bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of automotive disk brake noise behavior using piezoceramic actuators and sensors
Authors: Schlagner S. , Wagner U. von 
Published: December 2008

AbstractOne problem of disk brakes is the occurence of noise. This work in particular addresses the occurrence of disk brake squeal with frequencies from 1 up to 12 kHz which does generally not affect the basic functionality of the brake. Nevertheless it is a serious comfort problem and it causes a high amount of costs to design noiseless brake systems. This work examines methods to evaluate the noise behaviour of disk brakes using piezoceramic actuators and sensors. In comparison to conventional methods they provide the advantage to quantify the effect of new design features without the necessity to make the brake squeal. In this paper the investigation of phase shifts between characteristic dynamic state variables is examined more in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the piezoelectric shear effect in ultrasonic motors
Authors: Schönecker Martin , Conrado Ana 
Published: December 2008

AbstractA new actuator for piezoelectric ultrasonic motors (USM) using the d15 effect was conceived. Whereas the piezoelectric d33 and d31 effects are normally used in commercial motors, there exist hardly any USM based on shear actuation. The actuator is a piezoelectric block polarized in axial direction and electroded circumferentially with four electrodes. The suitable superposition of two standing waves generates ultrasonic traveling waves in the actuator, which drives the rotor. The dimensions of the actuator are optimized with respect to the dynamic piezoelectric coupling factor. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Explicit solutions for a general class of Markov processes
Authors: van Leeuwaarden Johan S.H. , Squillante Mark S. , Winands Erik M.M. 
Published: December 2008

AbstractWe derive explicit solutions for the matrix‐geometric stationary distribution (and related measures) of a general class of infinite multidimensional Markov processes based on the probabilistic interpretations of the fundamental solution matrices and Bernoulli excursions, leading to explicit expressions for these matrix elements in terms of hypergeometric functions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization over the Stiefel manifold
Authors: Fraikin C. , Hüper K. , Dooren P. Van 
Published: December 2008

AbstractIn this note we parameterize the Stiefel manifold Stk,n in a manner that allows to perform a constrained Newton step in a relatively simple way. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Critical exponents for large time asymptotics for fractal Hamilton‐Jacobi‐KPZ equations
Authors: Karch G. , Woyczynski W.A. 
Published: December 2008

AbstractNonlinear and nonlocal evolution equations of the form ut = ℒ︁u ± |∇u |q, where ℒ︁ is a pseudodifferential operator representing the infinitesimal generator of a Lévy stochastic process, have been derived (see, [6]) as models for growing interfaces in the case when the continuous Brownian diffusion surface transport is augmented by a random hopping mechanism. The goal of this note is to report properties of solutions to this equation resulting from the interplay between the strengths of the “diffusive” linear and “hyperbolic” nonlinear terms, posed in the whole space RN , and supplemented with nonnegative, bounded, and sufficiently regular initial conditions. The full text of the paper, including complete proofs and other results, will appear in the Transactions of the American Mathematical Society. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization in constrained crack problems
Authors: Kovtunenko Victor A. , Khludnev Alexander M. 
Published: December 2008

AbstractFollowing the optimization approach to brittle fracture, we consider the evolution of a crack in a domain as solution of the global problem of constrained minimization of the total potential energy with respect to both state variables (the displacement vector) and shape variables (parameters of the crack shape). This formulation describes the initiation of a crack in a homogeneous body and its stable as well as unstable propagation, which allows also a kink (topology change) of the crack during the evolution process. By this we assume that contact can occurs between the opposite crack faces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MPEG‐4 video transmission over UMTS mobile networks
Authors: Ali M. , Pathak B. , Childs G. 
Published: December 2008

AbstractThis paper presents an overview [1] of the MPEG‐4 (Motion Picture Experts Group) coded video file structure and the VOP (Video Object Plane) types followed by classification of errors and introduction of the NEWPRED mechanism in MPEG‐4 for error concealment. An UEP (Unequal Error Protection) scheme is described with a discussion on how the proposed scheme affects the UMTS (Universal Mobile Telecommunications System) network efficiency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On orthogonal collocation by the zeros of orthogonal 0‐interpolants
Authors: Bokhari M. A. , Al‐Attas H. 
Published: December 2008

AbstractThe orthogonal collocation method is quite prominent among the collocation methods that determine approximate solutions of boundary value problems. This method involves Gaussian knots as collocation points and, in general, has fourth order convergence. Here, we discuss a similar method in which the knots are based on pre‐assigned and free zeros of polynomials that arise in orthogonal 0‐interpolants. Some numerical results demonstrate an advantage of the proposed collocation points over the Gaussian knots. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wave propagation and diffraction in discrete structures: Effect of anisotropy and internal resonance
Authors: Chesnais Céline , Hans Stéphane , Boutin Claude 
Published: December 2008

