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  • 1995-1999  (787)
  • 1995  (787)
  • Engineering  (787)
  • Nuclear reactions
  • 1
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 74-74 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 77-94 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A two-dimensional lossy shunt TLM node is incorporated into a TLM system and adapted to model for the first time the Maxwell field equations in thin semiconductor samples. Both the characteristics of the node and the TLM system itself are fully described. By considering a parallel-plate structure containing a thin GaAs sample, driven by a voltage source, it is shown, with an example, that this TLM technique can simulate the response of non-stationary electromagnetic fields in a semiconductor to applied excitations.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 149-149 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 315-330 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Transmission-line laser models (TLLMs) are time-domain models suitable for the simulation of complex phenomena in semiconductor lasers. TLLMs include time-domain filters based on transmission-line stubs to model the spectral dependence of the material gain. In this paper, numerical simulations are presented which show that the accuracy of these gain models is dependent on the model's iteration timestep. Analytical formulae are derived that relate the accuracy of the filters to the timestep, filter centre frequency, and filter bandwindth. A new wideband stub filter which allows the material gain to be modelled using a larger timestep is presented. This is equivalent to a digital infinite-impulse-response filter, which is more computationally efficient than finite-impulse-response filters, and is unconditionally stable. The new gain model can improve the computational speed for simulating for multimode Fabry-Perot lasers by a factor of 10-100.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 383-383 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995) 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 221-232 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper describes a parallel three-dimensional finite difference time-domain (FDTD) code for electromagnetic field simulation that has been developed for the Connection Machine (CM-2). The CM-2 is briefly discussed. Then the FDTD method is reviewed using a one-dimensional example, and the extensions required for the 3-D case are outlined. The parallelization of the FDTD method is considered, and a simple analytical timing model is dervied. This model predicts the efficiency of the parallelized algorithm as a function of grain size. Some specific points relating to the implementation of the parallel FDTD algorithm in Fortrans-90 on the CM-2 are discussed. Timing data for the parallel 3-D FDTD code measured on a CM-2 is presented and compared qualitatively with the theoretical model. These results are then put into perspective for a particular computations electromagnetics problem, viz. the development of software tools for full-wave modelling of 3-D optical devices. Finally, we draw some conclusions about this work.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 455-455 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 447-454 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A novel procedure for synthesizing multilayered radar absorbing materials (RAMs) is presented. The procedure uses a method for global minimization of multimodal functions of continuous variables based on simulated annealing (SA). The technique is very flexible and reliable, allowing the design of absorbing materials for any grazing or normal angles over the specified frequency bandwidth. The technique is particularly suitable for the efficient design of broadband RAMs and hence for EMC applications.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 187-203 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This document describes the background and motivation behind the PEPSE project. It describes separately the components which make up PEPSE, the parallel design philosophy and aspects of parallel implementation.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 382-383 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 417-429 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The scattering of conducting regular polyhedrons of resonant size is studied by means of the electrical field integral equation (EFIE) and the method of moments (MoM). Two models are generated for each polyhedron, a wire grid model and a triangular patch model. Two numerical codes associated with those modelling techniques are used to obtain the radar cross section (RCS) of the polyhedrons. The calculated results are compared with the analytical results of the scattering of a perfectly conducting sphere. Practical criteria relating geometric properties of the sphere and the polyhedrons are investigated for the modelling of curved surfaces by facets in electromagnetic simulations.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 431-445 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The paper presents the application of nonlinear neural optimization networks to solve the linear complementarity problem. Two different approaches are presented and investigated: one leading to linear and the second to quadratic optimization programming. The numerical results of illustrative examples are given and discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995) 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 3-12 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper details the use of a circuit-based EM modelling technique combined with a harmonic balance simulator used to model the radiation from the microstrip bodies comprising an active antenna circuit. The modelling approach adopted for the planar bodies in the circuit will be shown to allow the use of concurrent algorithms in order to reduce overall computational time.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 13-27 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper presents an analysis of the numerical algorithms used to model microwave semiconductor devices. A comparison is made of the relative merits and features of the more popular finite difference schemes. A new generalized Scharfetter-Gummel formulation is presented which is compatible with drift diffusion and energy-transport formulations, and is suitable for implementing in two-dimensional simulations on personal computers. The treatment allows for fully degenerate semiconductors, but implementation for the nondegenerate situation is easily obtained as a special case. The convergence and stability properties of the generalized scheme are discussed. The simulation of a planar submicrometre gate length GaAs MESFET is used to illustrate the application of these algorithms.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 367-379 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The behaviours of parasitic bipolar transistors are investigated by exploring the physical mechanisms of negative resistance characteristics generated in a small-sized MOSFET structure. Physical experiments and three-dimensional simulations verify the expected negative resistance characteristics. The effects of variations of device parameters such as injected substrate current levels, doping concentrations, channel widths, and physical device sizes are investigated by simulation. According to simulation results, the operation of a parasitic bipolar transistor is initiated by the injected substrate current; this explains the negative resistance characteristics occurring at low operating voltages.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 243-248 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Two separate exercises on a similar theme are reported. In the first, the moment-method program NEC was extensively modified in order to optimize its performance on a four-processor Cray X-MP computer. In the second exercise, the MININEC moment-method program was completely rewritten into the occam programming language so that it could be executed directly by a transputer system. The NEC exercise exploited judicious use of vectorization and alternative parallelization techniques and achieved a reduction of run times by factors of about five or more. The MININEC exercise has so far achieved only a modest reduction in run-time but it has the potential for a much greater improvement if an optimum strategy for configuring the transputer network is implemented.