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  • 13551.
    Rudenko, Oleg
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Moscow MV Lomonosov State Univ, Phys Fac, Moscow 119991, Russia.;Russian Acad Sci, Prokhorov Gen Phys Inst, Moscow, Russia.;Russian Acad Sci, Schmidt Inst Phys Earth, Moscow, Russia.;Blekinge Inst Technol, Karlskrona, Sweden..
    Wave Excitation in a Dissipative Medium with a Double Quadratically-Modular Nonlinearity: a Generalization of the Inhomogeneous Burgers Equation2018In: Doklady. Mathematics, ISSN 1064-5624, E-ISSN 1531-8362, Vol. 97, no 3, p. 279-282Article in journal (Refereed)
    Abstract [en]

    Solutions of a forced (inhomogeneous) partial differential equation of the second order with two types of nonlinearity: power (quadratic) and nonanalytic (modular) are found. Equations containing each of these nonlinearities separately were studied earlier. A natural continuation of these studies is the development of the theory of wave phenomena in a medium with a double nonlinearity, which have recently been observed in experiments. Here solutions describing the profiles of intense waves are derived. Shapes of freely propagating stationary perturbations in the form of shock waves with a finite front width are found. The profiles of forced waves excited by external sources are calculated.

  • 13552.
    Rudenko, Oleg
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Оn strongly nonlinear waves and waves with strongly displayed weak nonlinearity2013In: Nonlinear Waves – 2012 / [ed] Gurbatov, S.N., Nizhny Novgorod: Institute of Applied Physics , 2013Chapter in book (Refereed)
  • 13553. Rudenko, Oleg
    et al.
    Crocker, Malcolm
    Nonlinear Acoustics2006In: Handbook of Noise and, New York: Wiley and Sons , 2006, p. 159-168Chapter in book (Other academic)
  • 13554.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Moscow MV Lomonosov State Univ, Phys Fac, Moscow 119991, Russia.;Nizhnii Novgorod State Univ, Radiophys Fac, Nizhn Novgorod, Russia.;Russian Acad Sci, Prokhorov Gen Phys Inst, Moscow, Russia.;Russian Acad Sci, Schmidt Inst Phys Earth, Moscow, Russia.;Blekinge Inst Technol, Karlskrona, Sweden..
    Gurbatov, S. N.
    Nizhnii Novgorod State Univ, RUS.
    Statistical Problems for the Generalized Burgers Equation: High-Intensity Noise in Waveguide Systems2018In: Doklady. Mathematics, ISSN 1064-5624, E-ISSN 1531-8362, Vol. 97, no 1, p. 95-98Article in journal (Refereed)
    Abstract [en]

    A one-dimensional equation is presented that generalizes the Burgers equation known in the theory of waves and in turbulence models. It describes the nonlinear evolution of waves in pipes of variable cross section filled with a dissipative medium, as well as in ray tubes, if the approximation of geometric acoustics of an inhomogeneous medium is used. The generalized equation is reduced to the common Burgers equation with a dissipative parameter-the "Reynolds-Goldberg number," depending on the coordinate. The method for solving statistical problems corresponding to specified characteristics of a noise signal at the input of the system is described. Integral expressions for exact solutions are given for the correlation function and the noise intensity spectrum experiencing nonlinear distortions during propagation in a waveguide. For waves in a dissipative medium, an approximate method of calculating statistical characteristics is given, consisting in finding an auxiliary correlation function and the subsequent nonlinear functional transformation. Solutions have a complicated form, so physical analysis of phenomena requires the numerical methods. For some correlation functions of stationary noise with initial Gaussian statistics and some waveguide systems, it is possible to obtain simple results.

  • 13555. Rudenko, Oleg
    et al.
    Gurbatov, Sergey
    Hedberg, Claes
    Nonlinear Acoustics Through Problems and Examples2010Book (Other academic)
    Abstract [en]

    The fundamentals of nonlinear acoustics are presented in form of problems followed by solutions, explanations and answers. As distinct from existing textbooks, this book of problems not only helps the reader to become familiar with nonlinear wave processes and the methods of their description, but contributes to mastering calculation procedures and obtaining numerical estimates of the most significant parameters. Thereby, skills are acquired which are indispensable for carrying out original scientific research. This book can be useful to undergraduate and postgraduate students and researchers working in the field of nonlinear wave physics and acoustics.

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  • 13556. Rudenko, Oleg
    et al.
    Gurbatov, Sergey
    Hedberg, Claes
    Nonlinear Acoustics through Problems and Examples (in Russian)2006Book (Other academic)
  • 13557.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gurbatov, Sergey N.
    Lobachevsky State University of Nizhni Novgorod, RUS.
    Tyurina, A. V.
    Lobachevsky State University of Nizhni Novgorod, RUS.
    Evolution of weak noise and regular waves on dissipative shock fronts described by the Burgers model2018In: Wave motion, ISSN 0165-2125, E-ISSN 1878-433X, Vol. 82, p. 20-29Article in journal (Refereed)
    Abstract [en]

    The interaction of weak noise and regular signals with a shock wave having a finite width is studied in the framework of the Burgers equation model. The temporal realization of the random process located behind the front approaches it at supersonic speed. In the process of moving to the front, the intensity of noise decreases and the correlation time increases. In the central region of the shock front, noise reveals non-trivial behaviour. For large acoustic Reynolds numbers the average intensity can increase and reach a maximum value at a definite distance. The behaviour of statistical characteristics is studied using linearized Burgers equation with variable coefficients reducible to an autonomous equation. This model allows one to take into account not only the finite width of the front, but the attenuation and diverse character of initial profiles and spectra as well. Analytical solutions of this equation are derived. Interaction of regular signals of complex shape with the front is studied by numerical methods. Some illustrative examples of ongoing processes are given. Among possible applications, the controlling the spectra of signals, in particular, noise suppression by irradiating it with shocks or sawtooth waves can be mentioned. © 2018 Elsevier B.V.

  • 13558.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gurbatov, S.N.
    Inverse problem of nonlinear acoustics: Synthesizing intense signals to intensify the thermal and radiation action of ultrasound2016In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 62, no 4, p. 418-428Article in journal (Refereed)
    Abstract [en]

    Inverse problems of nonlinear acoustics have important applied significance. On the one hand, they are necessary for nonlinear diagnostics of media, materials, manufactured articles, building units, and biological and geological structures. On the other hand, they are needed for creating devices that ensure optimal action of acoustic radiation on a target. However, despite the many promising applications, this direction remains underdeveloped, especially for strongly distorted high-intensity waves containing shock fronts. An example of such an inverse problem is synthesis of the spatiotemporal structure of a field in a radiating system that ensures the highest possible energy density in the focal region. This problem is also related to the urgent problems of localizing wave energy and the theory of strongly nonlinear waves. Below we analyze some quite general and simple inverse nonlinear problems. © 2016, Pleiades Publishing, Ltd.

