bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the absorption coefficient and material boundaries distribution on the acoustic pressure in the room with rigid walls
Authors: Blazejewski Andrzej , Krzyzynski Tomasz 
Published: February 2009

AbstractIn the paper a problem of distribution of an acoustic absorption materials on room's boundaries has been presented. A room with a harmonic sound source inside has been considered. A pressure distribution was described using modal analysis assumptions. Usually, most of real rooms have enough high boundaries' impedance (absorption coefficient), therefore the modal coupling can be neglected. Hence, pressure can be represented by a sum over a set of room's eigenfunctions and time components i.e. the modal amplitudes. Amplitudes are dependent of eigenfrequencies ωn, damping coefficients rn and a source function Qn. Conducting analysis of the modal amplitude function, in relation to ωn and rn, an optimal acoustical damping can be obtained. Taking triple criteria objective function into consideration, absorbtion material optimal distribution on boundaries has been found. In order to find minimum of the objective function genetic algorithm was used. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Forced stationary gas‐structure interaction vibrations in a rectangular parallelepiped tank
Authors: Gavrilova E. 
Published: February 2009

AbstractA closed rigid rectangular parallelepiped tank is filled with gas and a part of one of its walls is a thin linearly elastic rectangular plate. The problem about the determination of the forced stationary vibrations of the obtained gas–structure interaction system under the action of a source is considered. The method of the crossed strips of Warburton and the Bubnov–Galerkin method are used to create a method of investigation of the dynamic behavior of this gas–structure interaction system. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonance excitation and mode selection in smart structures with piezoelectric patch actuators
Authors: Glushkov E.V. , Glushkova N.V. , Kvasha O.V. , Seemann W. 
Published: February 2009

AbstractA system of piezoelectric flexible patch actuators bonded to an elastic layered substrate is considered. An integral equation based model for the smart structure under consideration has been developing. The rigorous solution to the patch–substrate dynamic contact problem extends the range of the model's utility far beyond the bounds of conventional simplified models that rely on plate, beam or shell equations for the waveguide part. The developed approach provides the possibility to reveal the effects of resonance energy radiation associated with higher modes that would be inaccessible using models accounting for the fundamental modes only. Algorithms that correctly account for the mutual wave interaction among the actuators via the host medium, for selective mode excitation in a layer as well as for body waves directed to required zones in a half–space, have also been elaborated and implemented in computer code. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scattering of acoustic waves by inhomogeneous obstacles
Authors: Morro Angelo , Caviglia Giacomo 
Published: February 2009

AbstractThe scattering of acoustic waves, produced by a continuously–stratified layer, is investigated through a Volterra integral formulation in the Fourier–transform domain. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inversion of seismic data: sensitivity and stability via SVD analysis
Authors: Silvestrov Ilya 
Published: February 2009

AbstractThe problem of recovery of seismic parameters of the media via wavefield produced by array of sources and recorded by array of receivers is considered in this work. In order to invert these data and recover elastic parameters one can use the optimization technique based on the gradient–like or Newton–like methods. In seismic applications this approach is known as “Full waveform inversion”. According to it we search for solution which minimizes mean–square deviation of the observed wavefield from the computed one for current values of elastic parameters. Surely convergence is governed by the properties of the Frechet derivative of nonlinear operator that maps medium parameters to the observed data. Thus studying these properties is an important step before development the numerical methods and algorithms of this inversion.For a simple case it can be shown that this derivative is a compact operator so implementation of any Newton–like approach is connected with necessity to resolve ill–posed problem of resolution of the first–order linear integral operational equation. In order to study the main peculiarities of this operator Singular Value Decomposition is applied. Two acquisition systems are dealt with – the offset vertical seismic profiling and cross–well tomography. Numerical results for realistic media are presented and the main differences of inverse problems for these two acquisition are shown. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The numerical analysis of burnishing rolling process with taking into account inaccuracy of surface preparation in previous treatment
Authors: Kuakowska Agnieszka , Kukielka Leon 
Published: February 2009

AbstractIn the paper the numerical analysis of burnishing rolling process with taking into account inaccuracy of surface preparation in previous treatment are shown. The researches were realized in two stages, in the first one outline of asperities was prepared in turning process. The ranges of outline deviation (height and distance) of triangular asperity after turning are shown as the result. In the second one the numerical analysis of burnishing rolling with different outline deviation were made. The application in ANSYS was elaborated. To solve problem explicit method was used. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Poincaré‐Andronov‐Hopf bifurcation with hyperbolic rotation symmetry
Authors: Konopleva Irina , Loginov Boris , Makeev Oleg , Rousaky Youri 
Published: February 2009

