Energy-Aware Real-Time Scheduling on Heterogeneous and Homogeneous Platforms in the Era of Parallel Computing

Multi-core processors increasingly appear as an enabling platform for embedded systems, e.g., mobile phones, tablets, computerized numerical controls, etc. The parallel task model, where a task can execute on multiple cores simultaneously, can efficiently exploit the multi-core platform\u27s computational ability. Many computation-intensive systems (e.g., self-driving cars) that demand stringent timing requirements often evolve in the form of parallel tasks. Several real-time embedded system applications demand predictable timing behavior and satisfy other system constraints, such as energy consumption. Motivated by the facts mentioned above, this thesis studies the approach to integrating the dynamic voltage and frequency scaling (DVFS) policy with real-time embedded system application\u27s internal parallelism to reduce the worst-case energy consumption (WCEC), an essential requirement for energy-constrained systems. First, we propose an energy-sub-optimal scheduler, assuming the per-core speed tuning feature for each processor. Then we extend our solution to adapt the clustered multi-core platform, where at any given time, all the processors in the same cluster run at the same speed. We also present an analysis to exploit a task\u27s probabilistic information to improve the average-case energy consumption (ACEC), a common non-functional requirement of embedded systems. Due to the strict requirement of temporal correctness, the majority of the real-time system analysis considered the worst-case scenario, leading to resource over-provisioning and cost. The mixed-criticality (MC) framework was proposed to minimize energy consumption and resource over-provisioning. MC scheduling has received considerable attention from the real-time system research community, as it is crucial to designing safety-critical real-time systems. This thesis further addresses energy-aware scheduling of real-time tasks in an MC platform, where tasks with varying criticality levels (i.e., importance) are integrated into a common platform. We propose an algorithm GEDF-VD for scheduling MC tasks with internal parallelism in a multiprocessor platform. We also prove the correctness of GEDF-VD, provide a detailed quantitative evaluation, and reported extensive experimental results. Finally, we present an analysis to exploit a task\u27s probabilistic information at their respective criticality levels. Our proposed approach reduces the average-case energy consumption while satisfying the worst-case timing requirement

Towards Computational Efficiency of Next Generation Multimedia Systems

To address throughput demands of complex applications (like Multimedia), a next-generation system designer needs to co-design and co-optimize the hardware and software layers. Hardware/software knobs must be tuned in synergy to increase the throughput efficiency. This thesis provides such algorithmic and architectural solutions, while considering the new technology challenges (power-cap and memory aging). The goal is to maximize the throughput efficiency, under timing- and hardware-constraints

Transformation for Smallholder Farmers: Pathways for Agricultural Development in Rwanda

Transformation for Smallholder Farmers: Pathways for Agricultural Development in Rwanda Jolly Dusabe This thesis asks: “What are the drivers of smallholder agricultural growth in Rwanda?” Since 2000, Rwanda has recorded unprecedented year on year growth in agricultural production, averaging more than 5% per annum. This growth, driven mainly from the food sector, has occurred after decades of stagnation. The government of Rwanda sees agricultural growth as a critical driver for poverty reduction and economic growth. The study examines policy measures adopted by the government of Rwanda in pursuit of this growth, evaluates the mechanisms for implementation, and asks farmers and other stakeholders which interventions were most significant. Chapter 1 introduces the study and its objectives. Chapter 2 outlines Rwanda’s history in the agricultural sector up to 2000, and describes the policies that were developed after 2000, and the launch of those policies into the field thereafter. It looks at government-led initiatives for land use consolidation, infrastructure and crop intensification, and also at the processes whereby the private sector is brought in to support growth. Chapter 3 reviews literature relevant to the role of the agricultural sector in development, and the processes by which change occurs. Chapter 4 outlines the mixed methods and methodological framing of the study. The four data chapters (Chapters 5, 6, 7 and 8) paint a detailed picture of policy generation processes and demonstrate how different participants experienced it. In Chapter 5 a survey of farmers shows the direct changes that have occurred in farming and farming practices. Chapter 6, on technology adoption, uses survey data and interviews to draw directly on farmer experience and decision-making. Chapter 7 explores survey data and focus group discussions to show how institutional development at grassroots level played a part in the process of change. Chapter 8 draws on testimony from a range of policymakers, donors, other stakeholders, local leaders and farmers to understand new alliances, partnerships and arrangements that demonstrate benefits of collective action in the process of growth. Chapter 9 draws conclusions from the study. It shows the extent to which policy institutions and has facilitated technology adoption in Rwanda since 2000, and highlights the new institutional arrangements that have emerged to drive the process of agricultural change for smallholder farmers.Rwandan government, Cambridge Trust, Queens’ College, Smuts Memorial Fund and Department of Political and International Studies (Polis

Architectural/Environmental Handbook for Extraterrestrial Design

Handbook on environmental and space utilization criteria for design of extraterrestrial manned spacecraft and shelter

Reconciling biodiversity conservation and agricultural development in the context of international and domestic law in Rwanda