  • 13559.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gurbatov, S.N.
    Noise Signal Propagation in Soft Biological Tissues2012In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 58, no 2, p. 243-245Article in journal (Refereed)
    Abstract [en]

    Mathematical models are formulated that discribe linear and nonlinear wave propagation in biological tissues. The basis of the method is evolutionary integro-differential equations with a kernel that takes into account the specific properties of tissue. An equation is obtained for the correlation function of acoustic noise in a medium with memory. The procedure for calculating the correlation function by the given type of kernel and noise spectrum at the entrance to the medium is described. It is shown that in different tissue, there is a difference in the laws of decrease in full intensity of a wideband signal with distance. It is demonstrated that the nonlinear equation in the limiting cases of "short-" and "long-term" memory reduces to equations that have been well studied in statistical nonlinear acoustics.

  • 13560.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gurbatov, S.N.
    Demin, I. Yu
    Nonlinear noise waves in soft biological tissues2013In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 59, no 5, p. 584-589Article in journal (Refereed)
    Abstract [en]

    The study of intense waves in soft biological tissues is necessary both for diagnostics and therapeutic aims. Tissue represents an inherited medium with frequency-dependent dissipative properties, in which waves are described by nonlinear integro-differential equations. The equations for such waves are well known. Their group analysis has been performed, and a number of exact solutions have been found. However, statistical problems for nonlinear waves in tissues have hardly been studied. As well, for medical applications, both intense noise waves and waves with fluctuating parameters can be used. In addition, statistical solutions are simpler in structure than regular solutions; they are useful for understanding the physics of processes. Below a general approach is described for solving nonlinear statistical problems applied to the considered mathematical models of biological tissues. We have calculated the dependences of the intensities of the narrowband noise harmonics on distance. For wideband noise, we have calculated the dependence of the spectral integral intensity on distance. In all cases, wave attenuation is determined both by the specific dissipative properties of the tissue and the nonlinearity of the medium.

  • 13561.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Gurbatov, S.N.
    Demin, I.Yu.
    Absorption of intense regular and noise waves in relaxing media2014In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 60, no 5, p. 499-505Article in journal (Refereed)
    Abstract [en]

    An integro-differential equation is written down that contains terms responsible for nonlinear absorption, visco-heat-conducting dissipation, and relaxation processes in a medium. A general integral expression is obtained for calculating energy losses of the wave with arbitrary characteristics-intensity, profile (frequency spectrum), and kernel describing the internal dynamics of the medium. It is shown that for weak waves, the general integral leads to well-known results of a linear approximation. Profiles of stationary solutions are constructed both for an exponential relaxation kernel and for other types of kernels. Energy losses at the front of week shock waves are calculated. General integral formulas are obtained for energy losses of intense noise, which are determined by the form of the kernel, the structure of the noise correlation function, and the mean square of the derivative of realization of a random process

  • 13562.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Gusev, V. A.
    Self-similar solutions of a Burgers-type equation with quadratically cubic nonlinearity2016In: Doklady. Mathematics, ISSN 1064-5624, E-ISSN 1531-8362, Vol. 93, no 1, p. 94-98Article in journal (Refereed)
    Abstract [en]

    Self-similar solutions are found for a quadratically cubic second-order partial differential equation governing the behavior of nonlinear waves in various distributed systems, for example, in some metamaterials. They are compared with self-similar solutions of the Burgers equation. One of them describing a single unipolar pulse is shown to satisfy both equations. The other self-similar solutions of the quadratically cubic equation behave differently from the solutions of the Burgers equation. They are constructed by matching the positive and negative branches of the solution, so that the function itself and its first derivative are continuous. One of these solutions corresponds to an asymmetric solitary N-wave of the sonic shock type. Self-similar solutions of a quadratically cubic equation describing the propagation of cylindrically symmetric waves are also found.

  • 13563.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Science. Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering. Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences. Blekinge Institute of Technology, Department of Telecommunications and Mathematics.
    A new equation and exact solutions describing focal fields in media with modular nonlinearity2017In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 89, no 3, p. 1905-1913Article in journal (Refereed)
    Abstract [en]

    Brand-new equations which can be regarded as modifications of Khokhlov–Zabolotskaya–Kuznetsov or Ostrovsky–Vakhnenko equations are suggested. These equations are quite general in that they describe the nonlinear wave dynamics in media with modular nonlinearity. Such media exist among composites, meta-materials, inhomogeneous and multiphase systems. These new models are interesting because of two reasons: (1) the equations admit exact analytic solutions and (2) the solutions describe real physical phenomena. The equations model nonlinear focusing of wave beams. It is shown that inside the focal zone a stationary waveform exists. Steady-state profiles are constructed by the matching of functions describing the positive and negative branches of exact solutions of an equation of Klein–Gordon type. Such profiles have been observed many times during experiments and numerical studies. The non-stationary waves can contain singularities of two types: discontinuity of the wave and of its derivative. These singularities are eliminated by introducing dissipative terms into the equations—thereby increasing their order. © 2017 The Author(s)

  • 13564.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Diffraction of high-intensity field in focal region as dynamics of nonlinear system with low-frequency dispersion2015In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 61, no 1, p. 28-36Article in journal (Refereed)
    Abstract [en]

    The stationary profile in the focal region of a focused nonlinear acoustic wave is described. Three models following from the Khokhlov-Zabolotskaya (KZ) equation with three independent variables are used: (i) the simplified one-dimensional Ostrovsky-Vakhnenko equation, (ii) the system of equations for paraxial series expansion of the acoustic field in powers of transverse coordinates, and (iii) the KZ equation reduced to two independent variables. The structure of the last equation is analogous to the Westervelt equation. Linearization through the Legendre transformation and reduction to the well-studied Euler-Tricomi equation is shown. At high intensities the stationary profiles are periodic sequences of arc sections having singularities of derivative in their matching points. The occurrence of arc profiles was pointed out by Makov. These appear in different nonlinear systems with low-frequency dispersion. Profiles containing discontinuities (shock fronts) change their form while passing through the focal region and are non-stationary waves. The numerical estimations of maximum pressure and intensity in the focus agree with computer calculations and experimental measurements. © 2015, Pleiades Publishing, Ltd.