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 277-281 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A parallel implementation of the finite difference time-domain algorithm for the analysis of planar microwave circuits is presented in this paper. For this the FDTD mesh is divided in equal-sized subspaces. Every processor of the parallel computer calculates the field in one subspace. Furthermore detailed efficiency investigations are made to predict the timing performance of the parallel FDTD simulator.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 293-299 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In this paper a parallel algorithm is created for solving electromagnetic wave scattering problems. The algorithm based on the finite difference time-domain (FDTD) representation of the Maxwell's equations written in 3L Parallel Fortran for use on a transputer array.The problem simulated consists of a space (air) where a spherical dielectric scatterer is located. This space is subdivided into fine equisize meshes extending throughout the 3-D domain; the excitation wave is of sinusoidal form. Geometric decomposition is used as the principal algorithm strategy.Results are presented for the performance of the classical sequential algorithm and compared with the parallel algorithm in terms of computational speed-up.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 385-398 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A typical application of numerical frequency-domain computations is the calculation of electromagnetic fields in cavities. Not only the field vectors of the desired modes, but also parameters such as the resonance frequency and, in the lossy case, the damping coefficient and the quality factor of the cavity can be obtained. This problem leads to an analytical eigenvalue equation, which can be transformed in an algebraic, complex, linear eigenvalue problem by the finite integration method.The consideration of energy losses in materials is straighforward in the analytical theory, using complex material quantities, but it is still a difficult subject area to solve a complex algebraic eigenvalue problem. Generally problems with very large, complex matrices (dimension 〉100,000) have to be solved, and no commonly applicable algorithm is known so far.This paper deals with a special variant of subspace iteration with polynomial acceleration, and some problems of the application of the complex Chebyshev polynomials are discussed. Two examples with weakly lossy cavities demonstrate the capability of the new algorithm, which is successfully applied to very large problems of up to 490, 000 real unknowns.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 265-275 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Parallel algorithms for the finite difference time-domain (FDTD), the planar generalized Yee (PGY), and the finite element time-domain (FETD) methods are presented. The FDTD and the PGY algorithms are both explicit time-domain solutions of Maxwell's equations, while the PGY algorithm is based on an unstructured grid. The FETD algorithm is a semi-implicit solution of Maxwell's equations using variational principles, and thus requires a matrix inversion for every time iteration. The three parallel algorithms are based on spatial decompositions of the discrete three-dimensional problem spaces. A comparative analysis of the parallel algorithms is presented based on their memory and computational efficiency as well as their parallel efficiency.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 313-313 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 381-381 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 399-416 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A non-stationary longitudinal model of a thermal two-component plasma is investigated with numerical methods based on so-called high-resolution schemes. The inhomogeneous model system is solved numerically applying a splitting method, where the homogeneous conservation laws for the electrons and ions are approximated by explicit Godunov-type schemes. Coupling of both plasma components is achieved by the electric field, which is also calculated in an explicit manner after reformulating Coulomb's law. A new numerical method is proposed for the expansion of the plasma into the vacuum. This tracking method is based on the solution of the vacuum Riemann problem and avoids the difficulties of numerical approximation introduced by the vacuum where the longitudinal plasma model is not valid. This new approach of tracking resolves sharply the plasma vacuum interface and captures this boundary very well during the temporal evolution of the model system. Two test problems show the interplay, the quality and properties of the approximation methods applied.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995) 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 153-168 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In electromagnetics, a numerical technique that finds immense application is the method of moments. This method reduces the boundary value problem containing integro-differential equations into the form AX = Y, where A is a full complex matrix, that is known and X is the unknown to be solved for the given excitation Y. In this paper, the matrix equation has been solved on various computers such as the VAX 3500, VAX 8530, Multimax 320, Alliant FX/80 and IBM 3090-600E. Two of the established methods, viz. gaussian elimination and the conjugate gradient method have been used to solve the above matrix equations. A detailed timing analysis has been done to bring out the features of various computer architectures.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 233-242 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper examines the use of parallel processing techniques for the electromagnetic field analysis of multilayered microwave interconnects. These techniques are applied to a full-wave formulation using an integral equation approach in the frequency domain. In order to demonstrate the feasibility of parallelization and to assess its performance advantages, several variations of the computer code have been developed. Performance tests using domain partitioning and load balancing were conducted on a 32-processor shared-memory machine (KSR1).
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 249-263 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The planar generalized Yee (PGY) algorithm is an extension of the generalized Yee algorithm and the discrete surface integral (DSI) methods, which are based on explicit time-marching solutions of Maxwell's equations. Specifically, the PGY algorithm exploits the planar symmetries of printed microwave circuit devices, achieving great savings in both CPU time and memory. Since the PGY algorithm is an explicit method, it has a high degree of parallelism. To this end, a highly scalable parallel algorithm based on a spatial decomposition of the general unstructured mesh is presented. Two spatial decompositions are compared, the recursive inertia partitioning (RIP) algorithm and the Greedy algorithm. The Greedy algorithm provides optimal load balance, whereas the RIP algorithm more effectively minimizes shared boundary interface lengths. Through numerical examples, It is demostrated that the Greedy algorithm provides superior speedups. It is also demonstrated that the parallel PGY algorithm is a highly scalable algorithm.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 283-291 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The finite difference time-domain (FDTD) method is a well known numerical technique that has been used to solve electromagnetic boundary value problems. However, the method requires large computational resources to solve a problem, restricting its use on sequential computers to small problems.This has led to the use of expensive supercomputers in the past to solve larger problems. In this paper we first discuss existing parallel implementations of the FDTD method. We then describe an approach to compute the FDTD equations based on distributed- memory computer architectures. Finally we evaluate a low-cost parallel implementation of the FDTD method that runs on a network of Workstations, utilizing spare network capacity.
