bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homogenization and Geometric Linearization for Multi‐Well Energies
Authors: Jesenko Martin , Schmidt Bernd 
Published: November 2013

AbstractThe concept of linear elasticity is to assume that the stored energy has one‐well structure and to consider small displacements. The energy function is then expanded around the equilibrium state and higher‐order terms are neglected. It was proved in [3] that this concept really gives results that provide a good approximation for the actual problem. On the other hand, for materials with fine periodic structure we accomplish a simplification of the problem in an analogous manner by homogenizing the energy. It was recently shown by Müller and Neukamm in [8] that both processes, homogenization and linearization, are interchangeable for such elastic energies. If we consider an energy with multiple wells then, under some reasonable conditions, it is also possible to (geometrically) linearize the problem. The second author proved that quasiconvexification of the limit function yields the desired result. We present that in this case both processes still commute. This is not a priori clear since the proof by Müller and Neukamm significantly rests upon the one‐well structure and properties of quadratic forms. They also provide an example when the statement does not hold. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Hencky strain energy ‖log U‖2 measures the geodesic distance of the deformation gradient to SO(n) in the canonical left‐invariant Riemannian metric on GL(n)
Authors: Neff Patrizio , Eidel Bernhard , Osterbrink Frank , Martin Robert 
Published: November 2013

AbstractThe well‐known isotropic Hencky strain energy appears naturally as a distance measure of the deformation gradient to the set of rigid rotations in a canonical left‐invariant Riemannian metric on the general linear group GL(n). Objectivity requires the Riemannian metric to be left‐GL(n) invariant, isotropy requires the Riemannian metric to be right‐O(n) invariant. The latter two conditions are satisfied for a three‐parameter family of Riemannian metrics on the tangent space of GL(n). Surprisingly, the final result is basically independent of the chosen parameters.In deriving the result, geodesics on GL(n) have to be parametrized and a novel minimization problem, involving the matrix logarithm for non‐symmetric arguments, has to be solved. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some Fixed Point Results for a Sequence of Mappings on G‐Metric Space
Authors: Gajić Ljiljana , Lozanov Crvenković Zagorka 
Published: November 2013

AbstractIn the setting of generalized metric spaces, so called G‐metric spaced introduced by Z. Mustafa and B. Sims in 2006, some fixed point results for mappings with contractive iterate at a point and common fixed point results for infinite family of self mappings will be presented. The results are generalizations of well known results in the metric space. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Smoothing inexact Newton methods for NCP with various nonmonotone techniques
Authors: Rapajić Sanja , Pap Zoltan 
Published: November 2013

AbstractVarious iterative methods for solving nonlinear complementarity problems (NCP) are developed in recent years. In this paper we propose Jacobian smoothing inexact Newton methods for NCP with different nonmonotone strategies. The methods are based on semismooth equation reformulation of NCP by Fischer‐Burmeister function. Nonmonotone line‐search techniques are used for globalization procedure. Numerical performance of algorithms are compared. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of Pareto‐fronts in the presence of epistemic uncertainty
Authors: Serafinska Aleksandra , Kaliske Michael , Graf Wolfgang 
Published: November 2013

AbstractNumerical design methods based on deterministic multi‐objective optimization provide — for conflicting objective functions — a Pareto‐optimal set including diverse trade‐off solutions. Based on the visualization of the set in the objective space — the Pareto‐front — the decision maker is able to choose a satisfying design. Though, the presence of uncertain input variables in the optimization task requires a new concept for the identification of the Pareto‐front and the projection of uncertainty within the front. In this contribution, an approach for considering the epistemic uncertainty within the evolutionary multi‐objective optimization method based on Nondominated Sorting Genetic Algorithm (NSGA‐II) is presented. The description of uncertainty occurs within the framework of the Fuzzy set theory. The proposed approach is coupled to the Finite Element Analysis and response surface approximations based on artificial neural networks. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced Identification of Process Parameters in Technological Forming
Authors: Rozgić Marco , Appel Robert , Stiemer Marcus 
Published: November 2013

AbstractMathematical optimisation of real technological forming processes requires expensive simulations to evaluate objective function and constraint values as well as their derivative and Hessian information. The costs of these evaluations are directly correlated to the refinement depth of the finite‐element discretisation. This work investigates the effect of the refinement level on the result and convergence behaviour of algorithmic process parameter identification with an elastoviscoplastic material model. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diagonal scaling of a special type and its benefits
Authors: Šanca Ernest , Kostić Vladimir 
Published: November 2013

AbstractFor certain subclasses of H‐matrices we will exploit the structure of their scaling matrix to improve known results in several areas of applied linear algebra: convergence theory of relaxation methods, estimation of infinity norm of the matrix inverse and determinant estimation. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effectiveness of cut‐off scales models for variable resolution methods
Authors: Basara Branislav 
Published: November 2013

