The theme of this thesis is one of the latest trends in IT -- Green IT. For companies implementation of green IT means not only acknowledging its responsibility towards society and environment, but also substantial financial benefits and improved public perception of their business. There are several motivations for companies to go green. Green IT initiatives are increasingly supported by the legislation and various standards. Different procedures and approaches to help companies in their transformation are developing as well. The objectives of this thesis include the identification of key players, the benefits and barriers to green IT, and new opportunities. The aim of this thesis is to bring a comprehensive view of the green IT trend and provide enough quality information to obtain an overall view of the green IT trend and a possible basis for deeper interest in the subject. Another objective is to analyze the frameworks used for the implementation of green IT initiatives in organizations. The achievement is approached through research and analysis, and information available in the literature, published reports and websites dealing with green IT were used. Thesis contribution lies particularly in analysis of green IT frameworks, within which there was evaluated their interests in terms of green IT waves, green IT objectives, their use in the process of implementation green IT solutions, their locus and other attributes.

Les progrès en termes de puissance de calcul ont entraîné de nombreuses évolutions dans le domaine de la science et de ses applications. La résolution de systèmes linéaires survient fréquemment dans le calcul scientifique, comme par exemple lors de la résolution d'équations aux dérivées partielles par la méthode des éléments finis. Le temps de résolution découle alors directement des performances des opérations algébriques mises en jeu.Cette thèse a pour but de développer des algorithmes parallèles innovants pour la résolution de systèmes linéaires creux de grandes tailles. Nous étudions et proposons comment calculer efficacement les opérations d'algèbre linéaire sur plateformes de calcul multi-coeur hétérogènes-GPU afin d'optimiser et de rendre robuste la résolution de ces systèmes. Nous proposons de nouvelles techniques d'accélération basées sur la distribution automatique (auto-tuning) des threads sur la grille GPU suivant les caractéristiques du problème et le niveau d'équipement de la carte graphique, ainsi que les ressources disponibles. Les expérimentations numériques effectuées sur un large spectre de matrices issues de divers problèmes scientifiques, ont clairement montré l'intérêt de l'utilisation de la technologie GPU, et sa robustesse comparée aux bibliothèques existantes comme Cusp.L'objectif principal de l'utilisation du GPU est d'accélérer la résolution d'un problème dans un environnement parallèle multi-coeur, c'est-à-dire "Combien de temps faut-il pour résoudre le problème?". Dans cette thèse, nous nous sommes également intéressés à une autre question concernant la consommation énergétique, c'est-à-dire "Quelle quantité d'énergie est consommée par l'application?". Pour répondre à cette seconde question, un protocole expérimental est établi pour mesurer la consommation d'énergie d'un GPU avec précision pour les opérations fondamentales d'algèbre linéaire. Cette méthodologie favorise une "nouvelle vision du calcul haute performance" et apporte des réponses à certaines questions rencontrées dans l'informatique verte ("green computing") lorsque l'on s'intéresse à l'utilisation de processeurs graphiques.Le reste de cette thèse est consacré aux algorithmes itératifs synchrones et asynchrones pour résoudre ces problèmes dans un contexte de calcul hétérogène multi-coeur-GPU. Nous avons mis en application et analysé ces algorithmes à l'aide des méthodes itératives basées sur les techniques de sous-structurations. Dans notre étude, nous présentons les modèles mathématiques et les résultats de convergence des algorithmes synchrones et asynchrones. La démonstration de la convergence asynchrone des méthodes de sous-structurations est présentée. Ensuite, nous analysons ces méthodes dans un contexte hybride multi-coeur-GPU, qui devrait ouvrir la voie vers les méthodes hybrides exaflopiques.Enfin, nous modifions la méthode de Schwarz sans recouvrement pour l'accélérer à l'aide des processeurs graphiques. La mise en oeuvre repose sur l'accélération par les GPUs de la résolution locale des sous-systèmes linéaires associés à chaque sous-domaine. Pour améliorer les performances de la méthode de Schwarz, nous avons utilisé des conditions d'interfaces optimisées obtenues par une technique stochastique basée sur la stratégie CMA-ES (Covariance Matrix Adaptation Evolution Strategy). Les résultats numériques attestent des bonnes performances, de la robustesse et de la précision des algorithmes synchrones et asynchrones pour résoudre de grands systèmes linéaires creux dans un environnement de calcul hétérogène multi-coeur-GPU. / Advances in computational power have led to many developments in science and its applications. Solving linear systems occurs frequently in scientific computing, as in the finite element discretization of partial differential equations. The running time of the overall resolution is a direct result of the performance of the involved algebraic operations.In this dissertation, different ways of efficiently solving large and sparse linear systems are put forward. We present the best way to effectively compute linear algebra operations in an heterogeneous multi-core-GPU environment in order to make solvers such as iterative methods more robust and therefore reduce the computing time of these systems. We propose new techniques to speed algorithms up the auto-tuning of the threading design, according to the problem characteristics and the equipment level in the hardware and available resources. Numerical experiments performed on a set of large-size sparse matrices arising from diverse engineering and scientific problems, have clearly shown the benefit of the use of GPU technology to solve large sparse systems of linear equations, and its robustness and accuracy compared to existing libraries such as Cusp.The main priority of the GPU program is computational time to obtain the solution in a parallel environment, i.e, "How much time is needed to solve the problem?". In this thesis, we also address another question regarding energy issues, i.e., "How much energy is consumed by the application?". To answer this question, an experimental protocol is established to measure the energy consumption of a GPU for fundamental linear algebra operations accurately. This methodology fosters a "new vision of high-performance computing" and answers some of the questions outlined in green computing when using GPUs.The remainder of this thesis is devoted to synchronous and asynchronous iterative algorithms for solving linear systems in the context of a multi-core-GPU system. We have implemented and analyzed these algorithms using iterative methods based on sub-structuring techniques. Mathematical models and convergence results of synchronous and asynchronous algorithms are presented here, as are the convergence results of the asynchronous sub-structuring methods. We then analyze these methods in the context of a hybrid multi-core-GPU, which should pave the way for exascale hybrid methods.Lastly, we modify the non-overlapping Schwarz method to accelerate it, using GPUs. The implementation is based on the acceleration of the local solutions of the linear sub-systems associated with each sub-domain using GPUs. To ensure good performance, optimized conditions obtained by a stochastic technique based on the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) are used. Numerical results illustrate the good performance, robustness and accuracy of synchronous and asynchronous algorithms to solve large sparse linear systems in the context of an heterogeneous multi-core-GPU system.

Problemas de escalonamento cuja função objetivo é o consumo de energia tem sido cada vez mais estudados. Neste trabalho, estudamos o problema conhecido, em inglês, por Dynamic Speed Scaling, um problema de escalonamento de tarefas bem definidas em processadores de velocidade variável, cujo consumo de energia é função da velocidade. Além disso, relacionamos este problema com outro conhecido como MOSP, sigla em inglês para Multi-Organization Scheduling Problem. Neste, queremos escalonar tarefas de múltiplas organizações independentes respeitando certas restrições individuais. Provamos, neste trabalho, que este novo problema é NP-Completo e desenvolvemos várias heurísticas eficientes cujos testes experimentais mostram economia de energia significativa. / We studied, in this work, the problem of scheduling a set of well-defined tasks in a variable speed processor with the objective of minimizing the energy consumption, that is given as a function of the processor\'s speed, field known as Dynamic Speed Scaling. Also, we relate this problem to another known as MOSP (Multi-Organization Scheduling Problem), problem in which several independent organizations share tasks and resources to achieve a better global solution, but also respecting selfish restrictions. For the combined problem, we show that it is NP-Complete and designed several efficient heuristics that achieves good results in a experimental setup.

