10,280 research outputs found
Exploring Application Performance on Emerging Hybrid-Memory Supercomputers
Next-generation supercomputers will feature more hierarchical and
heterogeneous memory systems with different memory technologies working
side-by-side. A critical question is whether at large scale existing HPC
applications and emerging data-analytics workloads will have performance
improvement or degradation on these systems. We propose a systematic and fair
methodology to identify the trend of application performance on emerging
hybrid-memory systems. We model the memory system of next-generation
supercomputers as a combination of "fast" and "slow" memories. We then analyze
performance and dynamic execution characteristics of a variety of workloads,
from traditional scientific applications to emerging data analytics to compare
traditional and hybrid-memory systems. Our results show that data analytics
applications can clearly benefit from the new system design, especially at
large scale. Moreover, hybrid-memory systems do not penalize traditional
scientific applications, which may also show performance improvement.Comment: 18th International Conference on High Performance Computing and
Communications, IEEE, 201
Graph Signal Processing: Overview, Challenges and Applications
Research in Graph Signal Processing (GSP) aims to develop tools for
processing data defined on irregular graph domains. In this paper we first
provide an overview of core ideas in GSP and their connection to conventional
digital signal processing. We then summarize recent developments in developing
basic GSP tools, including methods for sampling, filtering or graph learning.
Next, we review progress in several application areas using GSP, including
processing and analysis of sensor network data, biological data, and
applications to image processing and machine learning. We finish by providing a
brief historical perspective to highlight how concepts recently developed in
GSP build on top of prior research in other areas.Comment: To appear, Proceedings of the IEE
Fourier Neural Operator with Learned Deformations for PDEs on General Geometries
Deep learning surrogate models have shown promise in solving partial
differential equations (PDEs). Among them, the Fourier neural operator (FNO)
achieves good accuracy, and is significantly faster compared to numerical
solvers, on a variety of PDEs, such as fluid flows. However, the FNO uses the
Fast Fourier transform (FFT), which is limited to rectangular domains with
uniform grids. In this work, we propose a new framework, viz., geo-FNO, to
solve PDEs on arbitrary geometries. Geo-FNO learns to deform the input
(physical) domain, which may be irregular, into a latent space with a uniform
grid. The FNO model with the FFT is applied in the latent space. The resulting
geo-FNO model has both the computation efficiency of FFT and the flexibility of
handling arbitrary geometries. Our geo-FNO is also flexible in terms of its
input formats, viz., point clouds, meshes, and design parameters are all valid
inputs. We consider a variety of PDEs such as the Elasticity, Plasticity,
Euler's, and Navier-Stokes equations, and both forward modeling and inverse
design problems. Geo-FNO is times faster than the standard numerical
solvers and twice more accurate compared to direct interpolation on existing
ML-based PDE solvers such as the standard FNO
Randomness Quality of CI Chaotic Generators: Applications to Internet Security
Due to the rapid development of the Internet in recent years, the need to
find new tools to reinforce trust and security through the Internet has became
a major concern. The discovery of new pseudo-random number generators with a
strong level of security is thus becoming a hot topic, because numerous
cryptosystems and data hiding schemes are directly dependent on the quality of
these generators. At the conference Internet`09, we have described a generator
based on chaotic iterations, which behaves chaotically as defined by Devaney.
In this paper, the proposal is to improve the speed and the security of this
generator, to make its use more relevant in the Internet security context. To
do so, a comparative study between various generators is carried out and
statistical results are given. Finally, an application in the information
hiding framework is presented, to give an illustrative example of the use of
such a generator in the Internet security field.Comment: 6 pages,6 figures, In INTERNET'2010. The 2nd Int. Conf. on Evolving
Internet, Valencia, Spain, pages 125-130, September 2010. IEEE Computer
Society Press Note: Best Paper awar
Geometry-Informed Neural Operator for Large-Scale 3D PDEs
We propose the geometry-informed neural operator (GINO), a highly efficient
approach to learning the solution operator of large-scale partial differential
equations with varying geometries. GINO uses a signed distance function and
point-cloud representations of the input shape and neural operators based on
graph and Fourier architectures to learn the solution operator. The graph
neural operator handles irregular grids and transforms them into and from
regular latent grids on which Fourier neural operator can be efficiently
applied. GINO is discretization-convergent, meaning the trained model can be
applied to arbitrary discretization of the continuous domain and it converges
to the continuum operator as the discretization is refined. To empirically
validate the performance of our method on large-scale simulation, we generate
the industry-standard aerodynamics dataset of 3D vehicle geometries with
Reynolds numbers as high as five million. For this large-scale 3D fluid
simulation, numerical methods are expensive to compute surface pressure. We
successfully trained GINO to predict the pressure on car surfaces using only
five hundred data points. The cost-accuracy experiments show a
speed-up compared to optimized GPU-based computational fluid dynamics (CFD)
simulators on computing the drag coefficient. When tested on new combinations
of geometries and boundary conditions (inlet velocities), GINO obtains a
one-fourth reduction in error rate compared to deep neural network approaches
Difficulties in early ice detection with the Small Ice Detector 2 HIAPER (SID-2H) in maritime cumuli
© Copyright 2014 American Meteorological Society (AMS).The Small Ice Detector 2 HIAPER (SID-2H) was used to attempt to detect small ice particles in the early stages of ice formation in the high liquid water environment of tropical maritime cumulus clouds sampled during the Ice in Clouds Experiment - Tropical (ICE-T) field campaign. Its performance in comparison to other probes, and the development of new corrections applied to the data, are presented. The SID-2H detected small ice crystals among larger particles. It correctly identified water drops, and discriminated between round and irregular particle shapes in water-dominated clouds with errors less than 5%. Remaining uncertainties in the sensing volume, and the volume over which coincidence of particles occurred, result in the data being used here in a qualitative manner to identify the presence of ice, its habits and sizes.Peer reviewe
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