As energy use increases globally the environmental burdens increase alike. Many accusations have been made that carbon dioxide is a culprit of climate change. The University of Kentucky and Duke Energy Power have partnered to test carbon capture technology in a large scale project. To this end, the objective of this thesis is to investigate potential water media sources and nutrient sources at different volume scales for algae cultivation to help create a more environmentally viable and economically feasible solution. This work will conduct a life cycle assessment of water media sources and the effects of the inputs and outputs needed for each medium. The up-scaling objective of the research is to identify which parameters vary as a result of up-scaling and how to maintain a culture at the large scale that is standardized to the lab scale culture.

Submitted in fulfillment of the requirements of the degree of Masters of Engineering: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2018. / The anaerobic process is increasingly becoming a subject for many as it reduces greenhouse gas emissions and recovers carbon dioxide energy as methane. Even though these benefits are attainable, proper control and design of the process variables has to be done in order to optimize the system productivity and improve stability. The aim of this research was to optimize methane and biogas yields on the anaerobic co-digestion of sewage sludge using bio-chemical substrates as co-substrates. The first objective was to find the bio-chemical substrate that will generate the highest biogas and methane yields. The anaerobic digestion of these substrates was operated using 6 L digesters at 37.5℃. The substrate which generated the highest biogas and methane yield in the first batch experiment was then used for the second batch test. The objective was to optimize the anaerobic conditions (substrate to inoculum ratio, co-substrate concentration and temperature) in-order to optimize the biogas and methane yields. The second batch test was achieved using the conventional One-Factor-At-A-Time (OFAT) and the Design of Experiment (DOE) methods. Final analysis showed that the bio-chemical substrates could be substrates of interest to biogas generators. Amongst the substrates tested in the first batch experiment glycerol (Oleo-Chemical Product waste) generated the highest methane and biogas yields of 0.71 and 0.93 L. (g volatile solids added)-1, respectively. It was believed that glycerol contains significant amount of other organic substances such as lipids that have higher energy content than the other bio-chemical substrates, thus generating larger biogas and methane yields. Moreover, digestion of sewage sludge alone produced biogas yields of 0.19 L /g VS and 0.33 L/g COD, and methane yields of 0.16 L/g VS and 0.28 L/g COD. Generally, co-digestion yields were higher than digestion yields of sewage alone. Using the OFAT method the results of the second batch test on glycerol demonstrated highest amounts of volatile solids (VS) reduction, chemical oxygen demand (COD) reduction, biogas yield and methane yield of 99.7%, 100%, 0.94 L (g VS added)-1 and 0.75 L (g VS added)-1 at a temperature, substrate to inoculum ratio and glycerol volume of 50℃, 1 (on VS basis) and 10 mL, respectively. Above 22 mL and substrate to inoculum ratio of 1, the process was inhibited. The DOE results suggested that the highest methane and biogas yields were 0.75 and 0.94 L (g VS added)-1, respectively. These results were similar to the OFAT results, thus the DOE software may be used to define the biogas and methane yields equations for glycerol. In conclusion, anaerobic co-digestion of bio-chemical substrates as co-substrates on sewage sludge was successfully applied to optimize methane and biogas yields. / M

Fishers are among the biggest commercial resource users in the marine environment. In order to meet international, national and local policies, the UK has to designate a suite of marine protected areas (MPAs) and reach marine renewable energy (MRE) targets. Inevitably, there will be conflict between these two industries and marine conservation. This study uses a multi-disciplinary approach to examine evaluate the suitability of various sources of data, which could be used to detect, assess, and ultimately predict, fishing effort displacement within the different sectors of the > 15 m fleet in the South West of the UK. Gear-specific Vessel Monitoring System (VMS) data from 2005-2008 was used to assess potential effort displacement due to Haig Fras, a proposed MPA and Wave Hub, a marine renewable energy installation (MREI). The spatial distribution of fishing activity was highly heterogeneous and distinct areas of intense fishing could be identified for all gear-types. A closure of Haig Fras would have the greatest impact on gillnetters. Scallop dredgers also occasionally use the area. The current closure at Wave Hub has the greatest impact on potters and whelkers whose geographic specialisation is most pronounced and who use the area extensively. Longliners also use the area disproportionately would be affected. A simple index of variability was developed in order to determine baselines and two other sources of data were used. High resolution seabed data and low resolution catch data. A semi structured interview was conducted with forty fishers to elicit further information on the challenges, barriers to progress and priority issues in relation to MRE those fishers face. The theme of discontent with the consultation process scored highly throughout. Fishers’ Knowledge (FK) another source of data also scored highly, although further work must be carried out to identify what aspects of this data are useful in assessment of fishing effort displacement.

