421 research outputs found

    Near real-time security system applied to SDN environments in IoT networks using convolutional neural network

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    [EN] The Internet of Things (IoT) paradigm brings new and promising possibilities for services and products. The heterogeneity of IoT devices highlights the inefficiency of traditional networks' structures to support their specific requirements due to their lack of flexibility. Thus, Software-defined Networking (SDN) is commonly associated with IoT since this architecture provides a more flexible and manageable network environment. As shown by recent events, IoT devices may be used for large scale Distributed Denial of Service (DDoS) attacks due to their lack of security. This kind of attack is commonly detected and mitigated at the destination-end network but, due to the massive volume of information that IoT botnets generate, this approach is becoming impracticable. We propose in this paper a near real-time SDN security system that both prevents DDoS attacks on the source-end network and protects the sources SDN controller against traffic impairment. For this, we apply and test a Convolutional Neural Network (CNN) for DDoS detection, and describe how the system could mitigate the detected attacks. The performance outcomes were performed in two test scenarios, and the results pointed out that the proposed SDN security system is promising against next-generation DDoS attacks. (C) 2020 Published by Elsevier Ltd.This study was financed in part by the National Council for Scientific and Technological Development (CNPq) of Brazil under Grants 310668/2019-0 and 309335/2017-5; by the Ministerio de Economia y Competitividad in the "Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia, Subprograma Estatal de Generacion de Conocimiento" within the project under Grant TIN2017-84802-C2-1-P; by FCT/MCTES through national funds and when applicable co-funded EU funds under the Project UIDB/EEA/50008/2020; and by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) by the granting of a scholarship through the "Programa de Doutorado Sanduche no Exterior (PDSE) 2019". Finally, this work was supported by Federal University of Parana(UFPR) under Project Banpesq/2014016797.De Assis, MVO.; Carvalho, LF.; Rodrigues, JJPC.; Lloret, J.; Proenca Jr, ML. (2020). Near real-time security system applied to SDN environments in IoT networks using convolutional neural network. Computers & Electrical Engineering. 86:1-16. https://doi.org/10.1016/j.compeleceng.2020.1067381168

    Revisiting the S-matrix approach to the open superstring low energy effective lagrangian

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    The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic αN{\alpha'}^N order terms, it is necessary to know the open string (tree level) (N+2)(N+2)-point amplitude of massless bosons, at least expanded at that order in α\alpha'. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring nn-point amplitude is needed to find all the αN{\alpha'}^N order terms. In this `revisited' S-matrix approach we have checked that, at least up to α4{\alpha'}^4 order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the NN-point amplitudes and that important informations can be inferred, at least up to α4{\alpha'}^4 order, by only using the (tree level) 4-point amplitude.Comment: 34 pages, 3 figure, Submitted on Aug 4, 2012, Published on Oct 15, 201

    Epidemiology of Salmonella in two different finishing swine barns in Brazil

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    Many finishing barns in Brazil have lamina d\u27agua , a continuous water flow at the back of solid-floored adjacent pens. Prevalence of Salmonella shedding and environmental contamination in finishing barns with lamina d\u27agua and without it were assessed through a cross sectional study conducted in 6 farms. No difference was found between the two systems. Sixteen Salmonella strains were isolated from 4 farms, comprising 6 serotypes: S. Agona, S. Typhimurium, S. Senftenberg, S. Sandiego, S. Rissen and S. Javiana. Serotypes varied among farms and differed from those recently identified in Brazil. Epidemiology of salmonella in swine farms is complex and might vary between farms or even between barns in a same farm

    Antimicrobial resistance patterns of Salmonella isolated from finishing pigs and environmental samples

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    The aim of this study was to determine the antimicrobial resistance patterns of Salmonella isolates from pigs and environmental samples collected from modern swine facilities in Brazil. Sixteen samples from a total of 1,026 were positive to Salmonella and six serotypes were identified: Salmonella Typhimurium (1), Salmonella Agona (5), Salmonella Sandiego (4), Salmonella Rissen (1), Salmonella Senftenberg ( 4) and Salmonella Javiana (I). Resistance patterns were different among serotypes, but different isolates from a single serotype had the same antimicrobial pattern. The highest percentage of resistance was to tetracycline (100%), streptomycin (100%), nalidixic acid (100%), cefotaxime (12.5) and tobramycin ( 12.5). All serotypes were I 00% susceptible to ceftriaxone, norfloxacin, ciprofloxacin, ampicillin, gentamycin and chloramphenicol. Intermediate resistance to neomycin (93.5%), amikacin (12.5%) and trimethoprim (12.5%) was seen. The high resistance to tetracycline and streptomycin may be due to its extensive use in pig production

    Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter

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    Azimuthal angle \Delta\phi correlations are presented for charged hadrons from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200 GeV. With increasing p_T, the away-side distribution evolves from a broad to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side can be divided into a partially suppressed "head" region centered at Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi +/- 1.1. The p_T spectrum for the "head" region softens toward central collisions, consistent with the onset of jet quenching. The spectral slope for the "shoulder" region is independent of centrality and trigger p_T, which offers constraints on energy transport mechanisms and suggests that the "shoulder" region contains the medium response to energetic jets.Comment: 420 authors from 58 institutions, 6 pages, 4 figures. Submitted to Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    The contrast-enhanced Doppler ultrasound with perfluorocarbon exposed sonicated albumin does not improve the diagnosis of renal artery stenosis compared with angiography

