriques. Pour espérer une amélioration, des technologies en rupture sont désormais nécessaires. Au cours de ces dernières années, les technologies de semi-conducteurs dit « à grand gap », essentiellement à base de Nitrure de Gallium ou de Carbure de Silicium (resp. GaN et SiC) se sont considérablement amélioré et sont d’ores et déjà plus performant que les composants Si dans de nombreux cas. Les semi-conducteurs étant généralement plus performants lorsqu’ils ont une tenue en tension plus faible, on envisage ici de cumuler plusieurs avantages en envisageant la mise en série de composants GaN basse-tension pour améliorer l’intégration des convertisseurs de puissance. Dans un premier temps, un convertisseur multi-niveaux élémentaire de type Flying Capacitor (FlyCap) est mis en oeuvre. Des condensateurs de puissance intégrés sont utilisés, ce qui pourrait permettre de réduire l’empreinte de ces composants et de proposer une dissipation thermique commune par le dessus des composants. L’utilisation de composant au temps de commutation réduit est critique pour la fiabilité des convertisseurs. Une étude de l’influence des paramètres physique du circuit électrique sur les inductances parasites de la maille de puissance et de commande est menée permettant de mettre en évidence des règles de conception dans le but d’améliorer la fiabilité des convertisseurs. Dans un second temps, l’équilibrage dynamique de la topologie FlyCap qui est critique pour les formes d’onde et la sureté de fonctionnement est étudié. La prise en compte des pertes dans les semi-conducteurs permet d’améliorer l’estimation de la dynamique d’équilibrage. Une base de réflexion sur le dimensionnement d’un équilibreur passif est également proposée pour optimiser sa dynamique et les pertes associées. Un prototype expérimental à 5 cellules de commutation est présenté permettant d’atteindre une tension d’entrée de 270 V avec des composants 100V. / Performance, weight, volume, cost and reliability are key criteria to compare converters. Environment and economical context and the development of mobile applications lead electronics to have a wider field of application. Improving performances and tradeoff between conflicting characteristics (high efficiency and reduced weight for example) is thus constantly needed to impose this technology, which calls for design and optimization methods and tools. The specific case of aeronautics is no exception and there is in this field a high demand. Mass and volume reduction, efficiency and reliability improvement is one of the most important challenges, and the change from hydraulic and pneumatic systems to electric systems is expected to allow a global improvement of aircraft performances. Converter’s topology is a good candidate to improve and reduce the size of converters because it can reduce stress while improving the input and/or output waveforms. Meanwhile, conventional silicon components have taken advantage of wide advances in recent decades and are now close to their theoretical limits. To hope for a significant improvement, breaking technologies are now needed. In recent years, GaN and SiC Wide Band Gap semiconductors have seen significant development and are already often better than Si power devices. Lowvoltage semiconductors are generally better than higher voltage ones. Thus, we consider here cumulating advantages with a serial arrangement of low voltage GaN semi-conductors to improve power converter’s integration. First, a basic multilevel Flying Capacitor GaN-based converter is implemented. The integration of power capacitors is proposed to evaluate this technology, which could reduce the footprint of these components and could allow a common heatsink dissipation through the top of the components. Very fast turn-on and turn-off of GaN devices is critical for safe operation due to parasitic inductances. A study of physical parameters of the electrical circuit on parasitic inductances of power and control loop is conducted to lay down design rules in order to improve the reliability of converters. Secondly, dynamic balancing of Flying Capacitor which is critical for the waveforms and reliability is studied. Semi-conductor’s losses are considered to improve the estimation of dynamic balancing. A method for the design of a passive balancer is also proposed to optimize the balancing and associated losses. An experimental prototype with 5 switching cells is presented to achieve an input voltage of 270 V with 100 V rated voltage devices.