Cette thèse traite de la coopération et de la gouvernance climat dans l'ère post Copenhague. Son objectif est de caractériser l'évolution du régime climatique, prenant appui sur les positions de l'Union européenne, la Chine et les États-Unis, qui peuvent être désignés, à la fois en tant que gros émetteurs, économies majeures et grandes puissances. Deux déterminants sont considérés structurants pour cette analyse : les coûts d'atténuation des émissions et les coûts d'adaptation. Le point de départ de notre thèse se trouve dans l'évolution polarisée du régime climatique. Le fait le plus marquant de cette « métamorphose » est le passage, en 2009, de l'approche top-down à une approche bottom-up.Pour ce faire, nous mobilisons un cadre théorique hybride, qui comprend l'Économie politique internationale et l'économie du changement climatique. L'apport combiné de ces deux approches permet d'analyser la politique internationale du climat à travers l'économie de l'environnement et inversement, de renseigner l'incidence que ces relations peuvent avoir sur la logique économique. Nous proposons une approche spécifique de la coopération, basée sur la théorie du « k-groupe » de Duncan Snidal (1985).Dans ce cadre coopératif minilatéral, la thèse que nous soutenons est qu'il est possible d'avoir un k-groupe pour le climat et que celui-ci peut avoir un effet bénéfique sur la mise en place du régime climat. Nous argumentons que ce groupe peut être considéré comme un « club of the relevant » et que, pour former un k-groupe, il est nécessaire que les pays constituent une « coalition of the willing ». Ce qui structure la capacité et la volonté de l'action, ce sont principalement les coûts que cela implique, coûts d'atténuation et d'adaptation. En même temps, l'engagement de ce groupe se base sur le conditionnement. Le dispositif incitatif est constitué par l'idée d'une coopération de plus en plus large, qui atténue le problème du passager clandestin.Les résultats de recherche sont appréciés à la lumière de l'aboutissement de la COP 21. Si le k-groupe fonctionne, c'est que les trois pays décident d'aller de l'avant et acceptent d'endosser des coûts d'atténuation plus importants que les autres pays. Cet engagement collectif déclencherait un mouvement vertueux qui imposerait au régime climat un leadership partagé entre ces trois pays, ouvrant la voie aux autres. Si le k-groupe ne fonctionne pas, c'est parce que nos acteurs considèrent les coûts à court terme trop importants au regard de leurs propres intérêts et au regard du risque du free riding de la part des autres États. Compte tenu de la conjoncture économique dans laquelle se trouvent nos trois acteurs, ce scénario apparait comme étant probable.Enfin, dans notre modèle de l'analyse de la coopération nous privilégions le tandem Europe-Chine. Nous montrons que cette coopération tripartite devrait se construire à partir de ce binôme, du moment où, à la différence des États-Unis, c'est l'Europe qui apparait comme étant plus volontaire. La Chine, l'acteur incontournable du climat, qui risque de subir les conséquences du changement climatique de plein fouet, a plus d'intérêt à se rallier à l'Europe si elle souhaite obtenir un accord qui ne soit pas basé uniquement sur des contributions (nationales) minimales. / Our research focuses on the cooperation and climate governance in the post-Copenhagen era. Its main purpose is to observe and define the evolution of the climate regime, based on the positions of the European Union, China and the United States. These three countries can be considered as big emitters, major economies, as well as great powers. Two main drivers are taken into account in our analysis: mitigation and adaptation costs to climate change. The starting point for our research is to be found in the polarized evolution of the climate regime. The most illustrative aspect of this “metamorphosis” is the shift, in 2009, from the top-down to the bottom-up architecture of the climate regime.Thus, we resort to a hybrid theoretical background, which consists of both international political economy and climate change economy. The joint contribution of the two approaches allows us to analyze international political economy with climate economy as an input, as well as the impact of international relations on the main economic framework of climate change. Our research is based on a specific cooperation model, known as the “k-group” theory, as developed by Duncan Snidal (1985).Within this framework of minilateral cooperation, the thesis that we defend is that it is possible to have a climate k-group which may have a trigger effect in order to obtain an ambitious regime. The starting point for our argument is that this group can be considered as a “club of the relevant”, and that what it needs to achieve in order to constitute a k-group is to establish a “coalition of the willing”. The capacity and the willingness to act are mainly influenced by the costs they have to bear, that is the costs to mitigate their emissions and to adapt to the climate change consequences. Meanwhile, the group's collective commitment depends on other countries' actions. More precisely, the incentive mechanism is built on the idea that cooperation is meant to widen, in order to eventually prevent free riding.Our main results are to be regarded in the light of the COP 21 outcome. If the k-group works, it is because our three countries decide to move forward and accept to bear mitigation costs that are higher than those of other countries'. Their collective commitment should trigger a virtuous dynamic which would impose on climate regime a collective leadership of these three countries, thus leaving the others with no other way than to follow. If the k-group does not work, it is because our three actors consider upfront costs too high with respect to their own interests, as well as to the risk of free riding (if the others do not go along). Given our three actors' economic and political context, this scenario seems likely.Finally, we rather favor in our work the Europe-China tandem. We argue that the k-group should be built on this joint cooperation, since, unlike the United States, Europe appears to be more willing to endorse an ambitious regime, whereas China seems an unavoidable actor. Thus, China, which faces a major impact of climate change, should play along with Europe if it wishes to obtain an agreement that is not solely based on minimal (national) contributions.

