976 resultados para cloud computing, cloud federation, concurrent live migration, data center, qemu, kvm, libvirt
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The aim of this study is to evaluate the variation of solar radiation data between different data sources that will be free and available at the Solar Energy Research Center (SERC). The comparison between data sources will be carried out for two locations: Stockholm, Sweden and Athens, Greece. For the desired locations, data is gathered for different tilt angles: 0°, 30°, 45°, 60° facing south. The full dataset is available in two excel files: “Stockholm annual irradiation” and “Athens annual irradiation”. The World Radiation Data Center (WRDC) is defined as a reference for the comparison with other dtaasets, because it has the highest time span recorded for Stockholm (1964–2010) and Athens (1964–1986), in form of average monthly irradiation, expressed in kWh/m2. The indicator defined for the data comparison is the estimated standard deviation. The mean biased error (MBE) and the root mean square error (RMSE) were also used as statistical indicators for the horizontal solar irradiation data. The variation in solar irradiation data is categorized in two categories: natural or inter-annual variability, due to different data sources and lastly due to different calculation models. The inter-annual variation for Stockholm is 140.4kWh/m2 or 14.4% and 124.3kWh/m2 or 8.0% for Athens. The estimated deviation for horizontal solar irradiation is 3.7% for Stockholm and 4.4% Athens. This estimated deviation is respectively equal to 4.5% and 3.6% for Stockholm and Athens at 30° tilt, 5.2% and 4.5% at 45° tilt, 5.9% and 7.0% at 60°. NASA’s SSE, SAM and RETScreen (respectively Satel-light) exhibited the highest deviation from WRDC’s data for Stockholm (respectively Athens). The essential source for variation is notably the difference in horizontal solar irradiation. The variation increases by 1-2% per degree of tilt, using different calculation models, as used in PVSYST and Meteonorm. The location and altitude of the data source did not directly influence the variation with the WRDC data. Further examination is suggested in order to improve the methodology of selecting the location; Examining the functional dependence of ground reflected radiation with ambient temperature; variation of ambient temperature and its impact on different solar energy systems; Im pact of variation in solar irradiation and ambient temperature on system output.
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O estudo objetivou analisar a ocorrência de lesões em nadadores, associando-as a fatores de risco específicos da modalidade e do atleta. Fizeram parte desse estudo 215 atletas, de ambos os sexos, participantes dos principais campeonatos promovidos pela Federação Aquática Paulista. Os dados foram obtidos por meio de Inquérito de Morbidade Referida, constituído por perguntas relacionadas ao atleta, modalidade e referentes ao tipo, mecanismo e local da lesão. A análise entre variáveis antropométricas e presença de lesão foi realizada pelo teste t de Student ou pelo teste não paramétrico de Mann Whitney. Para relação entre as especificidades e o tipo, mecanismo e local da lesão, utilizou-se o teste de Goodman. Resultados significantes foram obtidos entre os atletas lesionados com mais idade e anos de treinamento. Segundo o mecanismo da lesão, o volume dos treinos é a principal causa de ocorrências de lesões e as tendinopatias são as lesões mais comuns. O ombro é o local mais acometido pelas diferentes especialidades, com exceção dos nadadores de peito que referiram a virilha. Conclui-se a partir dos achados que a exposição dos nadadores a prática esportiva associada ao volume de treinamento estão relacionadas com as frequentes lesões nestes atletas.
