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A Machine Learning-Based Distributed Denial of Service Detection Approach for Early Warning in Internet Exchange Points

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Computers, Materials & Continua 2023年第8期76卷 2235-2259页

作者： Salem Alhayani Diane r.Murphy School of Technology and Innovation College of Business InnovationLeadershipand Technology(BILT)Marymount UniversityArlingtonVirginia22207USA

The Internet service provider(ISP)is the heart of any country’s Internet infrastructure and plays an important role in connecting to theWorld *** exchange point(IXP)allows the interconnection of two or more separate network *** Internet traffic entering a country should pass through its ***,it is an ideal location for performing malicious traffic *** denial of service(DDoS)attacks are becoming a more serious daily *** actors in DDoS attacks control numerous infected machines known as *** are used to send numerous fake requests to overwhelm the resources of victims and make them unavailable for some *** date,such attacks present a major devastating security threat on the *** paper proposes an effective and efficient machine learning(ML)-based DDoS detection approach for the early warning and protection of the Saudi Arabia Internet exchange point(SAIXP)*** effectiveness and efficiency of the proposed approach are verified by selecting an accurate ML method with a small number of input features.A chi-square method is used for feature selection because it is easier to compute than other methods,and it does not require any assumption about feature distribution *** ML methods are assessed using holdout and 10-fold tests on a public large-size *** experiments showed that the performance of the decision tree(DT)classifier achieved a high accuracy result(99.98%)with a small number of features(10 features).The experimental results confirmthe applicability of using DT and chi-square for DDoS detection and early warning in SAIXP.

关键词： Internet exchange point Saudi Arabia IXP(SAIXP) distributed denial of service chi-square feature selection machine learning

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Systematic exploration of signal-based indicators for failure diagnosis in the context of cyber-physical systems

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Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 152-175页

作者： Santiago rUIZ-ArEnAS Zoltán rUSáK Imre HOrVáTH ricardo MEJí-GUTIErrEZ Faculty of Industrial Design Engineering Delft University of Technology Grupo de Investigación en Ingeniería de Diseno Universidad EAFIT

Malfunction or breakdown of certain mission critical systems(MCSs) may cause losses of life, damage the environments, and/or lead to high costs. Therefore, recognition of emerging failures and preventive maintenance are essential for reliable operation of MCSs. There is a practical approach for identifying and forecasting failures based on the indicators obtained from real life processes. We aim to develop means for performing active failure diagnosis and forecasting based on monitoring statistical changes of generic signal features in the specific operation modes of the system. In this paper, we present a new approach for identifying emerging failures based on their manifestations in system signals. Our approach benefits from the dynamic management of the system operation modes and from simultaneous processing and characterization of multiple heterogeneous signal sources. It improves the reliability of failure diagnosis and forecasting by investigating system performance in various operation modes, includes reasoning about failures and forming of failures using a failure indicator matrix which is composed of statistical deviation of signal characteristics between normal and failed operations, and implements a failure indicator concept that can be used as a plug and play failure diagnosis and failure forecasting feature of cyber-physical systems. We demonstrate that our method can automate failure diagnosis in the MCSs and lend the MCSs to the development of decision support systems for preventive maintenance.

关键词： Failure indicators Failure classification Failure detection and diagnosis Complex systems

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Landform Instability and Land-use Dynamics in Tropical High Mountains, Central Mexico

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Journal of Mountain Science 2012年第3期9卷 414-430页

作者： GArCíA-rOMErO Arturo ACEVES-QUESADA José Fernando ArrEDOnDO-LEón Carlos Departamento de Geografía Física Instituto de Geografía Universidad Nacional Autónoma de México. Circuito exterior s/n Ciudad Universitaria 04510 Mexico Distrito Federal Mexico Unidad Académica de Estudios regionales de la Coordinación de Humanidades Universidad Nacional Autónoma de México

