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On convergence and stability of a numerical scheme of Coupled Nonlinear Schrödinger Equations
PublicationRozważamy rozwiązania numeryczne układu sprężynowych równań nieliniowych Schrödingera. Udowodniliśmy stabilność i zbieżność. Testujemy za pomocą rozwiązań solitonowych.
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The equations for interactions of polarization modes in optical fibres including the kerr effect
PublicationWe have derived coupled nonlinear Schro¨ dinger equations (CNLSE) for arbitrary polarized light propagation in a single-mode fibre employing electromagnetic field complete description. We used a basis of transverse eigenmodes with appropriate projecting; hence, the nonlinear constants depend on the waveguide geometry. Accounting for a weak nonlinearity, which is connected to the Kerr effect, we have given explicit expressions for...
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Problem of proper decomposition and initialization of acoustic and entropy modes in a gas affected by the mass force
PublicationThe relations connecting perturbations specific for acoustic and entropy modes in an accelerated fluid or in a fluid affected by constant mass force, are derived. They allow to decompose the total vector of perturbations and the overall energy into acoustic and non-acoustic parts uniquely at any instant. In order to do this, three quantities are required, for example total perturbations in entropy, pressure and velocity. The evaluations...
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On analytical solution of stationary two dimensional boundary problem of natural convection
PublicationApproximate analytical solution of two dimensional problem for sta- tionary Navier-Stokes, continuity and Fourier-Kirchho equations describ- ing free convective heat transfer from isothermal surface of half innite vertical plate is presented. The problem formulation is based on the typ- ical for natural convection assumptions: the uid noncompressibility and Boussinesq approximation. We also assume that orthogonal to the plate component...
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Quantum corrections to quasi-periodic solution of Sine-Gordon model and periodic solution of phi^4 model
PublicationAnalytical form of quantum corrections to quasi-periodic solution of Sine-Gordon model and periodic solution of phi^4 model is obtained through zeta function regularisation with account of all rest variables of a d-dimensional theory. Qualitative dependence of quantum corrections on parameters of the classical systems is also evaluated for a much broader class of potentials u(x) = b^2 f(bx) + C with b and C as arbitrary real constants
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Ultrashort Opposite Directed Pulses Dynamics with Kerr Effect and Polarization Account
PublicationWe present the application of projection operator methods to solving the problem of the propagation and interaction of short optical pulses of different polarizations and directions in a nonlinear dispersive medium. We restrict ourselves by the caseof one-dimensional theory, taking into account material dispersion and Kerr nonlinearity. The construction of operators is delivered in two variants: for the Cauchy problem and for the...
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Quantum corections to SG equation solutions and applications
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Novel Analytic-Numerical Model of Free Convection: with Leading Edge Considered
PublicationA novel solution of the free convection boundary problem is represented in analytical form for velocity and temperature for an isothermal vertical plate, as an example. These fields are built as a Taylor Series in the x coordinate with coefficients as functions of the vertical coordinate (y). We restrict ourselves by cubic approximation for both functions. The basic Navier-Stokes and Fourier-Kirchhoff equations and boundary conditions...
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Coupled nonlinear Schrödinger equations in optic fibers theory
PublicationIn this paper a detailed derivation and numerical solutions of CoupledNonlinear Schr¨odinger Equations for pulses of polarized electromagnetic wavesin cylindrical fibers has been reviewed. Our recent work has been compared withsome previous ones and the advantage of our new approach over other methods hasbeen assessed. The novelty of our approach lies is an attempt to proceed withoutloss of information within the frame of basic...
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Study of free convective boundary layer of isothermal lateral surface of axisymmetrical horizontal body
PublicationPrzedstawiono rozwiązanie równań Naviera-Stokesa i Fouriera-Kirchhoffa we współrzędnych tau i sigma. Pierwsza jest styczną a druga normalną do konwekcyjnych linii prądu, wzdłuż jakich porusza się ogrzany od powierzchni płyn. Wynik w postaci równania na grubość warstwy przyściennej zweryfikowano dla granicznych przypadków ciała obrotowego o poziomej osi symetrii (stożka poziomego i kołowej pionowej płyty).
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Directed electromagnetic pulse dynamics: projecting operators method
PublicationIn this article, we consider a one-dimensional model of electromagnetic pulse propagation in isotropic media, takinginto account a nonlinearity of the third order. We introduce a method for Maxwell's equation transformation on thebasis of a complete set of projecting operators. The operators correspond to wave dispersion branches including thedirection of propagation. As the simplest result of applying the method, we derive a system...