In order to support the new paradigm shift in fifth generation (5G) mobile communication, radically different network architectures, associated technologies and network operation algorithms, need to be developed compared to existing fourth generation (4G) cellular solutions. The evolution toward 5G mobile networks will be characterized by an increasing number of wireless devices, increasing device and service complexity, and the requirement to access mobile services ubiquitously. To realise the dramatic increase in data rates in particular, research is focused on improving the capacity of current, Long Term Evolution (LTE)-based, 4G network standards, before radical changes are exploited which could include acquiring additional spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell-edge users vulnerable to heavy inter cell interference in addition to the other factors such as fading and path-loss. In this direction, this thesis focuses on improving the performance of cell-edge users in LTE and LTE-Advanced networks by initially implementing a new Coordinated Multi-Point (CoMP) technique to support future 5G networks using smart antennas to mitigate cell-edge user interference in uplink. Successively a novel cooperative uplink inter-cell interference mitigation algorithm based on joint reception at the base station using receiver adaptive beamforming is investigated. Subsequently interference mitigation in a heterogeneous environment for inter Device-to-Device (D2D) communication underlaying cellular network is investigated as the enabling technology for maximising resource block (RB) utilisation in emerging 5G networks. The proximity of users in a network, achieving higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the evolved Node B (eNodeB) i.e. by direct communication between User Equipment (UE), has been explored. Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for D2D receivers, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNodeB in the network. It is finally demonstrated that the application, as an extension to the above, of a novel receiver beamforming technique to reduce interference from D2D users, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond the-state-of-the-art LTE system-level-simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards.

Transfer to non-motorized transportation to the greatest extent possible is an important climate change mitigation strategy. Biking is a sustainable mean of transportation and increased biking is desirable on global, national, regional, local, and individual level. This study use Östersund, located in the middle of Sweden, as a case to analyse the conditions and challenges for increased biking and what role the biking infrastructure system, weather-related factors, and policies and programmes may play. A literature study on weather-related factors and policies and programmes was performed. How biking has developed over time was analysed and a distance analysis, the bike path infrastructures length and continuity, and accessibility was analysed in a geographical information system (GIS) environment. Investments on increased biking in Denmark and the Netherlands has been successful when a lot of effort has been put into development of the bike path infrastructure. The same result has been reached in Malmö, Sweden. However, the time aspect should not be underestimated since reaching high number of bikers seem to take many years, even decades. In the case of Östersund, temperature, wind and precipitation cause a decrease in biking. Number of bikers follow seasonal changes in temperature, the latter two have a temporary influence. Biking in Östersund is increasing even though there are fluctuations every other year. An interesting observation is that during the increased trend of biking the bike path infrastructure has been expanded. The bike path infrastructure is inconsistent with sudden ends every 2,03 km which may create a threshold for the increase of biking. Accessibility of the bike path system is high since over half the population has no longer than 100 m to a bike path. Distance may be a constricting factor since over half of randomised journeys are longer than a considerable comfortable biking distance of 5 km. Urban planning that treats biking as any other mean of transportation, development of a biking culture and individual habits is crucial for biking to increase. / <p>20180626</p>