AbstractThis paper is devoted to the study of wave propagation within anisotropic structures made of the periodic repetition of un‐braced frames. Thanks to the homogenization method of periodic discrete media, a macroscopic description of the system is obtained. Then the effects on the wave propagation of anisotropy and resonance in bending of the elements are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical modeling of chatter stability using multi‐dimensional approach
Authors: Budak E. 
Published: December 2008

AbstractMachining is one of the most common manufacturing processes in industry due to its high flexibility and ability to produce parts which excellent quality. Chatter, a type of self excited vibrations arising in metal cutting operations, is a major limitation in machining resulting in poor quality and reduced productivity. Under certain conditions, the cutting process may become unstable yielding oscillations with high amplitudes and cutting forces. Stability analysis of the dynamic cutting process can be used to determine chatter‐free machining conditions with high material removal rate. Usually, one dimensional models are used for stability analysis of machining. However, based on the geometry of the actual machining process, multi‐directions would have to be used for accurate modeling of the process dynamics and the stability. In this presentation, multi directional models for turning and milling processes are presented. The effects of multi directional process mechanics on the stability are demonstrated by applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the motion of magnetic domain walls
Authors: Kort Antonio Capella , Otto Felix 
Published: December 2008

AbstractIn certain regimes and for relative small applied fields, magnetic domain walls behave as mechanical particles in a viscous fluid. By analogy their dynamic can be described with an evolution equation of the form
Mq̈ + β–1 q̇ = H
where M and are the effective wall mass and wall mobility, and H is an applied forcing. These effective parameters depend on the particular geometrical configuration and dynamical model considered. We present a method that can be used to systematically estimate the wall mass and wall mobility in terms of the static wall geometry and various physical constants. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anatomically realistic finite element simulations of Pelvic floor mechanics
Authors: Cheng Leo K. , Noakes Kimberley F. , Bissett Ian P. , Pullan Andrew J. 
Published: December 2008

AbstractAn anatomically realistic computational model of the pelvic floor and anal canal regions was used to examine the mechanics of normal defecatory function within the female pelvic floor. The subject specific model was constructed from MR images acquired from a healthy nulliparous 32 year old female. Deformation of the levator ani was simulated during a ‘bear down’ manoeuvre. A pressure of 4 kPa was imposed on the mesh and the computed mesh displacements were compared to those obtained from dynamic MR images of the same subject. The average RMS difference between the simulated mesh position and that determined by the dynamic MRI was 14 mm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of wave dispersion in periodic composites by higher‐order asymptotic homogenization method
Authors: Andrianov Igor V. , Bolshakov Vladimir I. , Danishevs'kyy Vladyslav V. , Weichert Dieter 
Published: December 2008

AbstractWe present [1] an application of the higher‐order asymptotic homogenization method (AHM) to the study of wave dispersion in periodic composite materials. When the wavelength of a travelling signal becomes comparable to the size of heterogeneities, successive reflections and refractions of the waves at the components interfaces lead to the formation of a complicated sequence of pass and stop frequency bands. The AHM provides a long‐wave approximation valid in the low frequency range. Solution for the high frequencies is obtained on the basis of the Floquet–Bloch theorem by the plane‐wave (PW) expansions method. Anti‐plane shear waves in a fibre‐reinforced composite with a square lattice of cylindrical fibres are considered. The dispersion curves are obtained, the pass and stop bands are identified. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermomagnetic convection induced by a time‐modulated driving force in magnetic fluids
Authors: Engler H. , Odenbach S. 
Published: December 2008

AbstractIt is well‐known that the flow properties of magnetic fluids – so called ferrofluids – can be modified by applying an external magnetic field. Under certain conditions, the magnetic force induced by this external field causes a convective flow. What has yet to be investigated is what happens when this driving force is modulated in time. For this purpose, a horizontal ferrofluid layer has been exposed to an intermittent magnetic field, which causes a time‐modulated force. This force depends on the strength of the external magnetic field and the fluid temperature, and therefore the flow phenomenon generated is called thermomagnetic convection. In addition, if the fluid layer is heated from below, the classical thermal convection contributes to the flow system. In our studies, both effects – thermomagnetic and thermal – contribute together to the convection. The experimental results presented here confirm previous theoretical investigations about the influence of the frequency of the driving force on the strength of the convective flow, which reach minimum values at certain frequencies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A phase field model in electrowetting and related phenomena
Authors: Eck C. , Fontelos M. , Grün G. , Klingbeil F. , Vantzos O. 
Published: December 2008

