bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Investment Policy
Authors: Simeliene Nijole 
Published: January 2007

AbstractParticipation in conferences is one of the means of Knowledge Communication. Knowledge Communication might be an effective means to improve and to analyse optimization of investment policy. The analysis and improvement of overall performance in complex systems, the adaptation of models to new demands or conditions and the design of optimal systems are a few of challenges confronting engineers and systems scientists today. In many cases solutions of the problems in areas such as these may be found through the use of appropriate mathematical models. The tools for doing this are ways to formulate real‐world problems in detailed mathematical terms (mathematical models). All kinds of mathematical models which arise from practical problems are just approximate descriptions.This study provides an asymptotic analysis of the discrete multistage controlled dynamical systems in the finite spaces of state variables. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An a priori bound for eigenvalue computation by AMLS
Authors: Elssel Kolja , Voss Heinrich 
Published: January 2007

AbstractBased on Schur complements and modal approximations of submatrices on several levels AMLS constructs a projected eigenproblem which yields good approximations of eigenvalues at the lower end of the spectrum. Rewriting the original problem as a rational eigenproblem of the same dimension as the projected problem, and taking advantage of a minmax characterization for the rational eigenproblem we derive a bound for the AMLS approximation of eigenvalues. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Structure Preserving Index Reduction Method For MNA
Authors: Bächle S. , Ebert F. 
Published: January 2007

AbstractTransient analysis in industrial chip design leads to very large systems of differential‐algebraic equations (DAEs). The numerical solution of these DAEs strongly depends on the so called index of the DAE. In general, the higher the index of the DAE is, the more sensitive the numerical solution will be to errors in the computation. So, it is advisable to use mathematical models with small index or to reduce the index.This paper presents an index reduction method that uses information based on the topology of the circuit. In addition, we show that the presented method retains structural properties of the DAE. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Superconvergence Analysis of Galerkin FEM and SDFEM for Elliptic Problems with Characteristic Layers
Authors: Franz Sebastian , Linß Torsten 
Published: January 2007

AbstractWe analyse the superconvergence properties of the Galerkin FEM and of the streamline‐diffusion finite element method (SDFEM) using bilinear functions in the case of elliptic problems with characteristic layers. To resolve the layers we use appropriate Shishkin meshes.For the SDFEM we give an optimal choice for the streamline‐diffusion parameter δ for maximal stability in the induced streamline‐diffusion norm. In the characteristic layers we are able to show that δ can be chosen of order δ = Cε‐ ${1 \over 4}$ N–2 which is con.rmed by numerical results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multigrid and M‐Matrices in the Finite Pointset Method
Authors: Seibold Benjamin 
Published: January 2007

AbstractWe consider the Finite Pointset Method (FPM) for incompressible flows. In the classical FPM derivatives are approximated by a least squares approximation. In general this approach yields stencils with both positive and negative entries. We present how optimization routines can force the stencils to have only positive weights aside from the central point. This approach yields an M‐matrix structure, which is of interest for various linear solvers. We investigate algebraic multigrid to solve the arising linear systems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High Performance Computing Techniques for the FEM Simulation in Structural Mechanics
Authors: Wobker Hilmar , Turek Stefan , Svendsen Bob 
Published: January 2007

AbstractFor the solution of large scale simulations in structural mechanics iterative solving methods are mandatory. The efficiency of such methods can crucially depend on different factors: choice of material parameters, quality of the underlying computational mesh and number of processors in a parallel computing system. We distinguish between three aspects of ‘efficiency’: processor efficiency (degree to which the solving algorithm is able to exploit the processor's computational power), parallel efficiency (ratio between computation and communication times) and numerical efficiency (convergence behaviour). With the new FEM software package Feast we pursue the aim to develop a solver mechanism which at the same time gains high efficiencies in all three aspects, while trying to minimise the mentioned dependencies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal Data Selection for Piezoelectric Material Characterization
Authors: Lahmer Tom , Kaltenbacher Barbara , Schulz Volker 
Published: January 2007

