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Date 8-11 June 2010

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Displaying Results 1 - 25 of 46
  • [Front cover]

    Page(s): c1
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    Freely Available from IEEE
  • [Title page]

    Page(s): 2 - 3
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    Freely Available from IEEE
  • Obituary [Vladimir Sergeevitch Buldyrev]

    Page(s): 4
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    Freely Available from IEEE
  • The 80th birthday of V. M. Babich

    Page(s): 5
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    Freely Available from IEEE
  • Contents

    Page(s): 6 - 8
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    Freely Available from IEEE
  • The diffraction and dispersion of waves in the space-periodic structure with the 2-dimensional electronic gas

    Page(s): 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    This paper reports on the diffraction and dispersion of waves in the semiconductor space-periodic structure with the 2D electronic gas. The diffraction grating is needed to ensure a radiating mode. The problem of the electromagnetic wave on the semiconductor structure with a diffraction grating is solved in a rigorous formulation method. In addition, the reflection coefficient signal is investigated in a wide frequency range of the parameters of the structure. View full abstract»

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  • New approach to solution of sine-Gordon equation with variable amplitude

    Page(s): 10 - 15
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (917 KB) |  | HTML iconHTML  

    Methods of construction of functionally invariant solutions are represented for (3+1) sine-Gordon equation with variant amplitude. The solutions U(x, y, z, t) are expressed through arbitrary function of one f(α) or two f(α, β) ansatzes. Ansatzes (α, β) are defined as roots of the algebraic or mixed (algebraic and the first order differential) equations. The equations, defining ansatzes, also contain arbitrary functions, depending on (α, β). The offered methods allow to find U(x, y, z, t) for private, but wide class of the regular and singular amplitudes. These methods are easily generalized for the cases of spaces with arbitrary dimensions. It is possible to hope, that the found solutions will be useful for the description of the physical processes taking place in the media with real structure. View full abstract»

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  • Transition radiation in a waveguide with semi-bounded cold plasma

    Page(s): 16 - 21
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2494 KB) |  | HTML iconHTML  

    We analyze transition radiation of a charge crossing the boundary between vacuum and cold plasma in a waveguide. We obtain exact and approximate expressions with the steepest descend technique for the field components. It is shown that the electromagnetic field has the different structure in vacuum and cold plasma. We develop an algorithm for computation of the field based on a certain transformation of the integration path. Behavior of the field components depending on distance and time is explored for different velocities of the charge motion. Some important physical effects are noted. So, considerable increase and concentration of the field near the “wave front” in plasma is observed for the case of ultra-relativistic particle. As well, in plasma the envelope of the field has the zero point if the charge velocity is within certain limits. View full abstract»

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  • Dynamics of convecting elastic solids

    Page(s): 22 - 27
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    The dynamics of a class of convecting elastic media is considered. The general field equation governing small oscillations is derived variationally. The mathematical structure of the field equation thus derived is examined. The origins of the `gyroscopic' and the `centrifugal' effects are traced. These can be associated with various terms in the expression for the Lagrangian density. In particular, terms in the kinetic energy density that are independent the velocity field, those that are linear in the velocity field and those that are quadratic in the velocity field are associated with the centrifugal, gyroscopic, and inertia terms in the equation of motion respectively. A close mathematical analogy between the dynamics of this class of continua and the dynamics of discrete gyroscopic-centrifugal systems having fixed material particles is noted. The free vibration problem is posed in its generality. An appropriate Rayleigh quotient is defined. The stationarity associated with the quotient can potentially be used for computational work. Illustrative examples and applications are discussed. View full abstract»

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  • Connection between representations of nonstandard and standard Chebyshev oscillators

    Page(s): 28 - 34
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (476 KB) |  | HTML iconHTML  

    We continue consideration the generalized oscillator algebra related to Jacobi matrix which differs from ones for Chebyshev polynomials only by nonzero main diagonal, consisting from periodically repeated set of three numbers {i√(3), -i√(3), 0}. We show that representations of this algebra are connected with representations of three more simple generalized oscillator algebras, related to Chebyshev polynomials of second kind. This investigation is partially supported by RFBR grant No 09-01-00504-a. View full abstract»

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  • Dynamic equations for an orthotropic plate

