bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive numerical simulation of intracellular calcium dynamics
Authors: Nagaiah Chamakuri , Warnecke Gerald , Rüdiger Sten , Falcke Martin 
Published: December 2008

AbstractWe present the adaptive numerical simulation of intracellular calcium dynamics. The dynamics of intracellular calcium is determined by the liberation and uptake by cellular stores as well as reactions with buffers. This process is characterized by the existence of multiple length scales. The modeling of diffusion, binding and membrane transport of calcium ions in cells leads to a system of reaction‐diffusion equations. We used piecewise linear finite elements for the spatial discretization and time discretization by a linearly implicit Runge‐Kutta scheme. In our description the dynamics of IP3‐controlled channels remains discrete and stochastic. The strongly localized temporal behavior due to the on‐off behavior of channels as well as their spatial localization is treated by an adaptive numerical method. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applications of graph theory
Authors: Pirzada S. 
Published: December 2008

AbstractGraph theory is rapidly moving into the mainstream of mathematics mainly because of its applications in diverse fields. In this paper, we discuss certain ways of applying graph theoretical techniques to solve various problems and present the review of some of the applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A multiscale method for parameter estimation in reservoir simulation
Authors: Rodriguez A. , Klie H. , Wheeler M. 
Published: December 2008

AbstractWe consider a multiscale approach to the problem of parameter estimation or history matching in reservoir simulation. To do this, we look at the problem upscaling as the most important component of the proposed method. For upscaling we suggest a global approach which seeks to minimize the misfit between fine scale and coarse scale simulations and then used the Simultaneous Perturbation Stochastic Approximation (SPSA) method to deal with the minimization process. The essential idea of multiscale history matching comsists of constructing a coarsening sequence of models, so that each one of them minimizes the misfit between preditctions and observations. Then, the cosarsest model is downscaled one step into the sequence and used as an initial guess for the next step of refinement. The process is repeated until no improvement is observed in the solution. Numerical experiment indicate that this approach produces consistent results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A doubly optimal stopping of a risk process (Poster Presentation)
Authors: Karpowicz Anna , Szajowski Krzysztof 
Published: December 2008

AbstractProblems which lead to an optimal stopping of a risk process are considered. Let an insurance company be endowed with an initial capital a > 0, receive insurance premiums and pay out successive claims. The losses occur according to renewal process. At any moment the company may broaden or narrow down the offer, what entails the change of the parameters. These changes concern the rate of income, the intensity of renewal process and the distribution of claims. The model of the risk process with two types of claims stream is considered. After the change the management wants to know the moment of the maximal value of the capital assets. Our goal is to find two optimal stopping times: the best moment of change the parameters and the moment of maximal value of the capital assets. A dynamic programming method to calculate the expected capital at that times is used. Based on the model which combine two types of risk the model of reinsurance with two firms is formulated. In this case the aim is to find for the firms the equilibrium strategy. The equilibrium is constructed in class of strategies driven by their risks. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Toward a solution to the high Weissenberg number problem
Authors: Trebotich David 
Published: December 2008

AbstractWe present results of a numerical study of high Weissenberg number flows using the method of Trebotich, Colella and Miller, J. Comput. Phys. vol. 205 (2005). We consider benchmark viscoelastic flow of an Oldroyd‐B fluid in four to one sudden contractions for We = 1, 10, Re = 1. We conclude that (i) underlying wave behavior in the solution for flows at critical and supercritical elastic Mach number prevents the solution from reaching a steady‐state; and (ii) high resolution is needed to resolve structure in the solution downstream from the re‐entrant corner in order to determine convergence. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leaving and reaching the moon from a libration point orbit
Authors: Alessi E.M. , Gómez G. , Masdemont J.J. 
Published: December 2008

AbstractWe represent the Earth–Moon system as a Circular Restricted Three–Body Problem and we look for trajectories which allow the departure from the lunar surface and which might have played a role in the formation of impact craters. We take advantage of the central and hyperbolic invariant manifolds which exist in the neighbourhood of the collinear equilibrium points L1 and L2. Different types of semi–analytical and numerical methodologies are exploited. The most meaningful results are pointed out. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface melting and effective anchoring in nematics
Authors: Biscari Paolo , Turzi Stefano 
Published: December 2008

AbstractWe study the equilibrium configuration of a nematic liquid crystal bounded by a rough surface. If ξ and η are, respectively, the nematic coherence length and the characteristic wavelength of the roughness, we show that in both limiting cases ξ ≪ η and η ≪ ξ the wrinkling of the surface induces a nontrivial structure in the equilibrium solution which may be interpreted in terms of an effective weak anchoring potential. We also determine how the effective surface extrapolation length is related to the microscopic anchoring parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Iterative method for solving fractional differential equations
Authors: Daftardar‐Gejji Varsha , Bhalekar Sachin 
Published: December 2008