AbstractThe term electrowetting is commonly used for some techniques to change the shape and wetting behaviour of liquid droplets by the application of electric fields and charges. We developand analyze a model for electrowetting that combines the Navier‐Stokes system for fluid flow, a phase‐field model of Cahn‐Hilliard type for the movement of the interface, a charge transport equation, and the potential equation of electrostatics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Taylor‐model‐based enclosure of invariant manifolds for planar diffeomorphisms and applications
Authors: Grote Johannes , Berz Martin , Makino Kyoko , Newhouse Sheldon 
Published: December 2008

AbstractFundamental questions in the study of interesting dynamics of planar diffeomorphisms like the Hénon map involve homoclinic phenomena, topological entropy and strange attractors. Inherently, answering these questions requires knowledge about the stable and unstable manifolds, which in the typical case in the plane are smooth curves. We present a method to find highly accurate Taylor Model enclosures of the invariant curves near hyperbolic fixed points. Successive iteration of these local enclosures yields similarly accurate enclosures of pieces of the global manifold tangle. Applications presented include the automatic computation of rigorous enclosures of all homoclinic points up to finite iterates. This allows to find symbolic dynamics in the original system and consequently compute rigorous lower bounds for its topological entropy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some aspects about quantitative reconstruction for differential interference contrast (DIC) microscopy
Authors: Heise Bettina , Arminger Bernd 
Published: December 2008

AbstractWe demonstrate different appraches to reconstruct the optical path length map from DIC images: Line Integration, Deconvolution and solving the Laplace problem depending whether one or two orthogonally scanned images are available. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Data uncertainty analysis in environmental management
Authors: Hejč M. , Hřebíček J. 
Published: December 2008

AbstractImprecision of input data is an important characteristic feature of environmental monitoring. When making evaluations, conclusions and the decisions from collected data, one has to be very careful not to make fatal mistake. The important task of computing and current information and communication technology is to deal with the primary data uncertainty and thus to reduce the risk of mistake. At present new approaches and methodologies to handle environmental data uncertainty are explored as opposite to standard. The paper presents comparison of such new approach against European Environment Agency and U.S. Environmental Protection Agency standards in the several cases of the assessment environmental management indicators in the Czech Republic. The new approach brings more modular way of dealing with uncertainty and is supposed to bring better results and less workload then standard approach. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design strategies for libration point missions: theory to application
Authors: Howell Kathleen C. 
Published: December 2008

AbstractSpacecraft missions to the libration points in Sun‐planet and planet‐moon systems are of increasing interest. A number of such missions have already been launched. As the theoretical understanding of the dynamical structure in these regions of space expands, however, trajectory design to support actual mission requirements is more complex. Baseline trajectories for some recent mission scenarios are presented. Example approaches for transition of the designs to higher fidelity models is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vergleichende Messungen und Simulationen annähernd homogener Belastungsverteilungen
Authors: Alshuth Thomas , Hohl Carsten , Ihlemann Jörn 
Published: December 2008

AbstractExperimentell ermittelte Daten bezüglich homogener Belastungsverteilungen werden häufig zur Materialcharakterisierung und zur Identifizierung von Stoffgesetzparametern verwendet. Dementsprechend wichtig sind der Grad der im Experiment erreichbaren Homogenität und die Genauigkeit, mit der die nahezu homogen verteilten Spannungen und Verzerrungen aus den gemessenen Größen berechnet werden können. Zur Erfassung und Beurteilung dieser beiden Qualitätsmerkmale bei verschiedenen, in der Praxisüblichen Prüfmethoden wurden parallel zu einem umfassenden Programm vergleichender Messungen an einem Gummiwerkstoff FEM‐Simulationen der jeweiligen Spannungs‐ und Verzerrungsverteilungen durchgeführt. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multiscale deflation solvers for flow in porous media
Authors: Klie Hector , Rodriguez Adolfo , Wheeler Mary F. 
Published: December 2008

AbstractThis work describes a novel physics‐based deflation preconditioner approach for solving porous media flow problems characterized by highly heterogeneous media. The approach relies on high‐conductivity block solutions after rearranging the linear system coefficients into high‐conductive and low condutive blocks from a given physically driven threshold value. This rearranging relies on the Hoshen‐Kopelman (H‐K) algorithm that is commonly used to determine percolation clusters. The resulting preconditioner may alternatively be combined with a deflation preconditioning stage. The proposed approach is coined as a physics‐based 2‐stage deflation preconditioner (P2SDP). Numerical experiments on different permeability distributions reveal that P2SDP is a powerful means to solve pressure systems when compared to more conventional algebraic approaches such as the incomplete Cholesky factorization. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient parallel simulation of biphasic materials in biomechanics
Authors: Berrenberg Stefanie , Krause Rolf 
Published: December 2008

