Three-Dimensional Finite-Difference EEG forward problem solution on High Performance Computers

2006 ◽  
Author(s):  
S. Mininel ◽  
F. Vatta ◽  
A. Collaone ◽  
P. Bruno ◽  
P. Inchingolo
Keyword(s):  
Finite Difference ◽  
High Performance ◽  
Three Dimensional ◽  
Forward Problem ◽  
Problem Solution ◽  
High Performance Computers

scholarly journals A Family of Sixth-Order Compact Finite-Difference Schemes for the Three-Dimensional Poisson Equation

2010 ◽  
Vol 2010 ◽  
pp. 1-17 ◽  
Author(s):  
Yaw Kyei ◽  
John Paul Roop ◽  
Guoqing Tang
Keyword(s):  
Finite Difference ◽  
High Performance ◽  
Three Dimensional ◽  
Difference Schemes ◽  
Poisson’S Equation ◽  
Sixth Order ◽  
Finite Difference Schemes ◽  
Poisson's Equation ◽  
Compact Finite Difference ◽  
Compact Finite Difference Schemes

We derive a family of sixth-order compact finite-difference schemes for the three-dimensional Poisson's equation. As opposed to other research regarding higher-order compact difference schemes, our approach includes consideration of the discretization of the source function on a compact finite-difference stencil. The schemes derived approximate the solution to Poisson's equation on a compact stencil, and thus the schemes can be easily implemented and resulting linear systems are solved in a high-performance computing environment. The resulting discretization is a one-parameter family of finite-difference schemes which may be further optimized for accuracy and stability. Computational experiments are implemented which illustrate the theoretically demonstrated truncation errors.

Permeability Calculations in Three-Dimensional Fiber Networks

2008 ◽  
Author(s):  
T. Stylianopoulos ◽  
A. Yeckel ◽  
J. J. Derby ◽  
X. J. Luo ◽  
M. S. Shephard ◽  
...  
Keyword(s):  
High Performance ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Volume Averaging ◽  
Creeping Flow ◽  
Fibrous Media ◽  
Fiber Volume ◽  
Fiber Networks ◽  
Flow Through ◽  
High Performance Computers

The study of creeping flow in fibrous media is of considerable interest in many biological and biomedical applications. There is little work, however, on permeability calculations in three-dimensional random networks. Computational power is now sufficient to calculate permeabilities directly by constructing artificial fiber networks and simulating flow through them. Even with today’s high-performance computers, however, such an approach would be infeasible for large simulations. It is therefore necessary to develop a correlation based on fiber volume fraction, radius and orientation, preferably by incorporating previous studies on isotropic or structured networks. In this work, the direct calculations were performed, using the finite element method, on networks with varying degrees of orientation, and combinations of results for flow parallel and perpendicular to a single fiber or an array thereof, using a volume averaging theory, were compared to the detailed analysis.

Development of a Household Vacuum Cleaner With a New Cyclone Dust Collector

2007 ◽  
Author(s):  
Shoji Hayashi ◽  
Masatoshi Watanabe ◽  
Yukiji Iwase ◽  
Kyoichi Kanno ◽  
Keiichi Fujimori
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Cartesian Grid ◽  
Dust Collector ◽  
Grid System ◽  
Vacuum Cleaner ◽  
Pressure Losses ◽  
Stepped Surfaces ◽  
Cyclone Dust Collector ◽  
High Performance Computers

A household vacuum cleaner named “Tatsumaki cyclone” with a new cyclone dust collector was developed. It has a unique horizontal layout called the inverted cyclone layout that features a dust bunker adjacent to a cyclone cylinder with an up-draught airflow. It also has a new airflow arrangement called triple-suction airflow that separates airflow after removing dust at the cyclone cylinder. The main suction airflow is exhausted from the main port (which is downstream of the cyclone cylinder) through an inner cylinder. The sub-suction airflow is exhausted from the dust bunker after it heavily compresses the dust (sub port). The center suction airflow is exhausted from the center port. In this study, we used the Cartesian grid system to simulate the flow field inside the dust collector. This system uses only rectangular parallelepiped meshes; profiles of the dust collector were represented by stepped surfaces of cubic meshes. Each mesh was generated based on whether it was inside or outside the solid body of the dust collector. High-performance computers have recently been used to help generate super-fine meshes that fit closely the smooth shape of a dust collector. The Cartesian grid system has the advantage of being able to quickly generate square-meshes of complex shape that can be converted directly from the CAD data. We simulated the velocity distribution of single-suction, twin-suction and triple-suction models. The single-suction model had only a main port to exhaust airflow, the twin-suction model had a main port, and a sub port, and the triple-suction model had a main port, a sub port, and a center port. In this study, a Cartesian grid system with a finite difference method was used to correct the unsteady three-dimensional flows. After the simulation, we experimented with pressure losses and measured change in air quantity by the dust load of each model. These steps enabled us to develop a new cyclone dust collector called Tatsumaki cyclone as part of a compact household vacuum cleaner with lower pressure loss and a larger capacity dust bunker.