    Zusätzliches Material: 6 Ill.
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  • 31
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 301-312 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In this paper, the potential use of cellular automata machines for electromagnetic field solution is investigated. Cellular automata are computational models that operate on a discrete spatial lattice, evolve in discrete time, and employ simple discrete variables. We specifically examine the lattice gas automata which use simple variables to describe particles that interact with nearest neighbours on the lattice through simple rules. They are suitable for modelling the linear wave equation in two dimensions. A benefit of the cellular automata approach is that low-cost, special-purpose digital hardware exists for their efficient evaluation. The current state-of-the-art cellular automata machine is CAM-8. Computational experiments carried out on CAM-8 are provided for problems involving plane wave interaction with perfectly conducting and dielectric media in two dimensions. The examples indicate the potential use of lattice gas automata for modelling electromagnetics and their efficient evaluation using cellular automata machines.
    Zusätzliches Material: 7 Ill.
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  • 32
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 73-73 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995) 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 109-125 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper describes a computer program for generating finite element meshes for electron guns. Two new methods, the ‘projection’ and the ‘mesh density function’ methods, are used to generate the mesh. The new methods enable the mesh distribution to be set smothly and changed easily, and also enable the mesh distribution to be adjusted according to parameters associated with the gun configuration or by feedback from the electric field calculation. The new program, which can handle a large variety of complicated electron gun structures, has been used in conjunction with the SOGUN program which has been developed by Zhu and Munro for electron gun simulation.
    Zusätzliches Material: 14 Ill.
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  • 35
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995) 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 341-356 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A novel transmission-line model for the minority carrier transport through quasi-neutral arbitrarily doped layers is proposed. Based on detailed drift-diffusion equations, the novel TLEC includes the inductance that represents the influence of the relaxation-time term. Coupled with a object-orientated hybrid circuit simulator, the novel transmission-line model is implemented for the transient analysis of minority carrier transport. A substantial longer storage time of the minority carrier transient current at the collector end of ultra-narrow base is predicted owing to inclusion of the relaxation-time term.
    Zusätzliches Material: 10 Ill.
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  • 37
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 151-151 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 169-185 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper describes the implementation of transmission-line matirix (TLM) method algorithms on a massively parallel computer (DECmpp 12000), the technique of distributed computing in the UNIX environment, and the combination of TLM analysis with Prony's method as well as with autoregressive moving average (ARMA) digital signal processing for electromagnetic field modelling. By combining these advanced computation techniques, typical electromagnetic field modelling of microwave structures by TLM analysis can be accelerated by a few orders of magnitude.
    Zusätzliches Material: 10 Ill.
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  • 39
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 205-219 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: PMC-3D, a parallel three-dimensional (3-D) Monte Carlo device simulator for multicomputers is discussed. The parallel algorithm is and extension of the standard Monte Carlo device simulation model in three dimensions, that combines the stockastic Monte Carlo particle simulation method with a solution of Poisson equation for quasi-static problems, and full Maxwell's equations for microwave or electro-optic phenomena. While our implementation of the Poisson solver is based on an iterative method that uses and odd/even ordering with Chebyshev acceleration, a simple leapfrog method based upon the computational unit of Yee cell is used in a finite-difference, time-domain (FDTD) formulation to solve Maxwell's equations.The parallel algorithms were implemented on a 1024-node distributed memory nCUBE multicomputer. In this work, we present the application of PMC-3D to generate the static current-Voltage characteristics of GaAs MESFET, and to simulate photogenerated femtosecond electrical transients produced in coplanar stripline on a GaAs substrate.
    Zusätzliches Material: 10 Ill.
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  • 40
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 51-60 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Simulators in power electronics are less developed than in other electronic fields. The main modelling methods are between the numerical simulation of semiconductor device equations that hardly simulate circuits, and equivalent circuit models that show poor accuracy. We propose the application of the bond graph techniques to model modular power semiconductor devices. Furthermore, the IGBT is a new power device which combines a bipolar transistor with a MOSFET transistor. We develop a new IGBT bond graph model. The bond graph techniques give us good primary simulation results. We present in this paper the principle and the results of this modelling method.
    Zusätzliches Material: 16 Ill.
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  • 41
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 75-75 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 127-137 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Regular boundary integral elements are employed for the dual and complementary variational formulations of Laplace problems. The problems are defined only on the boundary as usual, but as in the manner of charge simulation method (CSM), the source terms are arranged outside the domain so that the singular integral can be avoided. The Laplace problems are analysed and the usefulness of the formulation is discussed in comparison with direct BEM. The scalar potential and electric displacement vector potential functions are used in the dual and complementary formulations, with which the upper and lower bounds of the system energy or the capacitance can also accurately be evaluated.
    Zusätzliches Material: 10 Ill.
