bluuebunny/crossref_metadata_2025_split huggingface dataset:
State Estimation and Fault Detection of an Aircraft Using Nonlinear Filters
Authors: Christmann Julia , Kappenberger Carsten , Marheineke Nicole 
Published: December 2011

AbstractAn aircraft is a complex technical system, which has to satisfy high safety standards. The whole system of an aircraft has to be monitored because more and more actions happen automatically. Therefore unpredictable errors should be detected as fast as possible. In this work two different nonlinear filters namely the Extended Kalman Filter (EKF) and the Particle Filter (PF) are studied for the application of fault detection with simultaneous estimations of states. Results show that EKF leads to better approximation for nearly linear problems, while PF yields a more accurate approximation for worst case scenarios. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncertainty relations for sets of self adjoint operators
Authors: Held Stefan 
Published: December 2011

AbstractUncertainty relations quantify the joint localisation in time respectively space domain and Fourier domain. For that reason they are an important tool in the design of wavelets. Uncertainty relations in higher dimension are most often realized as the tensor product of one dimensional uncertainty relations, whence these uncertainty relations are not invariant under rotations. The property of invariance with respect to rotation is however very desirable for image processing. We will give a new uncertainty relation for sets of self‐adjoint operators that yields the desired invariance in many examples. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transformations, Implementations, and Pitfalls
Authors: Sauer Tomas 
Published: December 2011

AbstractTransformations are ubiquitous in practically every field of signal processing and the choice of the right transformation can be crucial for extracting the information from the data. In computational practice, however, the fact that one tries to implement an infinite transformation defined on a continuum for finite discrete data can lead to unwanted and often also unexpected effects. Using the example of the continuous wavelet transform, this note points to some of these effects and gives explanation why this happens and how it can be avoided. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A fast Kriging‐based strategy for the optimization of electrical device
Authors: Chaigne Benoît , Trinitis Carsten 
Published: December 2011

AbstractThe primary goal of a shape optimization problem is to find the best design w.r.t. a given criterion. A however non less important goal is to achieve this task within a reasonable time. In realistic situations, a reliable but slow method might not always provide its best capacity if the computational resources are worked out before convergence. The expensive simulation‐based optimization of a physical system is one of these situations. In order to tackle this issue, we consider a fast but low‐fidelity model given by a Kriging method. We propose a simple adaptive scheme in order to enhance the reliability of the optimization procedure and thus avoid a premature convergence. Numerical experiments are conducted for the electrostatic design of a realistic device. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Massively Parallel Particle Simulations on Graphics Processing Units with CUDA
Authors: Fischer Katrin , Ostermeyer Georg‐Peter 
Published: December 2011

AbstractParticle methods are a powerful tool to model dynamic systems. Thereby, the system is discretized by a large number of particles, which are interacting via local, predefined particle‐particle interaction laws. The resulting computational effort includes neighborhood search, computation of interaction forces and state update via time integration. Particle methods are used in a lot of different fields of applications like computer science, physics and engineering sciences.As the analyzed systems' number of particles constantly grow, performance enhancement has become an important part of present algorithm development. Besides the well‐established approach of algorithm parallelization on multi‐core CPUs or CPU clusters, modern graphics processing units (GPUs) present a different and trend‐setting possibility for massive parallelization even on desktop computers. Among the top four supercomputers of the world, three are already using NVIDIA GPUs.In late 2006, NVIDIA introduced the first GPUs optimized for general purpose calculations. This was followed by the introduction of a new computing architecture differing from the standard graphics user‐interface like OpenGL. This architecture is called Compute Unified Device Architecture (CUDA). It enables the user to program the GPU using standard C commands with few additional runtime functions. The differences in architecture between CPU and GPU result in a completely different algorithm implementation.So, a performance evaluation of different types of particle systems implemented on a GPU using CUDA and on a standard CPU is presented. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Block Preconditioners in the Parallel Toolbox
Authors: Aurel Neic , Haase Gundolf 
Published: December 2011

