257 research outputs found

    THE ROLE OF GLOBAL RISK AVERSION IN EXPLAINING LATIN AMERICAN SOVEREIGN SPREADS

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    This paper explores the role of global risk aversion (GRA) and its main determinants, US economic growth and the US government bond yield, in explaining developments in Latin American sovereign spreads. We find that GRA is significant and positively related to Latin American sovereign spreads and that its impact varies across countries and over time. Those countries with the lowest risk, such as Chile, are more affected by GRA. Its relevance has also risen over time, particularly since the sharp change in the perception of risk stemming from the Enron scandal. Finally, an increase in both US economic growth and the US government bond yield are found to reduce sovereign spreads in most Latin American countries, while the opposite is true for US short-term interest rates.GLOBAL RISK AVERSION, SOVEREIGN SPREADS,LATIN AMERICA

    THE ROLE OF GLOBAL RISK AVERSION IN EXPLAINING LATIN AMERICAN SOVEREIGN SPREADS

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    This paper assesses empirically whether global risk aversion (GRA) and some if its determinants (US economic growth and the US long term interest rates) explain developments in Latin American sovereign spreads. We find that GRA is significant and positively related to Latin American sovereign spreads and that its impact varies across countries and over time. Chile, with a lower sovereign risk, is relatively more affected. The opposite is true for Argentina, Ecuador and Venezuela. In addition, the influence of GRA on spreads has risen since the Enron scandal. Finally, both an increase in US economic growth and US long term interest rates are found to reduce spreads while the opposite is true for US short-term interest rates.global risk aversion, sovereign spreads, Latin America

    A neural-visualization IDS for honeynet data

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    Neural intelligent systems can provide a visualization of the network traffic for security staff, in order to reduce the widely known high false-positive rate associated with misuse-based Intrusion Detection Systems (IDSs). Unlike previous work, this study proposes an unsupervised neural models that generate an intuitive visualization of the captured traffic, rather than network statistics. These snapshots of network events are immensely useful for security personnel that monitor network behavior. The system is based on the use of different neural projection and unsupervised methods for the visual inspection of honeypot data, and may be seen as a complementary network security tool that sheds light on internal data structures through visual inspection of the traffic itself. Furthermore, it is intended to facilitate verification and assessment of Snort performance (a well-known and widely-used misuse-based IDS), through the visualization of attack patterns. Empirical verification and comparison of the proposed projection methods are performed in a real domain, where two different case studies are defined and analyzedRegional Government of Gipuzkoa, the Department of Research, Education and Universities of the Basque Government, and the Spanish Ministry of Science and Innovation (MICINN) under projects TIN2010-21272-C02-01 and CIT-020000-2009-12 (funded by the European Regional Development Fund). This work was also supported in the framework of the IT4Innovations Centre of Excellence project, reg. no. CZ.1.05/1.1.00/02.0070 supported by the Operational Program 'Research and Development for Innovations' funded through the Structural Funds of the European Union and the state budget of the Czech RepublicElectronic version of an article published as International Journal of Neural Systems, Volume 22, Issue 02, April 2012 10.1142/S0129065712500050 ©copyright World Scientific Publishing Company http://www.worldscientific.com/worldscinet/ijn

    Visualization and clustering for SNMP intrusion detection

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    Accurate intrusion detection is still an open challenge. The present work aims at being one step toward that purpose by studying the combination of clustering and visualization techniques. To do that, the mobile visualization connectionist agent-based intrusion detection system (MOVICAB-IDS), previously proposed as a hybrid intelligent IDS based on visualization techniques, is upgraded by adding automatic response thanks to clustering methods. To check the validity of the proposed clustering extension, it has been applied to the identification of different anomalous situations related to the simple network management network protocol by using real-life data sets. Different ways of applying neural projection and clustering techniques are studied in the present article. Through the experimental validation it is shown that the proposed techniques could be compatible and consequently applied to a continuous network flow for intrusion detectionSpanish Ministry of Economy and Competitiveness with ref: TIN2010-21272-C02-01 (funded by the European Regional Development Fund) and SA405A12-2 from Junta de Castilla y Leon

    Herramienta web para la auto-evaluaciĂłn en ejercicios de programaciĂłn

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    PĂłster presentado en: VIII Jornadas de InnovaciĂłn Docente de la UBU, Burgos, 5 de abril de 2016, organizadas por el Instituto de FormaciĂłn e InnovaciĂłn Educativa-IFIE de la Universidad de Burgo

