Multilayer Packet Research Articles

Accurate Detection of Multi-layer Packet Dropping Attacks Using Distributed Mobile Agents in MANET

Detecting multi-layer packet drop attacks may result in extraordinary computational overhead in Mobile Ad Hoc Networks (MANET). Most of the existing works consider only data packet drop ignoring the routing packets drops. In this paper, a technique for accurate detection of malicious multi-layer packet drop attacks using mobile agents (MPDDMA) is proposed. In this technique, mobile agents are deployed in each node to detect selective dropping of routing and data packets by the malicious nodes. The source node identities the nodes whose route request and route reply count significantly differs from others by a margin. Similarly, the source node identifies the nodes whose packet received count significantly differs from others by another margin. The source then applies Fuzzy logic decision model with these margin values and MAC layer packet drop value as input variables and returns the output as probability of maliciousness (PrM). Experimental results show that MPDDMA technique achieves better detection accuracy and reduced packet drops.

NFV orchestration over disaggregated metro optical networks with end-to-end multi-layer slicing enabling crowdsourced live video streaming

Network infrastructure must support emerging applications, fulfill 5G requirements, and respond to the sudden increase of societal need for remote communications. Remarkably, crowdsourced live video streaming (CLVS) challenges operators’ infrastructure with tides of users attending major sport or public events that demand high bandwidth and low latency jointly with computing capabilities at the networks’ edge. The Metro-Haul project entered the scene proposing a cost-effective, agile, and disaggregated infrastructure for the metro segment encompassing optical and packet resources jointly with computing capabilities. Recently, a major Metro-Haul outcome took the form of a field trial of network function virtualization (NFV) orchestration over the multi-layer packet and disaggregated optical network testbed that demonstrated a CLVS use case. We showcased the average service creation time below 5 min, which met the key performance indicator as defined by the 5G infrastructure public private partnership. In this paper, we expand our field trial demonstration with a detailed view of the Metro-Haul testbed for the CLVS use case, the employed components, and their performance. The throughput of the service is increased from approximately 9.6 Gbps up to 35 Gbps per virtual local area network with high-performance VNFs based on single-root input/output virtualization technology.

Inverse problem analysis for nondestructive evaluation of structural characteristics of multilayered foundations

The evaluation of the parameters of multilayered foundations (pavements, runway strips, etc.) plays an important role in ensuring the safe movement of vehicles. An approach of model construction for estimating the mechanical and geometric parameters of such foundations based on the solutions of inverse problems for multilayered elastic packets is proposed. As input data for such problems the measured displacements (or velocities) of certain points on the package surface are used. The proposed approach is based on informational-probabilistic paradigm for inverse problem analysis, whose task is to obtain a posteriori probability density in the space of unknown parameters. The essence of the approach is the block-parametric approximation of the a priori probability density and likelihood function in the spaces of parameters and model data of the problem. The method allows estimating the parameters of the a priori distribution of unknown variable parameters, identifying and excluding outliers of the measured data from the created model, and constructing a posteriori estimation of the unknown parameters’ probability density with acceptable resolution. Proposed method can be used to create a new generation of equipment intended for nondestructive monitoring and estimating of the condition of pavements, runways and foundations of artificial structures. The appropriate software for such high-speed scanning devices that allow on-the-fly display of the diagnosed layered foundation parameters can be developed.

Hardening Mechanism in Low-Carbon Low-Alloy Steels with a Simultaneous Increase in Ductility and Fracture Toughness

The paper analyzes the nucleation and growth of bainite in low-carbon low-alloy 09Mn2Si steel doped with titanium carbonitride nanoparticles in impact toughness testing. The analysis shows that such particles segregate at low-angle boundaries, retarding the formation of high-angle ones, and when impacted into the steel, they curve the lattice and generate a new bainite phase at the curvature interstices. The mechanism of bainite nucleation and growth is sympathetic, obeys the angular momentum conservation law, and provides the formation of multilayered packets of bainite plates capable for unlimited thinning to sub-sub-subunits during deformation. Such bainite plates can respond to their stress-strain state by one or another rotation, showing a high relaxation capacity and providing a high impact toughness of the steel at low temperatures.