Massive data centers housing thousands of computing nodes have become commonplace in enterprise computing, and the power consumption of such data centers is growing at an unprecedented rate. Exacerbating such costs, data centers are often over-provisioned to avoid costly outages associated with the potential overloading of electrical circuitry. However, such over provisioning is often unnecessary since a data center rarely operates at its maximum capacity. It is imperative that we realize effective strategies to control the power consumption of the server and improve the energy efficiency of data centers. Adding to the problem is the inability of the servers to exhibit energy proportionality which diminishes the overall energy efficiency of the data center. Therefore in this dissertation, we investigate whether it is possible to achieve energy proportionality at the server- and cluster-level by efficient power and resource provisioning. Towards this end, we provide a thorough analysis of energy proportionality at the server and cluster-level and provide insight into the power saving opportunity and mechanisms to improve energy proportionality. Specifically, we make the following contribution at the server-level using enterprise-class workloads. We analyze the average power consumption of the full system as well as the subsystems and describe the energy proportionality of these components, characterize the instantaneous power profile of enterprise-class workloads using the on-chip energy meters, design a runtime system based on a load prediction model and an optimization framework to set the appropriate power constraints to meet specific performance targets and then present the effects of our runtime system on energy proportionality, average power, performance and instantaneous power consumption of enterprise applications. We then make the following contributions at the cluster-level. Using data serving, web searching and data caching as our representative workloads, we first analyze the component-level power distribution on a cluster. Second, we characterize how these workloads utilize the cluster. Third, we analyze the potential of power provisioning techniques (i.e., active low-power, turbo and idle low-power modes) to improve the energy proportionality. We then describe the ability of active low-power modes to provide trade-offs in power and latency. Finally, we compare and contrast power provisioning and resource provisioning techniques. This thesis sheds light on mechanisms to tune the power provisioned for a system under strict performance targets and opportunities to improve energy proportionality and instantaneous power consumption via efficient power and resource provisioning at the server- and cluster-level. / Ph. D.

Esta tese de Doutorado tem como objetivo apresentar uma arquitetura para metaescalonamento verde com provisão de qualidade de serviço em uma nuvem privada denominada GreenMACC. Essa nova arquitetura oferece a automatização na escolha de políticas em quatro estágios de escalonamento de uma nuvem privada, permitindo cumprir a negociação que foi estabelecida com o usuário. Devido a essa função, é possível garantir que o GreenMACC se comporte seguindo os princípios da computação verde sem deixar de se preocupar com a qualidade do serviço. Nesta tese o GreenMACC é apresentado, detalhado, discutido, validado e avaliado. Com os resultados apresentados pode-se concluir que a arquitetura proposta mostrou-se consistente, permitindo a execução dos serviços requisitados com diversas políticas de escalonamento em todos os seus estágios. Além disso, demonstrou flexibilidade em receber novas políticas, com focos verde e de qualidade de serviço, e eficiência na escolha das políticas de escalonamento de acordo com a negociação feita com o usuário. / This PhD thesis aims to present an architecture for green metascheduling with provision of quality of service in a private cloud called GreenMACC. This new architecture offers the possibility of choosing automatically the four stage scheduling policies of a private cloud, allowing to reach the users negotiation. As a result of this function, it is possible to ensure that GreenMACCs behavior follows the green computing principles and also is worried about the quality of the service. In this thesis Green- MACC is presented, particularized, discussed, validated and evaluated. The results show that the proposed architecture is consistent, allowing the execution of the requested services considering various scheduling policies in the stages. Moreover, GreenMACC proves to be flexible as allows new policies, focusing on green and quality of service, and to be efficient as chooses the scheduling policies following the users negotiation.

Recent economical crises, constant development of new technologies and faster globalisation cause different changes in all organisations all over the world. One of these changes are also different considerations about suistainable development and the impact different companies have. Those organisations are getting more and more involved into this topic and become more competitive within quickly developing global economics. They look for the ways how to contribute to suistainable development. One of the ways is also suistainable IT in a company focused on Green ICT. The aim of this thesis is to describe Green ICT, how it matches with suistainable development and what are the areas it covers. Firstly, the thesis contains an explanation of what Green ICT is. Secondly it focuses on the approach to this issue in different companies of different sizes in different industries. To achieve this aim, there are used different surveys from worldwide known companies. In the next part this thesis deals with two most important global IT companies, that significantly influence supply of ERP systems to the Czech market. This part specifies the areas covered by above mentioned companies and their main achievements. The main goal of this thesis is to analyze current state of Green ICT within local market. To achieve this goal, there was taken a survey focusing on Green ICT perception at ERP suppliers on the Czech market. Data from this survey were then analysed and evaluated. This thesis also provides a measuring scale for evaluation of Green ICT level. To demonstrate this, there were two global companies evaluated compared to three local companies evaluation.