AbstractWe present a parallel solver for second order scalar PDE called The Parallel Toolbox. We investigate certain performance issues which arise when high performance compute nodes with a relatively slow network interconnect are used. These performance issues motivate the introduction of block methods which reduce network usage and thus increase parallel performance. First benchmarks computed on a GPU cluster evaluate the success of this attempt. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the historical development of human walking dynamics
Authors: Schiehlen Werner 
Published: December 2011

AbstractHuman walking is an interdisciplinary research topic. It started in the Ancient World with early observations and questions in philosophy, it was treated in the Middle Ages with experiments and data collection by physiologists, and in the 20th century models were designed, equations of motion were generated and simulations by multibody dynamics approaches were performed. More recently parameter optimization was used to overcome the problem of muscle overactuation and inverse dynamics methods were introduced. In the first part of the paper the early developments and mechanism models are described while in the second part parameter optimization is applied to gait disorder simulations as an example of recent research results. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Jacobi‐Davidson method for two real parameter nonlinear eigenvalue problems arising from delay differential equations
Authors: Meerbergen Karl , Schröder Christian , Voss Heinrich 
Published: December 2011

AbstractThe critical delays of a delay‐differential equation can be computed by solving a nonlinear two‐parameter eigenvalue problem. For large scale problems, we propose new correction equations for a Jacobi‐Davidson type method, that also forces real valued critical delays. We present two different equations: one complex valued equation using a direct linear system solver, and one Jacobi‐Davidson style correction equation which is suitable for an iterative linear system solver. A numerical example of a large scale problem arising from PDEs shows the effectiveness of the method. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of probability density functions for nonlinear vibration systems
Authors: Martens Wolfram , von Wagner Utz 
Published: December 2011

AbstractTechnical systems are subjected to a variety of excitations that cannot generally be described in deterministic ways. Random excitations such as road roughness, wind gusts or loads on marine structures are commonly described by stochastic differential equations (SDEs). Given a set of SDEs, the main task is in finding probability density functions (PDFs), which yield statistical information about the system states. Monte‐Carlo simulations represent a general way of generating PDFs, however, reliable integration methods can be time‐consuming for complex systems. An alternative way of finding PDFs lies in the analysis of the Fokker‐Planck equation, a partial differential equation of the PDF. Linear problems under Gaussian excitation can be solved analytically, which is the case only for a small class of nonlinear problems. As a result, there are a number of methods of approximating PDFs for general problems. Most of these are restricted to comparably low dimensions, such as d=4 ("curse of dimensionality"), limiting the relevance to technical applications. This paper presents solutions to problems of dimensions up to d=10, applying a Galerkin‐method that expands approximate solutions into orthogonal polynomials. Problems include polynomial nonlinearities in damping and restoring terms, such as classical Duffing‐elements, as well as other types of nonlinearities, demonstrated on a typical problem in vehicle dynamics. All results are compared with results from Monte‐Carlo simulations or exact solutions, where available. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A three‐field, bi‐domain based approach to the strongly coupled electromechanics of the heart
Authors: Dal Hüsnü , Göktepe Serdar , Kaliske Michael , Kuhl Ellen 
Published: December 2011

AbstractWe propose a novel, unconditionally stable and fully coupled finite element method for the bidomain based approach to cardiac electromechanics. To this end, the transmembrane potential, the extracellular potential, and the displacement field are treated as independent variables such that the already coupled electrophysiology problem in the bidomain setting is further extended to the electromechanical coupling. In this multifield problem, the intrinsic coupling arises from both excitation‐induced contraction of cardiac cells and the deformation‐induced generation of intra‐cellular currents. The respective bidomain reaction‐diffusion and the momentum balance equations are recast into the corresponding weak forms through a conventional isoparametric Galerkin approach. The resultant set of non‐linear residual equations is consistently linearized. The monolithic scheme is employed to avoid stability issues that may arise due to the strong coupling between excitation and deformation. The performance of the put forward framework is further assessed through three‐dimensional representative electromechanical initial‐boundary value problems. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relaxed loading conditions for higher order homogenisation approaches
Authors: Jänicke Ralf , Uribe David , Ruiz Oscar E. , Steeb Holger 
Published: December 2011