AbstractIn the present paper non‐linear, time fractional advection partial differential equation has been solved using the new iterative method presented by Daftardar‐Gejji and Jafari [1]. The results are compared with those obtained by Adomian decomposition and Homotopy perturbation methods. It is demonstrated that the new iterative method gives the best approximation among these. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Force control of a fluidic muscle driven parallel platform
Authors: Singh Mahendra Dhanu , Liem Kusnadi , Neumann Rüdiger , Kecskeméthy Andrés 
Published: December 2008

AbstractIn this paper a new method for the force control of a parallel platform consisting of six fluidic‐muscles of type RRPS is presented. Fluidic muscles require that the gas model as well as the rubber nonlinearities are included in the control scheme. Moreover, the control law for the gas flow in the proportional directional control valve in 3/3‐way function needs to be taken into account. The present paper describes the basic dynamic models as well as testbed results for the existing fluidic‐muscle parallel platform “HexaSpine” [3]. Here each leg is equipped with a force sensor, a pressure sensor and a magnetostrictive position encoder. The control scheme for the platform comprises six control loops for the six operated actuators with a model based force control each. It is shown that the aforementioned control scheme leads to a stable force control of the platform driven by fluidic muscles. As an application, the device will be employed in fields of biomechanics, as well as in general environments requiring physical simulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some creative properties of the 2D and 3D lattice distributed interconnected chaotic oscillators and neuronal networks
Authors: Gontar Vladimir 
Published: December 2008

AbstractMathematical modeling and computer simulations of brain creativity & consciousness, artificial intelligence, mathematical imaging are the areas of research where the networks of interconnected oscillators playing an important role. Here we are presenting novel approach for mathematical modeling of brain creativity in a form of 2D symmetrical colored artistic patterns (ornaments) and 3D patterning. It was shown that special networks of chaotic oscillators simulated by the difference equations (discrete logistic equation, Henon equations and discrete chemical reactions basic equations [1]) possess creative patterns within their chaotic regimes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vortical flow in thermo‐acoustic devices
Authors: Ishigaki Masahiro , Kuzuu Kazuto , Adachi Shizuko , Ishii Katsuya 
Published: December 2008

AbstractTaconis oscillation in a closed long tube with large thermal gradient is studied by numerical calculation of the 2D compressible Navier‐Stokes equations. The both ends of tube are hot (T = TH), and the center of side wall is cold (T = TC). We analyze the pressure amplitude pamp and the time averaged temperature Tm in the closed tube. pamp is almost homogenous in the tube cross section, however, Tm is not homogenous in the central cold region. We also observe two steady states at the same temperature ratio θ = TH/TC. It is important to analyze the effects of the boundary layer in this cold region on Taconis oscillations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐polynomials spline methods for solving a fourth‐order parabolic equation
Authors: Khan Arshad 
Published: December 2008

AbstractIn this paper a fourth‐order variable coefficient parabolic partial differential equation, that governs the behaviour of a vibrating beam, is solved by using a three level method based on non‐polynomial quintic spline in space and finite difference discretization in time. We also obtain two new high accuracy schemes of O (k4, h6) and O (k4, h8) and two new schemes which are analogues of Jain's formula for the non‐homogeneous case. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of the vibration behavior of the DOBSON SPACE TELESCOPE
Authors: Kracht K. , Wagner U. von , Segert T. 
Published: December 2008

AbstractThe paper gives an overview about the results of modal analysis for the deployment structure of a lab model of the DOBSON SPACE TELESCOPE. The data of the modal analysis of the unfolded structure has been used to simulate the mechanical vibrations of the telescope forced by operating conditions.Furthermore the vibration response of the folded structure during launch conditions, which has been simulated by a shaker, has been examined. All results show that the aluminium model of the DOBSON SPACE TELESCOPE would be ready for service referring to the aspect of mechanical vibrations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of operator splitting in the solution of reaction‐diffusion equations
Authors: Ladics Tamas 
Published: December 2008

AbstractOperator splitting is a widely used method in the numerical solution of partial differential equations. A comparison of the different splitting techniques in the solution of 1 and 2 dimensional reaction‐diffusion equations is made. The process of the solution is a composition of certain splitting procedure and a given numerical method. We study the interaction between the different splitting procedures and different numerical schemes. The order of the convergence of this composed method is calculated. The error of the approximate solution is characterized as a funct ion of the applied splitting and numerical scheme. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real options in biodiversity conservation
Authors: Leroux Anke D. , Martin L. , Goeschl Timo 
Published: December 2008

