bluuebunny/crossref_metadata_2025 huggingface dataset:
Art, mathematics & cultural industry: new trends in the digital era
Authors: Lorenzi M.G. , Francaviglia M.
Published: December 2008

In view of modern technologies proper of the Digital Era we shortly discuss some recent activities of our research groups in the broad field of Cultural Industry, where Art, Mathematics and Physics are gaining new interrelationships concerning the use of Digital Art and Web Technologies in the domain of Scientific Communication and Visualization. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of a transport mediating switch
Authors: Gedeon Tomáš , Boczko Erik , Mischaikow Konstantin
Published: December 2008

We show that dynamics of a general toggle switch that mediates transport between cellular compartments, converges to a unique periodic orbit in two limiting cases. These results can be perturbed for a restricted, but biologically ubiquitous model. This robustness may be the reason why only the restricted switch appears to be operating in Nature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asymptotic methods for spherically symmetric MHD α2‐dynamos
Authors: Günther U. , Kirillov O.N.
Published: December 2008

We consider two models of spherically‐symmetric MHD α2–dynamos; one with idealized boundary conditions (BCs); and one with physically realistic BCs. As it has been shown in our previous work, the eigenvalues λ of a model with idealized BCs and constant α–profile α0 are linear functions of α0 and form a mesh in the (α0, λ)–plane. The nodes of the spectral mesh correspond to double‐degenerate eigenvalues of algebraic and geometric multiplicity 2 (diabolical points). It was found that perturbations of the constant α –profile lead to a resonant unfolding of the diabolical points with selection rules of the resonant unfolding defined by the Fourier coefficients of the perturbations. In the present contribution we present new exact results on the spectrum of the model with physically realistic BCs and constant α. For non‐degenerate (simple) eigenvalues perturbation gradients are found at any particular α0. We briefly discuss the spectral behavior of the α2–dynamo operator over a family of homotopic deformations of the BCs between idealized ones and physically realistic ones. Furthermore, we demonstrate that although the spectral singularities are lifted, a memory about their locations remains deeply imprinted in the homotopic family of spectral deformations due to a hidden underlying invariance. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanoscale dendritic organoplatinum antitumor drugs
Authors: Howell B.A. , Fan D. , Rakesh L.
Published: December 2008

Organoplatinum compounds exhibit broad antitumor activity. Cisplatin [cis‐ dichlorodiammine platinum (II)] is the most prominent of this family and is currently the most prescribed cancer drug. It is widely used for the treatment of human testicular, ovarian, bladder, head and neck carcinomas. However, it is an extremely toxic compound and side effects such as nephrotoxicity and myelotoxicity are major drawbacks for its use in clinical applications. A way to combat the side effects associated with the administration of platinum drugs would be to generate a prodrug conjugate that, when present in the extracellular fluid, would slowly release active platinum species at a level below the threshold for side effects. Traditionally, linear hydrophilic polymers have been examined for potential application as carrier platforms for these drugs. The advent of dendrimers, which are highly branched macromolecules with precisely controlled nanoscale size, shape and end‐group functionality, has provided an excellent opportunity to design and formulate novel multivalent time‐release drug systems. For example, treatment of a generation 4.5 (carboxylate surface) poly(amidoamine) [PAMAM] dendrimer with diaquo(1,2‐diaminocyclohexane) platinum(II) generates a nanoparticle with forty platinum moieties attached at the surface. This polymer‐drug conjugate displays a very good release profile for the platinum species. Under physiological conditions about 80% of the platinum units are released over the first 24 hours. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal long‐distance transport systems in nature: control and applications (Poster Presentation)
Authors: Kizilova Natalya
Published: December 2008

Long‐distance conducting systems in high plants and animals are presented by networks of rigid tubes with porous walls (in plants) or distensible tubes with impermeable walls (in animals). Geometrical relationships between the diameters, lengths and branching angles of separate conducting vessels have been studied and the results of the comparative analysis are presented. It was shown that the principles of construction of the transport systems are similar in animals and plants and correspond to the optimal pipelines with impermeable and permeable walls accordingly. The optimization criterion is the total energy expenses W for the fluid delivery and construction of the system. Global optimality at the systemic level is provided by local optimality conditions in each conducting element. It is shown that complexity of the branching system of the optimal tubes leads to certain regularities in the hydraulic and wave properties of the systems. The obtained regularities and the principles of design of the long‐distance transportation networks in Nature can be used in biomedical applications and technique. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Maximal growth rate at the Rosensweig instability: theory, experiment, and numerics
Authors: Knieling Holger , Lange Adrian , Matthies Gunnar , Rehberg Ingo , Richter Reinhard
Published: December 2008