Моделирование нестационарных процессов диффузии - конвекции - реакции в многослойном полупространстве и сцепленных полупространствах

A matrix method is developed for constructing the Fourier-Laplace symbol of the Green's function for a multilayer half-space and linked half-spaces for three-dimensional non-stationary problems of turbulent diffusion. The sources of emission of impurities can be external or internal, the number of considered layers can be large. The method allows solving boundary-value convection-diffusion-decay problems not only for piecewise constant media, but also for gradient media, all parameters of which depend on the vertical coordinate by discretization with a small vertical step. The multilayer half-space model is a better physical model of the atmosphere than the multilayer packet of layers, since the decrease in concentration in the upper layers in the half-space is caused not by the introduction of special boundary conditions, but by the natural decrease of the solution at infinity for half-space. It is shown that for a boundary value problem of the third kind for a homogeneous half-space in the non-stationary case, the occurrence of real poles is possible, as well as in the stationary case. For the case of the occurrence of real poles, a method for determining the correct integration contour for the Laplace transform is indicated. The proposed method for the numerical inversion of three-dimensional Fourier-Laplace integrals based on standard algorithms for integrating rapidly oscillating functions is very effective, which allows us to solve not only direct, but also some inverse problems of turbulent diffusion. The given example of the numerical solution of a three-dimensional non-stationary problem for two linked half-spaces can be considered as a model of impurity propagation at the boundary of the atmosphere and the ocean.

Модель распространения загрязняющих веществ в многослойной среде с периодическим источником излучения

Based on the equations of turbulent diffusion for convection-diffusion-decay processes, an algorithm has been developed for calculating the distribution of pollutants in a diffusion medium that are emitted by a time-periodic radiation source. The medium is a multilayer packet of layers with plane-parallel interfaces, the radiation source can be located either at the boundaries of the packet of layers or inside it. The solution is constructed in Fourier images using the symbols of the Green functions of boundary value problems for periodic sources. The inverse two-dimensional Fourier transform is calculated numerically. It is shown in the paper that the boundary value problem for a periodic source can be reduced to solving a slightly modified boundary value problem for stationary equations of turbulent diffusion. Methods for solving a stationary boundary value problem are developed in detail in previous works of the authors. It is noted that for a periodic source, in comparison with a stationary source, the computational volumes grow in proportion to the number of harmonics in the Fourier expansion of the periodic component of the source. An example of a numerical solution of the spatial boundary-value problem for a two-layer packet with an internal periodic radiation source is given. The example takes into account nine members of the Fourier series in the source statement. The developed numerical-analytical model has high accuracy and flexibility and can be used to simulate various periodic diffusion-convection-reaction processes, and to obtain various estimates in the field of ecology and environmental protection. The proposed method is effective for solving boundary value problems for semi-bounded multilayer media for which the traditionally used finite element and finite difference methods are not applicable.

Вологоперенос в багатошарових перев'язочних засобах

Prediction on the base of analysis of the laws of moisture transfer the property of multilayer packages of wound dressing to carry out the transfer of drugs and metabolic fluids in such systems.In the course of experimental studies of penetration of moisture through the packages of wound coatings, in which in different variants of the arrangement of used samples with different raw material composition and density (nonwoven cotton fabrics and linen fabric), were determined parameters of distribution of the liquid and the dimensions of the wetted zone in the upper, lower and middle layers.It has been found that, starting with a certain thickness, most of the liquid accumulates within the package, which changes the general shape of the wetting zone. The surfaces of wetted zones for different package variants, which show a fairly pronounced maximum inside the material, are obtained. The analysis of the dynamics of the change of the wetted zone surface allowed to formulate the problem of determining the location of additional material in the multilayer wound covering. This gives the opportunity to accumulate the highest moisture content inside the material package, which improves the quality of wound dressings. A study on the effects of additional wetting in multi-layer packets of textile medical materials has revealed for the first time the effect of increasing the concentration of fluid inside such systems, which we called "paradox of internal concentration". This effect appear in the fact that at certain ratios of discrete environmental parameters, the maximum propagation of the liquid occurs not on the material surface, but at a certain depth, in the place of location of the material of high density. The appearance of the effect is determined by the parameter that binds the geometric properties of the material and the discrete parameters of the liquid passing. Practical significance. The investigated processes of wetting of multilayer dressing materials can be used to predict conditions of their real functioning, proceeding from the requirements of operational situation. This allows solving problems of durability of bandages. The criterion of longevity may be the prevention of the exhaust outlet to the surface or the restriction of the exhaust emission area on the outer surface of the wound dressing in certain volumes.

Non-destructive control data analysis of railroad foundation constructions

The evaluation of the parameters of multi-layered foundations (railroad basis, foundations of railway structures, etc.) plays an important role in ensuring the safe movement of trains. The method of estimating the mechanical and geometric parameters of such foundations based on the solutions of inverse problems for multi-layered elastic packets is proposed. As input data for such problems the measured displacements of certain points on the package surface are used. The method allows estimating the parameters of the a priori distribution of unknown variable parameters, identifying and excluding outliers of the measured data from the created model, and constructing a posteriori estimation of the unknown parameters probability density with acceptable resolution. Proposed method can be used to create a new generation of equipment intended for non-destructive monitoring and estimating of the condition of the railroad basis and the foundations of artificial structures. The appropriate software of such vehicles based on the developed methods of data processing can be developed. The use of such equipment allows to operatively analyzing the state of individual areas of the railroad to decide on the need of repairing or replacing the railroad base or foundation of other elements of railroad infrastructure.