AbstractBiphasic materials are widely used for the modelling and the numerical simulation of articular cartilage within joints. In combination with contact, the numerical solution of the arising discrete systems is a demanding task, in particular for realistic geometries. We consider the stability and efficiency of different multilevel approaches for the numerical solution of the resulting non–smooth systems. Moreover, multilevel methods are derived which allow for the efficient numerical simulation of biphasic materials in contact. Numerical examples on problem specific geometries in three space dimensions are given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance & packet traffic dynamics of Packet Switching Network model
Authors: Lawniczak Anna. T. 
Published: December 2008

AbstractDynamics of packet traffic in data communication networks can be complex and often not well understood. Understanding of these complex dynamics is important for their control, prediction purposes and for the data networks design. The engineering community has described wired data networks architectures and studied them by means of a layered, hierarchical abstraction called ISO OSI (International Standard Organization Open System Interconnect) Reference Model. The Network Layer of the ISO OSI Reference Model is responsible for routing packets across the network from their sources to their destinations and for control of congestion in data networks. Using an abstraction of the Network Layer that we developed, we investigate packet traffic dynamics in our data network models of data communication networks of packet switching type, in particular near the phase transition point from free flow to congestion. We explore how these dynamics and network performance indicators are affected by network connection topology and routing algorithms. We consider static and adaptive routing algorithms. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the simulation of textile reinforced concrete using a multi scale approach
Authors: Lepenies Ingolf , Zastrau Bernd W. , Richter Mike 
Published: December 2008

AbstractTextile reinforced concrete (TRC) is a composite of textile structures made of multi‐filament yarns (rovings) within a cementitious matrix. Experimental investigations of textile reinforced concrete specimen show very complex failure mechanisms on different length scales. Therefore mechanical models on the micro, meso and macro scale are introduced. The paper presents a hierarchical material model of TRC on three scales. While on the micro scale the individual filaments of the fiber bundles are distinguished to determine an effective roving behavior, models on the meso scale are used to predict the macroscopic response of the composite material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FIO‐product representation of solutions to symmetrizable hyperbolic systems
Authors: Rousseau Jérôme Le 
Published: December 2008

AbstractThe solution operator of a symmetrizable hyperbolic system is approximated by a multi‐product of Fourier integral operators. Exact convergence is obtained as we let the number of operators in the product grow to infinity, which yields an alternative representation of the solution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Matched asymptotic expansions for the determination of the electromagnetic field near the edge of a patch antenna
Authors: Bendali Abderrahmane , Makhlouf Abdelkader , Tordeux Sébastien 
Published: December 2008

AbstractWe consider a simple but representative model incorporating the main behavior of the electromagnetic field near the edge of a patch antenna. Recall that this kind of antenna is obtained by a metal patch laying on a dielectric substrate covering a ground metallic plane. The functioning principle of such an electric device is based on the matching of an N‐dimensional behavior of the field outside the antenna with an (N‐1)‐dimensional one inside the zone limited by the patch and the ground plane, N = 3 or 2 according to the considered model. In this study, we make use of the technique of matched asymptotic expansions and computation of singularities to describe this behavior for the two‐dimensional case. Proved error estimates enable us to give a rigorous background to the underlying asymptotic analysis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ILU++: A new software package for solving sparse linear systems with iterative methods
Authors: Mayer Jan 
Published: December 2008

AbstractILU++ is a software package for solving sparse linear systems with iterative methods using state‐of‐the‐art incomplete multilevel LU‐factorisations as preconditioners. It implements several types of preprocessing (permuting and scaling both rows and columns prior to factorisation to make the matrix more suitable for LU‐factorisation), different pivoting strategies and a number of dropping rules to ensure sparsity. ILU++ is available under the GNU public licence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Occurrence of a delta‐shock in non‐linear chromatography
Authors: Mazzotti Marco 
Published: December 2008

AbstractWe consider a hyperbolic system of two first order partial differential equations that can be used to describe nonlinear chromatography, and the corresponding Riemann initial value problems. It can be shown that these equations admit classical solutions made of constant states separated by continuous (simple wave) or discontinuous (shock) transitions, but also – for exactly specified initial states – singular solutions. Such solutions are due to the occurrence of an overcompression condition that leads to the formation of a spike travelling at constant speed and increasing strength in space. Such singular solution can be observed by solving numerically a regularized form of the original equations, but eludes the application of techniques proposed in the literature to study singular shocks and delta‐shocks, which share with the system studied here its overcompressive character. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)