scholarly journals Combining Non-Uniform Time Slice and Finite Difference to Improve 3D Ghost Imaging

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 418 ◽  
Author(s):  
Fanghua Zhang ◽  
Jie Cao ◽  
Qun Hao ◽  
Kaiyu Zhang ◽  
Yang Cheng ◽  
...  
Keyword(s):  
Finite Difference ◽  
Traditional Method ◽  
High Performance ◽  
Three Dimensional ◽  
Field Of View ◽  
Time Slice ◽  
Ghost Imaging ◽  
Zero Crossing ◽  
Novel Structure ◽  
Differential Distance

Three-dimensional ghost imaging (3DGI) using a detector is widely used in many applications. The performance of 3DGI based on a uniform time slice is difficult to improve because obtaining an accurate time-slice position remains a challenge. This paper reports a novel structure based on non-uniform time slice combined with finite difference. In this approach, finite difference is beneficial to improving sensitivity of zero crossing to accurately obtain the position of the target in the field of view. Simultaneously, non-uniform time slice is used to quickly obtain 3DGI on an interesting target. Results show that better performances of 3DGI are obtained by our proposed method compared to the traditional method. Moreover, the relation between time slice and the signal-noise-ratio of 3DGI is discussed, and the optimal differential distance is obtained, thus motivating the development of a high-performance 3DGI.

New Method for Mitigating Weave-induced Differential Skew in PWBs

2014 ◽  
Vol 2014 (1) ◽  
pp. 000213-000216
Author(s):  
Taiga Fukumori ◽  
Tomoyuki Akahoshi ◽  
Daisuke Mizutani ◽  
Motoaki Tani
Keyword(s):  
Line Width ◽  
High Performance ◽  
Three Dimensional ◽  
New Method ◽  
Significant Problem ◽  
Electromagnetic Simulation ◽  
Printed Wiring Boards ◽  
Data Rates ◽  
High Performance Computers

Weave induced skew in printed wiring boards (PWB) in high-performance computers has become a significant problem as data rates have increased. We present a new method to reduce weave induced skew. Using three-dimensional electromagnetic simulation, we have discovered that skew can be reduced by adjusting the line width to a specific value, and that the specific values are approximately the same for both stripline and microstripline. We have ascertained the effect in actual PWB manufacturing and measurement. As a result, we have verified by measurement that skew can be reduced to less than one-third. Investigation of a wider range of line width / weave pitches by simulation suggests that skew can be reduced to less than one-tenth of a usual structure.

Improved 3-D reconstruction using stereo computer graphics and multiple tilt EM images

1995 ◽  
Vol 53 ◽  
pp. 630-631
Author(s):  
Lee D. Peachey ◽  
Lou Fodor ◽  
John C. Haselgrove ◽  
Stanley M. Dunn ◽  
Junqing Huang
Keyword(s):  
Computer Graphics ◽  
High Performance ◽  
Transverse Section ◽  
Three Dimensional ◽  
Stereo Pair ◽  
3D Reconstructions ◽  
Video Cameras ◽  
Biological Objects ◽  
Microscope Images ◽  
High Performance Computer

Stereo pairs of electron microscope images provide valuable visual impressions of the three-dimensional nature of specimens, including biological objects. Beyond this one seeks quantitatively accurate models and measurements of the three dimensional positions and sizes of structures in the specimen. In our laboratory, we have sought to combine high resolution video cameras with high performance computer graphics systems to improve both the ease of building 3D reconstructions and the accuracy of 3D measurements, by using multiple tilt images of the same specimen tilted over a wider range of angles than can be viewed stereoscopically. Ultimately we also wish to automate the reconstruction and measurement process, and have initiated work in that direction.Figure 1 is a stereo pair of 400 kV images from a 1 micrometer thick transverse section of frog skeletal muscle stained with the Golgi stain. This stain selectively increases the density of the transverse tubular network in these muscle cells, and it is this network that we reconstruct in this example.

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