AbstractIn the simulation and design of piezoelectric transducers the exact knowledge of the entries in the material tensors ‐ the elastic, dielectric and piezoelectric coupling coefficients ‐ is an important prerequisite. Our task is the identification of these coefficients from indirect measurements, namely electric impedance data at different frequencies. This leads to a parameter identification problem for a system of coupled PDEs, which we solve by regularized Newton iterations. A crucial issue is the selection of frequencies at which measurements are taken. Here, we discuss the problem of choosing these frequencies in an optimal way to preserve efficiency of our identification scheme while improving reliability of the reconstruction results. For this purpose, we formulate this task as an optimization problem with PDE constraints and propose two approaches for its solution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Active vibration suppression of smart beams
Authors: Betti Michele , Stavroulakis Georgios E. , Baniotopoulos Charalambos C. 
Published: January 2007

AbstractIn this paper an active vibration control technique for a smart beam is presented. The structure is made of two layers of piezoelectric material (PZT8) embedded on the surface of an aluminium beam. The active control is inserted into the finite element model by using programming tools of the general purpose code used here. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aufbau und Regelung einer Magnetführung für Werkzeugmaschinen
Authors: Denkena Berend , Neuber Cord‐Christian , Kallage Franz , Panning Lars 
Published: January 2007

AbstractDer größte Anteil der am Markt erhältlichen Werkzeugmaschinen ist mit Wälzführungen ausgestattet. Diese Führungen begrenzen aufgrund von Reibung, Verschleiß und geringer Dämpfung die Maschinendynamik. Gerade im Bereich der Hochgeschwindigkeitsbearbeitung (high speed cutting, HSC) wird dadurch die erreichbare Produktivität eingeschränkt. In diesem Beitrag wird ein für Werkzeugmaschinen vollkommen neuartiges Führungskonzept vorgestellt, das in einem Hochgeschwindigkeits‐Bearbeitungszentrum, der schnellen Maschine, umgesetzt wurde. Die Spindelachse dieser Maschine wird mit Hilfe einer aktiven Magnetführung kontaktfrei geführt. Schwerpunkt des Beitrags sind die sich ergebenden neuen Möglichkeiten der Einflussnahme auf das Maschinenverhalten durch eine intelligente Regelung der Magnetführung. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cell Mapping for Random Transformations
Authors: Gaull Andreas , Kreuzer Edwin 
Published: January 2007

AbstractThe method of Cell Mapping is a numerical tool to analyze the long‐term behavior of dynamical systems. For deterministic systems, which are described by nonsingular transformations, Cell Mapping is characterized by a certain discretization of the Frobenius–Perron operator first proposed by Ulam [3]. Our purpose is to extend the concept to dynamical systems which are generated by random transformations. At this, time evolution of absolutely continuous measures and the corresponding densities will be described by Markov operators whose fixed points refer to invariant measures and densities respectively. A discretization of the Markov operator on densities leads directly to the reformulation of Cell Mapping in the stochastic context. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A geometric modelling of nonlinear RLC networks
Authors: Ionescu Delia 
Published: January 2007

AbstractA new approach to nonlinear RLC circuits, which is based on the geometric Birkhoffian formalism, is described in this note. The configuration space and a special Pfaffian form, called Birkhoffian, are obtained from the constitutive relations of the involved resistors, inductors and capacitors and from Kirchhoff's laws. No assumptions are placed upon the topology of the network. Properties of the corresponding Birkhoffian such as its regularity, or its dissipativeness, are discussed in this context. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensitivity analysis of multi‐storey building due to blast loading
Authors: Majcher Krzysztof , Wójcicki Zbigniew , Mironowicz Władysław 
Published: January 2007

AbstractIn this paper the vibration problems of multi‐storey column‐slab buildings are considered. Vibrations are caused by the explosion in the building and destruction of some construction elements. The influence of sudden loss of these elements as well as the explosion pressure are taken into account. In particular, the influence of destruction location on the building vibrations is examined. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analogue Implementation of the Funnel Controller
Authors: Mandaloju Nagendra P. , Trenn Stephan 
Published: January 2007

