bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Navier‐Stokes equations with regularization
Authors: Asanalieva Nazgul , Varnhorn Werner 
Published: March 2010

AbstractWe consider the initial boundary value problem for the nonstationary Navier‐Stokes equations in a bounded three dimensional domain Ω with a sufficiently smooth compact boundary ∂Ω. These equations describe the motion of a viscous incompressible fluid contained in Ω for 0 < t < T and represent a system of nonlinear partial differential equations concerning four unknown functions: the velocity vector v = (v1 (t, x), v2 (t, x), v3 (t, x)) and the kinematic pressure function p = p(t, x) of the fluid at time t ∈ (0, T) in x ∈ Ω. The purpose of this paper is to construct a regularized Navier‐Stokes system, which can be solved globally in time. Our construction is based on a coupling of the Lagrangian and the Eulerian representation of the fluid flow. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinematical and dynamical analysis of closed kinematic chains using graphs and contour equations
Authors: Drewniak J. , Zawiślak S. 
Published: March 2010

AbstractThe classical method of determination of velocities and accelerations of the closed kinematical chains consists in calculation of derivatives of the position vector in relation to time. In the paper, the methods of kinematical and dynamical analysis of the closed kinematical systems based upon the graph representation are presented. Planetary gears are the exemplary mechanical systems which have been considered. Two types of graphs are assigned to the gears. Both graphs allow for derivation of systems of equations which constitute the kinematical analysis. The results of classical and graph‐based methods were compared. The graph based methods allow for further considerations like e.g. synthesis, enumeration of design solutions and even evolutionary design of mechanisms. Dynamical analysis is shown in graphical form, only. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Probabilistic sensitivity of limit states of structures. The Monte Carlo simulation
Authors: Skowronek M. 
Published: March 2010

AbstractThe main issue of the paper is the probabilistic sensitivity of the limit states of structures with respect to selected input design variables. Attempt to the problem is done by the dedicated Monte Carlo simulation procedure. Basic design variables are random variables of given probability distributions, presented in the form of random numbers. Uni‐parametrical increment of the dominant basic variable (basic variables) is done, finally achieving the structural limit state. The simulation procedure restuls in a set of limit multipliers. Statistical analysis leads to the estimate of the probability density function of the limit state. Thus the numerical image is presented of the probabilistic sensitivity of the structural limit state. Reliability or the probability of failure are to be estimated, as statistical parameters of the histogram. Numerical examples of engineering structures illustrate the method introduced in the paper, conclusions are formulated eventually. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reliability of silo structure with geometric imperfections
Authors: Górski Jarosław , Mikulski Tomasz 
Published: March 2010

AbstractReliability of a silo structure with geometric imperfections is estimated. As the silo cylindrical constructions can be loaded with pressure below the atmospheric any geometric discrepancies are very dangerous and can significantly reduce their capacities. A probabilistic approach was applied. Two cases were considered. The imperfections were described by a uniform and a truncated Gaussian distribution. In the first case an uncorrelated random field was considered while in the second a theoretical nonhomogeneous correlation function was formulated. The realizations of the random imperfection fields are generated using a conditional rejection method. A version of a stratified sampling method is applied. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A probabilistic description of footbridges vibration serviceability
Authors: Winkelmann Karol , Górski Jarosław 
Published: March 2010

AbstractVibration serviceability of pedestrian bridges is considered. Imperfections in the human walking force are described as changes in walking factors. Probability distributions of walking frequencies, step length, and amplitude of walking force are taken into account. The imperfections can influence the level of footbridge vibration response. The Monte Carlo method is applied. The generated realizations of the loads formulate a set of initial data for numerical calculations. The probability distribution of maximal vertical acceleration is obtained. The results are presented as a probability that the required level of vibration will not be exceeded. A reliability describing the footbridges serviceability is also estimated. The probabilistic based approach can be used for future optimalizations of footbridge design codes due to the dynamic force loads. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Computation of Parametric Induced Roll Motions in Random Seas
Authors: Dostal Leo , Kreuzer Edwin 
Published: March 2010

AbstractFor a vessel in open seas, the sudden appearance of roll motions due to waves from the front or rear leads to dangerous situations up to capsizing. The equations of motion used to analyze the roll motion include the righting lever curve. This curve is set up by means of hydrostatic calculations and approximated by polynomials for further analysis. The irregular waves are modeled in terms of a continuous‐time ARMA process. The resulting model of stochastic differential equations is investigated numerically by Local Statistical Linearization. The necessary stochastic moments and their derivatives are computed using Itô's differential rule and Gaussian closure. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On an one‐step modification of Gauss‐Newton method under generalized Lipschitz conditions for solving the nonlinear least squares problem
Authors: Shakhno Stepan , Iakymchuk Roman 
Published: March 2010

