321 research outputs found

    Comparison of ensemble simple feed forward neural network and deep learning neural network on Phishing Detection

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    Phishing attack is one of wide spread cybercrimes due to the advancement of the Internet. There are many forms of phishing attack and the most common one is through email. The attacker tries to pretend by sending email from an official organization or body to deceive the user in giving in their credential user name and password. The username and password are then used for malicious purpose. Many methods have been used to detect these phishing attacks; however, the attack evolved too quickly to be solved by manual approach. Therefore, automated phishing detection through artificial intelligence approach would be more feasible. In this paper, a comparison study for phishing detection between two neural networks which are the feedforward neural network and the deep learning neural network is carried out. The result is empirically evaluated to determine which method performs better in phishing detection

    Dynamical Breakdown of Symmetry in a (2+1) Dimensional Model Containing the Chern-Simons Field

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    We study the vacuum stability of a model of massless scalar and fermionic fields minimally coupled to a Chern-Simons field. The classical Lagrangian only involves dimensionless parameters, and the model can be thought as a (2+1) dimensional analog of the Coleman-Weinberg model. By calculating the effective potential, we show that dynamical symmetry breakdown occurs in the two-loop approximation. The vacuum becomes asymmetric and mass generation, for the boson and fermion fields takes place. Renormalization group arguments are used to clarify some aspects of the solution.Comment: Minor modifications in the text and figure

    Antiproton constraints on dark matter annihilations from internal electroweak bremsstrahlung

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    If the dark matter particle is a Majorana fermion, annihilations into two fermions and one gauge boson could have, for some choices of the parameters of the model, a non-negligible cross-section. Using a toy model of leptophilic dark matter, we calculate the constraints on the annihilation cross-section into two electrons and one weak gauge boson from the PAMELA measurements of the cosmic antiproton-to-proton flux ratio. Furthermore, we calculate the maximal astrophysical boost factor allowed in the Milky Way under the assumption that the leptophilic dark matter particle is the dominant component of dark matter in our Universe. These constraints constitute very conservative estimates on the boost factor for more realistic models where the dark matter particle also couples to quarks and weak gauge bosons, such as the lightest neutralino which we also analyze for some concrete benchmark points. The limits on the astrophysical boost factors presented here could be used to evaluate the prospects to detect a gamma-ray signal from dark matter annihilations at currently operating IACTs as well as in the projected CTA.Comment: 32 pages; 13 figure

    Sharp Trace Hardy-Sobolev-Maz'ya Inequalities and the Fractional Laplacian

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    In this work we establish trace Hardy and trace Hardy-Sobolev-Maz'ya inequalities with best Hardy constants, for domains satisfying suitable geometric assumptions such as mean convexity or convexity. We then use them to produce fractional Hardy-Sobolev-Maz'ya inequalities with best Hardy constants for various fractional Laplacians. In the case where the domain is the half space our results cover the full range of the exponent s(0,1)s \in (0,1) of the fractional Laplacians. We answer in particular an open problem raised by Frank and Seiringer \cite{FS}.Comment: 42 page

    Modelling of patient-specific femur with osteogenesis imperfecta to determine the fracture risk under various loads

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    Osteogenesis imperfecta (OI) is a fragile bone disease characterized by easy fractures. The femur consists of cortical and cancellous bone, each with different mechanical properties. Bone fractures often occur throughout patients’ lifetime. However, doctors still have no quantitative method to predict fractures. Therefore, this project’s purpose is to investigate the OI femoral fracture risk to help prevent fractures. The project consists of three sections; cortical and cancellous segmentation, reconstruction of 3D OI femoral model and finite element analysis (FEA) of the OI femur to obtain fracture risk. The fracture risk in daily activities and the fracture load were examined. All the stress values were judged by the fracture criteria, assumed as 115 MPa. The exercises that exerted force more than 6 times of body weight can cause fractures. In addition, the optimal compressive force and tensile force were 919.7 N and 912.1 N, respectively, while medial and lateral impact were 230.8 N. Cancellous bone was not affected even a fracture happen. Based on these findings, we can conclude that when the OI femur is subjected to lateral or medial forces, the femur breaks easily. The bone can be reconstructed into a solid body without having to separate bone into cortical and cancellous

    Screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

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    Objective: To examine the performance of screening for early-, preterm- and term-preeclampsia (PE) at 11 13 weeks’ gestation by maternal factors and combinations of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PLGF) and serum pregnancy associated plasma protein A (PAPP A). Methods The data for this study were derived from three previously reported prospective non intervention screening studies at 11+0 – 13+6 weeks’ gestation in a combined total of 61,174 singleton pregnancies, including 1,770 (2.9%) that developed PE. Bayes theorem was used to combine the prior distribution of the gestational age at delivery with PE, obtained from maternal characteristics, with various combinations of biomarker multiple of the median (MoM) values to derive the p patient specific risks of delivery with PE at <37 weeks’ gestation. The performance of such screening was estimated. Results In pregnancies that develop ed PE , compared to those without PE, the MoM values of UtA-PI and MAP were increased and PAPP A and PLGF were decreased and the deviation from normal was greater for early than late PE for all four biomarkers. Combined screening by maternal factors, UtA-PI, MAP and PLGF predicted 90% of early PE, 75% of preterm PE and 4 1 % of term PE, at screen positive rate of 10%; inclusion of PAPP A did not improve the performance of screening The performance of screening depended on the racial origin of the women; in screening by a combination of maternal factors, MAP, UtA-PI and PLGF and use of the risk cut off of 1 in 10 0 for PE at <37 weeks in Caucasian women, the screen positive rate was 10% and detection rates for early --, preterm and term PE were 88%, 69% and 40%, respectively. With the same method of screening and risk cut off in women of Afro Caribbean racial origin, the screen positive rate was 34% and detection rates for early --, preterm and term PE were 100%, 92% and 75%, respectively. Conclusion Screening by maternal factors and biomarkers at 11-13 weeks’ gestation can identify a high proportion of pregnancies that develop early- and preterm-PE

    PPPC 4 DM ID: A Poor Particle Physicist Cookbook for Dark Matter Indirect Detection

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    We provide ingredients and recipes for computing signals of TeV-scale Dark Matter annihilations and decays in the Galaxy and beyond. For each DM channel, we present the energy spectra of electrons and positrons, antiprotons, antideuterons, gamma rays, neutrinos and antineutrinos e, mu, tau at production, computed by high-statistics simulations. We estimate the Monte Carlo uncertainty by comparing the results yielded by the Pythia and Herwig event generators. We then provide the propagation functions for charged particles in the Galaxy, for several DM distribution profiles and sets of propagation parameters. Propagation of electrons and positrons is performed with an improved semi-analytic method that takes into account position-dependent energy losses in the Milky Way. Using such propagation functions, we compute the energy spectra of electrons and positrons, antiprotons and antideuterons at the location of the Earth. We then present the gamma ray fluxes, both from prompt emission and from Inverse Compton scattering in the galactic halo. Finally, we provide the spectra of extragalactic gamma rays. All results are available in numerical form and ready to be consumed.Comment: 57 pages with many figures and tables. v4: updated to include a 125 higgs boson, computation and discussion of extragalactic spectra corrected, some other typos fixed; all these corrections and updates are reflected on the numerical ingredients available at http://www.marcocirelli.net/PPPC4DMID.html they correspond to Release 2.

    Measuring Black Hole Spin using X-ray Reflection Spectroscopy

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    I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009
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