  • 13565. Rudenko, Oleg
    et al.
    Hedberg, Claes
    Nonlinear Dynamics of Grains in a Liquid-Saturated Soil2003In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 35, no 2, p. 187-200Article in journal (Refereed)
    Abstract [en]

    A new kind of nonlinearity of inertial type caused by accelerated motion of interacting particles is described. The model deals with an ensemble of grains immersed into a vibrating fluid. First, the nonlinear vibration of two connected grains is studied. The temporal behaviours of displacement and velocity, as well as spectrum of vibration, are analysed. Numerical simulations are performed. Then an infinite chain of grains is considered and the corresponding differential-difference equation is derived. For the continuum limit the inhomogeneous nonlinear wave equation is solved and temporal profiles are calculated. A new resonant phenomenon is described and the resonant curves are constructed.

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  • 13566. Rudenko, Oleg
    et al.
    Hedberg, Claes
    Nonlinear vibrations and waves in a granular and liquid-saturated medium2004In: Acoustics of Inhomogeneous Media, Russian Acoustical Society , 2004, p. 1-15Chapter in book (Other academic)
  • 13567.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Quadratically cubic Burgers equation as exactly solvable model of mathematical physics2015In: Doklady. Mathematics, ISSN 1064-5624, E-ISSN 1531-8362, Vol. 91, no 2, p. 232-235Article in journal (Refereed)
  • 13568.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. Blekinge Inst Technol, S-37179 Karlskrona, Sweden..
    SINGLE SHOCK AND PERIODIC SAWTOOTH-SHAPED WAVES IN MEDIA WITH NON-ANALYTIC NONLINEARITIES2018In: Mathematical Modelling of Natural Phenomena, ISSN 0973-5348, E-ISSN 1760-6101, Vol. 13, no 2, article id UNSP 18Article in journal (Refereed)
    Abstract [en]

    The review of new mathematical models containing non-analytic nonlinearities is given. These equations have been proposed recently, over the past few years. The models describe strongly nonlinear waves of the first type, according to the classification introduced earlier by the authors. These models are interesting because of two reasons: (i) equations admit exact analytic solutions, and (ii) solutions describe the real physical phenomena. Among these models are modular and quadratically cubic equations of Hopf, Burgers, Korteveg-de Vries, Khokhlov-Zabolotskaya and Ostrovsky-Vakhnenko type. Media with non-analytic nonlinearities exist among composites, meta-materials, inhomogeneous and multiphase systems. Some physical phenomena manifested in the propagation of waves in such media are described on the qualitative level of severity.

  • 13569.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Strong and weak nonlinear dynamics: Models, classification, examples2013In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 59, no 6, p. 664-650Article in journal (Refereed)
    Abstract [en]

    The difference between strong and weak nonlinear systems is discussed. A classification of strong nonlinearities is given. It is based on the divergence or inanity of series expansions of the equation of state commonly used in the study of weak nonlinear phenomena. Such power or functional series cannot be used in three cases: (i) if the equation of state contains a singularity; (ii) if the series diverges for strong disturbances; (iii) if the linear term is absent, and higher nonlinearity dominates. Strong nonlinearities are known in acoustics, optics, mechanics and in quantum field theory. Mathematical models, solutions and observed phenomena are presented. For example, an equation of Heisenberg type and its generalization for strongly nonlinear wave system are given. In particular, exact solutions of new “quadratically cubic” Burgers and Riemann–Hopf equations are discovered.

  • 13570.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Strong nonlinearity, anisotropy, and solitons in a lattice with holonomic constraints2019In: Wave motion, ISSN 0165-2125, E-ISSN 1878-433X, Vol. 89, p. 104-115Article in journal (Refereed)
    Abstract [en]

    The nonlinear dynamics of a crystal lattice where the atoms are positioned along parallel rods is studied. They may move only in one direction and this constraint leads to the appearance of nonlinearity even the forces between the atoms obey the linear Hooke's law. This nonlinearity turns out to be strong. The equations of motion of the individual lattice atoms are written, and. in the continuum limit when the lattice period is small in comparison with the wavelength, a new strongly nonlinear partial differential equation is derived. The waves traveling in the direction orthogonal to the rods are purely transverse slow waves, governed by an equation of the Heisenberg type. In the direction along the rods, a fast purely longitudinal wave can propagate. In general, when the wave travels at an arbitrary angle, it is neither purely longitudinal nor transverse and the periodic structure exhibits anisotropic properties. Their velocity depends strongly on the direction of propagation and the structure exhibits properties similar to a skeletal muscle with stretched fibers. Special attention is paid to the soliton solutions of this equation and their behavior is studied. For non-stationary quasi-longitudinal waves, a new evolution equation, rich in symmetries, is derived. One of the solutions with a fixed transverse structure is described by elliptic integrals and evolves in accordance with a cubic nonlinear equation of the Klein–Gordon type. © 2019 Elsevier B.V.

  • 13571.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Strongly nonlinear waves? A new trend of nonlinear acoustics2013Conference paper (Refereed)
    Abstract [en]

    Strongly nonlinear waves (SNWs) and extreme states of matter are key physical concepts. A SNW is a wave whose amplitude is on the order of the material's internal strength limit. When a shock front appears at a distance of 10∧2-10∧3 wavelengths in water, nonlinearity is weak but strongly expressed. The acoustic pressure is 10∧5-10∧6 Pa, much less than the internal pressure 2.2*10∧9 Pa. However, impurities decrease the breaking strength, and waves creates bubbles at smaller pressures. An explosive wave is also a SNW, breaking solids. For weakly nonlinear waves (WNWs) the equation of state can be expanded in power or functional series. However, these cannot be used in 3 cases. First, if the equation contains singularities, like for "clapping" and Hertz nonlinearities of heterogeneous solids. Secondly, if the series is divergent. Thirdly, when the linear term is absent and the higher nonlinearities dominate. Such SNWs appear in mechanics and in quantum field theory.

  • 13572.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    The phenomenon of self-trapping of a strongly nonlinear wave.2014In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, no 4Article in journal (Refereed)
    Abstract [en]

    Self means here an effect of a wave on itself. Several self-action phenomena are known in nonlinear wave physics. Among them are self-focusing of beams self-compression of light pulses self-channeling self-reflection (or self-splitting) waves with shock fronts self-induced transparency and self-modulation. These phenomena are known for weakly nonlinear waves of different physical origin. Our presentation at ASA meeting in Montreal [POMA 19 045080 (2013)] was devoted to strongly nonlinear waves having no transition to the linear limit at infinitesimally small amplitudes. Such waves can demonstrate particle-like properties. Self-trapping consists of the arrest of wave propagation and in the formation of a localized state. In particular the model generalizing the Heisenberg' ordinary differential equation to spatially distributed systems predicts periodic oscillations but no traveling waves. Different models for strongly nonlinear waves will be considered and some unusual phenomena will be discussed. Preliminary results were published in Ac. Phys. 59 584 (2013) and Physics-Uspekhi (Adv. Phys. Sci.) 183 683 (2013). [This work was supported by the Megagrant No.11.G34.31.066 (Russia) and the KK Foundation (Sweden).