CIRQUEIRA, Alexandre Correia. Um Mecanismo de Segurança com Adaptação Dinâmica em Tempo de Execução para Dispositivos Móveis. 2011. 110 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Computação, Fortaleza-CE, 2011. / Submitted by guaracy araujo (guaraa3355@gmail.com) on 2016-05-19T19:32:40Z No. of bitstreams: 1 2011_dis_accirqueira.pdf: 5491223 bytes, checksum: 7f1b8cc28f5bf56687e6d0e34acc337f (MD5) / Approved for entry into archive by guaracy araujo (guaraa3355@gmail.com) on 2016-05-19T19:33:29Z (GMT) No. of bitstreams: 1 2011_dis_accirqueira.pdf: 5491223 bytes, checksum: 7f1b8cc28f5bf56687e6d0e34acc337f (MD5) / Made available in DSpace on 2016-05-19T19:33:29Z (GMT). No. of bitstreams: 1 2011_dis_accirqueira.pdf: 5491223 bytes, checksum: 7f1b8cc28f5bf56687e6d0e34acc337f (MD5) Previous issue date: 2011 / The increasing use of mobile devices, wireless networks and mobile applications highlights the importance of ensuring information security. This concern arises because of the risks involved in traffic sensitive information via wireless, since it does not limit the risk of attacks, as in conventional networks. Additionally, the trend in the use of sustainable practices advocated by the Green Computing imposes the need for designing flexible applications that seek to reduce consumption of resources such as energy. Thus, mechanisms for providing confidentiality of information passing over the wireless medium should consider the efficient allocation of computing resources. This is a key issue to be considered when designing secure mobile applications. Therefore, the protection mechanisms should balance the security level required in accordance with the consumption of resources allocated to provide it. The use of information that characterizes the current situation (context) can assist in this task. Thus, the use of appropriate protective security requirements of applications and combined with the context can identify situations where you need to raise or lower the security level in order to reduce the resource consumption of the device. This work proposes a Security Mechanism Dynamic Adaptation (MeSAD), focusing on confidentiality, able to adapt the level of security according to the context and reduce the resource consumption of mobile devices. The main objective is to find the balance point in the tradeoff between the level of security and resource consumption. In order to achieve this goal, this paper presents a tool to support the use of MeSAD during the development of mobile applications, and enable the assessments on the performance of cryptographic algorithms that are used in different devices. / A crescente utilização de dispositivos móveis, redes sem fio e aplicações móveis evidencia a importância da garantia de segurança da informação. Esta preocupação surge devido aos riscos envolvidos no tráfego de informações sensíveis por meio sem fio, uma vez que o meio não limita os riscos de ataques, tal como nas redes convencionais. Adicionalmente, a tendência no uso de práticas sustentáveis defendidas pela Computação Verde impõe a necessidade de concepção de aplicações flexíveis que busquem a redução do consumo de recursos, como o de energia. Assim, mecanismos para o provimento de confidencialidade de informações que trafegam por meio sem fio devem considerar a alocação eficiente de recursos computacionais. Esta é uma questão chave a ser considerada no momento da concepção de aplicações móveis seguras. Portanto, os mecanismos de proteção devem balancear o nível de segurança requerido de acordo com o consumo de recursos alocados para provê-lo. O emprego de informações que caracterizam a situação corrente (contexto) pode auxiliar nessa tarefa. Assim, a utilização de proteção adequada aos requisitos de segurança das aplicações e combinada com o contexto pode identificar situações nas quais será necessário aumentar ou diminuir o nível de segurança, de forma a diminuir o consumo de recursos do dispositivo. Esse trabalho propõe, portanto, um Mecanismo de Segurança com Adaptação Dinâmica (MeSAD), com foco na confidencialidade, capaz de adaptar o nível de segurança de acordo com o contexto e reduzir o consumo de recursos dos dispositivos móveis. O objetivo principal consiste em encontrar o ponto de equilíbrio no tradeoff entre nível de segurança e consumo de recursos. A fim de atingir este objetivo, este trabalho apresenta também uma ferramenta de suporte à utilização do MeSAD durante o desenvolvimento de aplicações móveis, além de possibilitar a realização de avaliações sobre o desempenho dos algoritmos criptográficos que são utilizados nos diferentes dispositivos.