Este trabalho apresenta um modelo linearizado para ser utilizado em problemas de planejamento da expansão de sistemas de distribuição de energia elétrica (SDEE) com geração distribuída (GD), em um horizonte de curto prazo. O ponto de operação em regime permanente é calculado através de um modelo linearizado da rede, sendo as cargas e geradores representados por injeções constantes de corrente, o que torna possível calcular as correntes nos ramos e as tensões nas barras através de expressões lineares. As alternativas de expansão consideradas são: (i) alocação de bancos de capacitores; (ii) alocação de reguladores de tensão; e (iii) recondutoramento. Ainda, o modelo considera a possibilidade de seleção do tap dos transformadores de distribuição como alternativa para a redução das violações de tensão. A flexibilidade do modelo permite obter soluções considerando a contribuição das GDs no controle de tensão e potência reativa sem a necessidade de especificar uma tensão para a barra da subestação. O modelo de otimização proposto para a solução destes problemas utiliza uma função objetivo linear, além de restrições lineares e variáveis contínuas e binárias. Dessa forma, o modelo de otimização pode ser representado como um problema de programação linear inteira mista (PLIM) A função objetivo considera a minimização dos custos de investimento (aquisição, instalação e remoção de equipamentos e aquisição de condutores) e dos custos de operação, que correspondem aos custos anuais de manutenção somados aos custos das perdas de energia e das violações dos limites de tensão. A variação da carga é representada através de curvas de duração, sendo que os custos das perdas e das violações são ponderados pela duração de cada nível de carregamento. Utilizando uma abordagem de PLIM, sabe-se que existem condições suficientes que garantem a otimalidade de uma dada solução factível, além de permitir que a solução seja obtida através de métodos de otimização clássica. O modelo proposto foi implementado na linguagem de programação OPL e resolvido utilizando o solver comercial CPLEX. O modelo foi validado através da comparação dos resultados obtidos para cinco sistemas de distribuição com os resultados obtidos utilizando um fluxo de carga convencional. Os casos analisados e os resultados obtidos demonstram a precisão do modelo proposto e seu potencial de aplicação. / This work presents a linearized model to be used in short-term expansion planning problems of power distribution systems (PDS) with distributed generation (DG). The steady state operation point is calculated through a linearized model of the network, being the loads and generators modeled as constant current injections, which makes it possible to calculate the branch currents and bus voltages through linear expressions. The alternatives considered for expansion are: (i) capacitor banks placement; (ii) voltage regulators placement; and (iii) reconductoring. Furthermore, the model considers the possibility of adjusting the taps of the distribution transformers as an alternative to reduce voltage violations. The flexibility of the model enables solutions that includes the contribution of DGs in the control of voltage and reactive power without the need to specify the substation voltage. The optimization model proposed to solve these problems uses a linear objective function, along with linear constraints, binary and continuous variables. Thus, the optimization model can be represented as a mixed integer linear programming problem (MILP) The objective function considers the minimization of the investment costs (acquisition, installation and removal of equipment and acquisition of conductors) and the operation costs, which corresponds to the annual maintenance cost plus the costs related to energy losses and violation of voltage limits. The load variation is represented by discrete load duration curves and the costs of losses and voltage violations are weighted by the duration of each load level. Using a MILP approach, it is known that there are sufficient conditions that guarantee the optimality of a given feasible solution, besides allowing the solution to be obtained by classical optimization methods. The proposed model was written in the programming language OPL and solved by the commercial solver CPLEX. The model was validated through the comparison of the results obtained for five distribution systems with the results obtained through conventional load flow. The analyzed cases and the obtained results show the accuracy of the proposed model and its potential for application.