  • 13573.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    The quadratically cubic Burgers equation: an exactly solvable nonlinear model for shocks, pulses and periodic waves2016In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 85, no 2, p. 767-776Article in journal (Refereed)
    Abstract [en]

    A modified equation of Burgers type with a quadratically cubic (QC) nonlinear term was recently pointed out as a new exactly solvable model of mathematical physics. However, its derivation, analytical solution, computer modeling, as well as its physical applications and analysis of corresponding nonlinear wave phenomena have not been published up to now. The physical meaning and generality of this QC nonlinearity are illustrated here by several examples and experimental results. The QC equation can be linearized and it describes the experimentally observed phenomena. Some of its exact solutions are given. It is shown that in a QC medium not only shocks of compression can be stable, but shocks of rarefaction as well. The formation of stationary waves with finite width of shock front resulting from the competition between nonlinearity and dissipation is traced. Single-pulse propagation is studied by computer modeling. The nonlinear evolutions of N- and S-waves in a dissipative QC medium are described, and the transformation of a harmonic wave to a sawtooth-shaped wave with periodically recurring trapezoidal teeth is analyzed. © 2016 The Author(s)

  • 13574.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Wave Resonance in Media with Modular, Quadratic and Quadratically-Cubic Nonlinearities Described by Inhomogeneous Burgers-Type Equations2018In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 64, no 4, p. 422-431Article in journal (Refereed)
    Abstract [en]

    The phenomenon of “wave resonance” which occurs at excitation of traveling waves in dissipative media possessing modular, quadratic and quadratically-cubic nonlinearities is studied. The mathematical model of this phenomenon is the inhomogeneous (or “forced”) equation of Burgers type. Such nonlinearities are of interest because the corresponding equations admit exact linearization and describe real physical objects. The presence of “accompanying sources” (traveling with the wave) on the right-hand side of the inhomogeneous equations ensures the inflow of energy into the wave, which thereafter spreads throughout the wave profile, flows to emerging shock fronts, and then dissipates due to linear and nonlinear losses. As an introduction, the phenomenon of wave resonance in ideal and dissipative media is described and physical examples are given. Exact expressions for nonlinear steady-state wave profiles are derived. Non-stationary processes of wave generation, spatial “beating” of amplitudes with different relationship between the speed of motion of the sources and the natural wave velocity in the medium are studied. Resonance curves are constructed that contain a nonlinear shift of the absolute maxima to the “supersonic” region. The features of the resonance in each of the three types of nonlinearity are discussed. © 2018, Pleiades Publishing, Ltd.

  • 13575. Rudenko, Oleg
    et al.
    Hedberg, Claes
    Enflo, Bengt
    Finite-Amplitude Standing Acoustic Waves in a Cubically Nonlinear Medium2007In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 53, no 4, p. 455-464Article in journal (Refereed)
    Abstract [en]

    The behavior of the wave field in a resonator containing a cubically nonlinear medium is studied. The field is constructed as a linear superposition of two counter-propagating and strongly distorted waves. As distinct from a quadratic nonlinear medium the waves traveling in opposite directions are connected through their averaged (over the period) intensities. Both free and forced standing waves are studied. Profiles of discontinuous vibrations containing shock fronts of both compression and rarefaction are constructed. Resonant curves depicting the dependence of mean intensity on the difference between the frequency of vibration of the boundary and the natural frequency of one of the resonator’s mode are calculated. The structure of temporal profiles of strongly distorted forced waves is analyzed. It is shown, that shocks can appear only if the difference between the mean intensity and the discrepancy takes on definite negative values. The discontinuities are studied as jumps between the different solutions of a nonlinear integro-differential equation degenerating at weak dissipation to a third order algebraic equation with an undetermined coefficient. The dependence of the intensity of shocked vibrations on the frequency of vibration of the boundary is found. Nonlinear saturation is shown to appear: the intensity of wave field inside the resonator does not depend on the amplitude of boundary vibration when the amplitude is large. If the amplitude tends to infinity, the intensity tends to its limiting value determined by the nonlinear absorption at shock fronts. This maximum can be reached by smooth increase in frequency above the linear resonance. A hysteresis area and bistability appears, in analogy with the nonlinear resonance phenomena in localized vibration systems described by ordinary differential equations.

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  • 13576. Rudenko, Oleg
    et al.
    Hedberg, Claes
    Enflo, Bengt
    Nonlinear standing waves in a layer excited by periodic motion of its boundary2001In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 47, no 4, p. 452-460Article in journal (Refereed)
    Abstract [en]

    A new analytical approach is developed for the description of standing waves caused by arbitrary periodic vibration of a boundary. The approach is based on the nonlinear evolution equation written for an auxiliary function. This equation offers the possibility to study not only the steady-state acoustic field, but also its evolution in time. One can take into account the dissipative properties of the medium and the difference between one of the resonant frequencies and the fundamental frequency of the driving motion of the wall. An exact non-steady-state solution is derived corresponding to the sawtooth-like periodic vibration of the boundary. The maximal amplitude? values of the particle velocity and the energy of standing waves are calculated. The temporal profiles of standing waves at different points of the layer are presented. A new possibility of pumping a high acoustic energy into a resonator is indicated for the case of a special type of wall motion having the form of an ?inverse saw?. Theoretically, such a vibration leads to an ? explosive instability? and an unlimited growth of the standing wave. For a harmonic excitation, the exact non-steady-state solution is derived as well. The standing wave profiles are described by Mathieu functions, and the energy characteristics by their eigen-values.

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  • 13577. Rudenko, Oleg
    et al.
    Korobov, A
    Izosimova, M
    Nonlinearity of Solids with Micro- and Nanodefects and Characteristic Features of Its Macroscopic Manifestations2010In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, no 2, p. 151-157Article in journal (Refereed)
    Abstract [en]

    The meaning of the experimentally measured nonlinear parameters of a medium is discussed. The difference in meaning between the local nonlinearity, which is measured in the vicinity of a single defect and depends on the size of the region of averaging, and the effective volume nonlinearity of the medium containing numerous defects is emphasized. The local nonlinearity arising at the tip of a crack is calculated; this nonlinearity decreases with an increase in the region of second harmonic generation. The volume nonlinearity is calculated for a solid containing spherical cavities. The volume nonlinearity is also calculated for a medium containing infinitely thin cracks in the form of circular disks, which assume the shape of ellipsoids in the course of the crack opening. The nonlinear acoustic parameter is calculated with the use of the exact classical results of the theory of cracks.