We investigate the growth of a pattern of liquid crests emerging in a layer of magnetic liquid when subjected to a magnetic field oriented normally to the fluid surface. After a step like increase of the magnetic field, the temporal evolution of the pattern amplitude is measured by means of a Hall‐sensor array. The extracted growth rate is compared with predictions from linear stability analysis by taking into account the nonlinear magnetization curve M (H). The remaining discrepancy can be resolved by numerical calculations via the finite element method. By starting with a finite surface perturbation it can reproduce the temporal evolution of the pattern amplitude and the growth rate. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Knotted linear force‐free magnetic fields‐topological aspects
Authors: Kotiuga P. Robert
Published: December 2008

The problem of computing linear force‐free magnetic fields on a knotted multiply‐connected domain is considered. The domain is the support of the current distribution, and the linear force‐free fieldproblem reduces to finding an eigenfield of a self‐adjoint curl operator. In this context, the GKN Theorem is reformulated in terms of symplectic geometry in order to characterize the self‐adjoint extensions of the curl operator restricted to solenoidal vector fields. When further restricted to the isotopy invariant boundary conditions, the self‐adjoint extensions are parametrized by the Lagrangian subspaces of the symplectic form on the first homology group of the boundary. This paper discusses some of the topological aspects and gives some pointers for the associated finite element discretization. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variational splines for the numerical solution of singular differential equations
Authors: Gorbunov Vladimir , Lutoshkin Igor , Martynenko Yuliya
Published: December 2008

The numerical parametrization method (PM), originally created for optimal control problems, is specificated for classical calculus of variation problems that arise in connection with singular implicit (IDEs) and differential‐algebraic equations (DAEs). The PM for IDEs is based on representation of the required solution as a spline with moving knots and on minimization of the discrepancy functional with respect to the spline parameters. Such splines are named variational splines. For DAEs only finite entering functions can be represented by splines, and the functional under minimization is the discrepancy of the algebraic subsystem. The first and the second derivatives of the functionals are calculated in two ways – for DAEs with the help of adjoint variables, and for IDE directly. The PM does not use the notion of differentiation index, and it is applicable to any singular equation having a solution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical and physical modelling of seismic faults (Poster Presentation)
Authors: Diosdado A. Muñoz
Published: December 2008

Modelling of seismic faults by using spring block systems on a frictional surface, requires to solve coupled differential equation systems with a great number of equations, in order to avoid this problem, the spring‐block model is mapped into a continuous, non‐conservative cellular automaton. Every time the automaton is calculated a synthetic earthquake is obtained. We obtained catalogues of synthetic earthquake magnitude, which we can represent as a time series. Such series exhibit power law behavior so much for the magnitudes (Gutenberg‐Richter law) as for the duration times. The analysis of these time series with methods of non‐linear dynamics provides interesting results; for example, the time series show multifractality for large values of the conservation level. We present the correlation analysis of three kinds of time series: recurrence times, jumps or distance between consecutive earthquakes and magnitude for different thresholds. We obtained long correlations in recurrence times as it has been observed in real seismicity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multiparametric frequency‐domain criteria for stability of distributed systems with multiple equilibria (Poster Presentation)
Authors: Smirnova V.B. , Perkin A.A.
Published: December 2008

For integral Volterra equations with periodic nonlinear functions and nonlinear functions satisfying the sector condition, new frequency domain criteria for gradient‐like behavior are obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A short overview of some behavioural scenarios for derivative pricing in incomplete markets
Authors: Pinheiro D. , Pinto A. A. , Xanthopoulos S. Z. , Yannacopoulos A. N.
Published: December 2008

We shortly describe three different but related scenarios for determination of asset prices in an incomplete market: one scenario uses a market game approach whereas the other two are based on risk sharing or regret minimizing considerations. Furthermore, we point out some new dynamical schemes modeling the convergence of the buyer's and of the seller's prices of a given asset to a unique price. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab‐initio study of transition temperature of Mn‐doped GaN diluted magnetic semiconductor (Poster Presentation)
Authors: Rufinus J.
Published: December 2008

We study the effect of clustering and random metal atoms distribution on the transition temperature of Mn‐doped GaN Diluted Magnetic Semiconductors. To calculate the exchange coefficients between the Mn atoms, a Density functional theory‐based Locally Self Consistent Multiple Scattering (LSMS) method has been used. Here we present the results of our calculations, which show that random metal distribution increases the calculated transition temperature of the material while the clustering decreases it. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coupled cell networks: minimality
Authors: Aguiar Manuela A. D. , Dias Ana Paula S.
Published: December 2008

