Este projeto apresenta a proposta de uma arquitetura de Metaescalonador que leva em consideração o emprego de qualidade de serviço (QoS) para o ambiente de Computação em Nuvem. O Metaescalonador é capaz de realizar a alocação dos recursos dinamicamente, procurando atender as restrições temporais. Em resposta a esse dilema de escalonamento aplicado a Computação em Nuvem, este projeto propõe uma abordagem chamado MACC: Metascheduler Architecture to provide QoS in Cloud Computing. A função principal do MACC é distribuir e gerenciar o processamento das requisições de serviços entre os recursos disponíveis, cumprindo os termos agregados na SLA - Service Level Agreement. São apresentados resultados obtidos considerando-se diferentes algoritmos de roteamento e de alocação de máquinas virtuais. Os resultados apresentados são discutidos e analisados de acordo com as técnicas de planejamento de experimentos / This project proposes a Metascheduler architecture that takes into account the use of quality of service (QoS) to cloud computing environment. The Metascheduler is capable of dynamically allocating resources, trying to meet the timing constraints. In response to this scheduling dilemma applied to cloud computing, this project proposes an approach called MACC - Metascheduler Architecture to Provide QoS in Cloud Computing. The main function of the MACC is to distribute and to manage the service requests among the available resources, meeting the aggregate terms in the SLA - Service Level Agreement. Results are presented considering different routing algorithms and allocation of virtual machines. The results are discussed and analyzed in accordance with the techniques of experimental design

Em ambientes virtualizados, como nuvens computacionais, a capacidade efetiva de transmissão de dados via rede tende a ser inferior à de ambientes não virtualizados quando aplicações que fazem uso intensivo da rede são executadas. Uma das principais causas para essa diferença na capacidade de transmissão é a arquitetura da virtualização de rede, que adiciona passos para o sistema operacional transmitir e receber um pacote. Esses passos adicionais acarretam em maior utilização de memória e de processamento. Em ambientes virtualizados com o sistema operacional GNU/Linux, a New Application Programming Interface (NAPI) é utilizada para reduzir os impactos negativos da virtualização por meio de agregação de interrupções. Nesta dissertação de mestrado, são estudados mecanismos que modificam a configuração da NAPI. Experimentos mostram que esses mecanismos afetam o desempenho de máquinas virtuais e tem consequências diretas nas aplicações que fazem uso intensivo de rede e que são executadas em ambientes com os softwares de virtualização Xen, VMware e VirtualBox. / In virtualized environments, such as cloud computing, the effective capacity of data transmission via network cards tends to be lower than that in non-virtualized environments, when network intensive applications are executed. A major cause for this difference in the transmission capacity is the architecture of network virtualization, which adds some steps to be performed by the system when packets are transmitted or received. These additional steps cause more memory and processing usage. In virtualized environments with the GNU/Linux operating system, the New Application Programming Interface (NAPI) is used to reduce the negative impacts of virtualization through interrupt coalescence. In this dissertation, mechanisms that modify the configuration of NAPI are studied. Experiments show that these mechanisms affect the performance of virtual machines and have direct effects in applications that make intensive use of the network in environments with Xen, VMware and VirtualBox.