This investigation is an analysis of the influence of landform instability on the distribution of land-use dynamics in a hydrographical basin, located in the Mexican Volcanic Belt mountain range (central Mexico), currently affected by substantial changes in land use and deforestation. A landform map was produced, in addition to seven attribute maps - altimetry, drainage density, slope, relief energy, potential erosion, geology and tectonics - which were considered as factors for determining landform instability through Multi-criteria Evaluation Analysis. Likewise, the direction and rhythm of land-use dynamics were analyzed in four dates - between 1976 and 2000 - and cross tabulations were made between them, in order to analyze the trends and processes of land-use dynamics. Afterwards, the databases obtained were cross tabulated with the landform variables to derive areas, percentages and correlation indices. In the study area, high-instability landforms are associated with most ancient volcanic and sedimentary landforms, where high altitude, drainage density, slope and potential to develop gravitational and fluvial processes are the major factors favouring a land-use pattern, dominated by the conservation of extensive forest land, abandonment of human land use and regeneration of disturbed areas. In contrast, low-instability landforms correspond to alluvial plains and lava hills covered by pyroclasts, where low potential erosion to develop fluvial processes, added to water and soil availability and accessibility, have favoured a land-use pattern dominated by the expansion of agroforestry plantations and human settlements, showing a marked trend towards either intensification or permanence of the current land use and with little abandonment and regeneration.

关键词： Landform instability Multi-criteriaEvaluation Analysis Land-use change and processes Tuxpan river Basin

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new Insights on Energy Conserved Planar Motion

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Computer Modeling in Engineering & Sciences 2016年第2期111卷 119-127页

作者： Maruthi r.Akella Sofokli Cakalli Department of Aerospace Engineering and Engineering Mechanics The University of Texas at AustinAustinTX 78712USA.

The planar motion of a particle within an arbitrary potential field is *** particle is additionally subject to an external force wherein the applied thrust-acceleration is constrained to remain normal to the velocity *** system is thus non-conservative but since the thrust force is non-working,the total energy is a conserved *** this setting,a major result of fundamental importance is established in this paper:that the flight direction angle(more precisely,the sine of the angle between the position and velocity vectors)is shown to always satisfy a linear first-order differential equation with variable coefficients that depend upon the underlying potential *** a consequence,an analytical solution for the flight direction angle can be obtained directly in terms of the particle’s distance from the center of the field for a significant number of special cases for the potential *** the case of J2 perturbed spacecraft motion within equatorial orbits,the problem is reduced to that of solving an incomplete elliptic *** important implication of the main result established here is that motion problems subject to velocity-normal thrusting can always be reduced to the study of equivalent single degree-of-freedom conservative systems with an effective potential *** paper concludes with various examples of both academic and practical interest including the study of bounded two-body Keplerian orbits and hodograph interpretetions.

关键词： Energy conserved spacecraft motion flight direction angle velocitynormal thrusting effective potential hodograph interpretation

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Unilateral visual impairment in rural south India-Andhra Pradesh Eye Disease Study(APEDS)

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International Journal of Ophthalmology(English edition) 2016年第5期9卷 763-767页

作者： Srinivas Marmamula rohit C Khanna Gullapalli n rao Allen Foster Community Eye Health research Centre Gullapalli Pratibha Rao-International Centre for Advancement of Rural Eye careL V Prasad Eye Institute Brien Holden Eye research Centre L V Prasad Eye Institute School of Optometry & Vision Science University of New South Wales