Non‐isomorphic coupled cell networks with the same number of cells and with equivalent dynamics are said to be ODE‐equivalent. Moreover, they are all related by a linear algebra condition involving their graph adjacency matrices. A network in an ODE‐class is said to be minimal if it has a minimum number of edges among all the networks of the class. In this short paper we review the characterization of the minimal networks of an ODE‐equivalence class and we present an example for the case of non‐homogeneous networks. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
General solutions of the Stokes equations and their applications
Authors: Amaranath T.
Published: December 2008

A method to discuss Stokes flow in the presence of an ellipsoid is suggested. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffusion of nonstationary stirred fields
Authors: Arnaut L. R.
Published: December 2008

Rapid perturbations of the boundaries of an overmoded cavity for acoustic or electromagnetic fields cause nonstationary effects of the stochastic properties of the field. The associated Langevin–Itô and Fokker–Planck equations for the energy density and field amplitude are derived. Analytic solutions for the field magnitude and energy density are obtained, showing that the field dynamics can be characterized as a generalized diffusion process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
General solutions of the Oseen equations
Authors: Padmavati B. Sri
Published: December 2008

A new general solution of Oseen [3] equations has been suggested [4]. A necessary and sufficient condition for a divergence‐free vector to represent the velocity in an Oseen flow is given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On characteristics of investment projects efficiency
Authors: Bronshtein Efim
Published: December 2008

The class of investment projects (named correct projects) and its efficiency characteristic (named limited profitability) is defined. Some properties of limited profitability showing its practical advantage are established. It is proved that limited profitability coincides with Arrow‐Levhari characteristic. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On selective harvesting of an inshore‐offshore fishery: a bioeconomic model
Authors: Chaudhuri Kripasindhu
Published: December 2008

In the present paper, a bioeconomic model is developed for the selective harvesting of a single species, inshore‐offshore fishery, assuming that the growth of the species is governed by the Gompertz law. The dynamical system governing the fishery is studied in depth; the local and global stability of its non‐trivial steady state are examined. Existence of a bionomic equilibrium is established under different parametric considerations. The optimal harvest policy is discussed by invoking Pontryagin's Maximum Principle. Lastly, the results are illustrated with the help of a numerical example. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of precipitates on the evolution of a martensitic phase boundary
Authors: Dondl Patrick W. , Bhattacharya Kaushik
Published: December 2008

In this article, we study the role of defects in the quasistatic evolution of a martensitic phase boundary. The formulation of the model gives rise to a nonlocal free boundary problem, for which we present an implicit finite‐time discretization. For an approximate model, assuming a nearly flat interface, we show that the phase boundary exhibits a sick‐slip behavior in the presence of a heterogeneous environment, thus leading to a transition from viscous kinetics to rate‐independent behavior. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some exact controllability results for the linear KdV equation and uniform controllability in the zero‐dispersion limit
Authors: Glass Olivier , Guerrero Sergio
Published: December 2008

In this paper, we deal with controllability properties of linear and nonlinear Korteweg‐de Vries equations in a bounded interval. The main part of this paper is a result of uniform controllability of a linear KdV equation in the limit of zero‐dispersion. Moreover, we establish a result of null controllability for the linear equation via the left Dirichlet boundary condition, and of exact controllability via both Dirichlet boundary conditions. As a consequence, we obtain some local exact controllability results for the nonlinear KdV equation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the choice of initial conditions of difference schemes for parabolic equations
Authors: Berikelashvili Givi , Gupta Murli M. , Muskhelishvili N.
Published: December 2008

We study finite difference schemes to approximate the first initial‐boundary value problem for linear second order parabolic equations and obtain some convergence rate estimates. When difference schemes are constructed for such problems, in the process of obtaining convergence rate estimates compatible with smoothness of the solution, various authors assume that the solution of the problem can be extended to the exterior of the domain of integration, preserving the Sobolev class. Our investigations show that this restriction can be removed if, instead of using the exact initial condition, we use certain approximations of the initial conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The stopping and starting problem in the model with jumps
Authors: Hamadene S. , Hdhiri I.
Published: December 2008

We consider the problem of optimal two modes switching in finite horizon in the model with jumps. We first give a verification theorem to shape the problem and later we show that it is satisfied. Finally when randomness comes from a diffusion process we study the the associated PDI variational inequalities with inter‐connected obstacles. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling the viscoelasticity of cell shape changes
Authors: Hosking Roger J. , Husain Saiful A.
Published: December 2008