Influence of Knits Structure on Flammability and Comfortability

Abstract Investigations of the influence of the knit structure, i.e. the loop length and the number of yarns in a loop, on flammability and comfortability are presented in this paper. The investigations were carried out using single jersey knits from Delta TA 18 tex × 2 yarns with five variants of a loop length. Single yarn as well as folded yarn from two single yarns was used in the investigations. Comparison of the results of single-layer knits flammability and air permeability with those of multilayer packet was made. The results obtained show that an increase in the loop length of the knit increases their permeability to air and decreases the burning time as well as increase in the number of layers decreases the air permeability and increases the burning time. Moreover, the similar burning time with significantly different permeability to air can be achieved changing the basic knitting parameters, i.e. the loop length and/or the yarn linear density.

Influence of Chemical Surface Modification of Woven Fabrics on Ballistic and Stab Protection of Multilayer Packets

In order to achieve enhanced protective and wear (flexibility, less bulkiness) properties of ballistic and stab protecting panels the investigation of chemical surface modification of woven p-aramid fabrics was performed applying different chemical composition shear thickening fluid (STF) which improves friction inside fabric structure. For the chemical treatment silicic acid and acrylic dispersion water solutions were used and influence of their different concentrations on panels’ protective properties were investigated. Results of ballistic tests of multilayer protective panel have revealed that shear thickening effect was negligible when shooting at high energy range (E > 440 J). Determination of stab resistance of p-aramid panels has shown that different chemical composition of STFs had different influence on protective properties of the panels. Application of low concentrations of silicic acid determined higher stab resistance values comparing to higher concentrations of acrylic dispersion water solutions. At this stage of research stab tests results as ballistic ones determined that STF application for multilayer p-aramid fabrics protective panels is more efficient at low strike energy levels. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.3138

Production of Ti3SiC2-based materials by SHS forced compaction of layered composite Ti–SiC

A new method of synthesizing ceramic composite materials based on Ti3SiC2 using non-powder reaction compositions of titanium and silicon carbide was developed. Aceramic composite with a Ti3SiC2–TiSi2 matrix reinforced with SiC particles was obtained by SHS forced compaction of a multilayer packet of regularly packed layers of titanium foil and polymer film filled with silicon carbide particles. The particulars of the phase composition and microstructure of the material obtained were investigated.

Investigation of Dispersion Characteristics of Composites

AbstractThis numerical study of dispersion characteristics of some symmetric and asymmetric composites modelled as multilayered packets of layers with arbitrary anisotropy of each layer is carried out. The authors introduce a subsidiary boundary problem of three‐dimensional theory of elasticity for the system of partial differential equations describing the harmonic oscillations of the composite excited by a surface load. The authors obtained the curves and surfaces describing slowness of the wave front of Lamb waves propagating with respect to the direction of propagation. The method suggested by the authors of the present article does not impose any restrictions on the type of elastic anisotropy of the layers, their orientations and mutual positions. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Investigation of Lamb elastic waves in anisotropic multilayered composites applying the Green’s matrix

This article presents a numerical study of dispersion characteristics of some symmetric and antisymmetric composites modelled as multilayered packets of layers with arbitrary anisotropy of each layer. The authors introduce a subsidiary boundary problem of three-dimensional elasticity theory for the system of partial differential equations describing the harmonic oscillations of the composite caused by a surface load. The problem reduces to a boundary problem for ordinary differential equations by employing the Fourier transform. An algorithm of constructing the Fourier transform of the Green's matrix of the given boundary problem is presented. The wave numbers of Lamb waves propagating in composites, their phase velocity surfaces and group wave surfaces are presented through the poles of the transform of the Green's matrix. The authors obtain the dispersion curves for different directions and frequencies and investigate the dispersion curves and surfaces of wave numbers, phase velocities and group wave surfaces for various composites. The numerical results are then compared with the results obtained by applying other methods.

Physical foundations and fields of practical application of explosive welding of metals

Main kinematic and energy-related aspects of the formation of two-layer and multilayer joints upon explosive welding of metals are considered; the principal characteristic regions of this process are shown; the critical energy boundaries depending on the Astrov criterion have been established. The kinematics of plastic flow of metal in the heat-affected zone upon explosive welding under various regimes of collision has been studied; the energy balance in the system of collided plates has been analyzed. A new parameter for characterizing the process of explosive welding has been suggested, namely, the magnitude of a deforming pressure momentum. A mathematical model that describes the process of the acceleration and interaction of metallic plates in a multilayer packet upon welding with a simultaneous cladding scheme is presented. The main fields of practical application of layered composite materials produced by explosive welding are shown.