AbstractWe investigate convergence of the one‐step modification of Gauss‐Newton method using the divided differences and the weak generalized Lipschitz condition for the divided differences. Convergence order of the method was examined and the uniqueness ball for the solution of the nonlinear least squares problem was proved. Numerical experiments were also provided. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Local buckling design problem for topology optimized truss girders
Authors: Kutylowski Ryszard , Rasiak Bartosz 
Published: March 2010

AbstractThe paper presents practical applying of structural topology optimization algorithm based on the formulation of optimal design with compliance minimization. Problem was presented and discussed for several 2D examples. Analysis of local buckling problem was made for various results obtained by the algorithm and approximated into the truss structures. Real bridge load was considered for girders. Topology based optimal girders were compared to typical truss structure. Relation between rods thicknesses was considered. Stress level including buckling in compressed members was examined. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient Reliability Sensitivity Estimation for Optimization Under Uncertainty
Authors: Valdebenito M.A. , Schuëller G.I. 
Published: March 2010

AbstractIn this contribution, an efficient framework for performing reliability‐based optimization is presented. Key issues of the proposed approach are the decoupling of optimization and reliability estimation and efficient reliability sensitivity estimation. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applications of singular value decomposition in structural optimisation
Authors: Gerzen Nikolai , Barthold Franz‐Joseph 
Published: March 2010

AbstractThe usage of the singular value decomposition (SVD) in scope of structural optimisation is motivated. We briefly outline several applications of SVD from different scientific fields to point out their similarities with structural optimisation. Here, our focus is on model reduction, on numerical defects and on their quantitative description using SVD. In this context we address the singular value decomposition of matrices which appear in an optimisation algorithm, i.e. the pseudo load matrix and the sensitivity matrix. In this contribution on the example of topology optimisation we would like to clarify all the properties of SVD. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Model of the Internet mortgage market optimization
Authors: Mieloszyk Eligiusz , Orłowski Aleksander 
Published: March 2010

AbstractThe Internet mortgages are currently a fast growing market, allowing selling mortgages cheaper and faster than in the traditional methods such as in bank departments. Given the specificity of selling mortgages in the Internet, banks try to sell more mortgages by spending more money on advertising and paying higher commission to the brokers selling their products. It is important to optimise the amounts of money in both sectors (the balance of money for advertising and for brokers) and to compare these amounts with the level of mortgages can be sold within this period (which is related to the economic indicators such as the current level of interest rate, unemployment rate etc.)It is suggested to create a knowledge base rule model defining the Internet mortgage market which will include the variables important for the problem (preliminary choice of such indicators the level of commission that is paid to the brokers, the current interest rate in the country), restrictions concentrating optimising the amounts of money that will be spend with the correlation to the current possibilities of selling mortgages (defined by the current situation of the economy). The model will be supported with the data from two banks and two brokers representing the market. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New graph products of specified domains for configuration processing
Authors: Kaveh A. , Alinejad B. 
Published: March 2010

AbstractIn this paper new graph products are defined with specified domains. In these products the logical operations of the graph products are only applicable in specified domains, and therefore these products can produce configurations which do not need to be regular. Compound models can be generated and cut‐outs and other irregularities can be incorporated using these products. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The contributions regarding the conception, designing, modelling and the implementation in a flexible cell of fabrication of a modular serial robot
Authors: Petrişor Silviu Mihai , Ispas Viorel , Arghir Mariana 
Published: March 2010

AbstractThe authors of the presented paper are propose to relief the calculus, modelling and construction of the translation module of an industrial robot which possess in his cinematic chain five degrees of freedom, type TTRTR. It is propose a choosing variant of the direct current driving engine of the translation module, knowing the output momentum and calculating the input momentum. This is realized by equalize of an equation which results from dynamic modeling of the robot with a designing equation which keep in view the component elements of the structure of the module. The robot is composed by: module of translation on horizontal to the base of the robot (MTB‐Sil), module of translation on vertical (MTV‐Sil), module of rotation round the vertical axis from the robot's arm, module of translation from the structure of the robot's arm (MT‐Sil) and module of orientation assembled with clamping device. In the paper, also is presented an economic study regarding the implementation of the analyzed robot in a manufactural cell concerning the manufacturing and assembling of some types of car radiators. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Another derivation of the local double logarithmic reconstruction formula
Authors: Niessner Herbert 
Published: March 2010

