30,488 research outputs found
Artificial Immune Systems and Fuzzy Logic to Detect Flooding Attacks in Software-Defined Networks
No full textSoftware-defined Networking (SDN) has been discovered as an architecture that uses applications to make networks flexible and centrally controlled. Although SDN provides innovative management, it still susceptible to attacks daily. Traditional detection approaches may not be sufficient to contain these threats. In this paper, we present an Artificial Immune System based IDS named AIS-IDS, which is inspired by the human body's defense cells. AIS-IDS can detect variations in network behavior and identify attacks without prior knowledge about them. Along with AIS, the fuzzy logic is applied on detection to minimize the uncertainty when there is no clear boundary between anomalous and normal traffic behavior. We have simulated portscan and flooding attacks as well as used a public dataset with several types of DDoS attacks to assess our proposal. We compared the AIS-IDS performance with Naive Bayes, k-nearest neighbors, and the Local Outlier Factor. The AIS-IDS outperformed the compared algorithms, achieving f-measure rates 99.97% and 92.28% when submitted to a simulated and a public dataset, respectively
Unsupervised online anomaly detection in Software Defined Network environments
No full textSoftware Defined Networking (SDN) simplifies network management and significantly reduces operational costs. SDN removes the control plane from forwarding devices (e.g., routers and switches) and centralizes this plane in a controller, enabling the management of the network forwarding decisions by programming the control plane with a high-level language. However, its centralized architecture may be compromised by flooding attacks, such as Distributed Denial of Service (DDoS) and portscan. Facing this challenge, we propose an Intrusion Detection System (IDS) based on online clustering to detect attacks in an evolving SDN network taking advantage of the entropy of source and destination IP addresses and ports. Our proposal is focused on avoiding the demand for labeling and previous knowledge to provide a practical and accurate method to address real-life online scenarios. Moreover, our proposal paves the way for a comprehensive analysis by projecting the cluster's structure over the feature space, providing insights on intensity, seasonality, and attack type. Our experiments were carried out with the DenStream algorithm in several databases attacked by DDoS and portscan with different intensities, durations, and overlapping patterns. When comparing DenStream performance to Half-Space-Trees, an accurate online one-class classification algorithm for anomaly detection, it was possible to expose the capacity of our unsupervised proposal, overcoming the one-class solution, and reaching f-measure rates above 99.60%
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Elaboration on Kwapien's theorem: Representing bounded mean zero functions f as coboundary f = g ◦ T − g
No full textIn [8] Kwapien proved that every mean zero function f ∈ L∞[0, 1] we can write as f = g ◦ T − g for some g ∈ L∞[0, 1] and some measure preserving transformation T of [0, 1]. However, as was discovered in [4] there is a gap in the proof for the case that f is not continuous. The aim of this bachelor thesis is filling in that gap in the proof. We first extend Kwapien’s proof for continuous functions to certain other measure spaces. Thereafter, we use the method of proof suggested by Kwapien, to proof the theorem for mean zero function f ∈ L∞[0, 1] for which λ(f−1({x})) = 0 for all x ∈ R. Using this result we then proof that every mean zero function f ∈ L∞[0, 1] can be written as a sum f =(g1 ◦ T1 − g1) + (g2 ◦ T2 − g2) where g1, g2 ∈ L∞[0, 1] and where T1, T2 are measure preserving transformations of [0, 1]. We finish this thesis with an application of Kwapien’s theorem in the study to singular traces Applied Mathematic
TWO-PHOTON SPECTROSCOPY OF THE AND STATES OF
No full text Research supported by AFOSR K. Hoshiba et al. J. Phys. B 18, 1.875 (1985). T. Sakai et al., J. Phys. B. 21, 229 (1988).Author Institution: Molecular Physics Laboratory, SRI InternationalThe and states of are excited from the ground by two photons near 207 nm and detected by vuv fluorescence or by ionization by a third photon. The laser source for these measurements is an excimer-pumped dye laser operating with PBBO dye at 415 nm. This light is doubled in a crystal and focused into a cell containing a mixture of in He. The uv wavelengths were calibrated against the (3.0) band in NO, which was calibrated against in the visible. Vibrational levels were observed in the state and in the state, based on the previous electron-impact , and partially resolved rotationally (the effective excitation linewidth is ). These assignments are supported by simulations of the two-photon excitation spectra. Although the fluorescence has not yet been spectrally resolved, we believe that it arises predominantly from the triplet state even when the singlet is initially excited. In the latter case, the fluorescence is temporally delayed, and increases in intensity as the He density is increased. The two-phonon excitation scheme we have developed should be useful in investigating the kinetics of the 158 nm laser, which is believed to arise from a transition from the outer well of the state to a weakly bound state correlating to ground state atoms.$^{2}
Free product subgroups between Chevalley groups G(Φ,F) and G(Φ,F[t])
No full textAbstractWe investigate subgroups of a Chevalley group G=G(Φ,A) over a ring A, containing its elementary subgroup E=E(Φ,F) over a subring F⊆A. Assume that the root system Φ is simply laced and A=F[t] is a polynomial ring. We show that if G is of adjoint type, then there exists an element g∈E(Φ,A) such that 〈g,E(Φ,F)〉=〈g〉*E(Φ,F), where 〈X〉 denotes the subgroup, generated by a set X, and * stands for the free product.It follows that under the above assumptions the lattice L=L(E,G) is not standard. Moreover, combining the above result with theorems of Nuzhin and the author one obtains a necessary and sufficient condition for L to be standard provided that A and F are fields of characteristic not 2 and Φ≠G2
f(G,T) and its Cosmological Implications
No full textA coupled formulation of the Gauss-Bonnet invariant term G and the
energy momentum trace T term provide a modified f(G,T) gravity,
has been analyzed in this study. The functional form for the
f(G,T) gravity has been taken as f(G,T)=αT+ βGThe presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
b-Generalized Skew Derivations on Multilinear Polynomials in Prime Rings
No full textLet R be a prime ring of characteristic different from 2, Qr be its right Martindale quotient ring and C be its extended centroid. In this paper we define b-generalized skew derivations of prime rings. Then we describe all possible forms of two b-generalized skew derivations F and G satisfying the condition F(x)x − xG(x) = 0, for all x ∈ S, where S is the set of the evaluations of a multilinear polynomial f(x1, ..., xn) over C with n non-commuting variables. Several potential research topics related to our current work are also presented. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG
Corrigendum to “Presence and function of kisspeptin/KISS1R system in swine ovarian follicles” (Theriogenology (2018) 115 (1–8), (S0093691X1830147X), (10.1016/j.theriogenology.2018.04.006))
No full textThe authors regret the following changes to the author group G. Basinia, F. Grassellia, S. Bussolatia, R. Ciccimarraa, M. Maranesib, A. Bufalarib, C. Dall'Agliob, F. Parilloc,#, M. Zeranib,c,*. a Dipartimento di Scienze Mediche Veterinarie, Università di Parma, 43126 Parma, Italy. b Dipartimento di Medicina Veterinaria, Università di Perugia, 06126 Perugia Italy. c Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, 62024 Matelica Italy. # Deceased. * Corresponding author: tel.: +39 0755857642; fax +39 0755857654. E-mail address: [email protected] (M. Zerani). And to the acknowledgements and figures
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
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