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  • 43
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 150-150 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 357-366 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The Transmission line modelling (TLM) technique was used to simulate the class E power amplifier. An analytical method is also used to fix the required component values to ensure the desired output performance of the amplifier. An experiment was carried out to verify the simulation result of the combined method.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 1-1 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 29-49 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper describes a phase model of an induction motor based on Transmission-Line Modelling technique. Its main advantage compared to the existing TLM d-q model is the possibility of using a small part of the stator self-inductance of each pahase as a link model to connect the motor to external sources and drives. Unlike the d-q model, the phase model does not therefore require any additional components for connection purposes. The application of the phase model is demonstrated by and example representing a traction drive ciruit. Identical simulation results to those obtained from a different study based on a d-q model are derived.
    Zusätzliches Material: 25 Ill.
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  • 47
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 61-71 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An analogy is described between the TLM algorithm and discrete state-space control theory. The analogy is used to derive the characteristic equations corresponding to parametrized model structures. Characteristic equations corresponding to several widely used node structures are derived by this means and found to be consistent with the observed behaviour of corresponding TLM models. An example is given of the use of the analogy in teh predictive mode.
    Zusätzliches Material: 5 Ill.
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  • 48
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 95-107 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In this work, we show the implementation of two explicit three-dimensional finite-difference beam propagation methods (BPM) on two different parallel computers, namely a transputer array and a Connection Machine (CM). To assess the performance of using parallel computers, serial computer codes of the two methods have ben implemented and a comparison between the speed of the serial and paralledl codes has been made. Large gains in the speed of the paralled FD-BPMs has been obtained compared to the serial implementations. In addition, a comparison between the performance of the transputer array and the CM in executing the two FD-BPMs has been discussed. Finally, to assess and compare the two methods, three different rib waveguides and three different directional couplers have been analysed and the results compared with published results.
    Zusätzliches Material: 6 Ill.
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  • 49
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 139-147 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper presents a circuit-based model of a current carrying conductor that can provide instantaneous ohmic losses under surge conditions. The model is frequency independent and can be used to calculate transient current characteristics of surges on overhead transmission lines. The theoretical current distribution under lightning surge conditions is used to demonstrate the validity of the model and the results are compared with values obtained using a finite element analysis package. There is a good correlation between the two methods with the circuit-based model having the advantages of being less cumbersome, requiring shorter computation time and being simple to implement in transient analysis packages.
    Zusätzliches Material: 7 Ill.
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  • 50
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 8 (1995), S. 331-340 
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper presents a new method in TLM for very efficient computation of highly conducting thin shielding walls. Firstly, the impulse response of a finite conducting sheet is computed analytically via inverse Laplace transform. Subsequently, a recursive convolution integral is formulated with the analytical impulse response. This allows a very efficient and accurate calculation of the diffusion process through imperfectly conducting walls.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 415-429 
    ISSN: 1070-5325
    Schlagwort(e): indefinite ; inverse ; preconditioning ; symmetric ; Toeplitz ; Trench algorithm ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: A modification is presented of the classical O(n2) algorithm of Trench for the direct solution of Toeplitz systems of equations. The Trench algorithm is stable for symmetric matrices that are positive definite, but can be unstable for the indefinite case (and for general matrices). Our modification permits extension of the algorithm to compute approximate inverses of indefinite symmetric Toeplitz matrices, for which the unmodified algorithm breaks down when principal submatrices are singular. As a preconditioner, the approximate inverse has an advantage that only matrix - vector multiplications are required for the solution of a linear system, without forward and backward solves. The approximate inverse so obtained can be sufficiently accurate, moreover, that, when it is used as a preconditioner for the applications investigated, subsequent iteration may not even be necessary. Numerical results are given for several test matrices. The perturbation to the original matrix that defines the modification is related to a perturbation in a quantity generated in the Trench algorithm; the associated stability of the Trench algorithm is discussed.
    Zusätzliches Material: 1 Tab.
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  • 52
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 483-485 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 447-465 
    ISSN: 1070-5325
    Schlagwort(e): preconditioned iterative methods ; SSOR factorization ; parallelization ; connection machine ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: A class of parallelizable preconditioned iterative methods for the solution of certain finite difference or finite element linear systems of equations is presented. The methods are based on calculation of approximate inverses of the SSOR factorization. The speed of the methods may be increased by making the approximation of the inverse more accurate. The construction of the preconditioning as well as the solution of the preconditioning systems (realized by matrix-vector multiplication) can be made in parallel over the total amount of meshpoints. The methods are suitable for implementation on massively parallel computers such as connection machines. Problems with constant as well as strongly varying orthotropy are examined and the methods are compared to other parallel techniques with respect to rate of convergence, computational complexity and consumed CM200 computing time. We report a small but significant decrease in computing time compared to the (until now) most frequently used completely parallel preconditioning, the Jacobi method.
    Zusätzliches Material: 7 Ill.
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  • 54
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 533-541 
    ISSN: 1070-5325
    Schlagwort(e): plane rotation ; shear product ; Saxpy operation ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: An algorithm for pre- or post-multiplication of a matrix by a plane rotation, using only three vector saxpy operations instead of the four vector operations usually considered necessary, is described. No auxiliary storage for overwriting is required. The method is shown to be numerically stable.
    Zusätzliches Material: 6 Tab.
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  • 55
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 487-505 
    ISSN: 1070-5325
    Schlagwort(e): biharmonic equation ; rectangular finite elements ; preconditioning ; multilevel methods ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Recently, some new multilevel preconditioners for solving elliptic finite element discretizations by iterative methods have been proposed. They are based on appropriate splittings of the finite element spaces under consideration, and may be analyzed within the framework of additive Schwarz schemes. In this paper we discuss some multilevel methods for discretizations of the fourth-order biharmonic problem by rectangular elements and derive optimal estimates for the condition numbers of the preconditioned linear systems. For the Bogner-Fox-Schmit rectangle, the generalization of the Bramble-Pasciak-Xu method is discussed. As a byproduct, an optimal multilevel preconditioner for nonconforming discretizations by Adini elements is also derived.
