850 research outputs found

    Continuous implicit authentication for mobile devices based on adaptive neuro-fuzzy inference system

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.As mobile devices have become indispensable in modern life, mobile security is becoming much more important. Traditional password or PIN-like point-of-entry security measures score low on usability and are vulnerable to brute force and other types of attacks. In order to improve mobile security, an adaptive neuro-fuzzy inference system(ANFIS)-based implicit authentication system is proposed in this paper to provide authentication in a continuous and transparent manner. To illustrate the applicability and capability of ANFIS in our implicit authentication system, experiments were conducted on behavioural data collected for up to 12 weeks from different Android users. The ability of the ANFIS-based system to detect an adversary is also tested with scenarios involving an attacker with varying levels of knowledge. The results demonstrate that ANFIS is a feasible and efficient approach for implicit authentication with an average of 95% user recognition rate. Moreover, the use of ANFIS-based system for implicit authentication significantly reduces manual tuning and configuration tasks due to its self-learning capability

    Insulin Resistance and Left Ventricular Mass in Non-Diabetic Hemodialysis Patients

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    AbstractBackgroundInsulin resistance (IR) is frequently recognized in patients with uremia, and it is thought that IR has a basic role in the pathogenesis of cardiovascular disease.ObjectiveTo evaluate the effect of IR on cardiovascular risk in non-diabetic patients receiving hemodialysis (HD).MethodsWe performed a cross-sectional observational study that comprised 186 non-diabetic patients receiving HD (95 men; mean [SD] age, 46.4 [10.8] years; age range, 35–60 years) who had been receiving HD for 7.3 (3.5) years. Demographic variables and laboratory values were recorded. Insulin resistance was determined using the Homeostatic Model Assessment (HOMA), and the left ventricular mass index (LVMI) was calculated via echocardiography.ResultsAccording to HOMA-IR levels, patients were categorized as having IR (HOMA-IR score ≥2.5; n = 53) or not having IR (HOMA-IR score <2.5; n = 133). Insulin resistance was determined in 28.4% of study patients. Compared with the non-IR group, the IR group had been receiving HD longer; had greater body mass index; and had higher serum creatinine, uric acid, triglyceride, insulin, and C-reactive protein concentrations, leukocyte count, and LVMI (P < 0.05). Patients with increased LVMI had significantly higher body mass index, systolic blood pressure, serum cholesterol and C-reactive protein concentrations, and HOMA score. At multivariate analysis, systolic blood pressure (β = 0.22; P = 0.03) and HOMA score (β = 0.26; P = 0.01) affected LVMI.ConclusionsInsulin resistance and hypertension are independent risk factors for left ventricular hypertrophy in non-diabetic patients with uremia who are receiving HD. Further studies are needed to indicate the benefits of improving IR for cardiovascular mortality in this subgroup of patients with uremia

    Kaposi's Sarcoma following Chronic Lymphocytic Leukemia: A Rare Entity

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    Cutaneous manifestations can occur in the wide range of internal malignancy. They can occur by metastases or local spread, direct infiltration, or a site of primary malignancy itself. Sometimes these manifestations are related with an underlying malignancy but they do not contain malignant cells as paraneoplastic dermatological syndromes. Chronic lymphocytic leukemia (CLL) is the most common leukemia all over the world. Cutaneous lesions occur in up to 25% of patients. Most commonly seen cutaneous lesions in CLL are those of infectious or hemorrhagic origin. Skin cancer risk was also increased eightfold in CLL when compared with normal population, so cutaneous lesions in CLL can be the first manifestation of secondary skin malignancy. Herein, we report an interesting case of Kaposi's sarcoma which was diagnosed during the course of CLL

    Molecular simulations for dynamic nuclear polarization in liquids: a case study of TEMPOL in acetone and DMSO

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    A computational strategy for calibrating, validating and analyzing molecular dynamics (MD) simulations to predict dynamic nuclear polarization (DNP) coupling factors and relaxivities of proton spins is presented. Simulations of the polarizing agent TEMPOL in liquid acetone and DMSO are conducted at low (infinite dilution) and high (1 M) concentrations of the free radical. Because DNP coupling factors and relaxivities are sensitive to the time scales of the molecular motions, the MD simulations are calibrated to reproduce the bulk translational diffusion coefficients of the pure solvents. The simulations are then validated by comparing with experimental dielectric relaxation spectra, which report on the rotational dynamics of the molecular electric dipole moments. The analysis consists of calculating spectral density functions (SDFs) of the magnetic dipole–dipole interaction between the electron spin of TEMPOL and nuclear spins of the solvent protons. Here, MD simulations are used in combination with an analytically tractable model of molecular motion. While the former provide detailed information at relatively short spin–spin distances, the latter includes contributions at large separations, all the way to infinity. The relaxivities calculated from the SDFs of acetone and DMSO are in excellent agreement with experiments at 9.2 T. For DMSO we calculate a coupling factor in agreement with experiment while for acetone we predict a value that is larger by almost 50%, suggesting a possibility for experimental improvement

