A Bag-of-Tasks Scheduler Tolerant to Temporal Failures in Clouds

Cloud platforms have emerged as a prominent environment to execute high performance computing (HPC) applications providing on-demand resources as well as scalability. They usually offer different classes of Virtual Machines (VMs) which ensure different guarantees in terms of availability and volatility, provisioning the same resource through multiple pricing models. For instance, in Amazon EC2 cloud, the user pays per hour for on-demand VMs while spot VMs are unused instances available for lower price. Despite the monetary advantages, a spot VM can be terminated, stopped, or hibernated by EC2 at any moment. Using both hibernation-prone spot VMs (for cost sake) and on-demand VMs, we propose in this paper a static scheduling for HPC applications which are composed by independent tasks (bag-of-task) with deadline constraints. However, if a spot VM hibernates and it does not resume within a time which guarantees the application's deadline, a temporal failure takes place. Our scheduling, thus, aims at minimizing monetary costs of bag-of-tasks applications in EC2 cloud, respecting its deadline and avoiding temporal failures. To this end, our algorithm statically creates two scheduling maps: (i) the first one contains, for each task, its starting time and on which VM (i.e., an available spot or on-demand VM with the current lowest price) the task should execute; (ii) the second one contains, for each task allocated on a VM spot in the first map, its starting time and on which on-demand VM it should be executed to meet the application deadline in order to avoid temporal failures. The latter will be used whenever the hibernation period of a spot VM exceeds a time limit. Performance results from simulation with task execution traces, configuration of Amazon EC2 VM classes, and VMs market history confirms the effectiveness of our scheduling and that it tolerates temporal failures

Usucapião

Era inevitável. Toda vez que se começa a ouvir repetidamente uma palavra incomum, surge a interrogação no ar, desafiando o conhecimento dos mais velhos. E os mais velhos, coitados, nem sempre se acham apetrechados para responder a quem interroga. No momento, usucapião está ocupando o lugar que um dia pertenceu a plebiscito e depois foi ocupado por hermenêutica, informática, ergometria e outras nebulosas vocabulares, hoje mais ou menos decifradas. – Papai, que troço é esse de usucapião? – pergunta o garoto de curiosidade insaciável, que, de resto, pouco se importa em saber o sentido das palavras; prefere saber as coisas diretamente. E o pai, que há muitos anos ouvira falar nisso e não guardara na cabeça, responde: – Hem, usucapião? Usucapião é um negócio que... quer dizer... ora, “pra” que você quer saber, menino?Revista do Serviço Público - RSP, v. 57, n. 4, p. 573-575Direito PrivadoISSN Impresso: 0034-9240ISSN Eletrônico: 2357-8017RSP Revisitada: texto originalmente publicado na RSP Jan/Mar de 1982 (ano 39, n.1

Optimization of Port-of-Entry Operation in the U.S.: An Anti-human Trafficking Focus

Although decisions at the U.S. port-of-entries take into consideration many factors and stakeholders like government, citizens, travelers, security is their main priority. Officer\u27s decision relies on letting someone into the country or forbids their entrance if they present some threat. They are trained to detect criminals, but little focus is given to identify possible victims. This thesis presents a model that finds an optimal policy regarding how many travelers are going to be conducted to further screening to better detect human trafficking victims. A Bayesian Decision Model was developed and the estimation of costs for the different possible outcomes and scenarios were made and compared. Human trafficking costs and the POE operation were considered. Results showed that decisions were affected by the human trafficking and POE operation costs, as well as the expected number of victims at the border

Automatically generating Feynman rules for improved lattice field theories

Deriving the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially when improvement terms are present. This physically important task is, however, suitable for automation. We describe a flexible algorithm for generating Feynman rules for a wide range of lattice field theories including gluons, relativistic fermions and heavy quarks. We also present an efficient implementation of this in a freely available, multi-platform programming language (\python), optimised to deal with a wide class of lattice field theories

Kappa-symmetric deformations of M5-brane dynamics

We calculate the first supersymmetric and kappa-symmetric derivative deformation of the M5-brane worldvolume theory in a flat eleven-dimensional background. By applying cohomological techniques we obtain a deformation of the standard constraint of the superembedding formalism. The first possible deformation of the constraint and hence the equations of motion arises at cubic order in fields and fourth order in a fundamental length scale $l$. The deformation is unique up to this order. In particular this rules out any induced Einstein-Hilbert terms on the worldvolume. We explicitly calculate corrections to the equations of motion for the tensor gauge supermultiplet.Comment: 17 pages. Additional comments in section