    Zusätzliches Material: 3 Ill.
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  • 56
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 87-93 
    ISSN: 1070-5325
    Schlagwort(e): QR algorithm ; zero pattern ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The QR algorithm is a basic algorithm for computing the eigenvalues of dense matrices. For efficiency reasons it is prerequisite that the algorithm is applied only after the original matrix has been reduced to a matrix of a particular shape, most notably Hessenberg and tridiagonal, which is preserved during the iterative process. In certain circumstances a reduction to another matrix shape may be advantageous. In this paper, we identify which zero patterns of symmetric matrices are preserved under the QR algorithm.
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  • 57
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 95-113 
    ISSN: 1070-5325
    Schlagwort(e): arrowhead matrix ; band matrix ; inverse eigenvalue problem ; givens rotations ; singular value decomposition ; updating ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Various plane rotation patterns are presented, which provide stable algorithms for reducing a b-band matrix bordered by p rows and/or columns to (b + p)-band form. These schemes generalize previously presented O(N2) reduction algorithms for matrices of order N, b = 1, and p = 1 to the reduction of more general b-band, p-bordered matrices where b ≥ 1 and p ≥ 1. Moreover, by splitting the matrix into two similarly structured submatrices and chasing nonzeros to the corners in two directions, the newly proposed patterns reduce the number of required rotations and hence the computational cost by one half compared to the other existing one-way chasing algorithms. Symmetric, as well as more general matrices, are considered. An example of the first type is the symmetric arrowhead matrix that arises in solving inverse eigenvalue problems. Examples of the second type are found in updating the singular value decomposition (SVD) and the partial SVD.
    Zusätzliches Material: 7 Ill.
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  • 58
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 243-250 
    ISSN: 1070-5325
    Schlagwort(e): Cholesky ; norm inequality ; perturbation ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We show that a certain matrix norm ratio studied by Parlett has a supermum that is O(\documentclass{article}\pagestyle{empty}\begin{document}$\mathop \[\sqrt n \] $\end{document}) when the chosen norm is the Frobenius norm, while it is O(log n) for the 2-norm. This ratio arises in Parlett's analysis of the Cholesky decomposition of an n by n matrix.
    Zusätzliches Material: 1 Ill.
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  • 59
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 271-286 
    ISSN: 1070-5325
    Schlagwort(e): linear least squares ; backward perturbations ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Let A be an m × n matrix, b be an m-vector, and x̃ be a purported solution to the problem of minimizing ‖b  -  Ax‖2. We consider the following open problem: find the smallest perturbation E of A such that the vector x̃ exactly minimizes ‖b  -  (A+E)x‖2. This problem is completely solved when E is measured in the Frobenius norm. When using the spectral norm of E, upper and lower bounds are given, and the optimum is found under certain conditions.
    Zusätzliches Material: 1 Tab.
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  • 60
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 287-296 
    ISSN: 1070-5325
    Schlagwort(e): block Hessenberg matrix ; block Toeplitz matrix ; linear system ; queue ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: This paper describes a divide-and-conquer strategy for solving block Hessenberg systems. For dense matrices the method is as efficient as Gaussian elimination; however, because it works almost entirely with the original blocks, it is much more efficient for sparse matrices or matrices whose blocks can be generated on the fly. For Toeplitz matrices, the algorithm can be combined with the fast Fourier transform.
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  • 61
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. ii 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 62
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 507-531 
    ISSN: 1070-5325
    Schlagwort(e): Cholesky decomposition ; singular values ; eigenvalues ; null spaces ; noise spaces ; URV and ULV factorizations ; QR algorithm ; LR algorithm ; Jacobi methods ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The implicit Cholesky algorithm has been developed by several authors during the last 10 years but under different names. We identify the algorithm with a special version of Rutishauser's LR algorithm. Intermediate quantities in the transformation furnish several attractive approximations to the smallest singular value.The paper extols the advantages of using shifts with the algorithm. The nonorthogonal transformations improve accuracy.
    Zusätzliches Material: 4 Ill.
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  • 63
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 543-545 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 64
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 115-133 
    ISSN: 1070-5325
    Schlagwort(e): Krylov subspace ; Lanczos process ; symmetric matrix ; conjugate gradients ; minimum residual ; Lehmann intervals ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Approximations to the solution of a large sparse symmetric system of equations are considered. The conjugate gradient and minimum residual approximations are studied without reference to their computation. Several different bases for the associated Krylov subspace are used, including the usual Lanczos basis. The zeros of the iteration polynomial for the minimum residual approximation (harmonic Ritz values) are characterized in several ways and, in addition, attractive convergence properties are established. The connection of these harmonic Ritz values to Lehmann's optimal intervals for eigenvalues of the original matrix appears to be new.
    Zusätzliches Material: 3 Ill.
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  • 65
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 155-171 
    ISSN: 1070-5325
    Schlagwort(e): condition number ; norm of a matrix ; matrix completion ; dilation theory ; robust regularization of descriptor systems ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We study the problem of minimizing the norm, the norm of the inverse and the condition number with respect to the spectral norm, when a submatrix of a matrix can be chosen arbitrarily. For the norm minimization problem we give a different proof than that given by Davis/Kahan/Weinberger. This new approach can then also be used to characterize the completions that minimize the norm of the inverse. For the problem of optimizing the condition number we give a partial result.