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-04-26T17:59:28Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) guilherme_mendes_soares.pdf: 1467495 bytes, checksum: a12842857f82af37f5532c481c2dbbfc (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-05-16T19:03:21Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) guilherme_mendes_soares.pdf: 1467495 bytes, checksum: a12842857f82af37f5532c481c2dbbfc (MD5) / Made available in DSpace on 2017-05-16T19:03:21Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) guilherme_mendes_soares.pdf: 1467495 bytes, checksum: a12842857f82af37f5532c481c2dbbfc (MD5) Previous issue date: 2016 / O aumento significativo das concentra??es de CO2 atmosf?rico ap?s a Revolu??o Industrial tem agravado o efeito estufa natural do planeta, levando a eleva??o das temperaturas m?dias e ?s mudan?as clim?ticas globais. O tema tem preocupado cientistas, governo e sociedade, resultando em medidas para redu??o das emiss?es de gases de efeito estufa (GEEs) e mitiga??o de seus efeitos nocivos. Em 1997, o Protocolo de Quioto estabeleceu metas de redu??o de emiss?es de GEEs, sobretudo o CO2. Como esp?cies de r?pido crescimento s?o consideradas eficientes na fixa??o de carbono, nesta pesquisa foram utilizados tr?s clones de esp?cies de Eucalyptus e Corymbia, haja vista seu r?pido crescimento e sua alta produtividade. O objetivo deste trabalho foi avaliar pelo m?todo destrutivo, aos 12 meses de idade, a produ??o da massa de carbono da parte a?rea de tr?s clones: um h?brido espont?neo de Eucalyptus urophylla S. T. Blake, um h?brido tri-cross de E. urophylla x (Eucalyptus grandis W. Hill ex Maiden x Eucalyptus camaldulensis Dehnh), e um h?brido de Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson x Corymbia torelliana (F. Muell.) K. D. Hill & L. A. S implantados em diferentes espa?amentos de plantio: 3x3 m; 3x1,5 m; e 3x1 m. O estudo foi conduzido em uma ?rea experimental da empresa Aperam Bioenergia S/A, localizada no munic?pio de Itamarandiba, MG. Foram abatidas 36 ?rvores amostras, que foram cubadas, desgalhadas e desfolhadas, foram coletadas amostras de folhas, galhos, casca e madeira para determina??o de massa seca e teor de carbono dos componentes da parte a?rea. De acordo com os resultados encontrados, conclui-se que o espa?amento que registrou a maior fixa??o de carbono por unidade de ?rea foi o 3x1 m, e os clones mais produtivos foram os h?bridos de E. urophylla e o tri-cross de E. urophylla x (E. grandis x E. camaldulensis). Al?m disso, o espa?amento 3x3 m apresentou os valores mais elevados de massa seca e de carbono por ?rvore. Os clones utilizados neste experimento se apresentaram como alternativa potencial para projetos de sequestro de carbono e mitiga??o dos gases de efeito estufa. / Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / The significant increase in atmospheric CO2 concentrations since the Industrial Revolution has exacerbated the natural greenhouse effect on the planet, resulting in rising average temperatures and global climates changes. The issue has worried scientists, government and society, leading them to take action to reduce emissions of greenhouse gases (GHG) and mitigating its harmful effects. In 1997, the Kyoto Protocol established GHG emissions reduction targets, especially CO2. As a fast-growing species are considered efficient in carbon sequestration, this research were used three clones of species of Eucalyptus and Corymbia, given its rapid growth and high productivity. The objective of this study was to evaluate by the destructive method, at 12 months of age, the production of dry mass and carbon of the aerial part of three clones: a spontaneous hybrid of Eucalyptus urophylla ST Blake, an hybrid tri-cross E. urophylla x (Eucalyptus grandis W. Hill ex Maiden x Eucalyptus camaldulensis Dehnh), and a hybrid of Corymbia citriodora (Hook.) KD Hill & LAS Johnson x Corymbia torelliana (F. Muell.) K. D Hill & L. A. S deployed in different planting spacings: 3x3 m; 3x1.5 m; and 3x1 m. The study was conducted in an experimental area of the company Aperam Bioenergia S/A, located in the county of Itamarandiba, MG. Thirty six trees were felled , this were cubed, delimbed and leafless, samples of leafs, twigs, bark and wood were collected to determine the dry mass and shoot carbon of the aerial part components. According to the results, it is concluded that the spacing which recorded the largest allocation of carbon per unit area was 3x1 m, and the most productives clones were hybrids E. urophylla and of tri-cross E. urophylla x (E. grandis x E. camaldulensis). Furthermore, the spacing 3x3 m showed the highest values of dry mass and carbon per tree. The clones used in this experiment were presented as potential alternative for projects of carbon sequestration and mitigation of greenhouse gases.