    Page(s): 35 - 39
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    A hierarchy of dynamic plate equations is derived for an orthotropic elastic plate. Using power series expansions in the thickness coordinate for the displacement components, recursion relations are obtained among the expansion functions. Using these in the boundary conditions on the plate surfaces, a set of dynamic equations are derived. These can be truncated to any order and are believed to be asymptotically correct. A comparison for the dispersion curves is made with exact 3D theory and other approximate theories. View full abstract»

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  • Wave dynamics of non-harmonic internal gravity wave in stratified ocean

    Page(s): 40 - 41
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (107 KB) |  | HTML iconHTML  

    The uniform asymptotic form of the internal gravity waves field generated by a source moving above the smoothly varying bottom is constructed. The problem of reconstructing non-harmonic internal gravity wave packets generated by a source moving in a stratified ocean is considered. The solution is proposed in terms of wave modes, propagating independently at the adiabatic approximation, and described as a non-integral degree series of a small parameter characterizing the stratified medium. A specific form of the wave packets, which can be parameterized in terms of model functions (Airy functions), depends on a local behavior of the dispersion curves of individual wave mode. A modified space-time ray method was proposed, which belongs to the class of geometrical optics methods. The key point of the proposed technique is the possibility to derive the asymptotic representation of the solution in terms of a non-integral degree series of the some small parameter. View full abstract»

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  • Radio coverage simulation for three-dimensional urban environment using physical optics, physical theory of diffraction and the near-to-far-field transformation method

    Page(s): 42 - 47
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1525 KB) |  | HTML iconHTML  

    The objective of this paper is the presentation of a three-dimensional model which simulates the electromagnetic propagation in outdoor urban areas for GSM frequencies (900 - 1800 MHz), through the combination of separate propagation mechanisms. The simulation results of each propagation mechanism are analyzed in order to derive its contribution to the total received field. The simulation program is created using Matlab. The mechanisms considered for evaluation are the Line-of-Sight, scattering and diffraction. The produced radio coverage diagrams indicate the importance of scattering and diffraction as mechanisms of electromagnetic propagation in mobile telecommunications coverage in dense urban environments. They also provide a satisfactory radio coverage prediction for three-dimensional space taking into account the difference in height between the transmitter and the receiver. View full abstract»

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  • Oscillations of statistical scattering in Rayleigh limit

    Page(s): 48 - 54
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1465 KB)  

    Oscillations of statistical wave scattering in Rayleigh limit are theoretically found. These oscillations are violation of the Rayleigh law of scattering. They are caused by the diffraction of a new form which leads to the different frequency dependencies of the scattering coefficient in the Rayleigh limit and thus violates Rayleigh law of scattering. View full abstract»

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  • Asymptotics of the solution to the mixed boundary elliptic problem

    Page(s): 55 - 56
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (241 KB) |  | HTML iconHTML  

    The following two-dimension problem is considered: equation Δu = f(x) in some domain Ω ∈ ℝ2 with piecewise smooth boundary. The boundary condition is following: the derivative on a normal is equal zero everywhere, except a small segment γ, where function u(x) is given. The length of the segment equal to a small parameter ε. There is a problem to find the asymptotics of the solution u(x, ε) as ε → 0. The full asymptotic expansion was constructed and proved. View full abstract»

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  • Statement of the boundary-contact problems for the shells in acoustics

    Page(s): 57 - 62
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1189 KB) |  | HTML iconHTML  

    Shells are the elements of various constructions, particulary partially submerged into the water (see [1], Fig. 1). They are subjected to external forces of different kind. It is important to estimate the level of vibration fields in these composite systems and analyze energy and energy flow in them. Different shell models were considered in [2], [3], [4] for example. The shell models of Timoshenko and Kirchhoff-Love type, approach and results received in [2] are considered here. View full abstract»

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  • Iterative algorithms for multiple electromagnetic scattering in three dimensions

    Page(s): 63 - 68
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (458 KB) |  | HTML iconHTML  

    We describe and compare two iterative fully discrete high-order algorithms for simulation of electromagnetic scattering by multiple perfectly conducting three dimensional particles. Our hybrid surface integral algorithms use a combination of high-order approximations of the tangential surface current on each particle and iterative schemes to simulate the multiple scattering problem by solving several single particle scattering problems with each iteration efficiently taking into account reflected waves from all scatterers in the configuration. View full abstract»