Depuis quelques années, économiser l'énergie est devenu un enjeu majeur dans les technologies de l'information et de la communication (TIC). Celles-ci représentent en effet 2% des émissions de CO2 de la planète, soit autant que l'aviation. Les systèmes distribués (grilles, clouds, réseaux haute performance) constituent de gros consommateurs d'électricité. En effet, pour des besoins de haute disponibilité, leurs ressources sont allumées en permanence et notamment lorsqu'elles ne sont pas utilisées. Les systèmes de réservation garantissent qualité de service et respect des contraintes de l'utilisateur. Ils permettent également une gestion plus fine des ressources. Pour limiter la consommation électrique des systèmes distribués et des réseaux dédiés, nous avons proposé un système de réservation de ressources efficace en énergie. Ce système de réservation, appelé ERIDIS, a été adapté à trois infrastructures distribuées différentes: les centres de calcul et les grilles, les environnements de cloud et les réseaux filaires dédiés. Dans les trois cas, des validations ont été menées et elles ont montré que des économies d'énergie significatives pouvaient être réalisées en utilisant ERIDIS dans les systèmes distribués actuels et futurs. / Over the past few years, the energy consumption of Information and Communication Technologies (ICT) has become a major issue. Nowadays, ICT accounts for 2% of the global CO2 emissions, an amount similar to that produced by the aviation industry. Large-scale distributed systems (e.g. Grids, Clouds and high-performance networks) are often heavy electricity consumers because -- for high-availability requirements -- their resources are always powered on even when they are not in use. Reservation-based systems guarantee quality of service, allow for respect of user constraints and enable fine-grained resource management. For these reasons, we propose an energy-efficient reservation framework to reduce the electric consumption of distributed systems and dedicated networks. The framework, called ERIDIS, is adapted to three different systems: data centers and grids, cloud environments and dedicated wired networks. By validating each derived infrastructure, we show that significant amounts of energy can be saved using ERIDIS in current and future large-scale distributed systems.

Esta tese de Doutorado tem como objetivo apresentar uma arquitetura para metaescalonamento verde com provisão de qualidade de serviço em uma nuvem privada denominada GreenMACC. Essa nova arquitetura oferece a automatização na escolha de políticas em quatro estágios de escalonamento de uma nuvem privada, permitindo cumprir a negociação que foi estabelecida com o usuário. Devido a essa função, é possível garantir que o GreenMACC se comporte seguindo os princípios da computação verde sem deixar de se preocupar com a qualidade do serviço. Nesta tese o GreenMACC é apresentado, detalhado, discutido, validado e avaliado. Com os resultados apresentados pode-se concluir que a arquitetura proposta mostrou-se consistente, permitindo a execução dos serviços requisitados com diversas políticas de escalonamento em todos os seus estágios. Além disso, demonstrou flexibilidade em receber novas políticas, com focos verde e de qualidade de serviço, e eficiência na escolha das políticas de escalonamento de acordo com a negociação feita com o usuário. / This PhD thesis aims to present an architecture for green metascheduling with provision of quality of service in a private cloud called GreenMACC. This new architecture offers the possibility of choosing automatically the four stage scheduling policies of a private cloud, allowing to reach the users negotiation. As a result of this function, it is possible to ensure that GreenMACCs behavior follows the green computing principles and also is worried about the quality of the service. In this thesis Green- MACC is presented, particularized, discussed, validated and evaluated. The results show that the proposed architecture is consistent, allowing the execution of the requested services considering various scheduling policies in the stages. Moreover, GreenMACC proves to be flexible as allows new policies, focusing on green and quality of service, and to be efficient as chooses the scheduling policies following the users negotiation.