Scientific workflows are used in many scientific fields to abstract complex computations (tasks) and data or flow dependencies between them. High performance computing (HPC) systems have been widely used for the execution of scientific workflows. Cloud computing has gained popularity by offering users on-demand provisioning of resources and providing the ability to choose from a wide range of possible configurations. To do so, resources are made available in the form of virtual machines (VMs), described as a set of resource characteristics, e.g. amount of CPU and memory. The notion of VMs enables the use of different resource combinations which facilitates the deployment of the applications and the management of the resources. A problem that arises is determining the configuration, such as the number and type of resources, that leads to efficient resource provisioning. For example, allocating a large amount of resources may reduce application execution time however at the expense of increased costs. This thesis investigates the challenges that arise on resource provisioning and task scheduling of scientific workflows and explores ways to address them, developing approaches to improve energy efficiency for scientific workflows and meet the user's objectives, e.g. makespan and monetary cost. The motivation stems from the wide range of options that enable to select cost-efficient configurations and improve resource utilisation. The contributions of this thesis are the following. (i) A survey of the issues arising in resource management in cloud computing; The survey focuses on VM management, cost efficiency and the deployment of scientific workflows. (ii) A performance model to estimate the workflow execution time for a different number of resources based on the workflow structure; The model can be used to estimate the respective user and energy costs in order to determine configurations that lead to efficient resource provisioning and achieve a balance between various conflicting goals. (iii) Two energy-aware scheduling algorithms that maximise the number of completed workflows from an ensemble under energy and budget or deadline constraints; The algorithms address the problem of energy-aware resource provisioning and scheduling for scientific workflow ensembles. (iv) An energy-aware algorithm that selects the frequency to be used for each workflow task in order to achieve energy savings without exceeding the workflow deadline; The algorithm takes into account the different requirements and constraints that arise depending on the workflow and system characteristics. (v) Two cost-based frequency selection algorithms that choose the CPU frequency for each provisioned resource in order to achieve cost-efficient resource configurations for the user and complete the workflow within the deadline; Decision making is based on both the workflow characteristics and the pricing model of the provider.

Motivation. The motivation for this thesis is to explore the only recently evolved cloud accounting phenomenon which in essence is doing accounting no longer within the boundaries of a business, but connected to the Cloud. Problem statement. The aim of this thesis is to examine the way in which cloud computing impacts accounting practice. Few previous studies have been conducted so businesses have not been able to understand the cloud accounting phenomenon thoroughly, preventing businesses from adopting their business models on the basis of the Cloud. This means that businesses have potentially missed out on opportunities for competitive advantages and growth. The purpose of this thesis is to understand the cloud accounting phenomenon in an in-depth manner. Approach. This thesis can be classified as empirical positive qualitative research and empirical quantitative case study which uses an explanatory and exploratory research approach. The case study was conducted in in-depth interviews and the extent of this work encompasses primarily the Swedish accounting environment. It consists of six cloud accounting users and two cloud accounting provider. Results. This study contributes four main findings to the existing field of research. Firstly, the initial adoption decision and acceptance of cloud accounting Software-as-a-Service is based on the perceived usefulness that the Cloud enhances the accounting process in terms of efficiency and effectiveness. The usage decision is voluntary to obtain a better image and status. Secondly, trust was identified as a central component within the relationship between user and provider in cloud accounting service partnerships. Thirdly, the Cloud brings the possibility not only for accountants, but for the entire business to access an unlimited amount of resources. Users can become easily dependant on a provider if they perceive the service as a crucial asset for their business. The dilemma between the trade-off between autonomy and certainty occurs. Users are aware that they need to give up their right for self-government for the benefit of attaining a cloud service, and expressed concerns in respect to privacy and security, implementation issues, legal requirements, and increased costs. Moreover, users fear that they become dependant and locked in with a cloud accounting provider. Fourthly, the Cloud brings the possibility to access an unlimited amount of resources not only for accountants, but for the whole business. Cloud providers offer their service to a broad customer base which means that the structures in different businesses may possibly become more similar.