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  • 66
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 191-194 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 173-190 
    ISSN: 1070-5325
    Schlagwort(e): block algorithm ; LAPACK ; level 3 BLAS ; iterative refinement ; LU factorization ; backward error analysis ; block diagonal dominance ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Many of the currently popular ‘block algorithms’ are scalar algorithms in which the operations have been grouped and reordered into matrix operations. One genuine block algorithm in practical use is block LU factorization, and this has recently been shown by Demmel and Higham to be unstable in general. It is shown here that block LU factorization is stable if A is block diagonally dominant by columns. Moreover, for a general matrix the level of instability in block LU factorization can be bounded in terms of the condition number K(A) and the growth factor for Gaussian elimination without pivoting. A consequence is that block LU factorization is stable for a matrix A that is symmetric positive definite or point diagonally dominant by rows or columns as long as A is well-conditioned.
    Zusätzliches Material: 4 Tab.
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  • 68
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 135-153 
    ISSN: 1070-5325
    Schlagwort(e): orthogonal projection ; numerical rank ; total least squares ; rank revealing QR factorization ; acute perturbation ; subspace angle ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Overdetermined linear systems often arise in applications such as signal processing and modern communication. When the overdetermined system of linear equations AX ≍ B has no solution, compatibility may be restored by an orthogonal projection method. The idea is to determine an orthogonal projection matrix P by some method M such that [à B̃] = P[A B], and ÃX = B̃ is compatible. Denote by XM the minimum norm solution to ÃX = B̃ using method M. In this paper conditions for compatibility of the lower rank approximation and subspace properties of à in relation to the nearest rank-k matrix to A are discussed. We find upper and lower bounds for the difference between the solution XM and the SVD-based total least squares (TLS) solution XSVD and also provide a perturbation result for the ordinary TLS method. These results suggest a new algorithm for computing a total least squares solution based on a rank revealing QR factorization and subspace refinement. Numerical simulations are included to illustrate the conclusions.
    Zusätzliches Material: 4 Tab.
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  • 69
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995) 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 70
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 195-203 
    ISSN: 1070-5325
    Schlagwort(e): Jacobi matrix ; arrow matrix ; inverse problem ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We consider the problem of reconstructing Jacobi matrices and real symmetric arrow matrices from two eigenpairs. Algorithms for solving these inverse problems are presented. We show that there are reasonable conditions under which this reconstruction is always possible. Moreover, it is seen that in certain cases reconstruction can proceed with little or no cancellation. The algorithm is particularly elegant for the tridiagonal matrix associated with a bidiagonal singular value decomposition.
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  • 71
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 235-241 
    ISSN: 1070-5325
    Schlagwort(e): interior-point methods ; trust regions ; conic functions ; conjugate gradients ; linear programming ; nonlinear minimization ; Karmarkar's algorithm ; centering ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: An optimization method is developed based on ellipsoidal trust regions that are defined by conic functions. It provides a powerful unifying theory from which can be derived a variety of interesting and potentially useful optimization algorithms, in particular, conjugate-gradient-like algorithms for nonlinear minimization and Karmarkar-like interior-point algorithms for linear programming.
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  • 72
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 219-234 
    ISSN: 1070-5325
    Schlagwort(e): nonsymmetric matrices ; sparse matrices ; eigenvalue problem ; EISPACK ; LAPACK ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: With the growing demands from disciplinary and interdisciplinary fields of science and engineering for the numerical solution of the nonsymmetric eigenvalue problem, competitive new techniques have been developed for solving the problem. In this paper we examine the state of the art of the algorithmic techniques and the software scene for the problem. Some current developments are also outlined.
    Zusätzliches Material: 2 Tab.
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  • 73
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 251-269 
    ISSN: 1070-5325
    Schlagwort(e): eigenvalues ; eigenvectors ; symmetric matrices ; Rayleigh quotient iteration ; convergence ; basins of attraction ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The Rayleigh quotient iteration method finds an eigenvector and the corresponding eigenvalue of a symmetric matrix. This is a fundamental problem in science and engineering. Parlett and Kahan have shown, in 1968, that for almost any initial vector in the unit sphere, the Rayleigh quotient iteration method converges to some eigenvector. In this paper, the regions of the unit sphere which include all possible initial vectors converging to a specific eigenvector are studied. The generalized eigenvalue problem Ax = λBx is considered. It is shown that the regions do not change when the matrix is shifted or multiplied by a scalar. These regions are completely characterized in the three-dimensional case. It is shown that, in this case, the area of the region of convergence corresponding to the interior eigenvalue is larger than the area of those corresponding to any extreme one. This can be interpreted, with the appropriate choice of probability distribution, as: the probability of converging to an eigenvector corresponding to the interior eigenvalue is larger than the probability of converging to an eigenvector corresponding to any extreme eigenvalue. It is conjectured that the same is true for matrices of any order. Experiments in higher dimensions are presented which conform with the conjecture.
    Zusätzliches Material: 7 Ill.