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Oriented Gaussian beams for high-accuracy computation with accuracy control of X-ray propagation through a multi-lens system
PublicationA highly accurate method for calculating X-ray propagation is developed. Within this approach, the propagating wave is represented as a superposition of oriented Gaussian beams. The direction of wave propagation in each Gaussian beam agrees with the local direction of propagation of the X-ray wavefront. When calculating the propagation of X-ray waves through lenses, the thin lens approximation is applied. In this approximation,...
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GENERAL DYNAMIC PROJECTING OF MAXWELL EQUATIONS
PublicationA complete – system of Maxwell equations is splitting into independent subsystems by means of a special dynamic projecting technique. The technique relies upon a direct link between field components that determine correspondent subspaces. The explicit form of links and corresponding subspace evolution equations are obtained in conditions of certain symmetry, it is illustrated by examples of spherical and quasi-one-dimensional waves.
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The Dynamical Projectors Method Hydro and Electrodynamics
PublicationThe dynamical projectors method proves to reduce a multicomponent problem to the simplest one-component problem with its solution determined by specific initial or boundary conditions. Its universality and application in many different physical problems make it particularly useful in hydrodynamics, electrodynamics, plasma physics, and boundary layer problems. A great variety of underlying mechanisms are included making this book...
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Theoretical consideration of free convective heat transfer from a round isothermal plate slightly inclined from the vertical
PublicationA semi-analytical solution of simplified Navier-Stokes and Fourier-Kirchhoff equations describing free convective heat transfer from a round isothermal surface slightly inclined from the vertical is presented. The solution is based on the assumption, typical for natural convection, that the velocity component normal to the surface is negligibly small in comparison to the tangential one. Next we neglect the nonlinear inertia force...
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Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force
PublicationDiagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant...
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Different types of solvability conditions for differential operators
PublicationSolvability conditions for linear differential equations are usually formulated in terms of orthogonality of the right-hand side to solutions of the homogeneous adjoint equation. However, if the corresponding operator does not satisfy the Fredholm property such solvability conditions may be not applicable. For this case, we obtain another type of solvability conditions, for ordinary differential equations on the real axis, and...
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Constructive Controllability for Incompressible Vector Fields
PublicationWe give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen...
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Linear Time-Varying Dynamic-Algebraic Equations of Index One on Time Scales
PublicationIn this paper, we introduce a class of linear time-varying dynamic-algebraic equations (LTVDAE) of tractability index one on ar- bitrary time scales. We propose a procedure for the decoupling of the considered class LTVDAE. Explicit formulae are written down both for transfer operator and the obtained decoupled system. A projector ap- proach is used to prove the main statement of the paper and sufficient conditions of decoupling...
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Topological Behaviour of Solutions of Vibro-Impact Systems in the Neighborhood of Grazing
PublicationThe grazing bifurcation is considered for the Newtonian model of vibro-impact systems. A brief review on the conditions, sufficient for the existence of a grazing family of periodic solutions, is given. The properties of these periodic solutions are discussed. A plenty of results on the topological structure of attractors of vibro-impact systems is known. However, since the considered system is strongly nonlinear, these attractors...
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Rotating rod and ball
PublicationWe consider a mechanical system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points. The ball is reflected elastically when colliding with the rod and moves freely between consecutive hits. A sliding motion along the rod is also allowed. We prove the existence and uniqueness of the motion with a given position and velocity at a certain time...
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Inverse shadowing and related measures
PublicationWe study various weaker forms of the inverse shadowing property for discrete dynamical systems on a smooth compact manifold. First, we introduce the so-called ergodic inverse shadowing property (Birkhoff averages of continuous functions along an exact trajectory and the approximating one are close). We demonstrate that this property implies the continuity of the set of invariant measures in the Hausdorff metric. We show that the...
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Weak forms of shadowing in topological dynamics
PublicationWe consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomor- phisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing)...
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Stability by linear approximation for time scale dynamical systems
PublicationWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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One-dimensional chaos in a system with dry friction: analytical approach
PublicationWe introduce a new analytical method, which allows to find chaotic regimes in non-smooth dynamical systems. A simple mechanical system consisting of a mass and a dry friction element is considered. The corresponding mathematical model is being studied. We show that the considered dynamical system is a skew product over a piecewise smooth mapping of a segment (the so-called base map). For this base map we demonstrate existence of...