AbstractVariable resoltion methods can be divided in two groups, bridging and zonal methods. The bridging method is aimed to provide the best possible physical fidelity on any given numerical grid while varying seamlessly between Reynolds averaged Navier‐Stokes (RANS) model and Direct Numerical Simulations (DNS). Two of the most developed bridging methods are the partially integrated transport model (PITM) and partially averaged Navier‐Stokes (PANS) model. The PANS model was choosen here as the basic approach for the further theoretical extension but the conclusions derived in this work can be applied to the PITM model as well. It was shown in earlier studies that the implied cut‐off for the PANS method can be placed in any part of the spectrum including the dissipation range. This is done by varying the unresolved‐to‐total ratios of kinetic energy and dissipation. In the practice, the parameter which determines the unresolved‐to‐total kinetic energy ratio is defined by using the grid spacing and calculated integral length scale of turbulence. When the grid size is smaller, then more of the turbulent kinetic energy can be resolved. In the previous approach, the integral scale of turbulence is obtained by using resolved turbulence calculated as a difference between the instantaneous filtered velocity and the averaged velocity field. Such approach is impractical for cases with moving geometries or with transient boundaries. An alternative solution is to solve an additional equation for the resolved kinetic energy and then, the resolution parameter can be directly calculated as the equation for the unresolved kinetic energy is anyway solved. It must be only ensured that a modeled cut‐off length scale is larger than a numerical grid cell size. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal Actuator Placement for Dynamical Systems
Authors: Schäfer Carsten , Ulbrich Stefan 
Published: November 2013

AbstractVibrations occur in many industrial areas and produce undesirable side effects. To avoid respectively suppress these effects actuators can be attached to the structure. Actuators can transfer forces into the structure, which can be used to control the system behavior of the structure in order to achieve, for example, vibration absorption, noise reduction and/or exact positioning. The appropriate positioning of actuators is of significant importance for the controllability of the structure. We present a method for determining the optimal actuator placement.We consider applications, where the dynamics of a system can be described by a finite dimensional, controllable and observable state‐space model. The concept of controllability by Kálmán forms the basis for the definition of controllability measures. In this context, the controllability gramian plays an important role. In our approach actuators are placed in such a way that the selected controllability measure becomes maximal. This leads to an optimization problem with binary and continuous variables and linear matrix inequalities. The numerical results show the optimal actuator placement for a two dimensional flexible clamped plate. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ground Contact Detection with Shortstroke Buttons for Biped Robots
Authors: Ewald Alexander , Beutler Fabian , Buschmann Thomas 
Published: November 2013

AbstractRobust walking motion of humanoid robots requires a sensor system that can accurately sense the robot's state and its environment. Especially in case the ground is not modeled and uneven, information about the contact state is crucial to initiate an appropriate response. Many humanoid robots use strain gauge‐based force/torque sensors to obtain information about the contact state. In this paper, we propose the integration of shortstroke buttons in the foot design to detect ground contact faster and more reliably. Simulation results with our robot Lola suggest that impact forces in case of an unexpected ground contact can be reduced significantly by integrating these sensors. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling structural variability in reduced order models of machine tool assembly groups via parametric MOR
Authors: Benner Peter , Lang Norman , Saak Jens 
Published: November 2013

AbstractWe present a parametric model order reduction (PMOR) method applied to a parameter depending generalized state‐space system, which describes the evolution of the temperature field on a vertical stand of a machine tool assembly group induced by a moving tool slide. The position of this slide parametrizes the input matrix of the associated system. The main idea is to compute projection matrices Vj, Wj in certain parameter sample points μj and concatenate them to the projection bases V, W, respectively, as described in [1]. Instead of using the iterative rational Krylov algorithm (IRKA) to produce the projection matrices in each parameter sample point as suggested there, here we use the well known method of balanced truncation (BT). The numerical results show that for the same reduced order r obtained from V, W ∈ ℝn×r, BT produces a parametric reduced order model (ROM) of similar accuracy as IRKA in less time. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of Electrolytes in the Modeling of Batteries
Authors: Dreyer Wolfgang , Guhlke Clemens , Müller Rüdiger 
Published: November 2013

AbstractCalculating the cell voltage of a lead‐acid battery requires the solution of a complex multiphysical problem including electrochemical reactions on the electrode surfaces and diffusive transport in the enclosed electrolyte. Recently, the authors proposed a new electrolyte model with a thermodynamically correct coupling of mechanics to the diffusive transport. In the analysis of that model, formal asymptotic expansions were applied to handle sharp interface layers. Here, we use this analysis to formulate a simplified model for a lead‐acid battery such that it is not necessary to resolve the layers numerically, but instead there are jump conditions at double layers imposed. The cell voltage is then derived using Butler‐Volmer Formula. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new closure mitigating the sub‐shock phenomenon in the continuous shock‐structure problem
Authors: Schärer Roman P. , Torrilhon Manuel 
Published: November 2013