AbstractThe literature on optimal conversion defines rules that determine the rate at which land is irreversibly moved out of conservation into production. This paper explores the implications on these rules of allowing for a feedback between conversion decisions and the stochasticity of conservation benefits, using the well‐known ecological mechanism of extinction debt as an illustration. This yields a model with a controlled‐diffusion process at its core that is solved using a real‐options approach and that leads to the conventional conversion rule as a special case. Calibrating the model to a specific case (Costa Rica), the paper demonstrates the presence of an augmented quasi‐option value depending on the strength of the feedback. This results in quantifiable changes in land values and the amount of conservation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Constraint isomorphism and correction algorithms for violations
Authors: Munakata Toshinori , Fadlalla Adam 
Published: December 2008

AbstractWhen a problem can be characterized by different parameter sets, constraints imposed on one parameter set must be consistent with, or isomorphic to, constraints imposed on other parameter sets. When mapping among the parameter sets is not so visibly obvious, one might overlook consistency violations, which have occurred in the past. This paper examines such violations and possible correction algorithms. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The CONV method for pricing options
Authors: Lord R. , Fang F. , Bervoets F. , Oosterlee C.W. 
Published: December 2008

AbstractIn this paper, we discuss a convolution based method, the CONV method, for pricing options with early‐exercise features, in which the asset prices are modeled by Lévy processes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical and numerical solutions of a generalized hyperbolic non‐Newtonian fluid flow
Authors: Pakdemirli M. , Sarı P. , Solmaz B. 
Published: December 2008

AbstractGeneralized hyperbolic non‐Newtonian fluid model first proposed by Al‐Zahrani [1] is considered. The model was successfully applied to some drilling fluids with better performance in relating shear stress and velocity gradient compared to power‐law and Hershel‐Bulkley model. Special flow geometries namely pipe flow, parallel plate flow and flow between two rotating cylinders are treated. For the first two cases, analytical solutions of velocity profiles in the form of integrals are presented. For the flow between two rotating cylinders, the differential equation is solved by Runge‐Kutta method combined with shooting. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ground‐based measurement of ash distribution in volcanic plumes
Authors: Phillips Jeremy C. , Yamamoto Hiroko , Watson I. Matthew , Bluth Gregg J.S. 
Published: December 2008

AbstractMeasurement of ash particle distribution within volcanic eruption plumes is important for volcanic hazard prediction, but is difficult because of the inherent danger and inaccessibility of volcanoes, and the three‐dimensional time‐dependent dynamics of turbulent eruption plumes. A combined study using a novel UV camera coupled with classical analysis of the dynamics of finite‐volume buoyant plumes has been used to develop a detection algorithm for ground‐based volcanic ash monitoring. The method provides the capability to observe and measure the internal structure of the plume, and processes occurring during plume rise, including concentration of ash over time into the plume ‘head’, increased ash at the plume edges during early formation and dilution at the top of the plume head as entrainment of surrounding air occurs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On stability problems of the space elevator
Authors: Schwarzbart M. , Steindl A. , Troger H. 
Published: December 2008

AbstractA long dumb‐bell satellite in the radial configuration represents a simple model of a Space Elevator. The dumb‐bell moves with the angular velocity of the planet, but not relative to it. To calculate the stability of such a relative equilibrium we used the reduced energy‐momentum method. We considered dumb‐bell satellite models with rigid and elastic, but massless, rods. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear convective oscillations in multilayer systems
Authors: Simanovskii Ilya B. 
Published: December 2008

AbstractThe joint action of buoyancy and the thermocapillary effect in two‐ and three‐layer systems, is studied. Two types of boundary conditions, periodic boundary conditions and rigid heat–insulated lateral walls, are considered. In the case of periodic boundary conditions, regimes of traveling waves have been found. In the case of rigid heat‐insulated lateral walls, symmetric and asymmetric standing waves are observed. Transitions between different types of oscillatory motions are studied. The competition between buoyancy and the thermocapillary effect in a three‐layer system may lead to the complex dynamics and different unexpected effects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Drop deformation under surfactants adsorption
Authors: Stan Ioan‐Raducan , Tomoaia‐Cotisel Maria , Stan Aurelia 
Published: December 2008

AbstractThe movements of free liquid drops, resulting from unbalanced surface tension gradients, in our case the adsorption of a surfactant, constitute important surface phenomena (Marangoni effect). The aim of this paper is to correlate the effect of pressure forces on the drop, with the surface coverage degree, namely with the extent to which the drop surface is covered by the surfactant. Our model shows that for a covered degree less then about 68°, these forces are negative. This means that these forces exerted by the external liquid upon the drop are oriented towards the negative direction of the normal to the drop surface, acting like a hammer. Some numerical data are given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of a tritrophic food chain model
Authors: Tchuenche Jean M. 
Published: December 2008

