1,774 research outputs found

    A Security Pattern for Cloud service certification

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    Cloud computing is interesting from the economic, operational and even energy consumption perspectives but it still raises concerns regarding the security, privacy, governance and compliance of the data and software services offered through it. However, the task of verifying security properties in services running on cloud is not trivial. We notice the provision and security of a cloud service is sensitive. Because of the potential interference between the features and behavior of all the inter-dependent services in all layers of the cloud stack (as well as dynamic changes in them). Besides current cloud models do not include support for trust-focused communication between layers. We present a mechanism to implement cloud service certification process based on the usage of Trusted Computing technology, by means of its Trusted Computing Platform (TPM) implementation of its architecture. Among many security security features it is a tamper proof resistance built in device and provides a root of trust to affix our certification mechanism. We present as a security pattern the approach for service certification based on the use TPM.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Structural Complexity and Phonon Physics in 2D Arsenenes

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    In the quest for stable 2D arsenic phases, four different structures have been recently claimed to be stable. We show that, due to phonon contributions, the relative stability of those structures differs from previous reports and depends crucially on temperature. We also show that one of those four phases is in fact mechanically unstable. Furthermore, our results challenge the common assumption of an inverse correlation between structural complexity and thermal conductivity. Instead, a richer picture emerges from our results, showing how harmonic interactions, anharmonicity and symmetries all play a role in modulating thermal conduction in arsenenes. More generally, our conclusions highlight how vibrational properties are an essential element to be carefully taken into account in theoretical searches for new 2D materials

    The OTELO survey: a case study of [O III] λ 4959,5007 emitters at <z>=0.83

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    Context. The OSIRIS Tunable Filter Emission Line Object (OTELO) survey is a very deep, blind exploration of a selected region of the Extended Groth Strip and is designed for finding emission-line sources (ELSs). The survey design, observations, data reduction, astrometry, and photometry, as well as the correlation with ancillary data used to obtain a final catalogue, including photo-z estimates and a preliminary selection of ELS, were described in a previous contribution. Aims. Here, we aim to determine the main properties and luminosity function (LF) of the [O III] ELS sample of OTELO as a scientific demonstration of its capabilities, advantages, and complementarity with respect to other surveys. Methods. The selection and analysis procedures of ELS candidates obtained using tunable filter pseudo-spectra are described. We performed simulations in the parameter space of the survey to obtain emission-line detection probabilities. Relevant characteristics of [O III] emitters and the LF ([O III]), including the main selection biases and uncertainties, are presented. Results. From 541 preliminary emission-line source candidates selected around z = 0.8, a total of 184 sources were confirmed as [O III] emitters. Consistent with simulations, the minimum detectable line flux and equivalent width in this ELS sample are ∼5 × 10^(−19) erg s^(−1) cm^(2) and ∼6 Å, respectively. We are able to constrain the faint-end slope (α = −1.03 ± 0.08) of the observed LF ([O III]) at a mean redshift of z = 0.83. This LF reaches values that are approximately ten times lower than those from other surveys. The vast majority (84%) of the morphologically classified [O III] ELSs are disc-like sources, and 87% of this sample is comprised of galaxies with stellar masses of M* < 10^(10) Mͼ

    Galaxy evolution studies observing emission line galaxies with the GTC

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    Emission line galaxies are the most easily detected and studied objects in the high redshift Universe. They are being used to trace the evolution of the critical observables of the Universe such as star formation rate densities, starburst properties, and abundances. The GTC will b e a very powerful tool for studying the evolution of emission line galaxy populations at different redshifts. Large surveys, such as OTELO, carried out with OSIRIS and extended by follow-up spectroscopic studies in the near infrared using EMIR will enable the GTC to make a major impact in extragalactic astronomy

    "Arenaria cerastioides" Poiret en España

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    Se cita la presencia de Arenaria cerastioides Poiret en el Sur de España, incluyendo descripción y comentario de sus caracteres diferenciales con Arenaria hispanica Sprengel.Arenaria cerastioides Poiret is recorded from South Spain. Description, commentary and differencial characters from Arenaria hispanica Sprengel are included

    Gran Telescopio Canarias observations of an overdense region of Lyman alpha emitters at z=6.5

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    We present the results of our search near the end of the Reionization Epoch for faint galaxies. This has been done using very deep OSIRIS images obtained at the Gran Telescopio Canarias (GTC). Our observations focus around two close, massive Lyman alpha emitters (LAEs) at redshift 6.5, discovered in the SXDS field within a large-scale overdense region. The total GTC observing time in three medium band filters (F883w35, F913w25 and F941w33) is over 34 h covering 7.0 x 8.5 arcmin(2) (or similar to 30 000 Mpc(3) at z = 6.5). In addition to the two spectroscopically confirmed LAEs in the field, we have identified 45 other LAE candidates. The preliminary luminosity function derived from our observations, assuming a spectroscopic confirmation success rate of 2/3 as in previous surveys, suggests this area is about 2 times denser than the general field galaxy population at z = 6.5. If confirmed spectroscopically, our results will imply the discovery of one of the earliest protoclusters in the Universe, which will evolve to resemble the most massive galaxy clusters today

    The Asian and European Banking Systems: The case of Spain in the quest for development and stability

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    After a brief review of the literature on the determinants of financial development, the paper reviews the Asian and European financial systems in terms of their size and efficiency. It also compares the steps taken in the two regions in the quest for financial development and stability, which in a few cases are very similar but differ markedly in others. While there has been a clear move towards a more balanced financial structure in both regions, financial liberalization, as well as the strengthening of bank regulation and supervision occurred later in Asia and with a different speed and sequencing. The most striking difference between the two areas is the degree of international - and regional – financial integration, much lower for Asia. Finally, the case of Spain - as a European country with a finance-led convergence process - is analyzed in more detail. Lessons are drawn from the Spanish experience for Asian countries.Financial development, financial liberalization, Spanish financial system

    SerAPI: Machine-Friendly, Data-Centric Serialization for COQ: Technical Report

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    We present SerAPI, a library and protocol for machine-friendly communication with the COQ proof assistant. SerAPI is implemented using Ocaml's PPX pre-processing technology, and it is specifically targeted to reduce implementation burden for tools such as Integrated Development Environments or code analyzers. SerAPI tries to address common problems that tools interacting with COQ face, providing a uniform and data-centric way to access term representations, proof state, and an extended protocol for document building. SerAPI is work in progress but fully functional. It has been adopted by the jsCoq and PeaCoq Integrated Development Environments , and supports running inside a web browser instance. For the near future, we are focused on extending the document protocol and providing advanced display abilities to clients
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