    The first optical light from the supernova remnant G182.4+4.3 located in the Galactic anti-centre region

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    We report the discovery of optical filamentary and diffuse emission from G182.4+4.3 using 1.5-m Russian-Turkish telescope. We present the optical CCD images obtained with Halpha filter revealing the presence of mainly filamentary structure at the northwest, filamentary and diffuse structure at the centre, south and north regions of the remnant. The bright optical filaments located in northwest and south regions are well correlated with the prominent radio shell of the remnant strongly suggesting their association. From the flux-calibrated CCD imaging, the average [SII]/Halpha ratio is found to be ~0.9 and ~1.1 for south and northwest regions, which clearly indicates that the emission originates from the shock heated gas. We also present the results of X-ray data obtained from XMM-Newton that show diffuse emission with a very low luminosity of ~7.3x10^31 erg s^-1 at a distance of 3 kpc in 0.3-10 keV energy band. Furthermore, we find a surprisingly young age of ~4400 yr for this remnant with such a large radius of ~22 pc.Comment: 9 pages, 6 figures and 1 table, Accepted for publication in MNRA

    A deep X-ray observation of supernova remnant G304.6+0.1 (Kes 17) with Suzaku

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    In this paper, we present the analysis of a deep (99.6 ks) observation of G304.6 + 0.1 with the X-ray Imaging Spectrometer on board {\it Suzaku} satellite. The X-ray spectral data are well-fitted with a plasma model consisting of a thermal component in collisional ionization equilibrium and a non-thermal component. The thermal emission is well fitted with VMEKAL model with an electron temperature of kTe0.75kT_{\rm e}\sim 0.75 keV, a high absorbing column density of NH3.9×1022N_{\rm H}\sim 3.9\times10^{22} cm2\rm cm^{-2} and near/lower solar abundances which indicate that the X-ray emitting plasma of G304.6 + 0.1 is dominated by swept-up ambient medium. The non-thermal component is well fitted with a power-law model with photon index of Γ1.4\Gamma \sim 1.4. We found a relatively high electron density ne2.3f1/2n_{\rm e}\sim 2.3f^{-1/2} cm3^{-3}, age tt 1.4×104f1/2\sim 1.4\times10^4f^{1/2} yr, and X-ray emitting mass Mx380f1/2M_{\rm x}\sim 380f^{1/2} {M\sun} at an adopted distance of d=10 kpc. Using the morphological and spectral X-ray data, we confirm that the remnant is a new member of mixed-morphology supernova remnants.Comment: 8 pages, 4 figures, 2 table

    On the generalized Davenport constant and the Noether number

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    Known results on the generalized Davenport constant related to zero-sum sequences over a finite abelian group are extended to the generalized Noether number related to the rings of polynomial invariants of an arbitrary finite group. An improved general upper bound is given on the degrees of polynomial invariants of a non-cyclic finite group which cut out the zero vector.Comment: 14 page

    Ejecta detection in the middle-aged Galactic supernova remnant G296.1-0.5 observed with Suzaku

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    In this paper, we report the detection of ejecta in the middle-aged Galactic supernova remnant G296.1-0.5 with the X-ray Imaging Spectrometer onboard the Suzaku satellite. The spectra of three lobes, north, southeast and southwest and inter-lobe regions, consist of soft (0.3-2.0 keV) emission originated from non-equilibrium ionization plasma. In north, southeast and inter-lobe regions, the thermal emission can be represented by a one-component, in southwest region it can be represented by two- component non-equilibrium ionization (VNEI) model. The spectra of studied regions have lines of N, O, Ne, Mg and Si elements. Si emission from this remnant is shown for the first time in this work. Enhanced abundances of Ne, Mg and Si elements obtained show the ejecta contribution in all regions. Assuming that the remnant is in Sedov phase, we obtained ambient density n0 ~ 0.45 cm-3, age t ~ 2.8 x 104 yr, shock velocity Vs ~ 320 km s-1, shock temperature Ts ~ 1.2 x 106 K, and swept-up mass Msw ~ 340 M at an adopted distance of d=3 kpc.Comment: 9 pages, 5 figures, 2 table

    Physical Parameters of Some Close Binaries: ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg

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    With the aim of providing new and up-to-date absolute parameters of some close binary systems, new BVR CCD photometry was carried out at the Ankara University Observatory (AUG) for five eclipsing binaries, ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg between April, 2007 and October, 2008. In this paper, we present the orbital solutions for these systems obtained by simultaneous light and radial velocity curve analyses. Extensive orbital solution and absolute parameters for ET Boo system were given for the first time through this study. According to the analyses, ET Boo is a detached binary while the parameters of four remaining systems are consistent with the nature of contact binaries. The evolutionary status of the components of these systems are also discussed by referring to their absolute parameters found in this study.Comment: this accepted paper will be published in New Astronom
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