In the theory of linear viscoelasticity, creep and relaxation functions are the important delay kernels in the stress‐strain relations. Quite recently, a creep function power law has been obtained experimentally for an isolated living cell (on the scale of the cell). The corresponding form of the relaxation function is derived using the interconversion formula. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulations of flows in an elastic cylinder with two chambers
Authors: Lee Sunmi , Jung Eunok
Published: December 2008

We present a mathematical model of valveless pumping in a tube with two elastic chambers, which are motivated by the Liebau's two‐tank model. The tube consists of partially soft and partially (almost) rigid. We employ a two‐dimensional model using the immersed boundary method. In this new model, we have showed the important features of valveless pumping as the previous experiments and mathematical models have been discovered. For instance, we have observed that the direction and the amount of a net flow are sensitively dependent on the pumping frequency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carr's randomization for American options in regime‐switching models
Authors: Boyarchenko S. , Levendorskiĭ S.
Published: December 2008

In the paper, we solve the pricing problem for American put‐like options in Markov‐modulated Lévy models. The early exercise boundaries and prices are calculated using a generalization of Carr's randomization for regime‐switching models. An efficient iteration pricing procedure is developed. The computational time is of order m2, where m is the number of states, and of order m, if the parallel computations are allowed. The payoffs, riskless rates and class of Lévy processes may depend on a state. Special cases are stochastic volatility models and models with stochastic interest rate; both must be modelled as finite‐state Markov chains. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fitting TAR(1) models to Sheperd data
Authors: Lindström Torsten
Published: December 2008

A number of results that will be reported in detail elsewhere are outlined. The fundamental results are that typical models fitted to data of nonlinear mechanistic models possess non‐standard bifurcation routes and they in essential cases fit repellers to attractors of the true mechanistic map. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal design and optimal damping set for a hyperbolic problem (Poster Presentation)
Authors: Maestre Faustino , Münch Arnaud , Pedregal Pablo
Published: December 2008

In this work we analyze a 2D optimal design problem governed by a linear damped 1D wave equation. In this we would like to find simultaneously the spatio‐temporal layout of two isotropic materials of constants α and β (0 < α < β) and the static position of a damping set in order to minimize certain functional ([5]). By means of the gradient Young measures, we compute a full relaxation of the problem which is justified by the presence of microstructures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On conditions of flutter onset for elongated plate in supersonic gas flow
Authors: Loginov Boris , Makeev Oleg
Published: December 2008

The scheme developed in [1] of the investigation of Poincaré–Andronov‐Hopf bifurcation on the base of the Lyapounov‐Schmidt method is applied to two boundary value problems for nonlinear ordinary differential equation describing the oscillations of an elongated plate in supersonic gas flow. Necessary conditions for the existence of periodic solutions are obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A code for theTricomi equation
Authors: Neuberger J. W.
Published: December 2008

A code, which permits investigation of boundary conditions for the Tricomi equation on a region in which the equation is hyperbolic on one part and elliptic on another, is indicated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluating the impact of average cost based contracts on the industrial sector in the European emission trading scheme
Authors: Oggioni Giorgia , Smeers Yves
Published: December 2008

The degradation of the competitiveness of part of the European industry is progressively emerging as one of the possible consequences of the combination of the European Emission Trading Scheme (EU‐ETS) and the restructuring of the electricity sector. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal trajectories which are tangent to an affine distribution
Authors: Popescu Mihai , Pelletier Fernand
Published: December 2008

In this work we study the trajectories which are tangent to an affine sub‐bundle in the tangent bundle of a manifold and which minimize the “total energy”.We give some characterizations of such “regular” trajectories in terms of control theory and geometrical theory. We also build some sufficient conditions of existence for such curves. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cournot Duopoly with competition in the R&D expenditures
Authors: Pinto Alberto A. , Ferreira Fernanda A. , Ferreira Miguel , Oliveira Bruno M.P.M.
Published: December 2008

We present a new R&D investment in a Cournot Duopoly model and we analyze the different possible types of Nash R&D investments. We observe that the new production costs region can be decomposed in three economical regions, depending on the Nash R&D investment, showing the relevance of the use of patents in new technologies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A second‐order accurate method for solving the eikonal equation
Authors: Schwartz Peter , Colella Phil
Published: December 2008

We present a numerical method for computing the signed distance to a piecewise‐smooth surface defined as the zero set of a function. It is based on a marching method by Kim and a hybrid discretization of first‐ and second‐order discretizations of the eikonal equation. If the solution is smooth at a point and at all of the points in the domain of dependence of that point, the solution is second‐order accurate; otherwise, the method is first‐order accurate, and computes the computes the correct entropy solution in the presence of kinks in the initial surface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational approach to the cost analysis of dual machine interference model with general arrival distribution
Authors: Mishra S.S.
Published: December 2008