Submitted by Pablo Bettio Mendes (bettiomendes@hotmail.com) on 2018-10-10T15:48:29Z No. of bitstreams: 1 Dissertacao - Pablo - FINAL - 2018-OUT-10 (Rev.2).pdf: 2608147 bytes, checksum: 01299e2f6bfb9f6afd67d263d6a73aa0 (MD5) / Approved for entry into archive by Lucilene Cordeiro da Silva Messias null (lubiblio@bauru.unesp.br) on 2018-10-10T16:34:29Z (GMT) No. of bitstreams: 1 mendes_pb_me_bauru.pdf: 2608147 bytes, checksum: 01299e2f6bfb9f6afd67d263d6a73aa0 (MD5) / Made available in DSpace on 2018-10-10T16:34:29Z (GMT). No. of bitstreams: 1 mendes_pb_me_bauru.pdf: 2608147 bytes, checksum: 01299e2f6bfb9f6afd67d263d6a73aa0 (MD5) Previous issue date: 2018-08-24 / A erosão dos solos é fenômeno natural que ocorre tanto em áreas rurais como urbanas, atuando através da remoção e arraste de material, tendo consequências muito sérias ocasionando diversas perdas financeiras e até de vidas humanas. A necessidade de conter ou controlar esse processo de degradação inspirou o desenvolvimento de várias tecnologias ligadas à área de bioengenharia. Duas delas, biomanta e hidrossemeadura, são atualmente vendidas separadamente no mercado provavelmente por razões comerciais, mas possuem o potencial de ser trabalhadas de maneira integrada. O objetivo do presente trabalho foi testar a eficácia do uso integrado de duas técnicas de controle de erosão causada pela água em encostas e taludes: biomanta e hidrossemeadura. O trabalho foi realizado no município de Sorocaba em um talude com forte pendente disponibilizado dentro do Campus da Faculdade de Tecnologia (FATEC). Foram usados materiais de baixo custo, além do uso de rejeitos de material proveniente de cortes de vegetação de baixo porte que muitas vezes não tem um destino adequado. Para tanto foram construídas oito parcelas retangulares de aproximadamente seis metros de extensão por um metro de largura. Duas destas parcelas foram mantidas continuamente descobertas (condição controle de terreno natural) e as outras seis foram cobertas / protegidas com mantas biodegradáveis, sementes ou sistema integrado de palha e sementes. Ao todo foram construídos quatro pares, cada um deles com uma técnica diferente de combate a erosão. Durante a pesquisa, foram avaliadas e quantificadas as mudas das espécies que germinaram, também foi medido o volume de chuva durante o período. Sem prejuízo, fez-se, também, a quantificação do volume do material erodido (sedimento) em cada tipo de recobrimento após cada evento de chuva. / Soil erosion is a natural phenomenon that occurs in rural and urban areas, acting through the removal and dragging of material, with very serious consequences causing several losses including human lifes. The need to contain or control this degradation process has inspired the development of several technological alternatives linked to the area of bioengineering. Two of them are currently sold separately on the market, probably for commercial reasons, but have the potential to be worked on in an integrated fashion. The aim of the present work is to test the effectiveness of two techniques integrated to avoid erosion caused by water on slopes used together: bio-blanket and hydroseeding. The work was carried out in Sorocaba in a slope with strong inclination made available within the Campus of the Faculdade de Tecnologia (FATEC). For the work, low cost materials were used as the litter usually coming from the tailings, vegetation cuts that often did not have an adequate destination. For this, eight rectangular plots of approximately six meters in length by a meter of width each were constructed. Two of these plots were kept continuously discovered (natural land control condition) and the other six were covered / protected with biodegradable blanket, seeds or integrated straw and seed system. Altogether there are four pairs compared, each with a different solution from the each other. During the research, the seedlings of the species that germinated were evaluated and quantified. The volume of rain was quantified and also the volume of the eroded material (sediment) in each type of cover were also measured right after every rain event

