Precisão e repetibilidade de experimentos no planetlab

Orientador : Prof. Dr. Elias P. Duarte Jr.Co-orientador : Prof. Dr. Luis C. E. BonaDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 02/09/2014Inclui referênciasResumo: Desenvolvida como uma rede acadêmica, a Internet cresceu e evoluiu rapidamente. Hoje, 40 anos mais tarde, se tornou uma ampla plataforma de informação, interação social e comércio. Os usuários e as aplicações da Internet atualmente demandam características de desempenho, segurança, escalabilidade e mobilidade que não foram previstas no momento de sua criação. Testbeds de larga escala, como o PlanetLab, são peças chave para o desenvolvimento e avaliação de novas aplicações e arquiteturas que atendam a estas demandas. O PlanetLab é um testbed de escala planetária, composto por mais de mil nodos espalhados ao redor do mundo, que oferece aos seus usuários um ambiente real para a execução de experimentos. No entanto, a execução de experimentos no PlanetLab é uma atividade que pode se tornar muito complexa, especialmente por envolver uma grande quantidade de nodos e a existência de instabilidades no desempenho nos nodos e na rede que os conecta, prejudicando a precisão e repetibilidade dos resultados obtidos. Por estes motivos, existem diversas ferramentas para gerenciamento de experimentos e descoberta de recursos no PlanetLab. Neste trabalho, apresentamos uma avaliação experimental do impacto da utilização de subconjuntos de nodos selecionados por uma ferramenta de monitoramento da conectividade entre os nodos na precisão e repetibilidade dos resultados obtidos. São realizados experimentos utilizando aplicações com diferentes perfis de utilização de recursos e os resultados obtidos por diferentes subconjuntos de nodos são comparados. A estratégia de seleção de nodos estudada reduziu a variação dos resultados obtidos em até 27% e obteve média de execução até 26% mais baixa que uma das estratégias alternativas. Pode-se concluir que a utilização de subconjuntos de nodos selecionados por esta ferramenta contribui para a precisão, repetibilidade e reprodutibilidade de experimentos realizados no PlanetLab. Este trabalho também apresenta uma proposta de integração da ferramenta de seleção de nodos ao portal de gerenciamento de experimentos PlanetMon, com o objetivo de permitir que usuários do PlanetLab obtenham acesso a ferramenta de seleção de modo conveniente e transparente enquanto gerenciam seus experimentos.Abstract: The Internet was originally developed as an academic network more than four decades ago. Today, it has established itself as a global platform for human communications, allowing information exchange, social interaction, and e-commerce. Current Internet users and applications require high levels of performance, security, scalability and mobility. These characteristics were not predicted at the time of its creation. Large-scale testbeds like PlanetLab have been developed to allow the design and realistic evaluation of applications and architectures to supply the new Internet demands. PlanetLab is a planetary scale testbed, consisting of more than one thousand nodes spread around the globe, offering its users a realistic environment for experiment execution. However, experiment execution on PlanetLab can become a complex activity, especially because it involves configuring a large number of nodes, and because the environment is highly unstable, due to performance variations of both nodes and their network connections. These instabilities affect the precision and repeatability of the results obtained. There are several tools for experiment management and resource discovery on PlanetLab. In this work, we present an experimental evaluation of the impact of using subsets of nodes selected with different strategies on the precision and repeatability of the results obtained. Experiments using applications with different resource requirements were carried out and are reported. Results show that the selection strategy based on k-cores reduces the variation on the results obtained by up to 27% and resulted on an average execution time up to 26% faster compared to other alternatives. The utilization of subsets of nodes selected with this strategy can thus contribute to the precision, repeatability and reproducibility of experiments executed on PlanetLab. This work also presents the integration of the node selection strategy to the experiment management framework PlanetMon. This integration is intended to allow PlanetLab users to have access to the node selection tool in a convenient and transparent way for managing their experiments

A HyperNet Architecture

Network virtualization is becoming a fundamental building block of future Internet architectures. By adding networking resources into the “cloud”, it is possible for users to rent virtual routers from the underlying network infrastructure, connect them with virtual channels to form a virtual network, and tailor the virtual network (e.g., load application-specific networking protocols, libraries and software stacks on to the virtual routers) to carry out a specific task. In addition, network virtualization technology allows such special-purpose virtual networks to co-exist on the same set of network infrastructure without interfering with each other. Although the underlying network resources needed to support virtualized networks are rapidly becoming available, constructing a virtual network from the ground up and using the network is a challenging and labor-intensive task, one best left to experts. To tackle this problem, we introduce the concept of a HyperNet, a pre-built, pre-configured network package that a user can easily deploy or access a virtual network to carry out a specific task (e.g., multicast video conferencing). HyperNets package together the network topology configuration, software, and network services needed to create and deploy a custom virtual network. Users download HyperNets from HyperNet repositories and then “run” them on virtualized network infrastructure much like users download and run virtual appliances on a virtual machine. To support the HyperNet abstraction, we created a Network Hypervisor service that provides a set of APIs that can be called to create a virtual network with certain characteristics. To evaluate the HyperNet architecture, we implemented several example Hyper-Nets and ran them on our prototype implementation of the Network Hypervisor. Our experiments show that the Hypervisor API can be used to compose almost any special-purpose network – networks capable of carrying out functions that the current Internet does not provide. Moreover, the design of our HyperNet architecture is highly extensible, enabling developers to write high-level libraries (using the Network Hypervisor APIs) to achieve complicated tasks

Cyber physical approach and framework for micro devices assembly

The emergence of Cyber Physical Systems (CPS) and Internet-of-Things (IoT) based principles and technologies holds the potential to facilitate global collaboration in various fields of engineering. Micro Devices Assembly (MDA) is an emerging domain involving the assembly of micron sized objects and devices. In this dissertation, the focus of the research is the design of a Cyber Physical approach for the assembly of micro devices. A collaborative framework comprising of cyber and physical components linked using the Internet has been developed to accomplish a targeted set of MDA life cycle activities which include assembly planning, path planning, Virtual Reality (VR) based assembly analysis, command generation and physical assembly. Genetic algorithm and modified insertion algorithm based methods have been proposed to support assembly planning activities. Advanced VR based environments have been designed to support assembly analysis where plans can be proposed, compared and validated. The potential of next generation Global Environment for Network Innovation (GENI) networking technologies has also been explored to support distributed collaborations involving VR-based environments. The feasibility of the cyber physical approach has been demonstrated by implementing the cyber physical components which collaborate to assemble micro designs. The case studies conducted underscore the ability of the developed Cyber Physical approach and framework to support distributed collaborative activities for MDA process contexts

LSIM: execució d'aplicacions en entorns realistes a gran escala

LSim és una eina pel desplegament d'aplicacions en entorns distribuïts realistes. L'eina esta formada per una llibreria, que automatitza l'execució, coordinació i recollida de resultats, i per un framework que desplega automàticament l'aplicació als recursos que realitzaran les execucions a l'entor