  • 13578.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Sarvazyan, A.P.
    Wave anisotropy of shear viscosity and elasticity2014In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 60, no 6, p. 710-718Article in journal (Refereed)
    Abstract [en]

    The paper presents the theory of shear wave propagation in a "soft solid" material possessing anisotropy of elastic and dissipative properties. The theory is developed mainly for understanding the nature of the low-frequency acoustic characteristics of skeletal muscles, which carry important diagnostic information on the functional state of muscles and their pathologies. It is shown that the shear elasticity of muscles is determined by two independent moduli. The dissipative properties are determined by the fourth-rank viscosity tensor, which also has two independent components. The propagation velocity and attenuation of shear waves in muscle depend on the relative orientation of three vectors: the wave vector, the polarization vector, and the direction of muscle fiber. For one of the many experiments where attention was distinctly focused on the vector character of the wave process, it was possible to make a comparison with the theory, estimate the elasticity moduli, and obtain agreement with the angular dependence of the wave propagation velocity predicted by the theory.

  • 13579. Rudenko, Oleg
    et al.
    Sarvazyan, Armen
    Wave Biomechanics of the Skeletal Muscle2006In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 52, no 6, p. 720-732Article in journal (Refereed)
  • 13580. Rudenko, Oleg
    et al.
    Schvartburg, A
    Nonlinear and Linear Wave Phenomena in Narrow Pipes2010In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, no 4, p. 429-434Article in journal (Refereed)
    Abstract [en]

    Phenomena arising in the course of wave propagation in narrow pipes are considered. For nonlinear waves described by the generalized Webster equation, a simplified nonlinear equation is obtained that allows for low frequency geometric dispersion causing an asymmetric distortion of the periodic wave profile, which qualitatively resembles the distortion of a nonlinear wave in a diffracted beam. Tunneling of a wave through a pipe constriction is investigated. Possible applications of the phenomenon are discussed, and its relation to the problems of quantum mechanics because of the similarity of the basic equations of the Klein– Gordon and Schrödinger types is pointed out. The importance of studying the tunneling of nonlinear waves and broadband signals is indicated.

  • 13581.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Sobisevich, A. L.
    Sobisevich, L.E.
    Hedberg, Claes
    Blekinge Institute of Technology, School of Engineering, Department of Mathematics and Natural Sciences.
    Shamaev, N. V.
    Nonlinear model of a granulated medium containing viscous fluid layers and gas cavities2012In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 58, no 1, p. 99-106Article in journal (Refereed)
    Abstract [en]

    We analyze nonlinear oscillations and waves in a simple model of a granular medium containing inclusions in the form of fluid layers and gas cavities. We show that in such a medium, the velocity of one of the wave modes is low; therefore, the nonlinearity is high and the effects of interaction are more strongly expressed than usual.

  • 13582. Rudenko, Oleg
    et al.
    Sobisevich, A.L.
    Sobisevich, L.E.
    Hedberg, Claes
    Enhancements of energy and Q-factor of a nonlinear resonator with increase in its losses2002In: Doklady Akademii Nauk, ISSN 0869-5652, Vol. 383, no 1, p. 330-333Article in journal (Refereed)
    Abstract [en]

    A phenomenon that is paradoxical at first sight is studied: an appropriately-organized energy outflow from a resonator cavity results not in the attenuation of nonlinear vibrations but in their noticeable enhancement. An increase in the resonator Q-factor and in the energy accumulated in it is well pronounced when the frequencies of the higher harmonics generated in a nonlinear medium are close to the natural frequencies of the resonator. An important example of a nonlinear system with the necessary properties is an acoustic resonator with selective losses.

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  • 13583. Rudenko, Oleg
    et al.
    Sobisevich, L.E.
    Sobisevich, A.L.
    Hedberg, Claes
    Nonlinear response of a layer to pulse action in diagnostics of small inhomogenities2000In: Doclady, Section Mechanics (Reports of the Russian Academy of Sciences) / Doklady Akademii Nauk, ISSN 0869-5652 , Vol. 374 ; 1-3, p. 194-197Article in journal (Refereed)
    Abstract [en]

    Giant nonlinear respons are observed at acoustic irradiation of microscopic gas bubbles in liquids, cracks and fluid-filled pores in solids; and compressed contact of rough surfaces, and is used in diagnostics of materials of industrial and geological structures. Reconstruction of characteristics of a scattering inhomogeneity requires an analyses of complicated inverse problems. The problem of plane-wave incidence upon a layer is simple and serves a model for more complicated inhomogeneities; its response enables us to reconstruct the spectral composition and field structure of other nonlinear scatterers.

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  • 13584. Rudenko, Oleg
    et al.
    Stepanov, P. V. Lebedev
    Gusev, V. A.
    Korobov, A. I.
    Korshak, B. A.
    Odina, N. I.
    Izosimova, M.
    Molchanovb, S. P.
    Alfimov, M. V.
    Control of the Self-Assembly Processes in a Droplet of a Colloidal Solution by an Acoustic Field2010In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 56, no 6, p. 935-941Article in journal (Refereed)
    Abstract [en]

    The formation of structured films consisting of ensembles of micro- or nanoparticles and possessing preset functional characteristics is studied both experimentally and theoretically. The films are obtained by drying out droplets of colloidal solutions on a solid substrate under the acoustic effect produced by a standing SAW field.

  • 13585.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    YN, Makov
    SN, Gurbatov
    Blood flow dynamics under venipuncture and viscosity estimation from pressure and flow variations2013In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 59, no 1, p. 109-114Article in journal (Refereed)
    Abstract [en]

    We have calculated the nonstationary flow of a viscous liquid in a narrow tube under the action of pressure variations with time. Such a flow accompanies venipuncture the procedure of taking a sample from a vein with a hypodermic needle. We show how the changes in the flow characterstics during venipuncture make it possible to actively estimate viscosity. This method is "nonperturbative" for blood in the sense that the measurement process weakly affects the measured quantity. It may find application in medicine.

  • 13586.
    Rudolphson, Filip
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Mannerdahl, Anton
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Ord skapar mening, tecken skapar film: En undersökning om semiotiska teckens betydelse för ett berättande i en spelfilm2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis examines the construction of a narrative in a fictional film. The purpose is to acquire knowledge of what a narrative in a fictional film consist of and what it affects. Through the sign of semiotics, we get an understanding of how everything can get a significance and then be used to communicate something to the user. The concept of multimodality has then been used to understand how signs work in an interplay with each other. We examine the narrative by making our own fictional film that we then analyse to get a better understanding of the importance of the signs we used and how the narrative was influenced by our choices. We will present the results we achieved, the types of adversities we encountered and other discussions about the outcome.