AbstractIn many tracking control problems, pre‐specified bounds for the evolution of the tracking error should be met. The ‘funnel controller’ addresses this requirement and guarantees transient performance for a fairly large class of systems. In addition, only structural assumptions on the underlying system are made; the exact knowledge of the system parameters is not required. This is in contrast to most classical controllers where only asymptotic behaviour can be guaranteed and the system parameters must be known or estimated. Until now, the funnel controller was only studied theoretically. We will present the results of an analogue implementation of the funnel controller. The results show that the funnel controller works well in reality, i.e. it guarantees the pre‐specified error bounds. The implementation is an analogue circuit composed of standard devices and is therefore suitable for a broad range of applications. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Galerkin‐based Time Integrators for Geometrically Nonlinear Elasto‐Plastodynamics
Authors: Mohr Rouven , Menzel Andreas , Steinmann Paul 
Published: January 2007

AbstractComputational modelling often demands the incorporation of dynamic effects. The consideration of computational elastoplastodynamics requires in particular advanced numerical techniques to satisfy the classical balance laws like balance of linear and angular momentum or the laws of thermodynamics. Regarding the thermodynamical consistency of elasto‐plastodynamics, the conservation of the total energy in the elastic case and the fulfilment of the dissipation inequality in the plastic case are very important. In this contribution we deal with a mechanically and thermodynamically consistent Galerkin‐based time‐stepping scheme for finite elasto‐plastodynamics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High Gain Observers Using an Approximate Observer Normal Form
Authors: Röbenack Klaus 
Published: January 2007

AbstractIf one can transform a nonlinear system into observer normal form, it is possible to design an observer with exactly linear error dynamics. Unfortunately, many systems of practical relevance violate the existence conditions of the normal form. This drawback can be circumvented by means of an approximate observer normal form. The actual computation of the associated transformation may still be very difficult. We suggest a nonlinear observer design procedure that avoids this drawback. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New developments in robust synthesis with antiwindup compensation.Flight control actuators applications
Authors: Ursu Felicia , Ursu Ioan , Iorga Lucian 
Published: January 2007

AbstractWe first summarize some results recently published by the authors on the application of classical robust servomechanism problem (RSP) to electrohydraulic servos. We present a solution consisting of three compensators: an integrator of the tracking error, a LQR stabilizing compensator and an antiwindup compensator. In this work we extend the analysis of the proposed solution by investigating the stability of the closed loop system with saturated control. We present here an approach to this problem based on the Lyapunov function method. The domain of attraction of the origin is obtained and it is shown that the system stability is ensured by simply choosing a particular compensator design which solves RSP. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tip Vortex Wake Destabilization with and without Winglets
Authors: Hörnschemeyer Ralf , Kauertz Sebastian , Haverkamp Sven , Neuwerth Günther , Henke Rolf 
Published: January 2007

AbstractWake vortices are an inevitable by‐product of lift. Another airplane following too closely can be dangerously influenced by induced rolling moments. Consistent adherence to the prescribed safety margins ensures safe flight, however it also obstructs the capacity of large airports. To remedy the expected future capacity problems, research is being carried out world wide. This paper describes some results of the research work to decrease the hazard of the vortex wake accomplished at the ILR. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Role of mercerization of the bamboo strips on the impact properties and morphology of unidirectional bamboo strips–novolac composites
Authors: Das Mahuya , Chakraborty Debabrata 
Published: January 2007

AbstractBamboo strips were mercerized with varying concentrations of NaOH (10, 15, 20, and 25%). Impact test was made on composites made from the untreated as well as from the mercerized strips. Works of fracture for all the composites were evaluated and it was observed that the fracture energy undergoes an increase from composites made of untreated bamboo strips to those made from mercerized bamboo strips. Mercerization removed alkali sensitive material from the bamboo matrix and it leads to more cellulose fibril pull‐out from the lignocellulosic composites, which plays a great role in improving the work of fracture value. POLYM. COMPOS., 28:57–60, 2007. © 2007 Society of Plastics Engineers
Effect of chemical structure and composition of the resin phase on vinyl conversion of amorphous calcium phosphate‐filled composites
Authors: Skrtic D , Antonucci JM 
Published: January 2007