Tang, Yang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 60-65). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Policy-based File Assured Deletion --- p.7 / Chapter 2.1 --- Background --- p.7 / Chapter 2.2 --- Policy-based Deletion --- p.9 / Chapter 3 --- Basic Design of FADE --- p.13 / Chapter 3.1 --- Entities --- p.13 / Chapter 3.2 --- Deployment --- p.15 / Chapter 3.3 --- "Security Goals, Threat Models, and Assumptions" --- p.16 / Chapter 3.4 --- The Basics - File Upload/Download --- p.18 / Chapter 3.5 --- Policy Revocation for File Assured Deletion --- p.23 / Chapter 3.6 --- Multiple Policies --- p.23 / Chapter 3.7 --- Policy Renewal --- p.25 / Chapter 4 --- Extensions of FADE --- p.27 / Chapter 4.1 --- Access Control with ABE --- p.27 / Chapter 4.2 --- Multiple Key Managers --- p.31 / Chapter 5 --- Implementation --- p.35 / Chapter 5.1 --- Representation of Metadata --- p.36 / Chapter 5.2 --- Client --- p.37 / Chapter 5.3 --- Key Managers --- p.38 / Chapter 6 --- Evaluation --- p.40 / Chapter 6.1 --- Experimental Results on Time Performance of FADE --- p.41 / Chapter 6.1.1 --- Evaluation of Basic Design --- p.42 / Chapter 6.1.2 --- Evaluation of Extensions --- p.46 / Chapter 6.2 --- Space Utilization of FADE --- p.49 / Chapter 6.3 --- Cost Model --- p.51 / Chapter 6.4 --- Lessons Learned --- p.53 / Chapter 7 --- Related Work --- p.54 / Chapter 8 --- Conclusions --- p.58 / Bibliography --- p.60

Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2018-04-19T13:23:06Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernando_Angelin.pdf: 1204993 bytes, checksum: 3cf6b9f14201e8e7168987d5dfd7354b (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-04-19T14:44:30Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernando_Angelin.pdf: 1204993 bytes, checksum: 3cf6b9f14201e8e7168987d5dfd7354b (MD5) / Made available in DSpace on 2018-04-19T14:44:39Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernando_Angelin.pdf: 1204993 bytes, checksum: 3cf6b9f14201e8e7168987d5dfd7354b (MD5) Previous issue date: 2017-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A Computação em Nuvem vem apresentando um crescimento extraordinário nos últimos anos, em questão de quantidade e variedade de serviços oferecidos, estes, tomando uma forma onipresente no cotidiano. Com isso, usuários que necessitam, geralmente, de alta disponibilidade de processamento, buscam na Nuvem soluções que diminuam custos pontuais, como construção e manutenção de uma infraestrutura privada. A saída para tal é alugar infraestrutura em uma Nuvem ou até mesmo utilizar a Nuvem para dimensionar uma infraestrutura própria que supra sua demanda, sem sub ou superdimensionamento. Este trabalho apresenta um modelo de simulação mista, o qual busca comparar uma infraestrutura física limitada à uma infraestrutura virtual simulada com as mesmas características. Para isto, foram executados testes em uma infraestrutura física limitada e testes de simulação utilizando o CloudSim, escalando o tamanho das tarefas do tipo Bag of Tasks (BoT) e o número de hosts e núcleos computacionais. Para tais testes foram implementados algoritmos que realizam a transformação da entrada BoT para a execução na infraestrutura física e na simulada. Também, foram prototipadas classes para complementação do CloudSim, tanto para leitura dos BoTs transformados quanto para a criação da infraestrutura simulada.Com os testes realizados, notamos a estabilidade do sistema, quando simulados testes com BoT pequenos, médios e grandes em infraestruturas que, para nosso caso, foram classificadas como pequena, média e grande. Outra observação importante realizada foi a de que quando a infraestrutura oferece carga externa à execução desejada (utilização por outro usuário, por exemplo), o tempo final de execução dos BoTs aumenta proporcionalmente à quanto a infraestrutura está em utilização. Também percebemos que a granularidade das tarefas impacta na execução. Com relação à escalabilidade, foi percebido que BoTs classificados como grandes para infraestruturas categorizadas como pequenas foram agrupados como pequenos para infraestruturas identificadas como grandes. / Cloud Computing has been showing extraordinary growth in recent years, in terms of the quantity and variety of services offered, these, taking a ubiquitous form in everyday life. As a result, users who generally require high availability of processing, search on cloud solutions that reduce specific costs, such as building and maintaining a private infrastructure. The way out is to rent infrastructure in a Cloud or even use the Cloud to size an infrastructure that suits your demand, without sub or oversize. This dissertation presents a mixed simulation model, which seeks to compare a limited physical infrastructure to a simulated virtual infrastructure with the same characteristics. For this, tests were performed on a limited physical infrastructure and simulation tests using CloudSim, scaling the size of Bag of Tasks (BoT) tasks and the number of hosts and processing cores. For such tests, were implemented algorithms that perform the transformation of the BoT input for execution in real infrastructure and simulation. Also, classes to complement CloudSim were prototyped, both for reading the transformed BoTs and for creating the simulated infrastructure. With the tests carried out, we noticed the stability of the system when simulated small, medium and large BoT tests in infrastructures that, in our case, were classified as small, medium and large. Another important observation was that when the infrastructure offers external load to the desired execution (use by another user, for example), the final execution time of the BoTs increases proportionally to how much the infrastructure is in use. We also realize that the granularity of tasks impacts execution. With regard to scalability, it was noticed that BoTs classified as large for infrastructures categorized as small were grouped as small for infrastructures identified as large.