In this paper, a fresh attempt has been made to apply a computational approach to obtain the optimal total cost of the system as an important performance measure for the machine interference model with general arrival distribution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On portfolio optimization using fuzzy decisions
Authors: Sudradjat Supian , Preda Vasile
Published: December 2008

We consider stochastic optimization problems involving stochastic dominance constraints. We develop portfolio optimization model involving stochastic dominance constrains using fuzzy decisions and we concentrate on fuzzy linear programming problems with only fuzzy technological coefficients and aplication/implementation of modified subgradient method to fuzy linear programming problems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcation of the positive solutions to Henon equation
Authors: Yang Zhonghua , Li Zhaoxiang
Published: December 2008

Three algorithms based on the bifurcation method is applied to solving the D4 symmetric positive solutions to the boundary value problem of = Henon equation. Taking r in Henon equation as a bifurcation parameter, the D4 – ∑d (D4 – ∑1, D4 – ∑2) symmetry‐breaking bifurcation point on the branch of the D4 symmetric positive solutions is found via the extended systems. Finally, ∑d (∑1, ∑2) symmetric positive solutions = are computed by the branch switching method based on the Liapunov‐Schmidt reduction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Receptivity of the boundary layer with separation bubble to external sound waves
Authors: Zametaev V.B. , Kravtsova M.A.
Published: December 2008

The receptivity problem of laminar separated two‐dimensional boundary‐layer under influence of external acoustic waves is considered. Basic features of this theory were formulated by Ruban (1984) and then Goldstein (1985), but these investigations were limited by small perturbations of steady parallel flow only. The current paper takes into account essentially nonparallel regimes of base flow, including attached flows, flow with separated bubbles and the base flow at marginal value of parameter. The steady flow near a corner point of profile is of considerable interest and a question naturally arises about the sensitivity of separation bubble inside the boundary layer to external disturbances such as sound waves. Another question arises about the sensitivity of near critical base flow, namely if corner is concave there is a marginal angle which limits existence of such base flow. This fact usually is linked with sudden reconstruction of full flow pattern past a profile. Development of perturbations inside the interaction region may give some answers about the appearance of turbulence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Work‐roll surface degradation due to spalling of oxide layer
Authors: Zhang Wenge , Krempaszky Christian , Werner Ewald
Published: December 2008

Surface damage of work‐rolls in hot strip rolling mills is often associated with the local removal of the oxide layer developing in service. A simple thermomechanical stress analysis in combination with an estimated buckling stress shows that the size of oxide free spots on the roll surface is roughly the same as the lateral distance between the cracks in the observed crack pattern. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Large‐Eddy simulation of film cooling: treatment of inlet boundary conditions for the isobaric plenum and instantaneous vortex structures
Authors: Ziefle Jörg , Kleiser Leonhard
Published: December 2008

We present large‐eddy simulation (LES) results of a jet‐in‐crossflow configuration that was previously investigated in the experiments of Sinha et al. (J. Turbomach., Vol. 113, 1991). In this film‐cooling setup, relatively cool air is ejected from a large isobaric plenum through an oblique round nozzle into a hotter turbulent boundary layer. In accordance with typical film‐cooling conditions, the jet‐to‐crossflow velocity and temperature ratios were chosen as 0.25 and 0.5, respectively (defined with bulk quantities for the jet and freestream quantities for the boundary layer). The numerical simulations are performed with the compressible finite‐volume flow solver for structured multi‐block grids NSMB. The approximate‐deconvolution subgrid‐scale model (ADM) accounts for the non‐resolved scales. The problem of the unknown plenum pressure is handled by a combination of a sponge region with a non‐reflecting boundary condition at the plenum inlet. For computational economy, the turbulent boundary layer of the experiment is replaced by a steady mean turbulent inflow profile. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inverse homogenization with diagonal Padé approximants
Authors: Cherkaev Elena
Published: December 2008

The paper formulates inverse homogenization problem as a problem of recovery of Markov function using diagonal Padé approximants. Inverse homogenization or de‐homogenization problem is a problem of deriving information about the micro‐geometry of composite material from its effective properties. The approach is based on reconstruction of the spectral measure in the analytic Stieltjes representation of the effective tensor of two‐component composite. This representation relates the n‐point correlation functions of the microstructure to the moments of the spectral measure, which contains all information about the microgeometry. The problem of identification of the spectral function from effective measurements in an interval of frequency has a unique solution. The problem is formulated as an optimization problem which results in diagonal Padé approximation and exact formulas for the moments of the measure. The reconstructed spectral function can be used to evaluate geometric parameters of the structure and to compute other effective parameters of the same composite; this gives solution to the problem of coupling of different effective properties of a two‐component composite material with random microstructure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determining the optimal production policy for a system with imperfect production and shortage
Authors: Chiou Chuang‐Chun , Chen L. Ho‐Chun
Published: December 2008