La consommation d’énergie est une préoccupation importante pour les systèmes de traitement Big Data à grande échelle, ce qui entraîne un coût monétaire énorme. En raison de l’hétérogénéité du matériel et des conflits entre les charges de travail simultanées, les stragglers (i.e., les tâches qui sont relativement plus lentes que les autres tâches) peuvent augmenter considérablement le temps d’exécution et la consommation d’énergie du travail. Par conséquent, l’atténuation des stragglers devient une technique importante pour améliorer les performances des systèmes de traitement Big Data à grande échelle. Typiquement, il se compose de deux phases: la détection de stragglers et la manipulation de stragglers. Dans la phase de détection, les tâches lentes (par exemple, les tâches avec une vitesse ou une progression inférieure à la moyenne) sont marquées en tant que stragglers. Ensuite, les stragglers sont traités en utilisant la technique d’exécution spéculative. Avec cette technique, une copie du straggler détecté est lancée en parallèle avec le straggler dans l’espoir qu’il puisse finir plus tôt, réduisant ainsi le temps d’exécution du straggler. Bien qu’un grand nombre d’études aient été proposées pour améliorer les performances des applications Big Data en utilisant la technique d’exécution spéculative, peu d’entre elles ont étudié l’efficacité énergétique de leurs solutions.Dans le cadre de cette thèse, nous commençons par caractériser l’impact de l’atténuation des stragglers sur la performance et la consommation d’énergie des systèmes de traitement de Big Data. Nous observons que l’efficacité énergétique des techniques actuelles d’atténuation des stragglers pourrait être considérablement améliorée. Cela motive une étude détaillée de ses deux phases: détection de straggler et traitement de straggler. En ce qui concerne la détection de straggler, nous introduisons un cadre novateur pour caractériser et évaluer de manière exhaustive les mécanismes de détection de straggler. En conséquence, nous proposons un nouveau mécanisme énergétique de détection de straggler. Ce mécanisme de détection est implémenté dans Hadoop et se révèle avoir une efficacité énergétique plus élevée par rapport aux mécanismes les plus récentes. En ce qui concerne le traitement de straggler, nous présentons une nouvelle méthode pour répartir des copies spéculatives, qui prend en compte l’impact de l’hétérogénéité des ressources sur la performance et la consommation d’énergie. Enfin, nous introduisons un nouveau mécanisme éconergétique pour gérer les stragglers. Ce mécanisme fournit plus de ressources disponibles pour lancer des copies spéculatives, en utilisant une approche de réservation dynamique de ressources. Il est démontré qu’elle améliore considérablement l’efficacité énergétique en utilisant une simulation. / Energy consumption is an important concern for large-scale Big Data processing systems, which results in huge monetary cost. Due to the hardware heterogeneity and contentions between concurrent workloads, stragglers (i.e., tasks performing relatively slower than other tasks) can severely increase the job’s execution time and energy consumption. Consequently, straggler mitigation becomes an important technique to improve the performance of large-scale Big Data processing systems. Typically, it consists of two phases: straggler detection and straggler handling. In the detection phase, slow tasks (e.g., tasks with speed or progress below the average) are marked as stragglers. Then, stragglers are handled using the speculative execution technique. With this technique, a copy of the detected straggler is launched in parallel with the straggler with the expectation that it can finish earlier, thus, reduce the straggler’s execution time. Although a large number of studies have been proposed to improve the performance of Big Data applications using speculative execution technique, few of them have studied the energy efficiency of their solutions. Addressing this lack, we conduct an experimental study to fully understand the impact of straggler mitigation techniques on the performance and the energy consumption of Big Data processing systems. We observe that current straggler mitigation techniques are not energy efficient. As a result, this promotes further studies aiming at higher energy efficiency for straggler mitigation. In terms of straggler detection, we introduce a novel framework for comprehensively characterizing and evaluating straggler detection mechanisms. Accordingly, we propose a new energy-driven straggler detection mechanism. This straggler detection mechanism is implemented into Hadoop and is demonstrated to have higher energy efficiency compared to the state-of-the-art mechanisms. In terms of straggler handling, we present a new speculative copy allocation method, which takes into consideration the impact of resource heterogeneity on performance and energy consumption. Finally, an energy efficient straggler handling mechanism is introduced. This mechanism provides more resource availability for launching speculative copies, by adopting a dynamic resource reservation approach. It is demonstrated, via a trace-driven simulation, to bring a high improvement in energy efficiency.

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.