AIM： To report the prevalence and causes of unilateral visual impairment（UVI） in rural population of all ages in rural Andhra Pradesh, India.·METHODS： A population-based cross sectional study using a multi-stage cluster sampling methodology was carried out in West Godavari, Adilabad and Mahbubnagar districts in south India. A comprehensive eye examination that included presenting and best corrected visual acuity and dilated fundus examination was conducted by trained professionals. UVI is defined as presenting visual acuity 6/18 in one eye but ≥6/18 in other eye. Multiple logistic regression analysis was used to test association of UVI with socio-demographic risk factors.· rESULTS： Data were analyzed for 6634/7771 participants after excluding those with bilateral visual impairment. The mean age of the participants was 27.4y（Standard deviation： 17.9y）, 51.9% were women and49.1% were educated. The prevalence of UVI was 7.8%（95% CI： 7.2%- 8.5%）. Uncorrected refractive error（60.8%）, cataract（17.4%） and retinal causes（6.6%） were the leading causes of UVI. On multiple logistic regression analyses, older age, not having education, living in welloff district had significantly higher odds of being associated with UVI. UVI was not associated with gender.·COnCLUSIOn： UVI is common in rural south *** of it is due to cataract and refractive errors, both of which can be addressed at primary and secondary levelsof eye care. Burden of UVI should also be considered in planning eye care services.

关键词： visual impairment cataract refractive errors India Andhra Pradesh Eye Disease Study

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revealing the identity of regulatory T-cell-suppressed self-reactive CD4^(+)T cells

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Cellular & Molecular Immunology 2023年第10期20卷 1093-1094页

作者： Judith n.Mandl Heather J.Melichar Department of Physiology and McGill research Centre on Complex Traits McGill UniversityMontrealQCCanada Immunology-Oncology Unit Maisonneuve-Rosemont Hospital Research CenterMontrealQCCanada Department of Medicine Universitéde MontréalMontrealQCCanada

A recent study published in nature Immunology by Peter Savage and colleagues sought to characterize regulatory T-cell(Treg)-suppressed self-reactive CD4^(+)T cells using an elegant system combining the depletion of Tregs with T-cell receptor(TCr)sequencing of expanded conventional CD4^(+)T-cell *** tracking the fate of T cells engineered to express the identified TCrs,Lee et *** a‘new’subpopulation of CD4^(+)T cells bearing antigen receptors with high levels of self-reactivity that take on a T follicular helper(TFH)-like phenotype in the periphery in the absence of immune challenge[1].Antigen-specificαβTCrs are generated through the somatic recombination of V(D)J gene segments during thymic development,giving rise to T cells that can recognize an enormously diverse set of peptides presented by major histocompatibility complex(pMHC)molecules.A risk of this process is that it can also lead to the generation of potentially highly self-reactive TCrs.T cells with TCrs with high affinity for self-pMHC molecules are purged in the thymus by clonal deletion,a key tolerance mechanism that prevents ***,this process is incomplete,and highly self-reactive T cells can escape negative selection and join the peripheral naive T-cell ***,while the naive CD4^(+)T-cell pool is heterogeneous with regard to an individual T cell’s reactivity for self-pMHC molecules,the distribution of T cells with differing strengths of self-reactivity leaving the thymus is skewed toward those with relatively higher self-pMHC binding strengths[2].A subset of these highly self-reactive CD4^(+)T cells in the periphery are deleted,some become functionally anergic,and others differentiate into Tregs,which go on to play an important role in peripheral tolerance,holding other CD4^(+)T cells with potentially dangerous levels of self-reactivity in check[3].What is the fate of these Treg-suppressed self-reactive cells?

关键词： reactivity incomplete expanded

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Epididymis cholesterol homeostasis and sperm fertilizing ability

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Asian Journal of Andrology 2011年第1期13卷 11-17页

作者： Fabrice Saez Ouvrier and Joel r Drevet UMr GreD CnrS 6247 INSERM U931 Clermont Universite Equipe ＇Epididyme et maturation des gametes＇ Aubiere cedex 63171 France

Cholesterol, being the starting point of steroid hormone synthesis, is a long known modulator of both female and male reproductive physiology especially at the level of the gonads and the impact cholesterol has on gametogenesis. Less is known about the effects cholesterol homeostasis may have on postgonadic reproductive functions. Lately, several data have been reported showing how imbalanced cholesterol levels may particularly affect the post-testicular events of sperm maturation that lead to fully fertile male gametes. This review will focus on that aspect and essentially centers on how cholesterol is important for the physiology of the mammalian epididymis and spermatozoa.