Management solutions for current and future Infrastructure-as-a-Service (IaaS) Data Centers (DCs) face complex challenges. First, DCs are now very large infrastructures holding hundreds of thousands if not millions of servers and applications. Second, DCs are highly heterogeneous. DC infrastructures consist of servers and network devices with different capabilities from various vendors and different generations. Cloud applications are owned by different tenants and have different characteristics and requirements. Third, most DC elements are highly dynamic. Applications can change over time. During their lifetime, their logical architectures evolve and change according to workload and resource requirements. Failures and bursty resource demand can lead to unstable states affecting a large number of services. Global and centralized approaches limit scalability and are not suitable for large dynamic DC environments with multiple tenants with different application requirements. We propose a novel fully distributed and dynamic management paradigm for highly diverse and volatile DC environments. We develop LAMA, a novel framework for managing large scale cloud infrastructures based on a multi-agent system (MAS). Provider agents collaborate to advertise and manage available resources, while app agents provide integrated and customized application management. Distributing management tasks allows LAMA to scale naturally. Integrated approach improves its efficiency. The proximity to the application and knowledge of the DC environment allow agents to quickly react to changes in performance and to pre-plan for potential failures. We implement and deploy LAMA in a testbed server cluster. We demonstrate how LAMA improves scalability of management tasks such as provisioning and monitoring. We evaluate LAMA in light of state-of-the-art open source frameworks. LAMA enables customized dynamic management strategies to multi-tier applications. These strategies can be configured to respond to failures and workload changes within the limits of the desired SLA for each application.

The diploma thesis deals with the topic of cloud computing and its appropriate deployment in small and medium business. The objective of this thesis is to analyze the offer of Google products and to demonstrate measurable benefits of this solution. Introductory part of the thesis summarizes the history of IT and it is looking for the connection between history of IT and the term cloud computing. This term is described in detail with selected cloud computing characteristics. The main part of the thesis deals with analysis of Google services, technologies and platforms, which could be used in enterprise. The matters are viewed not only economically, but also from the technological and security point of view. In practical implementations are demonstrated measurable benefits of deployment to the Google cloud platform. Finally, the thesis provides the summary of platform's advantages and disadvantages with a description of practical advices for small and medium businesses

Focus of this diploma thesis is on cloud computing topic. Cloud computing is current trend that changes the method of IT services providing. The concept of cloud computing model is based on a provision of IT resources through services. This model offers companies many advantages. The aim of this diploma thesis is to provide an overview of the motivational forces, barriers and their solution in the transition of small and medium businesses to products in the cloud. The theoretical part deals with economic and technological aspects arising from the use of cloud computing model. The next stage is provided with an overview of adoption of cloud computing services in the Czech Republic and current trends. The practical part is focused on the research of motivation aspects and barriers resulting from adoption services built on the cloud computing concept. The main contribution of this thesis is primarily in providing an overview of motivational aspects and research-based barriers in the environment of Czech companies. This overview could help to these company representatives, who are considering deployment of cloud based services, but are struggling with the barriers that this model brings.