The classic EPQ model assumes that items are produced of perfect quality and no shortage is permitted. In the real world situation, however, due to process deterioration or other factors, the occurrence of imperfect quality items is inevitable. This paper develops an extended economic production quantity (EPQ) model with imperfect production, shortage, and imperfect rework. We assume that the quality scan is conducted during the production. The scanned imperfect items are classified as the repairable and scrap. We consider that not all of the repairable items can be restored to meet the specified quality standard. Only some portion of defective items can be restored as normal items, the other results in defective, due to repair failure, can be sold at a discounted price to a secondary market. The renewal reward theorem is utilized to deal with the variable cycle length. The production quantity and the shortage level are determined in an optimal manner so as to minimize the average system cost. A numerical example is used to demonstrate its practical usage. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling, analysis and simulation of the human femur: prosthesis of femur head
Authors: Bracamonte Orlando Martín Hernández , Quiñones José Manuel Olivencia
Published: December 2008

We report the results obtained when carrying out the analysis of the strengths and strains that take place when prosthesis of femur head are implanted in the human femur. The modeling is made with tools provided by Computer Aided Geometry Design, using Non Uniform Rational B‐Splines representations (NURBS). In the analysis of the strengths and strains, produced in the bone‐cement‐prosthesis interaction, partial differential equations of the coupled system are obtained for the displacements and deformations, that allow to analyze cases of physical and biological loads, under which will be work the implants during their useful life, which also is estimated; because of the frequent phenomenon of bony absorption and the consequent relaxation and loss of the replacement surgery. The obtained equations are solved by finite element method, with the corresponding estimation of the obtained errors. The simulations will be performed using high level software able to show realistic visualizations of the observed phenomena in real time. The fracture of the femur neck is a frequently observed trauma and has taken to the authors to make the present work. The obtained results will allow to make the modeling, analysis and simulation of other bony structures and the implants of the corresponding prosthesis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The numerical analysis of the influence of the blankholder force and the friction coefficient on the value of the drawing force
Authors: Kaldunski Pawel , Kukielka Leon
Published: December 2008

In this paper the numerical analysis of the drawing process with the blankholder is presented. The influence of the value of the blankholder force on the value of the drawing force and drawpiece height is examined. A different friction coefficient of the sheet metal for die and blankholder is considered. A defect at the lack of the blankholder is presented. The analysis in the system ANSYS/LS‐DYNA is passed. The material model with the mixed hardening, isotropic and isothermal is used. Technological parameters of the sheet‐metal to drawing, the die, the stamp and the blankholder from the literatures are chosen. Examples results of computer simulations are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coupling of atomistic and mesoscopic scales: Multiscale modeling of DNA translocation through nanopores
Authors: Melchionna Simone
Published: December 2008

The basic principles of a novel computational method to model nano‐sized systems, such as a polymer embedded in a fluctuating hydrodynamic solvent, are described. The approach is based on a concurrent multi‐scale technique rellying on Molecular Dynamics and Lattice Boltzmann in stochastic formulations.

We undertook a numerical study of a biopolymer translocating across a nanopore mimicking a device for automatic DNA sequencing. The study revealed that the translocation time obeys a power law dependence on the polymer length with an exponent in agreement with experimental measurements.The scaling behavior is captured by a mean‐field model taking into account both the hydrodynamic drag and thermodynamic effects. Results about multi‐file translocation of DNA in large pores are briefly described. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the uniform decay in an integro‐differential elastic equation
Authors: Messaoudi Salim A. , Al‐Jabr Nuha A.
Published: December 2008

In this paper we consider an integro‐differential elastic equation, in a bounded domain, and establish a uniform decay result under weaker conditions, on the relaxation function, than those usually found in the literature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scattering of flexural gravity waves by abrupt change in water depth
Authors: Karmakar D. , Sahoo T.
Published: December 2008