AbstractFor differential equations in Banach spaces with degenerate Fredholm operator at the derivative the general theorem about group symmetry inheritance by the relevant Lyapounov–Schmidt branching equation allows to construct its general form on admitted group symmetry. Here the solving of this problem is illustrated on the examples of the presence of SH(2) and H(2) symmetries. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical analysis of embossing process of regular inequalities with triangular outline
Authors: Patyk Radoslaw , Kukielka Leon 
Published: February 2009

AbstractThe paper presents the numerical analysis of plastic formation process of regular inequalities of surface with triangular outline. The physical and mathematical models of deformations (displacements and strains) and stress in the process were worked out. The process is considered as a geometrical and physical non–linear problem with unknown boundary conditions. The computer analyses were conducted with the use of Finite Elements Method (FEM). The solution of problem was conducted with use of updated Lagrangian description. In simulations material model of elasto/visco – plastic (E/VP) was used. The solution of variational equation of movement object was conducted applying the explicit method. The results of simulation are basis to projection of new technological operation – plastic formation of regular inequalities with triangular outlines as previous burnishing rolling process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Existence for an energetic problem in contact mechanics with dry friction
Authors: Schmid Florian 
Published: February 2009

AbstractA simplified contact problem with dry friction is considered for a non–linear elastic system with two degrees of freedom. The simplification consits in neglecting kinetic energies or equivalently inertial forces. By proving existence it is shown under which conditions such simplifications are justifiable. The main focus is on the influence of a curved obstacle surface on the question of existence. The friction is modelled according to the Coulomb law and the coefficient of friction may vary along the obstacle surface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On wellposedness in nonlinear acoustics
Authors: Kaltenbacher Barbara , Lasiecka Irena , Veljović Slobodan 
Published: February 2009

AbstractMotivated by a medical application from lithotripsy, we study the initial–boundary value problem given by Westervelt equation

in a bounded domain Ω. This models the nonlinear evolution of the acoustic pressure u excited at a part Γ0 of the boundary. Along with the excitation given by Neumann boundary condition as in (1), we also consider the Dirichlet type of excitation. Whereas shock waves are known to emerge after a sufficiently large time interval for appropriate initial and boundary conditions, we here prove existence and uniqueness as well as stability of a solution u for small data g, u0 and u1 or short time T, using a fixed point argument. Moreover we extend the result to the more general model given by the Kuznetsov equation

for the acoustic velocity potential ψ.
(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNS of stochastically forced laminar plane Couette flow
Authors: Khujadze G. , Oberlack M. , Chagelishvili G. 
Published: February 2009

AbstractBackground of three dimensional hydrodynamic/vortical fluctuations in a stochastically forced, laminar, incompressible, plane Couette flow is simulated by direct numerical simulations (DNS). It was found that the fluctuating field has well pronounced peculiarities: (i) The hydrodynamic fluctuations exhibits non–exponential, transient growth; (ii) Streamwise non–constant fluctuations with the characteristic length scale of the order of the channel width are predominant in the fluctuating spectrum; (iii) Existence of coherent structures in the fluctuating background; (iv) Stochastic forcing breaks the spanwise reflection symmetry (inherent to the linear and full Navier–stokes equations in a case of the Couette flow) and inputs an asymmetry on dynamical processes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A sub‐feasible correction step for non‐linear programming methods with equality constraints
Authors: Nikolayzik Tim , Büskens Christof 
Published: February 2009

AbstractDue to the sparsity of large–scale optimazation problems it can be useful to use the exact hessian matrix instead of update techniques for solving nonlinear optimization problems. Herewith it is possible to use techniques of the parametric sensitivity analysis to improve the feasibility of the NLP–problem in each iteration step of a solver. The main idea is to treat the measurable error between the general nonlinear equality constraints and the linear approximations inside the QP subproblems as a linear perturbation in the constraints. By special real–time optimization approximations this error can be reduced nearly without any extra computational costs. First results will be presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficiency and Applications
Authors: Postolică Vasile 
Published: February 2009

AbstractThis research work is concerned with the usual concepts of the efficiency and optimization. After a short introduction, we give some questions on the notion of the efficiency and we emphasize the Pareto optimality as one of the illustrative examples.We present the efficiency and optimization in the infinite dimensional vector spaces following also our recent results concerning the most general concept of approximate efficiency, as a natural generalization of the efficiency, with implications and applications in vector optimization and the new link between the approximate efficiency and the strong optimization by the full nuclear cones. An important extension of our coincidence result between the efficient points sets and the Choquet boundaries is developed . In this way, the efficiency is connected with Potential theory through the agency of optimization and conversely. Several pertinent references conclude the study. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analyse des Penalty‐Faktors in SIMP‐Methode in Bezug auf die Konvergenz der Lösung
Authors: Kutylowski Ryszard , Szwechlowicz Marek 
Published: February 2009