Analysis of layered bases-foundations models under seismic actions

The paper considers the dynamic behaviour of the two-layered and multi-layered plate packets under dynamic (seismic) loading. These models correspond to the base-foundation packet structures. The analysis of the various models, including the models of contact between the layers, is derived on the base of the precise solutions of elasticity theory equations. It is shown that the application of the seismoisolator or, in general, less rigid materials between the base and the foundation brings to reduction of the natural frequencies of free vibrations of the packet base-foundation, as well as to the significant reduction of the negative seismic effect on the structures.

Homologous series of layered tetradymite-like compounds in Bi-Te and GeTe-Bi2Te3 systems

Formation of the homologous series of layered compounds nBi2-mBi2Te3 and nGeTe mBi2Te3 is analyzed. For both series, the crystal structure contains two-layer (Bi2 or GeTe) and five-layer (Bi2Te3) packets perpendicular to the c axis. Unlike the Bi2 packets, the GeTe packets do not retain their individuality during crystal structure formation; they are linked to the Bi2Te3 five-layer packets to form new multilayer packets leading to a considerable change in the character of interatomic interactions.

The average equations of the dynamics of thin multilayered packets of arbitrary structure with contrasting directions of anisotropy in the elastic layers

Using the three-dimensional dynamical theory of elasticity, the asymptotic method [1, 2] is used to derive two-dimensional equations and elasticity relations for a packet with an arbitrary anisotropy and arrangement of the layers. It is assumed that the contact between layers is ideal and the packet is subject to stresses on the face surfaces with certain boundary conditions at the ends. It is also assumed that in addition to the usual small parameter e = h L ⪡ 1 for a long-wave approximation ( h is the half-thickness and L is the scale of the process in a longitudinal direction), the ratios of the elastic moduli in different directions in each layer can generate additional small parameters of the form ε p p > 0, ε → +0. Similar contrasting differences are permitted between groups of layers. The results are classified in terms of the contrast characteristics and types of anisotropy.

A dynamic mixed problem for a packet of elastic layers

A previously proposed method of solving scalar [1] and vector [2] integral equations with a meromorphic Fourier kernel symbol, which arise in problems of the dynamic contact of a punch with an elastic layer, is extended to the case of a multilayered packet of finite thickness. The general scheme for the solution (the search for the zeros and the poles of the symbol of the kernel, reduction to an infinite algebraic system starting from the conditions for the removability of the singularities of the Fourier transform and the regularization of the system by taking account of the nature of the singularity of the solution at the boundary of the contact area) remains on the whole as before. The main difference in the case of a multilayered packet is the increasing difficulties in constructing the symbol of the kernel and the search for its zeros and poles in the complex plane. A description of the special features in carrying out these steps is given and numerical results which show the trajectories of the motion of the poles in the complex plane for a continuous change in the elastic properties of the layers are represented, as well as the effect of the lamination on the form of the frequency dependence of the contact rigidity of the packet.

Thermoelastic deformation of multilayered shells of rotation under a local effect

A variant of the finite-shear theory was used to determine more accurately the functions of distribution of transverse tangential stresses over the thickness of a multilayered packet with the thermal sensitivity of the layer material taken into account. The results are presented of investigations of one-, three-, and five-layer cylindrical shells produced from thermally sensitive materials, under a local temperature effect.

Kinetics of the collision of metallic plates in a multilayer packet during explosion welding

The achievement of high strength in the compounding of metallic plates in layered composite material (LCM) during explosion welding (EW) in accordance with the {open_quotes}simultaneous{close_quotes} scheme requires strict and precise dosing of energy input on all of its interlayer boundaries, which can be achieved through the creation of specific conditions, during each act of collision in the packet, characterized by the properties of the metals being combined and by the kinematic parameters of the EW, the most important of which are usually considered to be the collision speeds V{sub l} of the layers. However, the task of the computational evaluation of the layer collision speeds in a multilayer packet corresponding to the actual physical picture of the process, in view of the complexity and transience of the phenomena occurring during welding, remains at present unsolved in many of its aspects. The present article investigates the true character of kinetics of the layer-by-layer collision of metal plates in a multi-layer packet during its explosive welding in accordance with the {open_quotes}simultaneous{close_quotes} scheme, which is frequently used in practice. In order to test the adequacy of the proposed kinematic model, a series of experiments in the EW of multilayer model composites was carriedmore » out in accordance with an improved method.« less