The surface gravity waves originated in the open sea interact with floating flexible structures and penetrates into the region covered by the flexible structures to generate flexural gravity waves. In the recent decades, there is a significant interest in analyzing the propagation of flexural gravity waves which find applications in both marine technology for ocean space utilization and polar engineering in the marginal ice zone (see Chen et al. (2006), and Porter and Porter (2004)). In the present paper, the scattering of flexural gravity waves due to an abrupt change in ocean depth is analyzed in case of finite depth in the linearized theory of water waves. In the present paper, Timoshenko‐Mindlin equation for the plate equation is used to include shear and inertia effect in the plate equation. The generalized expansion formulae along with the corresponding orthogonal mode‐coupling relations are used to obtain the velocity potential for the boundary value problem associated with the physical problem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical solution of fractional differential, integral and integro‐differential equations by using piecewise constant orthogonal functions
Authors: Shamloo A. Salimi , Babolian E.
Published: December 2008

We use operational matrices of piecewise constant orthogonal functions on the interval [0, 1] to solve fractional differential, integral and integro‐differential equations. We first use operational matrices and then convert the problem to a system of linear equations. Numerical examples show that the approximate solutions have a good degree of accuracy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite element method for viscoelastic fluids flows: approximation of the Maxwell model
Authors: Sandri D.
Published: December 2008

We discuss about the finite element approximation of viscoelastic fluid flow. We consider a fluid obeying the Oldroyd model and particularly we study the purely viscoelastic case, the so‐called Maxwell model, important in practice for the applications. We examine two kinds of methods used for the approximation of the Maxwell model: method using a splitting technique and finite element method satisfying inf‐sup conditions relating tensor and velocity. We present numerical results for these methods and we discuss about their stability. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Littlewood‐Paley spline wavelets: a simple and efficient tool for signal and image processing in industrial applications
Authors: Serrano Eduardo , Figliola Alejandra
Published: December 2008

In this work, we present the Littlewood‐Paley Spline Wavelets that are much more effective that the orthonormal discrete wavelets, although it cannot apply the multiresolution scheme. These wavelets carry the advantages of the splines functions what allows their implementation through simple numeric algorithms. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the accuracy of the normal approximation to the distributions of Poisson random sums
Authors: Shevtsova Irina
Published: December 2008

The analogue of the Berry–Esseen inequality for Poisson random sums is improved in 4–11 times depending on the maximal order 2 < s ≤ 3 of the finite absolute moment of the distribution of random summands. For the case, when s = 3, under additional assumption concerning the smoothness of distribution of summands we also obtained in some sense unimprovable estimate consisting of two summands: the first summand being the noncentral Lyapunov fraction with the coefficient equal to the unimprovable asymptotically exact constant and the second one decreases faster. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Absolutely inertial delays
Authors: Vlad S.E.
Published: December 2008

Asynchronous systems represent the models of asynchronous circuits from digital electrical engineering. A delay is an asynchronous system that models the delay circuit. The purpose of the paper is that of defining and characterising the absolute inertia of the delays. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aerodynamic characteristics of propeller in non‐axial flow
Authors: Vrdoljak Milan
Published: December 2008

Flow on running propellers installed on aircraft in general case is not axial what results in off‐axis forces and moments at the propeller. Lifting line method is applied for propeller blade model using set of discrete vortex filaments. Propeller wake defined by vortex sheet of discrete vortex filaments is modelled with application of free‐wake method. Presented propeller model combines the blade and the wake model and with its low computational cost realization it is suitable for preliminary prediction of propeller contribution to the aircraft aerodynamic characteristics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multigrid fictitious boundary and grid deformation methods for flow‐induced rotation of wing
Authors: Wan Decheng
Published: December 2008

Numerical simulations of flow‐induced rotation of wing by multigrid fictitious boundary and grid deformation methods are presented. The flow is computed by a special ALE formulation with a multigrid finite element solver. The solid wing is allowed to move freely through the computational mesh which is adaptively aligned by a special mesh deformation method. The advantage of this approach is that no expensive remeshing has to be performed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Robust analysis of discrete linear shift invariant systems represented by an interval matrix (Poster Presentation)
Authors: Delgado‐Romero Juan J. D. , González‐Garza Rodolfo S.
Published: December 2008

In this paper we describe a new bound in order to guaranteed the robust stability of a discrete linear shift invariant system which is represented by an interval matrix. This bound is based in the bound of Juang. The uncertainties are represented by an interval matrix. The system is represented in state variables with parametric uncertainty in the A matrix. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimentelle Untersuchungen von Stick‐Slip Schwingungen an Scheibenwischern
Authors: Grönefeld P. , Kröger M.
Published: December 2008

In Kraftfahrzeugen jeglicher Art werden Scheibenwischer zum Reinigen der Windschutzscheibe verwendet. Die Wischerblätter aus Gummi unterliegen dabei hohen Beanspruchungen durch Abgase, Sonneneinstrahlung, Verschmutzungen sowie Eis und Schnee. Die komplexe Reibcharakteristik des Materials führt bei gewissen Parameterzuständen aufgrund einer fallenden Reibkennlinie dazu, dass Stick‐Slip‐Schwingungen entstehen, die sich durch Rattern und Quietschen des Wischerblattes auf der Scheibe äußern und damit erhebliche Komfort‐ und Funktionseinbußen nach sich ziehen.