AbstractThe present paper deals with the formulation of minimal loading conditions for the application of numerical homogenisation techniques, namely the FE2 methodology. Based on the set of volume averaging rules connecting the heterogeneous micro and the homogeneous macro scale, the minimal constraints on the deformation of a micro volume are derived for a classical Cauchy continuum as well as for a micromorphic continuum theory. For both cases, numerical studies are included highlighting the main aspects of the proposed procedure within the context of small deformations. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Copper oxide thin films by chemical vapor deposition: Synthesis, characterization and electrical properties
Authors: Eisermann Sebastian , Kronenberger Achim , Laufer Andreas , Bieber Johannes , Haas Gunther , Lautenschläger Stefan , Homm Gerd , Klar Peter J. , Meyer Bruno K. 
Published: December 2011

AbstractCu2O thin films were grown on sapphire (0001) and MgO (100) substrates by chemical vapor deposition. The crystalline, vibrational and electrical properties of the layers and the amount of incorporated background impurities have been examined. X‐ray diffraction measurements revealed, that the polycrystalline films grew in (111) and (100) orientation on sapphire and in (100) orientation on MgO. Raman measurements indicated the presence of CuO inclusions in the films. The electrical properties are dominated by an acceptor level located 150 meV above the valence band. This level may originate from unintentionally incorporated silicon impurities.
Metal–semiconductor transition in SmxMn1−xS solid solutions
Authors: Aplesnin Sergey , Romanova Oxana , Har'kov Anton , Balaev Dmitrii , Gorev Michail , Vorotinov Alexander , Sokolov Vladimir , Pichugin Andrey 
Published: December 2011

AbstractThe electrical resistivity of the SmxMn1−xS (0.15 ≤ x ≤ 0.25) solid solutions in the temperature range of 80–300 K was measured. Minimum and maximum in the temperature dependence of the resistivity were found, respectively, at T = 220 K for x = 0.15 and at T = 100 K for x = 0.2 compounds. This behavior is explained from the result of the mobility‐edge movement, the disorder being due to elastic deformation and spin density fluctuations with short‐range order. Metal–semiconductor phase transition versus concentration at xc = 0.25 is observed. Resistivity is described by scattering electrons with acoustic phonon mode and with localized manganese spin. From the thermal expansion coefficient the compression of the lattice below the Néel temperature for Sm0.2Mn0.8S is found.
Influence of polymer dielectric surface energy on thin‐film transistor performance of solution‐processed triethylsilylethynyl anthradithiophene (TES‐ADT)
Authors: Chen Liang‐Hsiang , Lin Pang , Kim Choongik , Chen Ming‐Chou , Huang Peng‐Yi , Ho Jia‐Chong , Lee Cheng‐Chung 
Published: December 2011

AbstractThis study investigates the correlation between surface energy of polymer dielectrics and the film morphology, microstructure, and thin‐film transistor performance of solution‐processed 5,11‐bis(triethylsilylethynyl) anthradithiophene (TES‐ADT) films. The low surface energy polyimide (PI) dielectric induced large grains with strong X‐ray reflections for spin‐cast TES‐ADT films in comparison to high surface en‐ ergy poly(4‐vinyl phenol) (PVP) dielectric. Furthermore, thin‐film transistors based on spin‐cast TES‐ADT films on PI dielectric exhibited enhanced electrical performance, small hysteresis, and high stability under bias stress with carrier mobility as high as 0.43 cm2/Vs and a current on/off ratio of 107. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distributed OSGi built over message‐oriented middleware
Authors: Psiuk Marek , Żmuda Daniel , Zieliński Krzysztof 
Published: December 2011