A indústria da construção civil é considerada como uma das grandes causadoras de impactos negativos ao meio ambiente, desde a extração de matéria prima, até o fim de vida de seus empreendimentos. Dentre os principais impactos ambientais ocasionados pelo setor, destacase a geração de resíduos de construção civil (RCC), a qual é intensificada em função do desenvolvimento de grandes centros urbanos e a consequente necessidade de implantação de empreendimentos de infraestrutura. Nesse contexto, uma das estratégias mais eficientes para redução de RCC está associada à realização de escolhas adequadas na fase de projeto, com enfoque de prevenção na fonte geradora. No entanto, é complexa a inclusão de fatores de sustentabilidade, tais como os de minimização de RCC, em projetos da construção civil. Logo, torna-se relevante a adoção de métodos e ferramentas de suporte ao processo decisório. Contudo, os métodos existentes são direcionados, em sua maioria, a projetos de edificações, havendo uma importante lacuna associada a projetos de infraestrutura urbana. Assim sendo, esta pesquisa objetiva a proposição de mecanismos de apoio à tomada de decisão, para a minimização de RCC, em projetos de infraestrutura urbana, com dois diferentes enfoques: controle e avaliação; e estrutura de orientação. Para a composição dos mecanismos de controle e avaliação, foram identificadas boas práticas para redução da geração de RCC na fase de projeto, a partir de pesquisa bibliográfica, análise documental de projetos, e pesquisa quali-quantitativa junto a especialistas. Essas boas práticas deram origem a demandas ambientais a serem atendidas pelos projetos de infraestrutura urbana, motivando a elaboração de um método estruturado para gerenciamento de requisitos ambientais e de trade-offs, como apoio à tomada de decisão projetual. O método teve como base a ferramenta Quality Function Deployment (QFD), no qual foi desdobrada a Matriz da Qualidade, a partir da opinião de especialistas atuantes em diferentes etapas do desenvolvimento de projetos de infraestrutura urbana. Como principais contribuições da pesquisa, focada na minimização de RCC, podem ser consideradas: (i) a obtenção de um checklist, como instrumento de controle e avaliação da qualidade dos projetos a serem desenvolvidos; (ii) a identificação de requisitos e de indicadores ambientais prioritários associados a esses projetos; e (iii) a elaboração de uma sistemática para gerenciamento de trade-offs existentes em projetos de infraestrutura urbana menos impactantes ambientalmente. / The construction industry is considered as one of the great causes of negative impacts to the environment, from the extraction of raw material, until the end-of-life of its projects. Among the main environmental impacts caused by the sector, can be highlighted the generation of construction waste (CW), which is intensified due to the development of large urban centers and the consequent need to implement infrastructure projects. In that context, one of the most efficient strategies to reduce CW is associated with making adequate choices in the design phase, with a focus on prevention at the source. However, it is complex to include sustainability factors, such as CW minimization, in construction designs. Therefore, it is relevant to adopt methods and tools to support the decision-making process. However, the existing methods are mostly directed to building designs, with an important gap associated with urban infrastructure designs. Thus, this research aims at proposing mechanisms to support decision making for the CW minimization in urban infrastructure projects, with two different approaches: control and evaluation; and guidance structure. For the composition of the control and the evaluation mechanisms, best practices were identified to reduce the CW generation in the design phase, based on literature review, documentary analysis of projects, and qualitative and quantitative surveys with specialists. Those best practices have given rise to environmental demands to be met by urban infrastructure projects, motivating the elaboration of a structured method for managing environmental requirements and trade-offs, as a support for the decision making design. The method was based on the Quality Function Deployment (QFD) tool, in which the quality matrix deployment, based on the opinion of specialists working in different stages of the development of urban designs. The main contributions of the research, focused on the CW minimization, can be considered: (i) obtaining a checklist, as an instrument to control and evaluate the quality of the designs to be developed; (ii) identification of requirements and of priority environmental indicators associated with those projects; and (iii) the development of a systematic for managing tradeoffs in urban infrastructure projects that are less environmentally impacting.