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  • 13587.
    Rudraraju, Venkata Sai Krishna Varma
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Valishetty, Arjun
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Thermal Analysis of a Park Lock System in a DCT Transmission2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A park lock is a mechanism used to prevent unintentional movement of the vehicle. A failure in the proper function of this mechanism can lead to the safety concerns of an automobile. The main focus of this thesis is to understand the reason behind the failure of the park lock mechanism by FEM analysis in ANSA. For this, temperature build up during the park lock engagement has been studied in a dynamic explicit analysis. The FE results are compared to results from experiments on park lock. The modelling has been done in ANSA, ABAQUS was used as a solver for simulation and the results have been studied in META. The results indicate that there is a rise in the temperature. This is due to the friction between the contact surfaces and the oscillations generated in the vehicle. Based on the observations, discussions and conclusions are formulated and the research questions are answered.

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  • 13588.
    Rudvi, Emil
    Blekinge Institute of Technology, School of Computing.
    Digital Game Mechanics: to create an analog board game prototype2013Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    Analog games misses a lot of quick games in terms of game time and play time in the FPS genre. This genre often takes more time to play in an analog game. Could the game play become quicker by examining the different game mechanics in order to give the players a smoother game play by a reduction of downtime. Game mechanics that could be found in a digital FPS game such as Doom III, were converted to a prototype. These digital gameplay mechanics were converted so that an analog game could be played simultaneously. These game mechanics decrease the game time and down time in a way that a game using a turn based game order would not. The digital game Doom III was used to create the prototype and eight analog games of different types and genres were examined to collect more unique game mechanics. All were suited for a multiplayer type of gameplay. To get an understanding of what game elements were well liked in both digital and analog games, a questionnaire was created with twelve questions. The participants answered questions on the subjects of their favourite genre, missing game mechanics in both digital and analog games, well liked game mechanics, and also what the participants thought was impossible to create in a game in terms of game mechanics. The results of both the analysis of the eight analog games and the answers from the participants created the base plan for the development of the prototype focusing on low downtime, re-playability, and an average amount of luck. Several game mechanics were discussed and some of them were play tested. This resulted in keeping some game mechanics while others were removed because these game mechanics did not provide a rewarding gameplay. Several game mechanics were nearly impossible to implement without the use of a digital representation. An example on this type of issue was the first person view in the digital game. The perception of skill based game mechanics could be moved to an analog board game but would have to be determined by other game mechanics instead of the player’s physical capabilities. The conclusion lead to a prototype that could be played in an hour, which is a low game time for games in this genre. The FPS gameplay mechanics was converted to an analog game, but all game mechanics could not be transferred to the prototype without a conversion.

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  • 13589. Ruhe, Günther
    et al.
    Wohlin, ClaesBlekinge Institute of Technology, School of Computing.
    Software Project Management in a Changing World2014Collection (editor) (Other academic)
    Abstract [en]

    By bringing together various current direc­tions, Software Project Management in a Changing World focuses on how people and organizations can make their processes more change-adaptive. The selected chapters closely correspond to the project management knowledge areas introduced by the Project Management Body of Knowledge, including its extension for managing software projects. The contributions are grouped into four parts, preceded by a general introduction. Part I “Fundamentals” provides in-depth insights into fundamental topics including resource allocation, cost estimation, and risk management. Part II “Supporting Areas” presents recent experiences and results related to the management of quality systems, knowledge, product portfolios, and glob­al and virtual software teams. Part III “New Paradigms” details new and evolving software-development practices including agile, distributed, and open and inner-source development. Finally, Part IV “Emerging Techniques” introduces search-based tech­niques, social media, software process simulation and the efficient use of empirical data, and their effects on software-management practices. This book will attract readers from both academia and practice with its excellent balance between new findings and experience of their usage in new contexts. Whenever appropriate, the presentation is based on evidence from empirical evaluation of the proposed approaches. For researchers and graduate students, it presents some of the latest methods and techniques to accommodate new challenges facing the discipline. For professionals, it serves as a source of inspiration for refining their project-management skills in new areas.

  • 13590.
    Rulff, Lucas
    Blekinge Institute of Technology, School of Management.
    Supplier Relationship Management: Developments in Co-operative Initiatives2006Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The purpose of this thesis is to broaden the understanding of current supplier relationship management and to discover what, if any, are the new initiatives being used by organizations to support their suppliers from a co-operative standpoint. The research is completed from a global perspective and therefore adding further insight into the overall trends of SRM practices.

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  • 13591.
    Rundberg, Maja
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Health.
    Magnusson, Amira
    Blekinge Institute of Technology, Faculty of Engineering, Department of Health.
    Personers upplevelser efter en Gastric Bypass operation: En systematisk litteraturstudie2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Mängden genomförda Gastric Bypass operationer (GBP) har ökat stort sedan 90 talet. Tidigare forskning visar att personer som har genomgått operationen upplever en förbättrad hälsa och välbefinnande men även psykosociala problem som i sin tur leder till en psykisk ohälsa. För att sjuksköterskan ska kunna stödja personerna mot hälsa och välbefinnande och för att kunna utföra en god omvårdnad utifrån personernas behov är det betydelsefullt med djupare förståelse och ökad kunskap om personernas upplevelser efter en Gastric Bypass operation.

    Syfte: Syftet var att beskriva personers upplevelse efter en Gastric Bypass operation. Metod: En systematisk litteraturöversikt med kvalitativ ansats som baserades på 13 vetenskapliga artiklar. Artiklarna analyserades med hjälp av Lundman och Hällgren- Graneheims beskrivning av innehållsanalys.

    Resultat: Personer som genomgått en Gastric bypass operation beskrev att deras upplevelser efter operationen förändrades. Förändringarna kunde relateras till emotionella förändringar som handlade om positiva och negativa förändringar, psykologiska förändringar som handlade om förändrad kroppsuppfattning och en förändrad livssituation, fysiologiska förändringar som handlade om förbättrade fysiska förhållanden och negativa fysiologiska konsekvenser av operationen samt sociala förändringar som handlade om stöd och gemenskap samt socialisering.

    Slutsats: Efter en Gastric Bypass operation kan personen uppleva både positiva och negativa förändringar i sin hälsa. Sjuksköterskans roll i samband med stöd och uppföljning är väsentliga för att personen ska kunna bibehålla en god hälsa och välbefinnande.