Includes bibliographical referencesThis thesis explores the tensions between biodiversity conservation and agricultural development in a legal context in Rwanda, a small and poor African developing country. It does so against the backdrop of relevant international conventions, the relatively recent constitutional dispensation in the country as well as the land reform process which has been underway in the country over the last few decades. Partly based on the findings of an empirical study, the core of the work outlines, examines and critically assesses relevant domestic Rwandan policies, laws and institutions focusing on areas of particular concern namely the laws applicable to the conservation of soil, water and genetic resources in agriculture, including conservation of crop and livestock diversity. The conclusions and recommendations are embedded in the need for policies, laws and institutions to accommodate the increase in agricultural production to eradicate hunger, alleviate poverty as well as recognition of the interlinkages between agricultural development and biodiversity conservation. The study concludes that Rwandan laws are inadequate in that they have been disparately and inefficiently developed, that agricultural development and biodiversity policies be revised to aim at sustainable agricultural development and that a coordinated institutional framework with full involvement of all concerned stakeholders and appreciation of local knowledge and sustainable agricultural practices is required. Specific legal, policy and institutional shortfalls are highlighted including lack of implementing regulations; omission of necessary legislative provisions on key areas in the biodiversity and agricultural sectors and others. The work concludes by making specific recommendations and proposals to reconcile the need to promote agricultural development while facilitating biodiversity conservation and ultimately sustainable development

Hypoxia effect on genetic regulation and virulence in Acinetobacter baumannii and Pseudomonas aeruginosa, in vitro and in vivo, and on innate immune response in infections caused by both pathogens.

The emergence of multi-drug resistant Gram-negative bacilli infections is a well-recognized global health challenge in urgent need of effective solutions. These pathogens cause infections that are very difficult to treat due to the high rate of resistance strains to a lot or even all antimicrobials used in the clinical practice. Furthermore, these kinds of infections are associated to important mortality rates. Unfortunately, the increasing problem of multidrug resistance is not followed by the development of novel antimicrobials. For this reason, there is an important need to develop new strategies to combat multi-drug, extensively-drug and pan-drug resistantGram-negative bacilli. A new alternative to combat this kind of infections might be blocking specific bacterial virulence factors that bacteria need to infect. It is known that bacteria modulate their gene expression in function of the environment. Therefore, expression of virulence factors can change during the course of infection according to every microenvironment in which bacteria are found. Several studies have reported that hypoxia occurs in a wide range of infection, so it would be interesting to determine the gene profile of these multi-drug resistant pathogens in order to find out new virulence factors that we could block. Moreover, it is also important to know how hypoxia affects to this kind of infection to know better what is happening in vitro and in vivo. Because A. baumannii and P. aeruginosa are two of the most common pathogens that cause healthcare-acquired infection, we have chosen them to study their virulence mechanism under hypoxia in more depth. We have selected the strains A. baumannii ATCC 17978 and P. aeruginosa PAO1 because they are well-known sequenced strains which allow us to analyze virulence factors in a better way. On the other hand, septic shock patients present tissue hypoxia that might influence the disease. Moreover, septic shock is the most severe complication of sepsis and most studies about this syndrome report a high mortality rate. Hence, it would be useful to study the relationship between tissue hypoxia, HIF-1α levels and immune response, and to determine new biomarkers to predict the outcome.Premio Extraordinario de Doctorado U

The Nature, Causes, Effects and Mitigation of Climate Change on the Environment

This book examines global warming and climate change over the past five decades in mainly subtropical and tropical countries. The amount and types of changes in these countries vary with the environment but are often less than those occurring in the Arctic and northern countries. Chapters address such topics as the controversy surrounding global warming, the effects of climate change on agriculture, changes in land use and hydrology, and more

Diversity, specificity and evolutionary history of marine invertebrate symbioses and functions of the sulfur-oxidizing symbionts

Many marine invertebrates have established symbioses with chemosynthetic bacteria that metabolize reduced sulfur compounds and provide nutrition to their host. Two key questions in the field of symbiosis are: (1) How specific and evolutionarily stable are these symbioses? Chapters II, III and IV of this thesis contribute to a more comprehensive understanding of this question by investigating the diversity, specificity and evolutionary history of three sulfur-oxidizing symbioses: deep-sea vestimentiferan tubeworm endosymbioses, shallow water gutless phallodriline oligochaete endo- and stilbonematine nematode ectosymbioses. The studies emphasize the power of molecular analyses to uncover hidden symbiont diversity and highlight the remarkably stable and specific stilbonematine ectosymbioses. (2) What are the benefits for the symbiotic partners? Chapter V strengthens the hypothesis of stilbonematine ectosymbionts' nutritional role for their host and the genomic study in Chapter VI discusses potential additional functions of the ectosymbionts for their nematode host