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  • Trapped-mode, pass- and gap-band effects waveguides with obstacles

    Page(s): 69 - 72
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (721 KB) |  | HTML iconHTML  

    Resonance localization of incident wave energy near obstacles in the form of energy vortices resulting in sharp blocking, known as a trapped mode effect, is under investigation. While resonance response of a single obstacle works as a blocker, for the waveguide with several obstacles it is observed that it becomes opened in narrow vicinities of resonance frequencies. With the increase of defects number pass frequencies segments expand forming the same pass bands as the Bloch-Floquet theory predicts. View full abstract»

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  • Spring boundary conditions and modeling of 2D wave propagation in composites with imperfect interfaces

    Page(s): 73 - 78
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1716 KB) |  | HTML iconHTML  

    The possibility of applying spring boundary conditions to model propagation of elastic waves in layered composites with nonperfect contact between layers in studied. The stiffnesses in the spring boundary conditions are determined by the crack density, the effective size of microdefects, and the elastic properties of the materials via the Baik-Thompson and Boström-Wickham approaches. The efficiency of the model is analyzed for periodic structures with damaged layers. View full abstract»

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  • Seismic data processing in terms of locally supported wavelets

    Page(s): 79 - 84
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (917 KB) |  | HTML iconHTML  

    We develop a mathematical tool which is used for the regularization of a singular integral representation of the Helmholtz equation in a region with non-smooth boundaries with a constant parameter, i.e. in a medium with a constant velocity. The classical perturbation approach is then applied in order to calculate the Helmholtz equation with a variable parameter. Moreover, for media with strong variation in a velocity field, the combination with a solution of the eikonal equation can be used. Because such approach consider only waves with the shortest travel times, we apply it for a filtering, e.g. for the separating of down-going and up-going waves. View full abstract»

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  • On the extension of the wave based method

    Page(s): 85 - 92
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1027 KB) |  | HTML iconHTML  

    This paper discusses the possibility to apply the ideas of the wave based method, which has been developed for the steady-state acoustic areas, i.e. to solve Helmholtz type boundary value problems in a bounded domain, in non-acoustics areas such as steady-state temperature propagation, calculation of the velocity potential function of a liquid flux, calculation of the light irradience in a liver tissue/tumor, etc. We show a way to handle the inhomogeneity in the differential equation using the non-uniform non-rational B-splines. View full abstract»

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  • New analytical WA-systems of Kravchenko functions

    Page(s): 93 - 98
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1795 KB) |  | HTML iconHTML  

    In this representation the new class of analytical WA-systems of Kravchenko functions on the basis of the theory of atomic functions (AF) [1-5] are constructed and proof. The all wavelet conditions [3-8, 12-15] are satisfied exact. The constructed wavelets have a compact support and they are infinitely differentiable. New wavelet function using for the analysis of time series on examples of Solar activity, quasar apparent magnitude and electrocardiography [9-11, 16]. View full abstract»

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  • Radial atomic functions in digital signal processing

    Page(s): 99 - 101
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1129 KB) |  | HTML iconHTML  

    The new class of radial basis functions on the basis of the theory of the atomic functions (AF) [1-9] is consider. As it known [2-5, 7-9] that AF are the solutions of functional differential equations with shifted argument with compact support. The important thing is their smoothness and high speed of convergence of their basis. On their basis radial Kravchenko wavelet are constructed. Examples of filtering and wavelet-analysis of the radial signals are presented. View full abstract»

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  • Linearized system of magnetohydrodynamics for the ideal incompressible fluid

    Page(s): 102 - 105
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    This paper investigates wave propagation in the linearized system of magnetohydrodynamics (MHD). This system has characteristic roots of variable multiplicity. MHD system in incompressible ideal fluid is considered. View full abstract»

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  • Excitation of electromagnetic waves by a pulsed ring current in a magnetoplasma

    Page(s): 106 - 112
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    Pulsed radiation from a ring current source immersed in a magnetoplasma is studied. An expression for the radiated energy is derived and its distribution over the spatial and frequency spectra of the excited waves as a function of the source parameters is analyzed. Numerical results referring to the case where the frequency spectrum of the current is concentrated in the whistler frequency range are reported and discussed. View full abstract»

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