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The saga of a fish: from a survival guide to closing lemmas
PublicationIn the paper by D. Burago, S. Ivanov and A. Novikov, “A survival guide for feeble fish”, it has been shown that a fish with limited velocity can reach any point in the (possibly unbounded) ocean provided that the fluid velocity field is incompressible, bounded and has vanishing mean drift. This result extends some known global controllability theorems though being substantially nonconstructive. We give a fish a different recipe...
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Billiard in a rotating half-plane
PublicationThe main objective of this research is to study the properties of a billiard system in an unbounded domain with moving boundary. We consider a system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points and experiences elastic collisions with the ball. We define a mathematical model for the dynamics of such a system and write down asymptotic...
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Green function diagonal for a class of heat equations
PublicationA construction of the heat kernel diagonal is considered as element of generalized zeta function theory, which gradient at the origin defines determinant of a differential operator in a technique for regularizing quadratic path integral. Some classes of explicit expressions of the Green function in the case of finite-gap potential coefficient of the heat equation are constructed. An algorithm and program for Mathematica are presented...
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Quantum corrections to phi^4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are evaluated with account of rest d−1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of spacetime functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional integral...
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Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are valuated with account of rest d − 1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of space- time functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional...
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Experimental study of natural convection heat transfer from horizontal conic
PublicationPrzedstawiono badania eksperymentalne i ich wyniki konwekcji swobodnej w wodzie i powietrzu poziomych stożków o kącie przy podstawie 30, 45 i 60 deg. Wyniki badań wykazują dobrą zgodność z rozwiązaniem teoretycznym i z danymi literaturowymi.
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Study of free convective heat transfer from horizontal conic.
PublicationPrzedstawiono teoretyczne rozważania i badania eksperymentalne konwekcji swobodnej od izotermicznej powierzchni poziomego stożka w przestrzeni nieograniczonej. Rozwiązanie przeprowadzono dla wprowadzonego krzywoliniowego układu współrzędnych, opartego na krzywej linii prądu wokół powierzchni stożkowej.
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Natural convection from horizontal conic.
PublicationPrzedstawiono rozważania teoretyczne konwekcji swobodnej od powierzchni bocznej poziomego stożka.
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Tollmien- Shlichting and sound waves interaction: nonlinear resonances.
PublicationRozpatruje się oddziaływanie różnych typów modów hydrodynamicznych w warstwie lepkiej. Stwierdzono możliwość istnienia oddziaływania rezonansowego.Dokładne równania ewolucyjne kierujące dynamiką warstwy lepkiej zostały wypisane.
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A theoretical consideration of a free convective boundary layer on an isothermal horizontal conic.
PublicationPrzedstawiono rozwiązanie analityczne naturalnej konwekcji swobodnej od izotermicznego, poziomego stożka o kącie przy podstawie alfa. Rozwiązanie przeprowadzono w oparciu o typowe dla konwekcji swobodnej założenia upraszczające. Rozwiązania dla przypadków granicznych (poziomy walec i pionowa płyta kołowa) wykazują dobrą zgodność z danymi literaturowymi.
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Interaction of vortical and acoustic waves: from general equations to integrable cases
PublicationWyprowadzono operatory rzutu przepływu w warstwie lepkiej przyściennej na podstawowe typy ruchów. Wyprowadzono również układy równań dynamicznych sterujących przepływem. Zaproponowano metody analityczne dalszego rozwiązywania tych równań.
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Nonlinear evolution of components of electromagnetic field of helicoidal wave in plasma
PublicationWyprowadzilismy model równań opisujących oddziaływanie pomiedzy kołowo spolaryzowanymi paczkami fal helikoidalnych w dwuwymiarowej plazmie. Dla quasi-jednowymiarowego przypadku otrzymaliśmy warunek nieliniowego rezonansu dla oddziaływania N-fal. Nowym ''osiągnięciem'' badań w kontekscie teorii solitonów, jest znalezienie rozwiązań dla przypadku asynchronizmu fal, które wydaje się być podstawowym dla paczek falowych nachylonych...
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Three dimensional fluid equations from distribution function with discontinuity in velocity space
PublicationUkład równań typu hydrodynamicznego dla rozwarstwionego gazu w polu grawitacyjnym jest wyprowadzony z równania BKG przy użyciu metody kawałków ciągłej funkcji dystrybucji. Otrzymany układ równań uogólnia układ Naviera-Stokesa dla dowolnych liczb Knudsena.