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    There are no studies investigating the effect of the contrast infusion on the sensitivity and specificity of the main Doppler criteria of renal artery stenosis (RAS). Our aim was to evaluate the accuracy of these Doppler criteria prior to and following the intravenous administration of perfluorocarbon exposed sonicated albumin (PESDA) in patients suspected of having RAS. Thirty consecutive hypertensive patients (13 males, mean age of 57 ± 10 years) suspected of having RAS by clinical clues, were submitted to ultrasonography (US) of renal arteries before and after enhancement using continuous infusion of PESDA. All patients underwent angiography, and haemodynamically significant RAS was considered when ≥50%. At angiography, it was detected RAS ≥50% in 18 patients, 5 with bilateral stenosis. After contrast, the examination time was slightly reduced by approximately 20%. In non-enhanced US the sensitivity was better when based on resistance index (82.9%) while the specificity was better when based on renal aortic ratio (89.2%). The predictive positive value was stable for all indexes (74.0%–88.0%) while negative predictive value was low (44%–51%). The specificity and positive predictive value based on renal aortic ratio increased after PESDA injection respectively, from 89 to 97.3% and from 88 to 95%. In hypertensives suspected to have RAS the sensitivity and specificity of Duplex US is dependent of the criterion evaluated. Enhancement with continuous infusion of PESDA improves only the specificity based on renal aortic ratio but do not modify the sensitivity of any index

    Biochemical and genetic analysis of butyrylcholinesterase (BChE) in a family, due to prolonged neuromuscular blockade after the use of succinylcholine

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    Butyrylcholinesterase (BChE) is a plasma enzyme that catalyzes the hydrolysis of choline esters, including the muscle-relaxant succinylcholine and mivacurium. Patients who present sustained neuromuscular blockade after using succinylcholine usually carry BChE variants with reduced enzyme activity or an acquired BChE deficiency. We report here the molecular basis of the BCHE gene underlying the slow catabolism of succinylcholine in a patient who underwent endoscopic nasal surgery. We measured the enzyme activity of BChE and extracted genomic DNA in order to study the promoter region and all exons of the BCHE gene of the patient, her parents and siblings. PCR products were sequenced and compared with reference sequences from GenBank. We detected that the patient and one of her brothers have two homozygous mutations: nt1615 GCA > ACA (Ala539Thr), responsible for the K variant, and nt209 GAT > GGT (Asp70Gly), which produces the atypical variant A. Her parents and two of her brothers were found to be heterozygous for the AK allele, and another brother is homozygous for the normal allele. Sequence analysis of exon 1 including 5′UTR showed that the proband and her brother are homozygous for –116GG. The AK/AK genotype is considered the most frequent in hereditary hypocholinesterasemia (44%). This work demonstrates the importance of defining the phenotype and genotype of the BCHE gene in patients who are subjected to neuromuscular block by succinylcholine, because of the risk of prolonged neuromuscular paralysis

    Clonal diversity and conservation genetics of the medicinal plant Carapichea ipecacuanha (Rubiaceae)

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    The roots of the understorey shrub Carapichea ipecacuanha (ipecac) have medicinal properties, and the uprooting of wild plants has supplied most of the world demand for this species. Although under severe population decline, C. ipecacuanha lacks legal protection. In the wild, the aerial stems of ipecac clump together to form clusters with well-defined borders. Cluster size may range from several to hundreds of aerial stems. To investigate the extent of clonality among aerial stems in ipecac clusters, we sampled 50 wild clusters (a total of 291 aerial stems) and screened them with 89 inter-simple sequence repeat (ISSR) markers. The 291 aerial stems were grouped into 42 putative clones. The clonal groups generally consisted of aerial stems from the same cluster, and there was little or no genetic differentiation among aerial stems at the cluster level. These findings suggest that strategies designed to conserve ipecac in situ should not rely upon census data, which are based on the number of aerial stems per cluster and the number of clusters per population, because such data greatly underestimate the species effective population size and genetic diversity. Our results also indicate that this species needs protection at a federal level

    High p_T Direct Photon and pi^0 Triggered Azimuthal Jet Correlations in sqrt(s)=200 GeV p+p Collisions

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    Correlations of charged hadrons of 1 < pT < 10 GeV/c with high pT direct photons and pi^ 0 mesons in the range 5 <pT < 15 GeV/c are used to study jet fragmentation in the photon+jet and di-jet channels, respectively. The magnitude of the partonic transverse momentum, kT, is obtained by comparing to a model incorporating a Gaussian kT smearing. The sensitivity of the associated charged hadron spectra to the underlying fragmentation function is tested and the data are compared to calculations using recent global fit results. The shape of the direct photon-associated hadron spectrum as well as its charge asymmetry are found to be consistent with a sample dominated by quark-gluon Compton scattering. No significant evidence of fragmentation photon correlated production is observed within experimental uncertainties.Comment: 431 authors, 18 pages, 18 figures, 4 tables, RevTeX-4. Submitted to Physical Review D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Transverse momentum dependence of J/psi polarization at midrapidity in p+p collisions at sqrt(s)=200 GeV

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    We report the measurement of the transverse momentum dependence of inclusive J/psi polarization in p+p collisions at sqrt(s)=200 GeV performed by the PHENIX Experiment at RHIC. The polarization is studied in the helicity, Gottfried-Jackson, and Collins-Soper frames for p_T < 5 GeV/c and |y| < 0.35. The J/psi polarization in the helicity and Gottfried-Jackson frames is consistent with zero for all transverse momenta, with a slight (1.8 sigma) trend towards longitudinal polarization for transverse momenta above 2 GeV/c. No conclusion is allowed due to the limited acceptance in the Collins-Soper frame and the uncertainties of the current data. The results are compared to observations for other collision systems and center of mass energies and to different quarkonia production models.Comment: 384 authors from 62 institutions, 11 pages, 9 figures, 2 tables. v2 is expanded version submitted to Physical Review D. Plain text data tables for the points plotted in figures are available at http://www.phenix.bnl.gov/papers.htm
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