     

    Nyckelord: Gastric bypass, hälsa, innehållsanalys, litteraturöversikt, ohälsa, upplevelser

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  • 13592.
    Rundquist, Björn
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Joensen, Johan
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Medierade Verkligheter: Verklighetsuppfattningen i Virtual Reality2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Central to Virtual Reality is the experience of the digital as the real. But from where does this experience stem? By investigating several different perspectives on Virtual Reality, reality and deconstructions of concepts in previous Virtual Reality-science we’ve looked into the creation of this sensation of reality in Virtual Reality-games. Through a practical project, focusing on different types of scenes and control schemes, we then sought to create a discussion focusing on the practical application of the differing theories.

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  • 13593.
    Rundqvist, Emmy
    et al.
    Blekinge Institute of Technology.
    Andersson, Carl
    Den verbala kommunikationen vid överrapportering inom vården: -      En litteraturstudie2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Inom vården är kommunikation nödvändig för att kunna samarbeta. En av de vanligaste orsakerna till vårdskador är brister i kommunikationen. Kommunikationsproblem kan uppstå varsomhelst i vårdkedjan men är vanligast vid överrapportering av patient till annan vårdenhet.

    Syfte: Syftet med studien var att beskriva sjuksköterskans upplevelse av den verbala kommunikationen som sker vid överrapportering av patient inom slutenvården. Metod: Litteraturstudie baserad på tolv kvalitativa intervjustudier. Resultat: Analysen resulterade i fyra kategorier. Professionell kommunikation påverkar, adekvat och strukturerad information påverkar, bedside påverkar, arbetsmiljön påverkar. Slutsats: Sjuksköterskorna upplevde att informationen behövde vara mer strukturerad och att det fanns behov av kontinuitet. Sjuksköterskorna tyckte att involvering av patient var något som var främmande och togs emot med blandad respons. De negativa känslor som sjuksköterskan hade mot bedside överrapporteringen vägdes enligt sjuksköterskorna över av fördelarna. Vidare forskning från Sverige hade behövts då studier i svenska förhållanden var underrepresenterade och för att undersöka ifall bedside överrapportering kan vara något att implementera i svensk sjukvård. 

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  • 13594.
    Rundqvist, Nils
    Blekinge Institute of Technology, School of Planning and Media Design.
    Koncept i planering -definierade kvaliteter2009Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [sv]

    Sammanfattning Detta examensarbete grundar sig på idén om att stadens byggnader, och de arkitektoniska koncept som brukas, påverkar hur det offentliga rummet används och upplevs. Valet av arkitektoniskt koncept ger genomslag också på hur det offentliga rummet uppfattas, samt vilka prioriteringar som görs i den fysiska miljön i byggnadens närhet. Det handlar dels om att byggnaders skala, exploateringsgrad och verksamheter men också om att definiera vilka kvaliteter som är önskvärt, samt vad dessa begrepp egentligen står för. Examensarbetet ger ingen heltäckande översikt över stilformer och begrepp som förekommer inom arkitekturen och stadsplaneringen. Arbetets syfte är att visa hur koncept byggs upp, hur form definieras, samt ger exempel på hur detta kan appliceras på en specifik plats. Inventering och teoriavsnitt har resulterat i två experimentella modeller, i diskussionsavsnittet i detta examensarbete, ställs modellerna mot ett antal upplevelsevärden och olika dimensioner av stadsliv ur ett fotgängarperspektiv. Genom att genom att metodisk testa definierade förslag (experimentella modeller), kan de formmässiga estetiska dimensionerna av utformningen av staden, bättre belysas. Slutsatsen är att arbete med koncept och experimentella modeller kan ge Planeringsarkitekter ett användbart verktyg vid upprättande av exempelvis program för arkitekttävlingar.

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  • 13595.
    Rundström, Julia
    et al.
    Blekinge Institute of Technology, School of Health Science.
    Borg, Amanda
    Blekinge Institute of Technology, School of Health Science.
    Sambandet mellan levnadsvanor och depression hos individer över 60 år i Blekinge: En kvantitativ studie i samarbete med Swedish National study on Aging and Care – Blekinge2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund:  Den äldre befolkningen ökar i Sverige och det är den minskade dödligheten hos den äldre befolkningen som är den största faktorn. Depression är vanligt förekommande hos äldre och kommer med tiden få en högre förekomst. Ohälsosamma matvanor, otillräckligfysisk aktivitet, riskbruk av alkohol samt tobak är de ohälsosamma levnadsvanorna som bidrar till en hög sjukdomsbörda i Sverige.

    Syfte: Syftet var att undersöka eventuella samband mellan levnadsvanor och depression hos den äldre befolkningen över 60 år i Blekinge.

    Metod: Studien var en kvantitativ tvärsnittsstudie och var ett samarbete med Swedish National study on Aging and Care – Blekinge (SNAC-B). Studien genomfördes i två steg. Först undersökte den verkliga skillnaden mellan två gruppen, detta redovisades deskriptivt med korstabeller. Andra delen av studien bestod av att undersöka sambandet mellan depression och levnadsvanor. Detta gjordes med Spearmans korrelationsanayls. 

    Resultat: Resultatet visade inget samband mellan depression och de fyra levnadsvanorna. Däremot påträffades en verklig procentuell skillnad mellan Depressionsgruppen och Jämförelsegruppen.

    Slutsats: Sjuksköterskan kan genom den hälsofrämjande omvårdnaden hjälpa patienten att få hälsosammare levnadsvanor som främjar patientens hälsa. Depression skulle då kunna förebyggas samt lindras hos den äldre individen. Det behövs mer forskning inom området depression hos äldre samt forskning om sambandet mellan depression och levnadsvanor hos äldre. Ny forskning kan hjälpa sjuksköterskan att förbättra sin kompetens och därigenom förbättra den hälsofrämjande omvårdnaden för patienten.

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  • 13596.
    Rundén, Cecilia
    et al.
    Blekinge Institute of Technology, Faculty of Health Sciences, Department of Health.
    Nery, Sofia
    Blekinge Institute of Technology, Faculty of Health Sciences, Department of Health.
    Hur sjuksköterskan kan tillämpa personcentrerad omvårdnad vid vård-och omsorgsplanering via videokonferens: en intervjustudie2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bakgrund: Vid utskrivning av patient i slutenvård har vård- och omsorgsplanering via videokonferens implementerats i vissa delar av Sverige för att med stöd av ehälsa tillgodose nya vårdbehov. Vård- och omsorgsplanering är del i sjuksköterskans omvårdnadsarbete med målet att tillgodose patientens vård- och omsorgsbehov efter utskrivning och är styrt av lagar och föreskrifter. Ehälsa ställer sjuksköterskor inför nya krav och efter genomgång av vetenskapliga studier är det svårt att finna kunskap om sjuksköterskan möjlighet att tillämpa personcentrerad omvårdnad vid vård- och omsorgsplanering via videokonferens.