关键词： cholesterol homeostasis epididymosomes fertility post-testicular maturation spermatozoa

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The First Forty Years of a Technosol

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Pedosphere 2009年第1期19卷 40-52页

作者： r. SCALEnGHE S. FErrArIS DAAT Universit`a degli Studi di Palermo viale delle Scienze 13 90128 Palermo (Italy) IAMC Consiglio nazionale delle ricerche Capo Granitola 91020 Campobello di Mazara (Italy) DEIAFA Universit`a degli Studi di Torino via Leonardo da Vinci 44 10095 Grugliasco (Italy)

Soil formation is often a very slow process that requires thousands and even millions of years. Human influence, occasionally on a par with the function of climate or geological forces, can accelerate the process and can be viewed as a distinct soil forming factor. This paper describes a soil, Haplic regosol, in which anthrosolization dominates the soil forming process. Man-made soils, Technosols, were stabilized with techniques of ecological engineering (crib walls). We measured the main soil properties and focused on the movement of water (the reduction of soil weight is the key factor in stabilizing these calcschists). The newly deposited debris, sheltered by anthropic interventions, after four years differentiated an A/C profile while after forty years differentiated an O/A/AB/Bw/BC/C profile. Our results indicate that colonization by plants and the consequent success of vegetation establishment is influenced mainly by control of the factor of pedogenesis 'topography' and by the ability of these Technosols to retain nutrients.

关键词： ecological engineering speed of pedogenesis tension infiltrometer

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reflection and refraction of attenuated waves at boundary of elastic solid and porous solid saturated with two immiscible viscous fluids

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Applied Mathematics and Mechanics(English Edition) 2012年第6期33卷 797-816页

作者： M.KUMAr r.SAInI Department of Mathematics Kurukshetra University

The propagation of elastic waves is studied in a porous solid saturated with two immiscible viscous fluids. The propagation of three longitudinal waves is represented through three scalar potential functions. The lone transverse wave is presented by a vector potential function. The displacements of particles in different phases of the aggregate are defined in terms of these potential functions. It is shown that there exist three longitudinal waves and one transverse wave. The phenomena of reflection and refraction due to longitudinal and transverse waves at a plane interface between an elastic solid half-space and a porous solid half-space saturated with two immiscible viscous fluids are investigated. For the presence of viscosity in pore-fluids, the waves refracted to the porous medium attenuate in the direction normal to the interface. The ratios of the amplitudes of the reflected and refracted waves to that of the incident wave are calculated as a non- singular system of linear algebraic equations. These amplitude ratios are used to further calculate the shares of different scattered waves in the energy of the incident wave. The modulus of the amplitude and the energy ratios with the angle of incidence are computed for a particular numerical model. The conservation of the energy across the interface is verified. The effects of variations in non-wet saturation of pores and frequencies on the energy partition are depicted graphically and discussed,

关键词： dissipative porous solid immiscible viscous fluid elastic wave propagation,attenuation reflection and refraction coefficients

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Visco-elastic fluid flow past an infinite vertical porous plate in the presence of first-order chemical reaction

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Applied Mathematics and Mechanics(English Edition) 2010年第8期31卷 955-962页

作者： r.A.DAMSEH B.A.SHAnnAK Mechanical Engineering Department Al-Huson University College Al-Balqa Applied University

An analysis has been developed to study the unsteady free convection flow of an incompressible visco-elastic fluid on a continuously moving vertical porous plate in the presence of a first-order chemical reaction. The governing equations are solved numerically using an implicit finite difference technique. The obtained numerical solutions are compared with the analytical solutions. The velocity profiles are presented. A parametric analysis is performed to illustrate the influences of the visco-elastic parameter, the dimensionless chemical reaction parameter, and the plate moving velocity on the steady state velocity profiles, the time dependent friction coefficient, the nusselt number, and the Sherwood number.

关键词： visco-elastic fluid porous plate chemical reaction free convection

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