701,967 research outputs found
Theories, models, simulations: a computational challenge
In this talk I would like to illustrate with examples taken from Quantum
Field Theory and Biophysics how an intelligent exploitation of the
unprecedented power of today's computers could led not only to the solution of
pivotal problems in the theory of Strong Interactions, but also to the
emergence of new lines of interdisciplinary research, while at the same time
pushing the limits of modeling to the realm of living systems.Comment: 19 pages, 1 figure, conference pape
Efficient Localization of Discontinuities in Complex Computational Simulations
Surrogate models for computational simulations are input-output
approximations that allow computationally intensive analyses, such as
uncertainty propagation and inference, to be performed efficiently. When a
simulation output does not depend smoothly on its inputs, the error and
convergence rate of many approximation methods deteriorate substantially. This
paper details a method for efficiently localizing discontinuities in the input
parameter domain, so that the model output can be approximated as a piecewise
smooth function. The approach comprises an initialization phase, which uses
polynomial annihilation to assign function values to different regions and thus
seed an automated labeling procedure, followed by a refinement phase that
adaptively updates a kernel support vector machine representation of the
separating surface via active learning. The overall approach avoids structured
grids and exploits any available simplicity in the geometry of the separating
surface, thus reducing the number of model evaluations required to localize the
discontinuity. The method is illustrated on examples of up to eleven
dimensions, including algebraic models and ODE/PDE systems, and demonstrates
improved scaling and efficiency over other discontinuity localization
approaches
Computationally efficient stratified flow wet angle correlation for high resolution simulations
n high resolution two-phase pipe flow simulations, such as slug capturing simulation for liquid-gas pipe flow, explicit calculation of stratified flow wet angle has been proposed to improve computational speed of simulations. Most phenomenological and approximate models for obtaining reliable predictions for stratified flow wet angle employ iterative methods or contain long explicit equations which reduce computational efficiency of these models in high-resolution simulations. Therefore, the aim of this study is to adapt a simple mathematical model for predicting stratified flow wet angle to achieve computationally efficient high-resolution liquid-gas pipe flow simulations
Observation of large-scale multi-agent based simulations
The computational cost of large-scale multi-agent based simulations (MABS)
can be extremely important, especially if simulations have to be monitored for
validation purposes. In this paper, two methods, based on self-observation and
statistical survey theory, are introduced in order to optimize the computation
of observations in MABS. An empirical comparison of the computational cost of
these methods is performed on a toy problem
Sound Generation by a Turbulent Flow in Musical Instruments - Multiphysics Simulation Approach -
Total computational costs of scientific simulations are analyzed between
direct numerical simulations (DNS) and multiphysics simulations (MPS) for sound
generation in musical instruments. In order to produce acoustic sound by a
turbulent flow in a simple recorder-like instrument, compressible fluid dynamic
calculations with a low Mach number are required around the edges and the
resonator of the instrument in DNS, while incompressible fluid dynamic
calculations coupled with dynamics of sound propagation based on the
Lighthill's acoustic analogy are used in MPS. These strategies are evaluated
not only from the viewpoint of computational performances but also from the
theoretical points of view as tools for scientific simulations of complicated
systems.Comment: 6 pages, 10 figure files, to appear in the proceedings of HPCAsia0
Computational Thermodynamics and Kinetics in Materials Modelling and Simulations
Over the past two decades, Computational Thermodynamics and Kinetics have been tremendously contributed to materials modeling and simulations and the demands on quantitative
conceptual design and processing of various advanced materials arisen from various industries and academic
institutions involved in materials manufacturing, engineering and applications are still rapidly increasing
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