    Syfte: Syftet med studien var att belysa hur sjuksköterskan kan tillämpa personcentrerad omvårdnad vid vård- och omsorgsplanering via videokonferens.

    Metod: En kvalitativ forskningsansats användes vid studien, där kvalitativa enskilda intervjuer med stöd av en intervjuguide låg till grund för insamlad data. Ett urval av fyra sjuksköterskor som arbetar inom slutenvård deltog i studien. De transkriberade intervjuerna analyserades med en manifest innehållsanalys med latenta inslag.  

    Resultat: Analysen ledde fram till två kategorier; sjuksköterskans förutsättningar till vård- och omsorgsplanering vid videokonferens, sjuksköterskans förmåga att göra patient och anhöriga delaktiga. Resultatet visade att sjuksköterskorna kan till viss del tillämpa personcentrerad omvårdnad men de upplevde också många hinder.

    Slutsats: Ökad medvetenhet bland sjuksköterskor relaterat till hur miljö och teknik påverkar tillämpning av personcentrerad omvårdnad kan hjälpa sjuksköterskan att hitta nya sätt att jobba på så att anpassningar efter nya verktyg i vården underlättas. Teknik och miljö får inte vara ett hinder i kommunikation om vård- och omsorgsplanering via videokonferens ska kunna användas för att ge möjlighet till snabb och säker hemgång.

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  • 13597.
    Runesson, Anna Dyberg-Ek och Ewa-Lotta W
    Blekinge Institute of Technology, School of Management.
    Kundnöjdhet trots minskad fysisk interaktion2004Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Problem: Vilka faktorer påverkar kundnöjdhet i en icke fysisk bankrelation? Syfte: Syftet med denna uppsats är att undersöka vad som påverkar kundnöjdhet i en icke fysisk bankrelation. Detta undersöker vi genom att göra en fallstudie där vi studerar åsikter hos kunder som använder sig av FöreningsSparbankens Internetbank. Metod: Vi har använt en kvalitativ datainsamlingsmetod genom vilken vi fått svar från våra respondenter vilka vi därefter tolkat för att få fram information att analysera. I vår empiriska studie har vi använt en fallstudie i vilken vi har valt att intervjua både kunder och medarbetare för att få svar på vår problemställning. Resultat: Vi har kommit fram till fem faktorer som vi menar påverkar Internetkunder att bli mer nöjda med ett erbjudande. Kunden vill kunna utföra sina bankärenden oavsett tid och plats det vill säga, kunden vill ha en ökad tillgänglighet. Kunden vill även själv kunna bestämma hur och när de ska kontakta banken varför banken måste vara flexibel i sitt bemötande mot kund och användandet av olika medier. Det ska vara enkelt att hitta rätt information och den ska vara enkel att förstå. Kunderna menar att det är viktigt att möjligheten till rådgivning finns kvar även om de inte behöver gå in på banken för det. En rådgivning kan ske via en webbkamera och en chatfunktion i realtid. Det är dock viktigt att tekniken fungerar och att personligheten finns kvar även om interaktionen sker via en dator. Det är viktigt för kunden att känna att medarbetarna finns kvar bakom tekniken för att känna tillit till organisationen och tjänsterna.

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  • 13598. Runsten, Jakob
    et al.
    Pålsson, Anton
    Upplevelsen och Uppfattningen av ett narrativ.2021Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
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    Upplevelsen och Uppfattningen av ett narrativ.
  • 13599.
    Rutabayiro Ngoga, Said
    Blekinge Institute of Technology, School of Computing.
    On Dynamic Spectrum Access in Cognitive Radio Networking2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The exploding increase of wireless communications combined with the existing inefficient usage of the licensed spectrum gives a strong impetus to the development and standardization of cognitive radio networking and communications. In this dissertation, a framework for Dynamic Spectrum Access (DSA) is first presented, which is the enabling technology for increasing the spectral efficiency of wireless communications. Based on that, Cognitive Radio (CR) can be developed as an enabling technology for supporting the DSA, which means that the wireless users are provided with enhanced capability for sensing the operating radio environment and for exploiting the network side information obtained from this sensing. The DSA concept means that the users of a wireless system are divided into a multi-tiered hierarchy with the primary users (PUs) entitled to protection and with cognitive radio capable secondary users (SUs). The improved spectrum efficiency is obtained by means of a medium access control protocol with knowledge about the statistical properties or available local information of the channels already occupied by PUs as well as knowledge about the interference tolerance within which the interference to PUs is kept to a given level. Related to this, emphasis is laid on the protocol capability to determine the efficiency of the secondary sharing of spectrum. Based on the type of available local information, the capacity of opportunistic communication is investigated for three models. These are: with dynamic, distributed channels information; with dynamic, parallel channels information; and under a dynamic sub-channels allocation scheme. The results indicate that this capacity is robust with reference to the uncertainty associated with localized sensing of distributed dynamic channels and with timely sensing of parallel dynamic channels. The extension to dynamic parallel sub-channels enables resource allocation to be carried out in sub-channels. The analytical results on the performance of sub-channel allocation indicate a robust traffic capacity in terms of blocking probability, drop-out probability and delay performance as function of PUs traffic loads.

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  • 13600.
    Rutabayiro Ngoga, Said
    et al.
    Blekinge Institute of Technology, School of Computing.
    Yao, Yong
    Blekinge Institute of Technology, School of Computing.
    Popescu, Adrian
    Blekinge Institute of Technology, School of Computing.
    On Multi-channel Opportunistic Access in Heterogeneous Cognitive Radio Networks2013Conference paper (Refereed)
    Abstract [en]

    In the paper, we study optimal transmission strategies in multi-channel opportunistic spectrum access (OSA) networks where one secondary user (SU) opportunistically accesses multiple orthogonal channels of primary users (PUs) under a continuous time Markov chain modeling of the channel occupancy by the PUs. Referred to as tunable threshold strategy, at a given time the SU chooses one channel of a given PU, decides if it should transmits or not and if so it protects the PU of this channel. To be operational, such a structure depends on the capability of the SU radio front-end to perform channel sensing. We consider one scenario where the SU node can simultaneously sense multiple channels and another scenario where the SU node can sense only one channel at a time. For each scenario, we develop the structure of the optimal transmission strategy and analyse the performance. We show that the optimal transmission strategy can be implemented using a simple tunable threshold algorithm.

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269270271272273274275 13551 - 13600 of 17072
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