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  • 74
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 205-217 
    ISSN: 1070-5325
    Schlagwort(e): Lanczos method ; spectral Lanczos ; decompostion method ; eigenpairs ; matrix functions ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: Many researchers are now working on computing the product of a matrix function and a vector, using approximations in a Krylov subspace. We review our results on the analysis of one implementation of that approach for symmetric matrices, which we call the spectral lanczos decomposition method (SLDM).We have proved a general convergence estimate, relating SLDM error bounds to those obtained through approximation of the matrix function by a part of its Chebyshev series. Thus, we arrived at effective estimates for matrix functions arising when solving parabolic, hyperbolic and elliptic partial differential equations. We concentrate on the parabolic case, where we obtain estimates that indicate superconvergence of SLDM. For this case a combination of SLDM and splitting methods is also considered and some numerical results are presented.We implement our general estimates to obtain convergence bounds of Lanczos approximations to eigenvalues in the internal part of the spectrum. Unlike Kaniel-Saad estimates, our estimates are independent of the set of eigenvalues between the required one and the nearest spectrum bound.We consider an extension of our general estimate to the case of the simple Lanczos method (without reorthogonalization) in finite computer arithmetic which shows that for a moderate dimension of the Krylov subspace the results, proved for the exact arithmetic, are stable up to roundoff.
    Zusätzliches Material: 1 Ill.
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  • 75
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 311-312 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 76
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 313-315 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 77
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 297-310 
    ISSN: 1070-5325
    Schlagwort(e): dynamical systems ; eigenvalues ; QR algorithm ; Francis shift ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: For many years techniques from numerical analysis have been applied fruitfully to the study of dynamical systems. In this paper it is shown that the theory of dynamical systems may be applied to certain computational problems. In particular the question of global convergence of various QR algorithms can be reduced to the study of certain vector iterations derived from Schur forms of matrices. The technique is illustrated in determining the convergence behavior of normal Hessenberg matrices under the Francis and multishift QR iterations.
    Zusätzliches Material: 3 Ill.
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  • 78
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995) 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 79
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 335-346 
    ISSN: 1070-5325
    Schlagwort(e): multisplittings ; overlapping ; comparison results ; M-matrices ; waveform relaxation ; parallel algorithms ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: We show that certain multisplitting iterative methods based on overlapping blocks yield faster convergence than corresponding nonoverlapping block iterations, provided the coefficient matrix is an M-matrix. This result can be used to compare variants of the waveform relaxation algorithm for solving initial value problems. The methods under consideration use the same discretization technique, but are based on multisplittings with different overlaps. Numerical experiments on the Intel iPSC/860 hypercube are included.
    Zusätzliches Material: 2 Tab.
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  • 80
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 317-334 
    ISSN: 1070-5325
    Schlagwort(e): envelope reduction ; eigenvalues of graphs ; Gibbs - King algorithm ; Gibbs - Poole - Stockmeyer algorithm ; Laplacian matrices ; reordering algorithms ; reverse Cuthill - McKee algorithm ; sparse matrices ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: The problem of reordering a sparse symmetric matrix to reduce its envelope size is considered. A new spectral algorithm for computing an envelope-reducing reordering is obtained by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. This Laplacian eigenvector solves a continuous relaxation of a discrete problem related to envelope minimization called the minimum 2-sum problem. The permutation vector computed by the spectral algorithm is a closest permutation vector to the specified Laplacian eigenvector. Numerical results show that the new reording algorithm usually computes smaller envelope sizes than those obtained from the current standards such as the Gibbs - Poole - Stockmeyer (GPS) algorithm or the reverse Cuthill - McKee (RCM) algorithm in SPARSPAK, in some cases reducing the envelope by more than a factor of two.
    Zusätzliches Material: 5 Ill.
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  • 81
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 401-414 
    ISSN: 1070-5325
    Schlagwort(e): conjugate gradient ; distributed computing ; analytic model ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: In this paper, we demonstrate the scalability of the Reduced System Conjugate Gradient (RSCG) algorithm on distributed memory architectures. We present speed-up results obtained on the Intel iPSC/860 that compare one-, two-, and three-dimensional decompositions of the domain for both positive definite and positive semidefinite test problems. We develop a model for the RSCG algorithm to analyze computational and communication costs. The model is validated using experimental data and then used to examine and predict behavior of the RSCG algorithm as a function of architecture parameters including communication latency and transmission times and memory access costs.
    Zusätzliches Material: 2 Ill.
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  • 82
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 481-481 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 83
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995), S. 467-479 
    ISSN: 1070-5325
    Schlagwort(e): generalized conjugate gradient ; orthogonal residual ; rate of convergence ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Notizen: To solve a linear system of equations with a generally nonsymmetric matrix, a generalized conjugate gradientorthogonal residual method is presented. The method uses all previous search directions (or a truncated set of them) at each step but, contrary to standard implementations of similar methods, it requires storage of only one set with a linearly growing number of vectors (or the number in the truncated set). Furthermore, there is only one vector (the residual), which must be updated using all the vectors in this set, at each step. In this respect it is similar to the popular GMRES method but it has the additional advantage that it can stop at any stage when the norm of the residual is sufficiently small and no extra computation is needed to compute this norm. Furthermore, the new method can be truncated.The rate of convergence of the method is also discussed.
    Zusätzliches Material: 3 Tab.
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  • 84
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    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 2 (1995) 
    ISSN: 1070-5325
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik
    Materialart: Digitale Medien
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  • 85
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    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995) 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
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  • 86
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    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. iii 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
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  • 87
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    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 1-11 
    ISSN: 1069-8299
    Schlagwort(e): vibration ; spline prism method ; thick rectangular plate ; 3D elasticity theory ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: The paper presents an application of the spline prism method to analyse vibration of isotropic, thick rectangular plates with two opposite edges simply supported. Three-dimensional spline prism models are formulated by combining B-spline functions with beam eigenfunctions. Because of the orthogonality of the beam functions, three-dimensional problems are reduced to a series of two-dimensional ones. To demonstrate the accuracy and convergence of the semi-numerical method, the results are compared with those obtained by other numerical methods. Good convergence and accuracy are obtained. The effects of the ratio of thickness to width and the aspect ratio on the frequencies of thick rectangular plates with several boundary conditions are analysed, and the results are compared with those calculated by the Mindlin plate theory.