AbstractMoment equations offer an attractive framework for modeling non‐equilibrium processes in moderately rarefied gases. We present a new hyperbolic closure for the 5‐moment system in the one‐dimensional setting that couples the conservation laws of mass, momentum and energy to two evolution equations of higher, non‐equilibrium moments. The new closure, given in closed‐form, depends on a regularization parameter β that is related to the non‐linearity around the equilibrium state, so as to mitigate the appearing sub‐shock in the continuous shock‐structure problem. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DAE‐index monitoring for semi‐discretized viscous Cosserat rod models
Authors: Schießl Stefan , Arne Walter , Marheineke Nicole , Wegener Raimund 
Published: November 2013

AbstractThe dynamics of viscous jets due to external forces like gravity and aerodynamics can be described by Cosserat rod models consisting of a system of partial and ordinary differential equations. Depending on the formulation of the equations, in particular the compatibility conditions, the semi‐discretization in space yields systems of differential‐algebraic equations (DAE) in time of different indices. We present a DAE‐index monitoring and discuss the numerical results for the application in a rotational 2d fiber spinning scenario. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Eigenvalues of Schrödinger operators and Dirichlet‐to‐Neumann maps
Authors: Behrndt Jussi , Kühn Christian , Rohleder Jonathan 
Published: November 2013

AbstractEigenvalues and eigenspaces of selfadjoint Schrödinger operators on ${\rm I\!R}^n$ are expressed in terms of Dirichlet‐to‐Neumann maps corresponding to Schrödinger operators on the upper and lower half space. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Damage and delamination processes in thermo‐viscoelastic materials
Authors: Thomas Marita 
Published: November 2013

AbstractThis contribution addresses several models for rate‐independent damage and delamination processes in thermo‐viscoelastic materials. In the spirit of continuum damage mechanics, both degradation phenomena are modeled by means of internal variables, governed by a rate‐independent flow rule. The latter is coupled in a highly nonlinear way with the heat equation and the momentum balance for the displacements. We present a suitable weak formulation for this class of models, and discuss existence and approximation results in the framework of variational convergence. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of boundary approximation on transfer operators between non‐nested meshes
Authors: Dickopf Thomas , Krause Rolf 
Published: November 2013

AbstractFinite element methods with non‐matching meshes can offer increased flexibility in many applications. Although the specific reasons for the use of non‐matching meshes are apparently diverse, the common difficulty in all these numerical methods is the transfer of finite element approximation associated with one mesh to finite element approximation associated with another mesh. This paper complements previous quantitative studies of transfer operators between finite element spaces associated with unrelated meshes (T. Dickopf, R. Krause, Evaluating local approximations of the L2‐orthogonal projection between non‐nested finite element spaces, Tech. Rep. 2012‐01, Institute of Computational Science, Università della Svizzera italiana, 2012). We study the important use case in which functions are mapped between a regular background mesh and an unstructured mesh of a complex geometry. Here, the former does not approximate the latter. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructure Evolution during Nanoindentation by the Quasicontinuum Method
Authors: Amelang Jeffrey S. , Venturini Gabriela N. , Kochmann Dennis M. 
Published: November 2013

AbstractA new energy‐based quasicontinuum formulation is presented which is based on sampling the crystal energy at carefully‐chosen lattice sites and which allows for efficiently bridging from the atomistic to the continuum length scale. The presented technique is applied to experiments of nanoindentation whose microstructure‐induced size effects can now be studied with full atomistic detail at the micrometer scale without the necessity of phenomenological material models. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Residual saturated porous media – from oscillating water blobs to waves in ground earth
Authors: Kurzeja Patrick , Steeb Holger 
Published: November 2013

AbstractA model for wave propagation in residual saturated porous media is presented distinguishing enclosed fluid clusters with respect to their eigenfrequency and damping properties. The additional micro‐structure information of cluster specific damping is preserved during the formal upscaling process and allows a stronger coupling between micro‐ and macro‐scale than characterisation via eigenfrequencies alone.A numerical example of sandstone filled with air and liquid clusters of different eigenfrequency and damping distributions is given. If energy dissipation due to viscous damping dominates energy storage due to cluster oscillations, the damping distribution is more influential than the eigenfrequency distribution and vice versa. Spreading the damping distribution around a constant mean value supported the effect of capillary forces and spreading the eigenfrequency distribution around a constant mean value supported the effect of viscous damping in the investigated samples. For a wide distribution of the liquid clusters' damping properties, two damping mechanisms of propagating waves occur at the same time: damping due to viscous effects (for highly damped clusters) and energy storage by cluster oscillations (for underdamped clusters). (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PTEN loss and KRAS activation leads to the formation of serrated adenomas and metastatic carcinoma in the mouse intestine
Authors: Davies Emma J , Marsh Durban Victoria , Meniel Valerie , Williams Geraint T , Clarke Alan R 
Published: November 2013