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Spam classification methods besed on users e-mail communication graphs
PublicationW artykule poddano analizie grafy zbudowane w oparciu o logi serwerów pocztowych. Węzły grafów reprezentują nadawców i odbiorców wiadomości e-mail natomiast krawędzie przedstawiają procesy wymiany wiadomości e-mail. Analiza grafów pozwala na znalezienie korelacji pomiędzy topologią grafów a relacjami pomiędzy użytkownikami serwisu pocztowego. W oparciu o te relacje zaproponowano algorytm klasyfikujący wymieniane wiadomości e-mail...
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CENTRUM w systemie STRADAR – funkcje, architektura i realizacja
PublicationSystem STRADAR jest rozwiązaniem umożliwiającym utworzenie infrastruktury komunikacyjno-teleinformatycznej przeznaczonej dla Morskiego Oddziału Straży Granicznej. Artykuł ten jest kolejną z cyklu publikacji opisujących architekturę i rozwiązanie systemu i dotyczy jego centralnego elementu, jakim jest CENTRUM. Przedstawiono i opisano funkcje, architekturę i realizację oprogramowania CENTRUM, które może być zainstalowane na dowolnym...
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Standard IEC 61850 w sieci rozdzielczej średniego napięcia CERN
PublicationArtykuł stanowi skrótowy opis wyników pracy autora w okresie od 01.10.2009 do 30.09.2010 w Engineering Department, High-Voltage Section w CERN. Przedstawiono system zasilania elektroenergetycznego obiektów CERN wraz automatyką ATS w sieci 18 kV. Zdefiniowano założenia dla automatyki w ramach planowanych modernizacji sieci średniego napięcia, wskazując na wymóg zgodności ze standardem IEC 61850. Zaproponowano trójpierścieniową topologię...
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Bezprzewodowy system monitoringu zanieczyszczeń powietrza
PublicationW referacie zaprezentowano mobilny system monitoringu, który umożliwia pomiar gazowych zanieczyszczeń powietrza atmosferycznego, zarówno pochodzenia przemysłowego jak i będących efektem dużego natężenia ruchu ulicznego. W opracowanym systemie stacja monitorująca charakteryzuje się stosunkowo niewielkimi rozmiarami i zawiera układ elektroniczny autorskiego rozwiązania do pomiaru, zapisu i transmisji drogą radiową na serwer pomierzonych...
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MAPSERVER – INFORMATION FLOW MANAGEMENT SOFTWARE FOR THE BORDER GUARD DISTRIBUTED DATA EXCHANGE SYSTEM
PublicationIn this paper the architecture of the software designed for management of position and identification data of floating and flying objects in Maritime areas controlled by Polish Border Guard is presented. The software was designed for managing information stored in a distributed system with two variants of the software, one for a mobile device installed on a vessel, an airplane or a car and second for a central server. The details...
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Teleinformatyczna akwizycja i przetwarzanie danych dla potrzeb diagnostyki środowiska aglomeracji miejskich
PublicationRozdział przedstawia koncepcję aktualnie opracowywanego systemu służącego do monitorowania hałasu i ruchu drogowego w aglomeracjach miejskich, stanowiącego funkcjonalną część szerszego rozwiązania dotyczącego monitorowania środowiska w miastach. System taki składa się z rozmieszczonych w mieście autonomicznych i uniwersalnych stacji monitorujących oraz serwera gromadzącego, przetwarzającego i prezentującego wyniki z wykorzystaniem...
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Prediction Model for Hemorrhagic Complications after Laparoscopic Sleeve Gastrectomy: Development of SLEEVE BLEED Calculator
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Long-Term Outcomes of Laparoscopic Sleeve Gastrectomy—a Single-Center, Retrospective Study
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Case-Control Study of Postoperative Blood Pressure in Patients with Hemorrhagic Complications after Laparoscopic Sleeve Gastrectomy and Matched Controls
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The First Report on Hybrid NOTES Adjustable Gastric Banding in Human
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A 5-Year Experience with Laparoscopic Adjustable Gastric Banding—Focus on Outcomes, Complications, and Their Management
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Preliminary Outcomes 1 Year after Laparoscopic Sleeve Gastrectomy Based on Bariatric Analysis and Reporting Outcome System (BAROS)
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