AbstractThe objective of this study was to elucidate the effect of chemical structure and composition of the polymer matrix on the degree of vinyl conversion (DC) of copolymers (unfilled resins) and their amorphous calcium phosphate (ACP) composites attained upon photopolymerization. The DC can also be an indicator of the relative potential of these polymeric materials to leach out into the oral environment un‐reacted monomers that could adversely affect their biocompatibility. The following resins were examined: (1) 2,2‐bis[p‐(2′‐hydroxy‐3′‐methacryloxypropoxy)phenyl]propane (Bis‐GMA)/triethylene glycol dimethacrylate (TEGDMA) (1:1 mass ratio; BT resin) combined with hydroxyethyl methacrylate (HEMA; BTH resin) and with HEMA and zirconyl dimethacrylate (BTHZ resin); (2) urethane dimethacrylate (UDMA)/HEMA resins; and (3) pyromellitic glycerol dimethacrylate (PMGDMA)/TEGDMA (PT resin). To make composite specimens, resins were mixed with a mass fraction of 40% zirconia‐hybridized ACP. Copolymers and their composites were evaluated using near infrared spectroscopy for DC after 1 d and 28 d post‐cure at 23 °C. Inclusion of HEMA into the BT and UDMA resins yielded copolymers and composites with the highest DCs. The significantly lower DCs of PT copolymers and their composites are attributed to the rigid aromatic core structure, tetravinyl functionality and limited methacrylate side‐chain flexibility of the surface‐active PMGDMA monomer. There was, however, an increase in the 28 d DC for the PT materials as there was for the BTHZ system. Surprisingly, the usual decrease observed in DC in going from unfilled polymer to composite was reversed for the PT system. Published in 2007 by John Wiley & Sons, Ltd
The influence of hard‐segments on two‐phase structure and shape memory properties of PCL‐based segmented polyurethanes
Authors: Ping Peng , Wang Wenshou , Chen Xuesi , Jing Xiabin 
Published: January 2007

AbstractPoly(ε‐caprolactone)‐based segmented polyurethanes (PCLUs) were prepared from poly(ε‐caprolactone) diol, diisocyanates (DI), and 1,4‐butanediol. The DIs used were 4,4′‐diphenylmethane diisocyanate (MDI), 2,4‐toluenediisocyanate (TDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI). Differential scanning calorimetry, small‐angle X‐ray scattering, and dynamic mechanical analysis were employed to characterize the two‐phase structures of all PCLUs. It was found that HDI‐ and MDI‐based PCLUs had higher degree of microphase separation than did IPDI‐ and TDI‐based PCLUs, which was primarily due to the crystallization of HDI‐ and MDI‐based hard‐segments. As a result, the HDI‐based PCLU exhibited the highest recovery force up to 6 MPa and slowest stress relaxation with increasing temperature. Besides, it was found that the partial damage in hard‐segment domains during the sample deformation was responsible for the incomplete shape‐recovery of PCLUs after the first deformation, but the damage did not develop during the subsequent deformation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 557–570, 2007
Palivizumab efficacy in preterm infants with gestational age ≤30 weeks without bronchopulmonary dysplasia
Authors: Grimaldi Marianne , Gouyon Béatrice , Sagot Paul , Quantin Catherine , Huet Frédéric , Gouyon Jean‐Bernard ,   for the Burgundy Perinatal Network
Published: January 2007

AbstractThe present study was designed to determine the efficacy of administration of palivizumab to preterm infants with gestational age (GA) ≤30 weeks without bronchopulmonary dysplasia (BPD). All patients born with GA ≤30 weeks without BPD on Day 28 and hospitalized for RSV bronchiolitis in Burgundy (12 hospitals) from December 1 to April 30 of the next year were included in this prospective observational study during five successive RSV seasons (1999–2000, 2000–2001, 2001–2002, 2002–2003, and 2003–2004). Palivizumab was given to premature infants with a gestational age ≤30 weeks without BPD in the 2002–2003 and 2003–2004 periods only. In the cohort of premature infants with GA ≤30 weeks without BPD, the respiratory syncytial virus (RSV) bronchiolitis hospitalization rate was reduced significantly (P < 0.01) in the two seasons with palivizumab prophylaxis (2002–2003: 0% and 2003–2004: 2%) versus the three previous RSV seasons (1999–2000: 14.3%; 2000–2001: 16.7%; 2001–2002: 10.2%). The number needed to treat to prevent one hospitalization for RSV bronchiolitis was 6 (95%CI: 4–11). Such favorable results have not been always found in the few available postmarketing epidemiological studies on hospitalization rate after palivizumab prophylaxis. Differences in health care organization could explain those discrepancies. Pediatr Pulmonol. 2007; 42:189–192. © 2007 Wiley‐Liss, Inc.
Cardiopulmonary responses of asthmatic children to exercise: Analysis of systolic and diastolic cardiac function
Authors: Alioglu Bulent , Ertugrul Turkan , Unal Mehmet 
Published: January 2007