Made available in DSpace on 2016-06-02T20:00:25Z (GMT). No. of bitstreams: 1 DissMAC.pdf: 2706358 bytes, checksum: 3e701f115f72927096a96e8493b36d2d (MD5) Previous issue date: 2004-08-12 / Lasting for 150 years of development and still playing the role of irretrievable, the tire, when turned into solid waste, becomes environmental concern. In Brazil, due to the considerable amount generated and the long-life of this solid waste, the disposal environmental risks reach large proportions, mainly in urban areas. For this reason, this is a subject which demands responsible management, along local governmental articulation, direct an indirect in charge subordinated by the rules of CONAMA nº 258 / 99 e 301 / 02, and ruled by Instrução Normativa nº 08/02, of IBAMA. As far as it may concern, this paper aims a critical investigation on operational procedures as well as on the technologies regarding tire solid waste management in the country, mainly under the legislation above-mentioned. The literature survey made possible the evaluation of procedures development on managing, by a diagnoses of present tire solid waste management in the country as much as its interfaces with environmental legislation. Also, it has supported the understanding of the level of involving and awareness of those in charge with the matter, and the present Technologies for minimizing the generated waste. This paper has been conceived to accomplish tire solid waste management regarding collecting strategies and good use in the ground of an interaction among the responsible segments. Its goal is the minimization of environmental impact and public health damage, which derive from improperly manipulation of solid waste in urban site, in order to appease future generations none of the problems that are faced nowadays. / O pneu, após mais de 150 anos de desenvolvimento e ainda com um papel insubstituível e fundamental na vida atual, quando se torna inservível constitui um passivo ambiental. No Brasil, em face da quantidade significativa gerada, e da durabilidade dos pneumáticos inservíveis, os problemas ambientais decorrentes de sua disposição final inadequada assumem grandes proporções, principalmente, no meio ambiente urbano, se tornando necessária à minimização desses resíduos sólidos especiais por meio de seu gerenciamento, com a articulação de ações da municipalidade e dos responsáveis diretos e indiretos identificados pelas Resoluções CONAMA nº 258 / 99 e 301 / 02, e pela Instrução Normativa nº 08/02, do IBAMA. Considerando esse contexto, esta pesquisa teve como objetivo principal, analisar, criticamente, os procedimentos operacionais e as tecnologias que vêem sendo adotados para o gerenciamento de pneumáticos inservíveis no território nacional, após a instituição das Resoluções CONAMA retro mencionadas. A pesquisa bibliográfica realizada possibilitou avaliar a evolução dos procedimentos de manejo, diagnosticando a situação atual do gerenciamento desses resíduos sólidos especiais, no território nacional, as suas interfaces com as legislações ambientais em vigor, o grau de envolvimento e conscientização dos responsáveis indiretos, bem como as alternativas tecnológicas existentes para a minimização destes resíduos. Espera-se que este trabalho possa contribuir para o aprimoramento do gerenciamento de pneumáticos inservíveis com ênfase nas estratégias para coleta e aproveitamento destes resíduos e maior interação entre segmentos responsáveis. Dessa forma, os impactos ambientais e os problemas de saúde pública, decorrentes do manejo inadequado desses inservíveis no meio urbano poderão ser minimizados, possibilitando que não se transfira às futuras gerações problemas que, atualmente, são enfrentados.

In this thesis we provide a unifying framework for two decades of work in an area of Machine Learning known as cost-sensitive Boosting algorithms. This area is concerned with the fact that most real-world prediction problems are asymmetric, in the sense that different types of errors incur different costs. Adaptive Boosting (AdaBoost) is one of the most well-studied and utilised algorithms in the field of Machine Learning, with a rich theoretical depth as well as practical uptake across numerous industries. However, its inability to handle asymmetric tasks has been the subject of much criticism. As a result, numerous cost-sensitive modifications of the original algorithm have been proposed. Each of these has its own motivations, and its own claims to superiority. With a thorough analysis of the literature 1997-2016, we find 15 distinct cost-sensitive Boosting variants - discounting minor variations. We critique the literature using {\em four} powerful theoretical frameworks: Bayesian decision theory, the functional gradient descent view, margin theory, and probabilistic modelling. From each framework, we derive a set of properties which must be obeyed by boosting algorithms. We find that only 3 of the published Adaboost variants are consistent with the rules of all the frameworks - and even they require their outputs to be calibrated to achieve this. Experiments on 18 datasets, across 21 degrees of cost asymmetry, all support the hypothesis - showing that once calibrated, the three variants perform equivalently, outperforming all others. Our final recommendation - based on theoretical soundness, simplicity, flexibility and performance - is to use the original Adaboost algorithm albeit with a shifted decision threshold and calibrated probability estimates. The conclusion is that novel cost-sensitive boosting algorithms are unnecessary if proper calibration is applied to the original.