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Fungi are a diverse group of organisms with an overall global number of 1.5 M up to 3.3 M species on Earth. Besides their ecological roles as decomposers, fungi are important in several aspects of applied research. Here, we review how culture collections may promote the knowledge on diversity, conservation and biotechnological exploitation of fungi. The impact of fungi diversity on biotechnological studies is discussed. We point out the major roles of microbial repositories, including fungal preservation, prospecting, identification, authentication and supply. A survey on the World Data Center for Microorganisms (WDCM) powered by the World Federation for Culture Collections and on the Genetic Heritage Management Council (CGEN) database revealed that 46 Brazilian culture collections registered in these databases are dedicate to preserving fungi. Most of these culture collections are located in the Southeast of Brazil. This scenario also demonstrates that Brazil has many collections focused on fungal strains, but the lack of up-to-date information in WDCM as well as of a solid national platform for culture collections registration do not allow accurate assessment of fungal preservation. © 2013 Elsevier Inc. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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A chegada de imigrantes japoneses ao Peru, a bordo do navio Sakura Maru, em 1899, para trabalharem nas fazendas da costa peruana, coincide com os anos áureos da exploração da borracha na Amazônia, o que fez essa região atrativa aos migrantes que não permaneceram nessas fazendas. No mesmo ano da chegada do navio Sakura Maru, 91 desses imigrantes se deslocaram para o atual departamento de Madre de Dios ao sul da Amazônia peruana. Passado o ciclo da exploração da borracha, muitos imigrantes japoneses permaneceram na Amazônia e em Madre de Dios se estabeleceram ao redor de Puerto Maldonado, surgindo uma próspera comunidade japonesa que se mantêm até hoje. Na época da exploração da borracha alguns japoneses migraram para o atual estado do Acre (Brasil), chamados de Peru kudari (os descidos do Peru), mas poucos se fixaram, espalhando-se, após a queda da economia da borracha, por outros lugares do Brasil e outros países. Assim, esta tese pretende demonstrar que a migração de japoneses para o departamento de Madre de Dios, na Amazônia peruana, e o surgimento e consolidação de uma comunidade de japoneses em Puerto Maldonado (capital desse departamento), foram causados por três fatores principais: 1) Uma política contínua em prol da imigração japonesa para o Peru durante as primeiras décadas do século XX voltada para prover mão-de-obra nas fazendas de cana-de-açúcar e algodão da costa; 2) Envolvimento dos imigrantes japoneses em atividades econômicas demandadas durante a expansão da exploração da borracha na Amazônia peruana; e 3) Fortalecimento dessas atividades após a queda da economia da borracha para garantir o fornecimento de produtos necessários à população remanescente, inclusive, substituindo produtos não mais importados ou fornecidos por grandes empresas. Esses fatores não foram encontrados entre japoneses que avançaram até o Acre (Brasil), não conseguindo, portanto, a fixação de comunidades japonesas que permanecessem até a atualidade. As fontes utilizadas para a realização do estudo foram compostas de literatura sobre os movimentos migratórios internacionais, dados dos censos peruanos e brasileiros, jornais da época, documentos diplomáticos, e relatórios provinciais, entre outras. A tese é um estudo de demografia histórica utilizando dados quantitativos e qualitativos, na busca da compreensão do processo histórico do objeto pesquisado, com intuito de explicar os desdobramentos que ocorreram nas comunidades de imigrantes japoneses tanto em Madre de Dios (Peru) quanto no Acre (Brasil).
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The objective this study was to highlight the prospects of a group of teachers of Physical Education, highlighting the factors identified as critical to a continuing education "ideal" for a teacher professional development and for the practice pedagogical. Qualitative research, inspired by the method of approaching the history of the present time, in order to register as memory the time when these teachers live. The data source used was oral sources collected by the technique of semistructured interviews and official documents. The data generated were discussed with the production of literature and the highlights are three axes in the reports of teachers: the relationship between theory and practice, the importance of listening to students and the continuity of training activities.
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We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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The differential production cross section of electrons from semileptonic heavy-flavor hadron decays has been measured at midrapidity (\y\ < 0.5) in proton-proton collisions at root s = 7 TeV with ALICE at the LHC. Electrons were measured in the transverse momentum range 0.5 < p(t) < 8 GeV/c. Predictions from a fixed-order perturbative QCD calculation with next-to-leading-log resummation agree with the data within the theoretical and experimental uncertainties. DOI: 10.1103/PhysRevD.86.112007
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The effect of event background fluctuations on charged particle jet reconstruction in Pb-Pb collisions at root s(NN) = 2.76 TeV has been measured with the ALICE experiment. The main sources of non-statistical fluctuations are characterized based purely on experimental data with an unbiased method, as well as by using single high p(t) particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-k(t) jet finder. The influence of a low transverse momentum cut-off on particles used in the jet reconstruction is quantified by varying the minimum track p(t) between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with p(t) > 0.15 GeV/c, the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet finding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to 4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for varying particle momentum thresholds, by folding the measured fluctuations with steeply falling spectra.
