3,468 research outputs found
A Study of Speed of the Boundary Element Method as applied to the Realtime Computational Simulation of Biological Organs
In this work, possibility of simulating biological organs in realtime using
the Boundary Element Method (BEM) is investigated. Biological organs are
assumed to follow linear elastostatic material behavior, and constant boundary
element is the element type used. First, a Graphics Processing Unit (GPU) is
used to speed up the BEM computations to achieve the realtime performance.
Next, instead of the GPU, a computer cluster is used. Results indicate that BEM
is fast enough to provide for realtime graphics if biological organs are
assumed to follow linear elastostatic material behavior. Although the present
work does not conduct any simulation using nonlinear material models, results
from using the linear elastostatic material model imply that it would be
difficult to obtain realtime performance if highly nonlinear material models
that properly characterize biological organs are used. Although the use of BEM
for the simulation of biological organs is not new, the results presented in
the present study are not found elsewhere in the literature.Comment: preprint, draft, 2 tables, 47 references, 7 files, Codes that can
solve three dimensional linear elastostatic problems using constant boundary
elements (of triangular shape) while ignoring body forces are provided as
supplementary files; codes are distributed under the MIT License in three
versions: i) MATLAB version ii) Fortran 90 version (sequential code) iii)
Fortran 90 version (parallel code
Tunable plasmonic resonances in highly porous nano-bamboo Si-Au superlattice-type thin films
We report on fabrication of spatially-coherent columnar plasmonic
nanostructure superlattice-type thin films with high porosity and strong
optical anisotropy using glancing angle deposition. Subsequent and repeated
depositions of silicon and gold lead to nanometer-dimension subcolumns with
controlled lengths. The superlattice-type columns resemble bamboo structures
where smaller column sections of gold form junctions sandwiched between larger
silicon column sections ("nano-bamboo"). We perform generalized spectroscopic
ellipsometry measurements and finite element method computations to elucidate
the strongly anisotropic optical properties of the highly-porous nano-bamboo
structures. The occurrence of a strongly localized plasmonic mode with
displacement pattern reminiscent of a dark quadrupole mode is observed in the
vicinity of the gold subcolumns. We demonstrate tuning of this quadrupole-like
mode frequency within the near-infrared spectral range by varying the geometry
of the nano-bamboo structure. In addition, coupled-plasmon-like and inter-band
transition-like modes occur in the visible and ultra-violet spectral regions,
respectively. We elucidate an example for the potential use of the nano-bamboo
structures as a highly porous plasmonic sensor with optical read out
sensitivity to few parts-per-million solvent levels in water
Recent Advances in Graph Partitioning
We survey recent trends in practical algorithms for balanced graph
partitioning together with applications and future research directions
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