AbstractThe aim of this study was to evaluate aerobic exercise capacity, cardiac features and function in a group of asthmatic children who underwent medical treatment. Dynamic exercise testing was done to evaluate aerobic exercise capacity. Echocardiography was performed to identify the effects that asthma‐induced pulmonary changes have on respiratory and cardiac function in these patients. The study involved 20 asthmatic children (aged 7–16 years) who were followed at our hospital and 20 age‐ and sex‐matched, healthy control subjects. Sixteen of the asthma cases were moderate and four were severe. All 40 subjects underwent similar series of assessments: multiple modes of echocardiography, treadmill stress testing, pulmonary function testing. The means for forced expiratory volume in 1 sec, forced expiratory flow 25–75%, maximal voluntary ventilation and inspiratory capacity were all significantly higher in the control group. The patient group had significantly lower mean maximal oxygen uptake and mean endurance time than the controls but there were no significant differences between the groups with respect to respiratory exchange ratio or the ventilatory threshold. The control group means for ejection fraction, fractional shortening, left ventricular mass, and left ventricular mass index were significantly higher than the corresponding patient group results. Children with moderate or severe asthma have lower aerobic capacity than healthy children of the same age. The data suggest that most of these children have normal diastolic cardiac function, but exhibit impaired systolic function and have lower LVM than healthy peers of the same age. Pediatr Pulmonol. 2007; 42:283–289. © 2007 Wiley‐Liss, Inc.
Comparative study of the β″‐phase in a 6xxx Al alloy by 3DAP and HRTEM
Authors: Hasting H. K. , Lefebvre W. , Marioara C. , Walmsley J. C. , Andersen S. , Holmestad R. , Danoix F. 
Published: January 2007

AbstractThe metastable β″‐hardening phase in aged 6xxx‐series Al alloys has been investigated by three‐dimensional atom‐probe in order to evaluate the composition (Mg5Si6) of the structure, previously determined by high‐resolution transmission electron microscopy (HRTEM) and electron diffraction. For β″, a significant number of Mg and Si atoms are found to be lost during detection in atom‐probe analysis. The reason of this is non‐resolved events, in which the correlation between the time‐of‐flight (TOF) and the detected position of the field‐evaporated ion is lost. The problem is attributed to uneven evaporation and can be avoided by the use of an advanced delay‐line detector (ADLD), which is capable of discriminating extremely closely spaced detection events. Preliminary analysis of a β″‐particle using this detector gave a Mg/Si ratio of 0.9 and a composition of 15 at.% Al. The Al level is significantly lower than those previously measured by other atom‐probe detectors, because of the higher efficiency of the ADLD in detecting Mg and Si in particles. Atom‐probe analysis with the ADLD detector is consistent with the β″ Mg/Si ratio derived from electron microscopy analysis. The measurements indicate that Al atoms may substitute both Si and Mg positions. Copyright © 2007 John Wiley & Sons, Ltd.
Hearing: Individual Differences in Perceiving
Authors: McGuinness Diane 
Published: January 2007

Four different types of hearing were investigated using 25 men and 25 women as subjects: pure tone threshold, judgment of loudness, pitch discrimination, and annoyance of a repeating stimulus. Differences were found at high frequency thresholds (above 6000 Hz), in loudness judgment, and in the annoyance test. The pitch discrimination test showed no effect of sex, but a large effect of years of musical training. None of the four hearing parameters investigated bore any statistical relationship to any other, demonstrating that these hearing types are distinct and will vary within, as well as between subjects. Personality assessment showed no relationship to any type of-hearing, with the exception of extraversion and loudness judgment, suggesting that fairly pure sensitivity factors are being measured.