SUMMARYThis paper describes key aspects of remote service invocation in federations of OSGi containers. It refers to the OSGi Remote Service Admin specification and describes its efficient implementation over message‐oriented middleware. Scalability problems of several different approaches to implementation are identified, and a solution in a form of innovative Remote Service Admin model extension is proposed. The extension, named On‐demand Remote Service Admin, is analyzed and validated in the context of a motivating scenario. Validation includes performance and scalability evaluation, which confirms that all assumed requirements have been satisfied by the constructed prototype. Finally, the presented research is compared with related works. Copyright © 2011 John Wiley & Sons, Ltd.
Wireless local area network cards identification based on transient fingerprinting
Authors: Zhao Caidan , Chi Ting‐Yun , Huang Lianfen , Yao Yan , Kuo Sy-Yen 
Published: December 2011

ABSTRACTThis paper proposes a time–frequency‐based fingerprinting identification approach by extracting the transient characterizations regarding highly integrated wireless local area network (WLAN) cards. The transient energy envelope is derived from the slice of spectrogram in the time–frequency domain. Then this transient response is fitted to a polynomial under least square criteria, and the polynomial coefficients are regarded as the feature vector. A data acquisition system has been set up to capture IEEE 802.11b Wi‐Fi (wireless fidelity) signals. The results exhibit an approving distinctiveness of up to 94% to classify different manufactories of WLAN cards and of 78.4% for the WLAN cards of the same manufactory. Copyright © 2011 John Wiley & Sons, Ltd.
Production of the Finnish Wind Atlas
Authors: Tammelin Bengt , Vihma Timo , Atlaskin Evgeny , Badger Jake , Fortelius Carl , Gregow Hilppa , Horttanainen Matti , Hyvönen Reijo , Kilpinen Juha , Latikka Jenni , Ljungberg Karoliina , Mortensen Niels Gylling , Niemelä Sami , Ruosteenoja Kimmo , Salonen Kirsti , Suomi Irene , Venäläinen Ari 
Published: December 2011

ABSTRACTThe Finnish Wind Atlas was prepared applying the mesoscale model AROME with 2.5 km horizontal resolution and the diagnostic downscaling method Wind Atlas Analysis and Application Programme (WAsP) with 250 m resolution. The latter was applied for areas most favourable for wind power production: a 30 km wide coastal/offshore zone, highlands, large lakes and large fields. The methodology included several novel aspects: (i) a climatologically representative period of real 48 months during 1989–2007 was simulated with the mesoscale model; (ii) in addition, the windiest and calmest months were simulated; (iii) the results were calculated separately for each month and for sectors 30° wide; (iv) the WAsP calculations were based on the mesoscale model outputs; (v) in addition to point measurements, also radar wind data were applied for the validation of the mesoscale model results; (vi) the parameterization method for gust factor was extended to be applicable at higher altitudes; and (vii) the dissemination of the Wind Atlas was based on new technical solutions. The AROME results were calculated for the heights of 50, 75, 100, 125, 150, 200, 300 and 400 m, and the WAsP results for the heights of 50, 75, 100, 125 and 150 m. In addition to the wind speed, the results included the values of the Weibull distribution parameters, the gust factor, wind power content and the potential power production, which was calculated for three turbine sizes. The Wind Atlas data are available for each grid point and can be downloaded free of charge from dynamic maps at www.windatlas.fi. Copyright © 2011 John Wiley & Sons, Ltd.
Verification of computational simulations of the NREL 5 MW rotor with a focus on inboard flow separation
Authors: Chow Raymond , van Dam C. P. 
Published: December 2011

ABSTRACTThe aerodynamic characteristics of the NREL 5 MW rotor have been examined using a Reynolds‐averaged Navier–Stokes method, OVERFLOW2. A comprehensive off‐body grid independence study has been performed. A strong dependence on the size of the near‐body wake grid has been found. Rapid diffusion of the wake appears to generate an overprediction of power and thrust. A large, continuous near‐wake grid at a minimum of two rotor diameters downstream of the rotor appears to be necessary for accurate predictions of near‐body forces. The NREL 5 MW rotor demonstrates significant inboard flow separation up to 30% of span. This separation appears to be highly three dimensional, with a significant amount of radial flow increasing the size of the separated region outboard. A simple, continuous full‐chord fence was applied at the maximum chord location of the blade, within the region of separation. This non‐optimized device reduced the boundary‐layer cross‐flow and resulting separation. The fence increased energy capture by nearly 1% at a wind speed of 8 m s−1 and slightly increased blade loading over the length of the span. Copyright © 2011 John Wiley & Sons, Ltd.
The Production of Conjugated α‐Linolenic, γ‐Linolenic and Stearidonic Acids by Strains of Bifidobacteria and Propionibacteria
Authors: Hennessy Alan A. , Barrett Eoin , Paul Ross R. , Fitzgerald Gerald F. , Devery Rosaleen , Stanton Catherine 
Published: December 2011