AbstractWe consider a tritrophic food chain model in which the classical assumption of the domino effect is supplemented with an adaptive parameter. Dynamical behaviours such as boundedness, existence of periodic orbits, persistence, as well as stability are analyzed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variational principle and reaction‐diffusion front speeds in random flows
Authors: Nolen James , Xin Jack 
Published: December 2008

AbstractWe summarize recent advances of analyzing Kolmogorov‐Petrovsky‐Piskunov (KPP) fronts in random compressible and incompressible flows. In particular, a long standing open problem of the existence and characterization of the so called turbulent flame speed is resolved for KPP fronts in space‐time random incompressible flows under certain regularity and moment conditions on the flow fields. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A numerical method to approximate the solutions of non‐linear absorption diffusion equations
Authors: Dumitrache Alexandru 
Published: December 2008

AbstractThis paper investigates the motivation for the n‐dimensional absorption‐diffusion equation. First, the one‐dimensional, nonlinear absorption‐diffusion equation was mathematically developed. A numerical method to computationally solve it and diffusion‐free equations were also developed. For the cases tested, the numerical diffusion solutions are always less than the numerical diffusion‐free solutions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theory of fundamental operator‐functions of singular differential operators in Banach spaces and this applications
Authors: Falaleev Mikhail V. 
Published: December 2008

AbstractIn this paper we consider applications of the abstract theory of singular differential equations in Banach spaces to applied problems about processes of transfer of moisture, swelling of metallic beams, processes of filtration of fluids in inhomogeneous mediums, oscillation processes in molecules of DNA, transverse vibration of membrane, theory of viscoelastic and others. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Method for evaluation of movement resistance in scraper pipe conveyors
Authors: Furmanik K. , Pracik M. 
Published: December 2008

AbstractRational designing of scraper pipe conveyors requires new approach to evaluation of motion resistance. The results of theoretical and experimental investigations of this resistance and final conclusions have been presented in the paper. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical and physical aspect of the solution of the Cauchy problem for a system of equations describing a nonlocal model of propagation of heat with finite speed
Authors: Gawinecki Jerzy August , Łazuka Jarosław , Rafa Józef 
Published: December 2008

AbstractIn our paper we present a new system of equations describing a nonlocal model of propagation of heat with finite speed in three‐dimensional space. Such a system of equations is described by a system of integral – differential equations. At first using the modiffied Cagniard de Hoop method, we construct the fundamental solution of this system of equations. On the basis of the constructed fundamental solution we obtain the explicite formulate of the solution of the Cauchy problem for this system of equations and applying the method of Sobolev and Biesov spaces, we get Lp – Lq time decay estimate for the solution of the Cauchy problem. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent results on dislocations dynamics and homogenization
Authors: Forcadel Nicolas , Imbert Cyril , Monneau Régis 
Published: December 2008

AbstractIn this note, we present recent results about the homogenization of systems of particles with two‐body interactions, describing dislocation dynamics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Existence of best approximant in nonconvex domain
Authors: Nashine Hemant Kumar 
Published: December 2008

AbstractThe present work deals with the establishment of an existence result on best approximation for the nonexpansive noncommuting mappings which is not necessarily linear and as defined on non‐starshaped domain of q‐normed space following Meinardus [7] hypothesis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The special routes in plane graphs
Authors: Panyukova Tatiana 
Published: December 2008

AbstractLet plane undirected graph G = (V, E) be set of items of all manipulator possible trajectories. The problem is constructing of routes satisfying different restrictions. The restrictions can be classified as local and global. For local restrictions the next edge in a route is defined by the conditions set for current vertex or edge. Otherwise restriction is called global. Examples of local restrictions are straightforward paths; a route in which the next edge is defined by the given cycle order on the set of edges incident the current vertex; a route where some edges should be passed in predefined order. The example of global restriction is problem of constructing the cover with ordered enclosing. The paper presents some ways to formalize restrictions and also information about algorithms for constructing of Eulerian covering for plane graph by the sequence of allowed trails. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the stability of the Ekman boundary layer
Authors: Giga Yoshikazu , Saal Jürgen 
Published: December 2008

AbstractWe present a result on well‐posedness and stability of the Ekman boundary layer problem in the space FM(ℝ2, L2(ℝ+)3), i.e., in the space of L2(ℝ+)3‐valued Fourier transformed finite Radon measures. In particular we obtain stability in the angle velocity of rotation, which is important in the analysis of fast oscillating singular limits. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)