AbstractIn [1] Artebrant and Schroll presented a finite volume method for hyperbolic conservation laws of 3rd order accuracy with no limiter and no special shock treatment. The method is based on local reconstruction of a double logarithmic function from cell averages on a 3‐point stencil. Results shown in [1] make it appear very attractive and highly efficient. The derivation of the reconstrucion formula however starts with a relativ complex expression in some way anticipating the final result. In the following a more lucid one is shown proceeding from scratch and permitting symmetries to be clearly seen. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Boundary Integral Formulation for Poroelastic Materials
Authors: Schanz Martin , Steinbach Olaf , Urthaler Peter 
Published: March 2010

AbstractWave propagation in porous media is an important topic, e.g. in geomechanics or the oil‐industry. We formulate a linear system of coupled partial differential equations based on Biot's theory with the solid displacements and the pore pressure as the primary unknowns. To solve this system of coupled partial differential equations in a semi‐infinite homogeneous domain the BEM (Boundary element method) is especially suitable. Starting from a representation formula a system of two boundary integral equations is derived. These boundary integral equations are used to solve related boundary value problems via a direct approach. Coercivity of the resulting bilinear form is shown, from which unique solvability of the variational formulation follows from injectivity. Using these results we derive the unique solvability of the related boundary integral equations. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Optimal Control of a Free Surface Flow
Authors: Repke Sabine , Marheineke Nicole 
Published: March 2010

AbstractWe discuss an optimal control approach for a 2D Stokes flow with a free surface. The aim is to optimize the shape of a polymer film by adjusting the ambient pressure in a casting process. The resulting minimization problem is solved by the method of steepest descent. Numerical results will be presented. Furthermore we state the adjoint system for the Lagrangian formalism. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical solutions for optimal control of monodomain equations
Authors: Nagaiah Chamakuri , Kunisch Karl , Plank Gernot 
Published: March 2010

AbstractWe present the numerical solutions of optimality systems corresponding to optimal control problems governed by the mono‐domain equations which are widely used for describing the electrical activity of the cardiac tissue. This mono‐domain model is based on a parabolic equation and a system of stiff ordinary differential equations. The space discretization of the state variables and dual variables is done using piecewise linear finite elements and the time discretization is based on linearly implicit Runge‐Kutta methods. The main goal of this work is to study the optimal control behavior of the electrical potentials under the influence of extracellular ionic currents as control variables. The numerical results presented are based on first and second order optimization methods. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A priori estimates for optimal Dirichlet boundary control problems
Authors: Deckelnick Klaus , Günther Andreas , Hinze Michael 
Published: March 2010

AbstractWe consider variational discretization of control constrained elliptic Dirichlet boundary control problems on smooth twoand three‐dimensional domains, where we take into account the domain approximation. The state is discretized by linear finite elements, while the control variable is not discretized. We obtain optimal error bounds for the optimal control in two and three space dimensions. Furthermore we prove a superconvergence result in two space dimensions under the assumption that the underlying finite element meshes satisfy certain regularity requirements. We confirm our findings by a numerical experiment. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel digitally controlled drive for the vibratory conveyors
Authors: Kucharski Tomasz , Jakubowski Piotr , Zurek Krzysztof 
Published: March 2010

AbstractThe vibratory conveyors are used in the industry for continuous transportation of loose substances over short distances (2–10 m). The presented conveyor is designed for transportation in aseptic conditions. To obtain high efficiency for granulated mass with different size of grain and different physical properties it is necessary to set the appropriate vibration amplitude independently of vibration frequency. This is not possible with the conveyors currently being used. Therefore it was proposed to apply the novel drive made up of rotary exciter with digital controller. Moreover some methods for dynamic stiffening of the panels were developed and their effectiveness was ascertained. A digitally controlled exciter allowed dynamic panel stiffening by using light closed panels in construction of the conveyor. The control system with encoders for measuring the vibration amplitude of the panel was also established. A study of the conveyor's prototype shows the effectiveness of the drive system. The possibility of digitally setting the vibration amplitude of the light panel to obtain the maximum productivity for particular materials was also shown in results of the research. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibration surveillance during milling of flexible details with a use of the optimal control
Authors: Kaliński Krzysztof , Chodnicki Marek 
Published: March 2010