Made available in DSpace on 2016-08-17T14:52:38Z (GMT). No. of bitstreams: 1 Dissertacao_Renato Ubaldo Moreira e Moraes.pdf: 1378349 bytes, checksum: c8d418a48e72c6d94fdc632323dcf508 (MD5) Previous issue date: 2014-09-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nowadays, there was a massive inclusion of smart mobile devices, known as smartphones, and with this accession, there s consequently a large increase in the consumption of information, especially from the internet. To support the great demand for information access, it s created a numerous devices to facilitate both access, the creation and the storage of such information, among the best known and disseminated currently is cloud computing. The feedback takes currently, an increasingly important and even critical for some entities, size and value turns out to be very desirable. Being often target capture and espionage attempts. To obtain data confidential information hackers use numerous devices, and more is used to scan networks. In other words can be described as scan "Scans notifications in computer networks, in order to identify which computers are active and which services are available for them. It is widely used by attackers to identify potential targets because it allows associate potential vulnerabilities to services enabled on a computer " [10]. According to [10] the number of attacks has been widening each year as shown in Figure 1.1 and 1.2 which are in section 1.1. Based on this high number incidents, the growth of the information consumer by means of devices furniture and the need to improve energy costs, the proposed establishment of the Office Security for Context Aware of authentication (Serviço de Segurança para Autenticação Ciente do Contexto(SSACC)) is required for today. The ssacc focus to provide a secure channel for transfer files to a server, using context information and reducing energy waste, thus saving resources and framing the Green Computing. Made based on the Secure Socket Layer (SSL), which is a widely used protocol that provides secure communication through a network. It uses several different cryptographic processes to ensure that data sent through the network is secure. It provides a security enhancement for the Transport Control Protocol (TCP) / Internet Protocol (IP) standard, which is used for communication with the Internet. SSL uses public key cryptography to provide authentication. The SSL protocol also uses encryption of the private key and digital signatures to ensure privacy and the integrity of data " [26]. / Atualmente houve uma adesão em massa aos dispositivos móveis inteligentes, conhecidos como smartphones, e, com essa adesão, houve consequentemente um grande aumento no consumo da informação, principalmente proveniente da internet. Para atender a grande demanda de acesso à informação foi criado inúmeros artifícios para facilitar tanto o acesso, quanto a criação e o armazenamento dessas informações, dentre os mais conhecidos e difundidos atualmente está a computação em nuvem. A informação assume, hoje em dia, uma importância crescente e até vital para algumas entidades, e com tamanho valor acaba se tornando muito desejada, sendo muitas vezes alvo de tentativas de captura e espionagem. Para se obter dados de informações confidenciais hackers usam inúmeros artifícios, e o mais usado é o scan de redes, que em outras palavras pode ser descrito scan como "notificações de varreduras em redes de computadores, com o intuito de identificar quais computadores estão ativos e quais serviços estão sendo disponibilizados por eles. É amplamente utilizado por atacantes para identificar potenciais alvos, pois permite associar possíveis vulnerabilidades aos serviços habilitados em um computador" [10]. De acordo com o [10] o número de ataques só vem crescendo a cada ano como mostra a figura 1.1 e 1.2 que estão na seção 1.1. Com base nesse alto número de incidentes, o crescimento do consumo da informação por meio de dispositivos móveis e a necessidade de melhorar gastos de energia, a proposta de criação do Serviço de Segurança para Autenticação Ciente do Contexto (SSACC) é necessária para a atualidade. O SSACC tem como principal objetivo fornecer um canal seguro para transferência de arquivos para um servidor, fazendo uso de informações de contexto e diminuindo o desperdício de energia, consequentemente economizando recursos e se enquadrando à Computação Verde. Feito com base no Secure Socket Layer(SSL), que é um "protocolo amplamente utilizado que fornece comunicação segura através de uma rede. Ele usa vários processos criptográficos diferentes para garantir que os dados enviados por meio de rede são seguras. Ele fornece um aprimoramento de segurança para o protocolo Transport Control Protocol (TCP)/ Internet Protocol (IP) padrão, que é usado para comunicação com a internet. SSL utiliza criptografia de chave pública para fornecer autenticação. O protocolo SSL também usa criptografia de chave privada e assinaturas digitais para garantir a privacidade e a integridade dos dados" [26].