Mit Hilfe unterschiedlicher Prüfstände und Proben werden durch die Variation von Parametern wie Anpresskraft, Geschwindigkeit und Nässezustand verschiedene Belastungen getestet und die entstehenden Schwingungen untersucht. Die so ermittelten Grenzzykel können Aufschluss über Möglichkeiten zur Optimierung der Wischerkonstruktion geben. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The dynamics of open quantum systems: accessibility results
Authors: Kurniawan I. , Dirr G. , Helmke U.
Published: December 2008

In this paper we study the accessibility properties of finite dimensional (N‐level) open quantum systems in the presence of dissipation and relaxation described by the Lindblad master equation. We specifically focus on the unital Lindbladian case where general results can be obtained. The theory of transitive Lie‐group actions is used to classify the system Lie‐algebras of the Lindblad equation for which the reachable sets have nonempty interior. For the special case of n ‐coupled spin‐1/2 systems, we obtain a particularly simple characterization. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A combined chebyshev polynomials and sumudu transform for solving the neutron transport equation (Poster Presentation)
Authors: Kadem Abdelouahab , Li Zhaoxiang
Published: December 2008

In the present paper we present a new approximation for the one dimensional transport equation, using Chebyshev polynomials [1] combined with the Sumudu transform. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Feedback protocol laws for immunotherapy
Authors: Kassara K. , Moustafid A.
Published: December 2008

We set immunotherapy control as a target control problem under state‐control constraints, taking into account a general tumor dynamics. Then we use a set‐valued approach based on viability theory to build feedback protocol laws by which cancer cells are asymptotically destroyed. An immunotherapy model is examined in order to illustrate our approach. (© 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

This 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 conductive 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)
Hierarchical multilevel optimization for reliability target allocation in probabilistic design of decomposed systems
Authors: Kokkolaras Michael
Published: December 2008

Analytical target cascading (ATC) is a methodology for translating system‐level design targets to subsystem and component design specifications in hierarchically decomposed optimal system design problems. In previous work we extended the ATC formulation to account for uncertainties, where the bounds of the probabilistic design constraints were chosen arbitrarily and held fixed during the ATC process. In this work, we extend the probabilistic ATC formulation to include reliability targets in the vector of cascaded quantities. In this manner, we quantify the optimality‐reliability tradeoffs for each element of the decomposed system and compute the probabilistic constraint bounds required to satisfy the overall system reliability target. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid method to determinate the states of deformation and stress in material during the tensile test
Authors: Malag Leszek , Kukielka Leon
Published: December 2008

One of the basic problems occurring in calculations engineering of finite element method (FEM) is to acceptance the suitable form of mathematical model, describing the mechanical properties of the analysed materials as well as to appoint the constants in this model. The macroscopic models of material published in literature, elaborated on the basic tensile test and compression test, which are the basic tests permitting to appoint plasticity properties and ultimate strength. The indeed of factor the influence on value of stresses and strains is the shape and dimension of specimen. The tensile test described in the EN 10002‐1:2001 norm with foundation is the test of averaging the properties ultimate strength the studied specimens. Using these properties in numerical calculations it causes the essential differences between results calculations and experimental measurements occurrence both qualitative and quantitative. The paper presents the new hybrid methodology on macro and micro scale of determining the states of stresses and strains in metallic specimens, using in the uniaxial tensile test. The application was carried out the FEM in ANSYS/LS‐DYNA programme to determinate the stresses and strains in arbitrarily place specimen and in the time duration of the tensile test process. The same examples of numerical simulation are shown. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New proximity and complexity result for P*(κ)‐linear complementarity problem (Poster Presentation)
Authors: Peyghami M. Reza
Published: December 2008

One of the main ingredients of interior point methods is the proximity functions to measure the distance of the iterates from the central path of linear optimization problems. In this paper, an interior point method for solving P*(κ)‐linear complementarity problem, κ ≥ 0, is proposed. For this version, we use a new class of proximity functions induced by new kernel functions. Using some mild and easy to check conditions, we show that the large‐update primal‐dual interior point methods for solving P*(κ)‐linear complementarity problem enjoy the so far best worst case theoretical complexity, namely O (κ √n log n log n /ε) iteration bound, with special choices of the parameters p, q ≥ 1. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)