AbstractIn vorliegender Arbeit wurde das Problem des Penalty–Faktors in der SIMP–Methode in Bezug auf Geschwindigkeit und Konvergenz der Lösung analysiert. Der Penalty–Faktor tritt in der Formel zur Berechnung des Elastizitätsmoduls auf [1]. Man hat diese Aufgabe unternommen, weil es in der Literatur an Beweisen fehlt, die durch eine ausführliche Analyse des angenommenen Wertespin der Formel zur Berechnung des Elastizitätsmoduls belegt wären (1). Beim Formulieren des Problems der Topologieoptimierung wurde die Nachgiebigkeit einer Struktur als Zielfunktional angenommen. Man hat optimale Topologie gesucht, indem man die Nachgiebigkeit einer Struktur bei der Einschränkung der Körpermasse minimalisierte. Mit der FEM–Anwendung wurden Berechnungen für verschiedene Potenzenpdurchgeführt, das heißt, die so genannten “benchmarks” wurden analysiert. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On solution of total least squares problems with multiple right‐hand sides
Authors: Hnětynková Iveta , Plešinger Martin , Strakoš Zdeněk 
Published: February 2009

AbstractConsider a linear approximation problem AX≈B with multiple right–hand sides. When errors in the data are confirmed both to B and A, the total least squares (TLS) concept is used to solve this problem. Contrary to the standard least squares approximation problem, a solution of the TLS problem may not exist. For a single (vector) right–hand side, the classical theory has been developed by G.H. Golub, C.F. Van Loan [2], and S. Van Huffel, J. Vandewalle [4], and then complemented recently by the core problem approach of C.C. Paige, Z. Strakoš [5,6,7]. Analysis of the problem with multiple right–hand sides is still under development. In this short contribution we present conditions for the existence of a TLS solution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the efficient update of the Singular Value Decomposition
Authors: Stange Peter 
Published: February 2009

AbstractWe introduce a new method for updating the singular value decomposition subject to a rank–one modification. Using the secular equation and exploiting arising matrix structures our algorithm has a computational complexity of O(n2log2n). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient computation of non‐isothermal highly viscous incompressible flow
Authors: Kopecz Stefan , Meister Andreas , Ouazzi Abderrahim , Turek Stefan , Wünsch Olaf 
Published: February 2009

AbstractWe consider the numerical solution of the non–isothermal incompressible Navier–Stokes equations using a discrete projection method. The computation of velocity and temperature subproblems is carried out on different meshes chosen with respect to the physical behavior of these quantities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FETI‐DP Methods for P‐Elasticity
Authors: Klawonn Axel , Neff Patrizio , Rheinbach Oliver , Vanisy Stefanie 
Published: February 2009

AbstractA FETI–DP method is introduced for the problem of linear P–elasticity which arises from linear elasticity by the introduction of a matrix P and which is motivated by micromorphic models. Numerical results as well as a condition number estimate are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Advanced Optimal Feedback Control for Tracking of Real‐Life Applications
Authors: Stach Ramona , Büskens Christof , Tietjen Jan 
Published: February 2009

AbstractCalculating the open–loop solution of an optimal control problem is just the first step to cope with the practical realization of real life applications. Feedback controllers, like the classical Linear Quadratic Regulator (LQR), are needed to compensate pertubations appearing in reality. Although these controllers have proven to be a powerful tool in many applications and to be robust enough to countervail most differences between simulation and practice, they are not optimal if disturbances in the system data occur. If these controllers are applied in a real process, the possibility of data disturbances force recomputing the feedback control law in real–time to preserve stability and optimality, at least approximately. For this purpose, variations of the classical closed–loop controller with the extention to a trackingtype controller are analysed by means of an industrial application of container cranes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parameter Identification in Radio‐Frequency Ablation
Authors: Tiesler Hanne , Bueskens Christof , Preusser Tobias 
Published: February 2009

AbstractThe prediction of the temperature profile for radio frequency ablation—a minimal form of tumor treatment—depends on a variety of material parameters (e.g. electric and thermal conductivities) as the coefficients of a system of partial differential equations. We discuss a basic model for the identification of such material parameters from measured temperature data, which bases on an objective function of tracking type which is constrained by the system of PDE. After the discretization of the PDE system with a standard finite element method we optimize the discrete system with an SQP solver. Numerical results are shown for a test scenario consisting of an artificial tumor and artificially generated target temperature profile. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Necessary conditions of optimality in quasilinear systems with delays
Authors: Tsintsadze M. , Tsintsadze Z. 
Published: February 2009