    Zusätzliches Material: 2 Ill.
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  • 88
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 33-40 
    ISSN: 1069-8299
    Schlagwort(e): boundary conditions ; streamfunction-vorticity equations ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: The appropriate specification of boundary conditions is the main difficulty in the finite element solution of the streamfunction-vorticity equations for two-dimensional incompressible laminar flows. In this context, we show that the appropriate specification of both the outflow and the inflow boundary conditions is required for the successful modelling of two well known test problems.
    Zusätzliches Material: 3 Ill.
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  • 89
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    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 13-23 
    ISSN: 1069-8299
    Schlagwort(e): mass transport problems ; error estimation ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: In order to make an exact estimation of discretization error for finite/infinite element methods, it is necessary to develop analytical solutions for some transient mass transport problems in infinite media. These transient mass transport problems may be viewed as the benchmark problems for the discretization error estimation of a new numerical method so that they generally have the following characteristics: (1) their initial and boundary conditions can be exactly modelled by the finite/infinite element method; (2) their solutions can be rigorously expressed in a closed form. In this paper, several of the aforementioned problems have been constructed and solved mathematically for transient mass transport problems in both 1D and 2D infinite media.
    Zusätzliches Material: 7 Ill.
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  • 90
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 25-32 
    ISSN: 1069-8299
    Schlagwort(e): Riccati equation ; transmission line modelling ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: In this communication, the application of the transmission line modelling (TLM) technique to the solution of the differential Riccati equation is described. A comparison is made between the TLM, fourth-order Runge-Kutta and the first-order Gear methods, for the case where one is applying the Kalman filter to the estimation of a voltage in a passive analogue circuit. In the particular example studied, the state equation is second-order. It is found that, when the system is underdamped, the fourth-order Runge-Kutta method has the best performance, followed by the TLM method. When the system is overdamped and stiff, the TLM method yields results that are closest to the analytical solution. Finally, a discussion is presented of the effects of errors in the TLM solution of the Riccati equation on the accuracy of the solution to the continuous Kalman filter estimation equation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 49-58 
    ISSN: 1069-8299
    Schlagwort(e): gears ; fracture mechanics ; service life ; fatigue process ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: The paper describes the influence of contact area on the service life of dynamically loaded gears with a crack in a tooth root. Numerical results obtained with the finite element method using the program package BERSAFE are compared with the experimental results obtained on the universal testing machine INSTRON 1255. Numerical and experimental results are in good agreement. The analysis shows that the contact area directly influences the speed and direction of the crack propagation and the service life of the gear with a crack in a tooth root.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 41-47 
    ISSN: 1069-8299
    Schlagwort(e): shear correction ; laminates ; cylindrical bending hypothesis ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: Mindlin-type plate and shell finite elements are the most widely used ones in the analysis of laminated composite structures. In the commercially available finite element programs, the transverse shear correction factors for these elements are usually the same as for structures made of isotropic materials. In the paper the shear correction factors are determined using energy principles for general laminates in cylindrical bending. Results for various materials and laminates are presented.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 59-68 
    ISSN: 1069-8299
    Schlagwort(e): RLW equation ; finite elements ; splines ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: A B-spline finite element method is used to solve the regularized long wave equation numerically. This approach involves a Galerkin method with quadratic B-spline finite elements so that there is continuity of the dependent variable and its first derivative throughout the solution range. Time integration of the resulting system of ordinary differential equations is effected using a Crank-Nicolson approximation. Standard problems are used to validate the algorithm, which is then used to model the smooth development of an undular bore.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 69-72 
    ISSN: 1069-8299
    Schlagwort(e): finite element method ; thermoplasticity ; internal dissipation ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: In the paper, a simple modification of the internal dissipation term in coupled thermoplastic finite element equations is presented. A modified form of the heat capacity and the thermomechanical coupling matrices are derived. These modifications are based on a decomposition of the internal dissipation term into two parts, which depend on the total strain rate and the rate of temperature change, respectively.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 91-92 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 93-94 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 95-95 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 73-90 
    ISSN: 1069-8299
    Schlagwort(e): circular plate ; viscoelasticity ; equilibrium states ; deformation map ; Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: The geometrically non-linear response of a circular plate is investigated by means of a ‘deformation map’. The plate is subjected to static radial forces and bending moments, both uniformly distributed along the supported edges, in addition to a transverse load. The deformation map gives the complete picture for the investigated structure. The classical formulation of large deformation for the above-mentioned problem goes back to Timoshenko (1940). To create a deformation map, it is necessary to convert the boundary value problem into an initial value problem (Cauchy's problem). The Runge-Kutta (RK) method can then be used to solve numerically the equilibrium equations for the above-mentioned circular plate. In the paper several kinds of transverse loading are considered and their influence on the plate response is examined. It is shown that in some cases the plate's behaviour is chaotic-like (unpredictable), in the sense that various equilibrium states are possible for a certain given set of loads. Yet, it is shown that the viscoelasticity reduces the range of the possible equilibrium states, and thus stabilizes the system.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995) 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. iii 
    ISSN: 1069-8299
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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