    Mutating network scans for the assessment of supervised classifier ensembles

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    As it is well known, some Intrusion Detection Systems (IDSs) suffer from high rates of false positives and negatives. A mutation technique is proposed in this study to test and evaluate the performance of a full range of classifier ensembles for Network Intrusion Detection when trying to recognize new attacks. The novel technique applies mutant operators that randomly modify the features of the captured network packets to generate situations that could not otherwise be provided to IDSs while learning. A comprehensive comparison of supervised classifiers and their ensembles is performed to assess their generalization capability. It is based on the idea of confronting brand new network attacks obtained by means of the mutation technique. Finally, an example application of the proposed testing model is specially applied to the identification of network scans and related mutationsSpanish Ministry of Science and Innovation (TIN2010-21272-C02-01 and CIT-020000-2009-12) (both funded by the European Regional Development Fund). The authors would also like to thank the vehicle interior manufacturer, Grupo Antolin Ingenieria S. A., within the framework of the MAGNO2008 - 1028.- CENIT. Project also funded by the MICINN, the Spanish Ministry of Science and Innovation (PID 560300-2009-11) and the Regional Government of Castile-Leon (CCTT/10/BU/0002). This work was also supported in the framework of the IT4Innovations Centre of Excellence project, reg. no. (CZ.1.05/1.1.00/02.0070) supported by the Operational Program 'Research and Development for Innovations' funded through the Structural Funds of the European Union and the state budget of the Czech Republic.This is a pre-copyedited, author-produced PDF of an article accepted for publication in Logic Journal of the IGPL following peer review. The version of record: Javier Sedano, Silvia Gonzålez, Álvaro Herrero, Bruno Baruque, and Emilio Corchado, Mutating network scans for the assessment of supervised classifier ensembles, Logic Jnl IGPL, first published online September 3, 2012, doi:10.1093/jigpal/jzs037 is available online at: http://jigpal.oxfordjournals.org/content/early/2012/09/03/jigpal.jzs03

    Photoexcited-induced sensitivity of InGaAs surface QDs to environment

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    A detailed analysis of the impact of illumination on the electrical response of In0.5Ga0.5As surface nanostructures is carried out as a function of different relative humidity conditions. The importance of the surface-to-volume ratio for sensing applications is once more highlighted. From dark-to-photo conditions, the sheet resistance (SR) of a three-dimensional In0.5Ga0.5As nanostructure decays two orders of magnitude compared with that of a two-dimensional nanostructure. The electrical response is found to be vulnerable to the energy of the incident light and the external conditions. Illuminating with high energy light translates into an SR reduction of one order of magnitude under humid atmospheres, whereas it remains nearly unchanged under dry environments. Conversely, lighting with energy below the bulk energy bandgap, shows a negligible effect on the electrical properties regardless the local moisture. Both illumination and humidity are therefore needed for sensing. Photoexcited carriers can only contribute to conductivity if surface states are inactive due to water physisorption. The strong dependence of the electrical response on the environment makes these nanostructures very suitable for the development of highly sensitive and efficient sensing devices

    El desarrollo de las redes académicas en América Latina: los casos de Argentina y México

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    The Latin American academic networks have had a troublesome development. The first section of this article focuses on the privatization processes in the Argentine and Mexican telecommunications sectors. In the second part, we present a study about added value electronic resources, considering the Online Public Access Catalogs (OPACs).The Latin American academic networks have had a troublesome development. The first section of this article focuses on the privatization processes in the Argentine and Mexican telecommunications sectors. In the second part, we present a study about added value electronic resources, considering the Online Public Access Catalogs (OPACs)

    Calculation of multiple eigenvalues of the neutron diffusion equation discretized with a parallelized finite volume method

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    [EN] The spatial distribution of the neutron flux within the core of nuclear reactors is a key factor in nuclear safety. The easiest and fastest way to determine it is by solving the eigenvalue problem of the neutron diffusion equation, which only contains spatial derivatives. The approximation of these derivatives is performed by discretizing the geometry and using numerical methods. In this work, the authors used a finite volume method based on a polynomial expansion of the neutron flux. Once these terms are discretized, a set of matrix equations is obtained, which constitutes the eigenvalue problem. A very effective class of methods for the solution of eigenvalue problems are those based on projection onto a low-dimensional subspace, such as Krylov subspaces. Thus, the SLEPc library was used for solving the eigenvalue problem by means of the Krylov-Schur method, which also uses projection methods of PETSc for solving linear systems. This work includes a complete sensitivity analysis of different issues: mesh, polynomial terms, linear systems solvers and parallelization.This work has been partially supported by the Spanish Ministerio de Eduacion Cultura y Deporte under the grant FPU13/01009, the Spanish Ministerio de Ciencia e Innovacion under the project ENE2014-59442-P, the Spanish Ministerio de Economia y Competitividad and the European Fondo Europeo de Desarrollo Regional (FEDER) under the project ENE2015-68353-P (MINECO/FEDER), the Generalitat Valenciana under the project PROMETEOII/2014/008, and the Spanish Ministerio de Economia y Competitividad and the European Fondo Europeo de Desarrollo Regional (FEDER) under the project TIN2016-075985-P.Bernal-Garcia, A.; Roman, JE.; MirĂł Herrero, R.; VerdĂș MartĂ­n, GJ. (2018). Calculation of multiple eigenvalues of the neutron diffusion equation discretized with a parallelized finite volume method. Progress in Nuclear Energy. 105:271-278. https://doi.org/10.1016/j.pnucene.2018.02.006S27127810

    Synthesis and characterization of GaAsSb-capped InAs-based QDIPs

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    Quantum dot infrared photodetectors (QDIPs) are very attractive for infrared imaging applications due to its promising features such as high temperature operation, normal incidence response and low dark current [1]. However, the key issue is to obtain a high quality active region which requires a structural optimization of the nanostructures. With using GaAsSb capping layer, the optical properties, such as the PL intensity and its full width at half maximum (FWHM), of InAs QDs have been improved in the range between 1.15 and 1.5 m, because of the reduction of the compressive strain in QDs and the increment of QD height [2]. In this work, we have demonstrated strong and narrow intraband photoresponse spectra from GaAsSb-capped InAs-based QDIP
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