AbstractThe optimal control problem for the processes described with quasilinear system of differential equations in presence of mixed restrictions on phase and control variables in case of delays on both variables is considered. Using the Lagrange principle of taking restrictions off necessary conditions of optimality for such kind of systems are given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptive FEM for PDE Constrained Optimization with Pointwise Constraints on the Gradient of the State
Authors: Wollner Winnifried 
Published: February 2009

AbstractWe are concerned with an interior penalty method for an optimal control problem with an elliptic PDE constraint and additional pointwise constraints on the gradient of the state variable. We will derive an estimator that gives qualitative information about the error in the cost functional due to the interior penalty parameter and for the discretization of the PDE. These can be used to balance the error contributions of both types of errors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechatronic Design of the 2 DOF PRRRP Parallel Robot
Authors: Besoiu S. , Mătieş V. , Stan S.‐D. 
Published: February 2009

AbstractMechatronics consists in integration of three fields in engineering: mechanics, electronics and information technology. The paradigm of mechatronics is the integration concept, being the first step in the design of complex mechatronic systems. The need for an integrated approach to the design of complex engineering system involving electronic engineering, mechanical engineering and computing has led to the growth of the concept of mechatronics. The paper presents details regarding the integration process for the kinematic axis in mechatronic. The example of the positioning system based on dc motor and screw–nut transmission is analysed. This actuator is further used for driving a 2 DOF PRRRP parallel robot. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant Excitation of a Composite Beam
Authors: Rudolf Christian , Seemann Wolfgang 
Published: February 2009

AbstractPhase–locked loops are widely used within communication technology for synchronizing signals by tracking their phases. Their functional principle can be applied for maintaining the resonant excitation of a beam whose eigenfrequency changes over time and, thus, representing an alternative excitation method for the adaptronic strut for machine tools shown in [1]. In this contribution an experimental set–up for resonant excitation of a composite beam is introduced. A particle is mounted on the beam, its position and mass are are adjustable to modify the eigenfrequency of the beam. The simulation results of the analytical examination of the test–rig are compared with the experimental results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inversion‐Based Feedforward Control for the Transient Shaping of a Piezo‐Actuated Cantilevered Kirchhoff Plate
Authors: Schröck Johannes , Meurer Thomas , Kugi Andreas 
Published: February 2009

AbstractNowadays piezoelectric actuators are successfully applied for vibration suppression in structural mechanics. The progress in material and actuator development allows to put focus also on novel applications. In this contribution, a systematic approach for inversion–based feedforward control and motion planning is presented for the realization of a transient deflection profile of a cantilevered piezo–actuated plate modeling an adaptive wing. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recursive Control of a 7 dof Robotic Arm
Authors: Simonidis Christian , Seemann Wolfgang 
Published: February 2009

AbstractThis paper provides a short insight into tracking control of uncertain nonlinear plants with the focus on ease of application and simple parameter tuning. The advanced control scheme is based on recursive control laws which have been shown in the last decades to be efficient in control of robotic motion. The algorithm is recursive rapidly convergent and robust. The development of humanoid robotic arms within the collaborative research center (CRC588) requires a class of easy implementable and robust nonlinear controllers to accomplish manipulation tasks in permanently alternating scenarios. The ability of the controller is tested by simulation for several robotic arms with increasing dof and variable end–effector mass for given human arm movements provided from a motion capture system. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability Analysis of an Orbiting Plate with Finite Elements
Authors: Steiner Wolfgang 
Published: February 2009

AbstractThis paper contributes to the analysis of rotating equilibria of non–driven systems (sometimes called relative equilibria), which are characterized by the fact that their angular momentum is conserved and non–zero. Interesting applications are usually found in space dynamics, in particular if large earth orbiting structures such as the space elevator are considered.For flexible structures relative equilibria can be found with Finite Element software packages. However, in this case the stability analysis is a non–trivial task since one usually has only limited account to the internal data of commercial FE solvers. Therefore, in [5] a new finite element based stability test was developed and applied to one–dimensional structural elements. Here, we consider a large–scale flexible plate orbiting around the earth in order to demonstrate that this method works well also for two dimensional shell–elements. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flatness of boundary coupled second order partial differential equations
Authors: Woittennek Frank , Mounier Hugues 
Published: February 2009

AbstractWe sketch algebraic and trajectory related controllability results for systems described by boundary coupled partial differential equations of second order in one spatial dimension. Those systems may be described by modules over a Bézout domain ℛℚ generated by particular Mikusinski–Operators with compact support. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability of nonlinear multiresolution analysis
Authors: Harizanov Stanislav 
Published: February 2009

AbstractStability of nonlinear subdivision and multiresolution has recently been addressed in [1]. Here we give applications to convexity/monotonicity preserving schemes introduced in [2], [3]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)