AbstractConjugated fatty acids are regularly found in nature and have a history of biogenic activity in animals and humans. A number of these conjugated fatty acids are microbially produced and have been associated with potent anti‐carcinogenic, anti‐adipogenic, anti‐atherosclerotic and anti‐diabetogenic activities. Therefore, the identification of novel conjugated fatty acids is highly desirable. In this study, strains of bifidobacteria and propionibacteria previously shown by us and others to display linoleic acid isomerase activity were assessed for their ability to conjugate a range of other unsaturated fatty acids during fermentation. Only four, linoleic, α‐linolenic, γ‐linolenic and stearidonic acids, were converted to their respective conjugated isomers, conjugated linoleic acid (CLA), conjugated α‐linolenic acid (CLNA), conjugated γ‐linolenic acid (CGLA) and conjugated stearidonic acid (CSA), each of which contained a conjugated double bond at the 9,11 position. Of the strains assayed, Bifidobacterium breve DPC6330 proved the most effective conjugated fatty acid producer, bio‐converting 70% of the linoleic acid to CLA, 90% of the α‐linolenic acid to CLNA, 17% of the γ‐linolenic acid to CGLA, and 28% of the stearidonic acid to CSA at a substrate concentration of 0.3 mg mL−1. In conclusion, strains of bifidobacteria and propionibacteria can bio‐convert linoleic, α‐linolenic, γ‐linolenic and stearidonic acids to their conjugated isomers via the activity of the enzyme linoleic acid isomerase. These conjugated fatty acids may offer the combined health promoting properties of conjugated fatty acids such as CLA and CLNA, along with those of the unsaturated fatty acids from which they are formed.
Aberrations in Plasma Phospholipid Fatty Acids in Lung Cancer Patients
Authors: Murphy Rachel A. , Bureyko Taylor F. , Mourtzakis Marina , Chu Quincy S. , Clandinin M. Thomas , Reiman Tony , Mazurak Vera C. 
Published: December 2011

AbstractAbnormalities in lipid metabolism have been frequently observed in cancer and are associated with a poor prognosis. However, a detailed, longitudinal characterization of fatty acid status is lacking. This study aimed to assess plasma phospholipid fatty acids before chemotherapy, immediately after and 1 month following chemotherapy in a group of 50 patients newly diagnosed with lung cancer and explore factors which may contribute to aberrations in fatty acids. Their mean ± SD characteristics: age 64 ± 8.5 years, 75% advanced stage disease, body mass index 27.0 ± 5.4 kg/m2, 6 month weight loss −4.6 ± 6.1%. Compared to patients with early stage disease, patients with advanced disease had abnormal fatty acid profiles including significantly lower (P < 0.05) amounts of total phospholipid fatty acids, saturated, and polyunsaturated fatty acids (linoleic, arachidonic, eicosapentaenoic and docosahexaenoic). Longitudinal analysis revealed that patients with advanced disease who completed chemotherapy had stable fatty acid levels and continued to maintain levels 1 month following completion of chemotherapy. Comparatively, patients who did not complete chemotherapy due to toxicity or disease progression had progressive loss of total phospholipid fatty acids, stearic, linoleic and n‐6 fatty acids and a trend towards lower docosahexaenoic, arachidonic, palmitic, n‐3 and saturated fatty acids. These results suggest that loss of fatty acids is prevalent, progressive and potentially influenced by advanced disease and chemotherapy treatment.