AbstractThe paper concerns vibration surveillance during ball end milling of curved flexible details. Here is explained dynamic analysis of non‐stationary vibrating system, from which are separated subsystems: modal, structural and connective. An assessment of coincidence of the calculation model results with those from investigation on milling machine is performed. Ball end milling of flexible details is observed very frequently in case of modern machining centres. It is obvious that tool‐workpiece relative vibration plays principal role during cutting process. The most important task is to create a FE‐model of machined flexible detail and obtain its good correlation with the results of experimental modal analysis. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of the Internal Dynamics of Underactuated Robots
Authors: Seifried Robert 
Published: March 2010

AbstractA robot is underactuated if it possesses less control inputs than degrees of freedom, e.g. due to passive joints. The analysis of the mechanical design of these kinds of underactuated robots often shows that they are non‐minimum phase, i.e. they have an internal dynamic which is not asymptotically stable. Therefore, feedback linearization is not possible, and output trajectory tracking becomes a very challenging task. It is shown that through an optimization procedure the mechanical design of an underactuated robot can be altered in such a way that the internal dynamics becomes stable. Thus feedback linearization of the underactuated robot becomes possible. In the optimization procedure, the design parameters are additional masses which are added to defined locations at different un‐actuated links of the robot. The optimization criteria is two‐stage and firstly requires that all eigenvalues of the linearized zero‐dynamics are in the left half‐plane and secondly that initial errors in the zero‐dynamics decay rapidly. Due to the two‐stage criteria computation the optimization problem is discontinuous. Also there might be many local minima. Therefore a particle swarm optimization procedure is used. The efficiency of this optimization approach is demonstrated by simulation of an underactuated robot. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mu‐Synthesis for Magnetic Bearings of Flywheel
Authors: Mystkowski Arkadiusz 
Published: March 2010

AbstractIn this paper, the μ‐Synthesis Control method is applied to control Active Magnetic Bearings (AMBs) Flywheel. The dynamics of the open‐loop system is influenced by external disturbances, nonlinearities, uncertainties and signal limits. Thus, a design methodology, which covers the practical issues of optimal robust control like the modelling of uncertainties, selection of optimal weighting functions is presented. The goal of this paper is the experimental evaluation robust performance of the AMBs system. The laboratory stand with the high speed rotor supported magnetically was built and presented. The stable operation, good stiffness of the rotor suspension and robust performances of the closed‐loop AMBs is reached. Finally, the success of the robust control is demonstrated through results of computer simulations and experimental results. The experimental results show the effectiveness of the control system as well as good vibrations reduction of the designed controllers. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Spiral Tribometer for Dynamic Friction Measurements
Authors: Al Natsheh Naser , Ostermeyer Georg‐Peter 
Published: March 2010

AbstractBasically there exists a significant interest in dynamic friction models [1]. These dynamic models describe μ as a time dependent process parameter. The indentification of the belonging parameters needs a special kind of measurements. This is due to the fact that the measurements with the classical pin on disk arrangement give stationary values of μ only, the measurements of dynamic properties are even infeasible. A new advanced tribometer has been developed. This tribometer allows measurements of complex unsteady friction processes. The experimental characteristics and the realization of this novel tribometer are presented by concrete measurements. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Implementation of genetic algorithm for controlling the electromagnetic motor
Authors: Pecolt Sebastian , Krzyzynski Tomasz , Kuznicki Andrzej 
Published: March 2010

AbstractThe paper deals with the problem of implementing a genetic algorithm (GA) to calculate a pareto‐optimal function of voltage in time‐domain powering solenoids, used to control a linear electromagnetic motor (e.m.). The method proposed assumes minimising two criteria: the time of motion of the linear electromagnetic motor and the energy input. The results have been obtained for a set position with a narrow range of power supply. The work of electromagnetic motor is based on electromagnetic repulsion. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mixed algorithm in searches of mechanical system steady‐state conditions for low precision of the state estimation
Authors: Lipinski Krzysztof 
Published: March 2010

AbstractThis paper focuses on algorithms of numerical solution of nonlinear system of equations. Analytical formulas of their nonlinear functions my not be calculated with the requested precision. Additionally, analytical formulas of the partial derivatives are unknown. They are evaluated numerically by finite differences method. It effects in erroneous estimations. Described situation is critical when steady state conditions are searched for mechanical systems. According to the precision of the numerical procedures, their dynamic equations are known with limited precision. This same stands for the system's final conditions (obtained by a numerical integration). It the actual case, the classical Newton‐Raphson algorithm can be ineffective. As an alternative, a mixed search algorithm is proposed in the paper. By contrast to the classical algorithm, within the search direction defined by the Newton‐Raphson indication, (potentially erroneous) a local minimum is searched. Both the algorithms are tested on analytical functions; on randomized functions and on a model of a mechanical system. (© 2009 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)