Dans cette nouvelle ère du numérique, l'accès à l'information est entré désormais dans une autre dimension. Nous assistons à la dominance d'un modèle fondé sur les opportunités offertes par un accès mondialisé à l'Internet et à son application phare : le "World Wide Web". Les services se sont multipliés. Les terminaux se sont diversifiés. Les technologies de transport se sont améliorées. Les attentes se sont élevées. Dans cette spirale que nous nous abstenons de qualifier, les opérateurs se trouvent désormais confrontés à une croissance soutenue du trafic dans leurs réseaux, en grande partie due au transport de flux vidéo. Les fournisseurs de services sur Internet se trouvent aussi concernés par la problématique de la qualité de service dont dépend la satisfaction de leurs utilisateurs. Pour l'ensemble des acteurs, ces nouvelles tendances présentent à la fois des défis et des opportunités. Les défis se concentrent dans la problématique de gestion de la demande croissante du trafic tout en maintenant une qualité d'expérience appropriée pour les utilisateurs. Les opportunités proviendront de l'adéquation entre une demande croissante des services Web en termes de qualité de services et des ressources qui devront supporter la distribution de ces services. Il est crucial pour chaque acteur de bien se positionner dans la chaîne de valeur pour gérer cette adéquation. Le rôle que prendra le réseau support, simple ensemble de tuyaux surdimensionnés, ou bien réseau intelligent offrant des fonctions avancées de contrôle illustre parfaitement cet enjeu. Ces deux alternatives sont respectivement connues sous les termes "dumb-pipe" ou "smart network". Dans cette thèse, nous considérons une nouvelle approche, qui se veut simple, efficace et adaptée pour faire face à ces défis. Les opérateurs réseaux et les fournisseurs de services sont mutuellement gagnants dans l'amélioration du transport de données dans les réseaux tout en continuant à opérer leur propre infrastructure. Cette démarche coopérative est le point de départ de nos travaux qui visent à définir un cadre, une architecture et des techniques appropriées qui amèneront ces acteurs à collaborer en vue de gérer conjointement cette problématique. Cette collaboration est nécessaire car chaque acteur quoique prisonnier de ses contraintes peut les transformer en relations contractuelles dans un processus client fournisseur pour l'optimisation de la gestion du trafic. / In this new digital world, driven by the dominance of a model based on the opportunities offered by global access to the Internet and its killer app: the World Wide Web, access to information is becoming a matter of a good experience and responsiveness. We are witnessing the Web services are of increasing popularity. New types of terminals are proposed. Communications technologies are improved. Users expectations are becoming higher. In such a context, network operators are facing serious challenges arising from the management of a massive traffic growth, largely driven by the increasing amount of video streams while internet services providers are also concerned by the issue of providing an adequate quality of experience to their end-users. For both actors, these dual trends present both challenges and opportunities. The challenges arise from the issues of managing the growing demand for traffic while maintaining appropriate quality of experience for users. Opportunities come from a smart management of the increasing demands of Web services in terms of quality of services and of the resources that will support the delivery of these services. It is then crucial for each actor to be well-positioned in the value chain to take part in this process. The role that will be played by the networks, as a basic set of oversized pipes, or as an intelligent network providing advanced management facilities, perfectly illustrates this issue. These two alternatives are respectively known as the "dumb-pipe" or "smart networks". In this thesis, we consider a new approach, which is simple, effective and adapted to meet these challenges. Network operators and service providers can mutually benefit from improving the data delivery in the networks while continuing to fully control their infrastructures. This collaborative approach is the starting bloc of our work aiming at defining a framework, an architecture and appropriate procedures to bring these actors to work together to manage this problem. This collaboration is particularly necessary because each actor, though prisoner of its constraints and capacities, can turn them into a contractual relation with the other in a client-supplier process for the optimization of traffic management.