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Measurements of the sphericity of primary charged particles in minimum bias proton-proton collisions at root s = 0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is measured in the plane perpendicular to the beam direction using primary charged tracks with p(T) > 0.5 GeV/c in vertical bar eta vertical bar < 0.8. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity (N-ch) is reported for events with different p(T) scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low N-ch, whereas the event generators show an opposite tendency. The combined study of the sphericity and the mean p(T) with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators.
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The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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The P-T-differential inclusive production cross section of the prompt charm-strange meson D-s(+) in the rapidity range vertical bar y vertical bar < 0.5 was measured in proton-proton collisions at root s = 7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98 x 10(8) events collected with a minimum-bias trigger. The corresponding integrated luminosity is L-int = 4.8 nb(-1). Reconstructing the decay D-s(+) -> phi pi(+) with phi -> K-K+, and its charge conjugate, about 480 D-s(+/-) mesons were counted, after selection cuts, in the transverse momentum range 2 < P-T < 12 GeV/c. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D-0, D+, D*+ and D-s(+)) were determined both as a function of p(T) and integrated over p(T)after extrapolating to full p(T) range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e(+)e(-), ep and pp interactions at various centre-of-mass energies. (C) 2012 CERN. Published by Elsevier By. All rights reserved.
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In this work we are concerned with the analysis and numerical solution of Black-Scholes type equations arising in the modeling of incomplete financial markets and an inverse problem of determining the local volatility function in a generalized Black-Scholes model from observed option prices. In the first chapter a fully nonlinear Black-Scholes equation which models transaction costs arising in option pricing is discretized by a new high order compact scheme. The compact scheme is proved to be unconditionally stable and non-oscillatory and is very efficient compared to classical schemes. Moreover, it is shown that the finite difference solution converges locally uniformly to the unique viscosity solution of the continuous equation. In the next chapter we turn to the calibration problem of computing local volatility functions from market data in a generalized Black-Scholes setting. We follow an optimal control approach in a Lagrangian framework. We show the existence of a global solution and study first- and second-order optimality conditions. Furthermore, we propose an algorithm that is based on a globalized sequential quadratic programming method and a primal-dual active set strategy, and present numerical results. In the last chapter we consider a quasilinear parabolic equation with quadratic gradient terms, which arises in the modeling of an optimal portfolio in incomplete markets. The existence of weak solutions is shown by considering a sequence of approximate solutions. The main difficulty of the proof is to infer the strong convergence of the sequence. Furthermore, we prove the uniqueness of weak solutions under a smallness condition on the derivatives of the covariance matrices with respect to the solution, but without additional regularity assumptions on the solution. The results are illustrated by a numerical example.
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L'obiettivo della tesi è la valutazione delle prestazioni delle migrazioni di reti di macchine virtuali. Ci si è concentrati sul trasferimento delle memorie di tali macchine virtuali in quanto è l'azione che maggiormente comporta l'impiego di tempo e risorse. Allo scopo, si è scelto l'approccio pre-copy in quanto utilizzato dagli hypervisor più diffusi. Si è costruito un modello in grado di descrivere il sistema in esame, analizzandolo sia dal punto di vista matematico, che simulativo. Proprio grazie ai simulatori proposti si sono confrontati i valori del tempo di migrazione e del downtime, indici fondamentali per la migrazione in tempo reale, nel caso di trasferimento in serie e in parallelo delle macchine di un insieme. Si sono considerate anche reti di macchine virtuali aventi diversa dimensione delle memorie, analizzando e confrontando, anche questa volta, gli indici di prestazione con quelli degli altri processi. Si è prestata particolare attenzione anche alla caratterizzazione della dirtying-rate, parametro importante dell'approccio pre-copy.
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Con l'avanzare della tecnologia, i Big Data hanno assunto un ruolo importante. In questo lavoro è stato implementato, in linguaggio Java, un software volto alla analisi dei Big Data mediante R e Hadoop/MapReduce. Il software è stato utilizzato per analizzare le tracce rilasciate da Google, riguardanti il funzionamento dei suoi data center.