11,667 research outputs found
Parallel Computation of Finite Element Navier-Stokes codes using MUMPS Solver
The study deals with the parallelization of 2D and 3D finite element based Navier-Stokes codes using direct solvers. Development of sparse direct solvers using multifrontal solvers has significantly reduced the computational time of direct solution methods. Although limited by its stringent memory requirements, multifrontal solvers can be computationally efficient. First the performance of MUltifrontal Massively Parallel Solver (MUMPS) is evaluated for both 2D and 3D codes in terms of memory requirements and CPU times. The scalability of both Newton and modified Newton algorithms is tested
Online Correction of Dispersion Error in 2D Waveguide Meshes
An elastic ideal 2D propagation medium, i.e., a membrane, can be simulated by
models discretizing the wave equation on the time-space grid (finite difference
methods), or locally discretizing the solution of the wave equation (waveguide
meshes). The two approaches provide equivalent computational structures, and
introduce numerical dispersion that induces a misalignment of the modes from
their theoretical positions. Prior literature shows that dispersion can be
arbitrarily reduced by oversizing and oversampling the mesh, or by adpting
offline warping techniques. In this paper we propose to reduce numerical
dispersion by embedding warping elements, i.e., properly tuned allpass filters,
in the structure. The resulting model exhibits a significant reduction in
dispersion, and requires less computational resources than a regular mesh
structure having comparable accuracy.Comment: 4 pages, 5 figures, to appear in the Proceedings of the International
Computer Music Conference, 2000. Corrected first referenc
The role of HiPPI switches in mass storage systems: A five year prospective
New standards are evolving which provide the foundation for multi-gigabit per second data communication structures. The lowest layer protocols are so generalized that they encourage a wide range of application. Specifically, the ANSI High Performance Parallel Interface (HiPPI) is being applied to computer peripheral attachment as well as general data communication networks. The HiPPI Standards suite and technology products which incorporate the standards are introduced. The use of simple HiPPI crosspoint switches to build potentially complex extended 'fabrics' is discussed in detail. Several near term applications of the HiPPI technology are briefly described with additional attention to storage systems. Finally, some related standards are mentioned which may further expand the concepts above
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Application of Advanced Early Warning Systems with Adaptive Protection
This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings âencroachâ on the relaysâ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers
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