The Role of Genomic Context in Bacterial Growth Homeostasis

The growth of bacteria is a complex but well-orchestrated dance involving the repetitive and reproducible production of their diverse cellular components in order to divide. A lot can go astray and therefore the cell has developed several strategies in order to ensure everything remains synchronized. This problem is only further complicated as the cells adjust their growth rate to their living conditions resulting in ripple effects throughout the cell physiology. One notable change is that as nutrient availability and quality increases so too does the average size and the concentration of ribosomes in the cell. The latter enables the production of the largest macromolecule faction in the cell (proteins) including the production of more ribosomes required to maintain the protein synthesis requirements. With the increase in volume of the cell comes a required increase in surface area, and a disbalance between these two would result in untenable levels of internal pressure. How then do bacteria ensure that volume growth is synchronized with the production of cell envelope components so that cell homeostasis is maintained, especially in the face of fluctuating growth rate? Genomic context is known to assist in co-regulation of genes thereby synchronizing them to respond to different cellular stimuli. As the bacterial genome is highly fluid, the existence of conserved genomic contexts suggests important loci of co-regulation. Could it be in these gene clusters that a possible link between growth and surface expansion is found? To answer this question this thesis undertook three missions, firstly we established a genome comparison tool (www.GenCoDB.org) that will take advantage of the ever-growing availability of bacterial genomes to assist us in the analysis, comparison, and quantification of genome contexts. This will rely on novel strategies in order to: accommodate the breadth of genome data available in a computationally efficient manner, reduce the effect of sampling bias that plague most bacterial datasets and ensure candidates are considered significant for their evolutionary context. The availability of GenCoDB is sure to facilitate genomic context research in the microbiology community and improve accessibility to non-bioinformatics to this wellspring of important biological data. With the swath of genomic neighbourhood data, we then sought to understand and analyse the evolution of conserved gene clusters in order to narrow down possible volume-surface regulating candidates. By tracking the evolution of gene clusters throughout the Bacteria kingdom we found that co-orientation is strongly conserved, however, this does not influence the subsequent context around the cluster nor the expansion of the cluster. We found that vertical transmission and not horizontal gene transfer was found to be the driving factor of gene cluster occurrence in chromosomes and that the origin and terminus are hotspots for cluster maintenance. Finally, we found that despite the apparent frequency of operon organization in gene clusters, gene clusters appear to be maintained due to other selective pressures such as within-cluster protein-protein interactions and the essential status of their genes. We suggest that operons are a consequence and not a cause co-localization over evolutionary time. We identified a single gene cluster candidate that met all the requirements we believe are required for cell growth homeostasis of synchronized surface and volume expansion. These requirements were a broad conservation within Bacteria, and a connection between ribosome-associated proteins (growth) with cell envelope synthesizes. In agreement with our evolution studies we found that whilst the cluster was co-regulated this did not appear to be the selective pressure that brought these different processes together. Instead we found a potential role of genomic channelling, linking the production of pyrimidines with the synthesis of the cell envelope which is reliant on the co-localization of this cluster. Together, this work will forward the understanding of chromosome evolution in Bacteria and the potential implications of genomic context in metabolite utilization. It challenges the roles that operons and horizontal gene transfer play in the long-term evolution of gene order and it provides a new quantitative and statistical resource providing access to over 1.9 million gene neighbourhoods

An integrated, landscape-based approach to model the formation and hydrological functioning of wetlands in semiarid headwater catchments of the Umzimvubu River, South Africa

Wetlands are very important elements of the landscape in almost every environment. Addressing the continued loss of wetland area worldwide, wetlands are recognized as highly vulnerable with regard to natural and anthropogenic system changes. Consequently, the research of their natural and socio-economical functions, importance for the water and nutrient cycles and their role as wildlife habitats received increasing scientific and public awareness in the past decades. The landscape of the semi-arid Eastern Cape Province, South Africa, is characterized by the occurrence of different types of palustrine wetlands. Intensive afforestation in the headwaters of the Umzimvubu catchment since 1989 has changed downstream wetland characteristics, but little attention was given to evaluate and quantify these impacts. Addressing this research deficit, the main objectives of this dissertation are the development of an integrated, landscape-based research approach to improve the understanding of the formation, functioning and dynamics of wetlands and the prognostic modeling and assessment of afforestation impacts on these wetland systems. The conceptual and methodological approach of this dissertation is based on three individual aspects: i) observation and data mining; ii) integrated system analysis; and iii) system modeling and assessment integrating empirical field studies, laboratory analysis, GIS and remote sensing techniques, system analysis and process-oriented, plant growth and hydrological modeling, This integrated research approach provides information regarding a generalized understanding of dominant environmental processes at wetland and catchment scale and the impact of afforestation on wetland and basin hydrology. By means of this effort three main wetland types, being different in terms of landscape position, extent and size of the tributary catchment, soils, vegetation composition and hydrological dynamics, could be identified. The hydrodynamics of plateau and slope wetlands are mainly controlled by recharge mechanisms, while larger valley bottom wetlands are driven by interlinked ground-/surface water dynamics, discharge/recharge processes and direct rainfall input. Coupling plant growth and hydrological modeling, it was found that wetland dynamics and their landscape functions will be influenced by afforestation in terms of altered recharge/discharge mechanisms; reduced base flows addressed to increased interception losses and reduced water retention capability as a result of net loss of wetland area. In addition, such changes will affect environmental functions and biodiversity due to habitat loss and alterations. Integrating the results and information of the present study, an integrated landscape model was developed aiming to characterize wetland formation and emphasizing impacts of human activities on past and recent wetland and landscape dynamics