AbstractMutation or loss of the genes PTEN and KRAS have been implicated in human colorectal cancer (CRC), and have been shown to co‐occur despite both playing a role in the PI3' kinase (PI3'K) pathway. We investigated the role of these genes in intestinal tumour progression in vivo, using genetically engineered mouse models, with the aim of generating more representative models of human CRC. Intestinal‐specific deletion of Pten and activation of an oncogenic allele of Kras was induced in wild‐type (WT) mice and mice with a predisposition to adenoma development (Apcfl/+). The animals were euthanized when they became symptomatic of a high tumour burden. Histopathological examination of the tissues was carried out, and immunohistochemistry used to characterize signalling pathway activation. Mutation of Pten and Kras resulted in a significant life‐span reduction of mice predisposed to adenomas. Invasive adenocarcinoma was observed in these animals, with evidence of activation of the PI3'K pathway but no metastasis. However, mutation of Pten and Kras in WT animals not predisposed to adenomas led to perturbed homeostasis of the intestinal epithelium and the development of hyperplastic polyps, dysplastic sessile serrated adenomas and metastasizing adenocarcinomas with serrated features. These studies demonstrate synergism between Pten and Kras mutations in intestinal tumour progression, in an autochthonous and immunocompetent murine model, with potential application to preclinical drug testing. In particular, they show that Pten and Kras mutations alone predispose mice to the spectrum of serrated lesions that reflect the serrated pathway of CRC progression in humans. Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk
Hydrophilic nanocomposites based on polyurethane/poly(2‐hydroxyethyl methacrylate) semi‐IPNs and modified/unmodified nanosilica for biomedical applications
Authors: Stamatopoulou Constantina , Klonos Panagiotis , Koutsoumpis Stefanos , Gun'ko Vladimir , Pissis Polycarpos , Karabanova Lyudmyla 
Published: November 2013

ABSTRACTNanocomposites based on sequential semi‐interpenetrating polymer network (semi‐IPN) of cross‐linked polyurethane and linear poly(2‐hydroxyethyl methacrylate) with 0.25 and 3 wt % of nanosilica filler were prepared and investigated. The unmodified silica, carboxyl‐modified, and amino‐modified silica were used in an attempt to control the microphase separation of the polymer matrix by polymer–filler interactions. A variety of experimental techniques were used to study morphology, thermal transitions, mechanical properties, and polymer dynamics of the nanocomposites. Special attention was paid to the investigation of the hydration properties of the nanocomposites in the perspective of biomedical applications. The results show that the good hydration properties of the semi‐IPN matrix are preserved in the nanocomposites. Effects of water on polymer dynamics were found to be particularly pronounced for the secondary βsw,PHEMA and the βPU relaxations, in agreement with interpretations in terms of hydrogen bonding interactions with specific groups in the structure of the two polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 397–408
Towards area‐wide control of Bactrocera invadens: prospects of the sterile insect technique and molecular entomology
Authors: Ogaugwu Christian E 
Published: November 2013

AbstractIt is 10 years since the first detection of the invader fruit fly, Bactrocera invadens, in sub‐Saharan Africa. The pest continues to hamper fruit production and create barriers to trade. Strategies currently employed to control B. invadens are insufficient, and more effective area‐wide strategies are needed. The sterile insect technique and molecular entomology approaches have high potential and could help to bring about effective area‐wide control of the pest if adopted and used as components of area‐wide integrated pest management. © 2013 Society of Chemical Industry
A dynamic malware analyzer against virtual machine aware malicious software
Authors: Pektaş Abdurrahman , Acarman Tankut 
Published: November 2013

ABSTRACTNowadays, cyber‐world is being enriched by a large variety of digital information technology‐based services. An increasing rate of remote and mobile usage leads to a remarkable dependency on information security. Analysis and detection of malicious software or so‐called malware is a challenging task due to the introduction of advanced obfuscation techniques by malware authors. In this study, we mainly concentrate on anti‐virtual machine evasion techniques to provide secure and reproducible environments for malware analysis and its implementation issues. Malwares are identified on the basis of their behaviors by taking precautions related to the anti‐virtual machine detection techniques. The dynamic malware analyzer tool is deployed to execute anti‐virtual machine‐aware malware samples in VMware environment. Dynamic malware analyzer monitors system resources such as connections, processes, windows registry, and file operations. Success ratio of detection is tested by using public malware sets with an accuracy of 92%. The effectiveness and success of the behavior‐based malware analyzer tool is exploited and current state of the art of malware detection schemes is presented. Copyright © 2013 John Wiley & Sons, Ltd.