22,880 research outputs found
Fast computation of the performance evaluation of biometric systems: application to multibiometric
The performance evaluation of biometric systems is a crucial step when
designing and evaluating such systems. The evaluation process uses the Equal
Error Rate (EER) metric proposed by the International Organization for
Standardization (ISO/IEC). The EER metric is a powerful metric which allows
easily comparing and evaluating biometric systems. However, the computation
time of the EER is, most of the time, very intensive. In this paper, we propose
a fast method which computes an approximated value of the EER. We illustrate
the benefit of the proposed method on two applications: the computing of non
parametric confidence intervals and the use of genetic algorithms to compute
the parameters of fusion functions. Experimental results show the superiority
of the proposed EER approximation method in term of computing time, and the
interest of its use to reduce the learning of parameters with genetic
algorithms. The proposed method opens new perspectives for the development of
secure multibiometrics systems by speeding up their computation time.Comment: Future Generation Computer Systems (2012
A Reconfigurable Vector Instruction Processor for Accelerating a Convection Parametrization Model on FPGAs
High Performance Computing (HPC) platforms allow scientists to model
computationally intensive algorithms. HPC clusters increasingly use
General-Purpose Graphics Processing Units (GPGPUs) as accelerators; FPGAs
provide an attractive alternative to GPGPUs for use as co-processors, but they
are still far from being mainstream due to a number of challenges faced when
using FPGA-based platforms. Our research aims to make FPGA-based high
performance computing more accessible to the scientific community. In this work
we present the results of investigating the acceleration of a particular
atmospheric model, Flexpart, on FPGAs. We focus on accelerating the most
computationally intensive kernel from this model. The key contribution of our
work is the architectural exploration we undertook to arrive at a solution that
best exploits the parallelism available in the legacy code, and is also
convenient to program, so that eventually the compilation of high-level legacy
code to our architecture can be fully automated. We present the three different
types of architecture, comparing their resource utilization and performance,
and propose that an architecture where there are a number of computational
cores, each built along the lines of a vector instruction processor, works best
in this particular scenario, and is a promising candidate for a generic
FPGA-based platform for scientific computation. We also present the results of
experiments done with various configuration parameters of the proposed
architecture, to show its utility in adapting to a range of scientific
applications.Comment: This is an extended pre-print version of work that was presented at
the international symposium on Highly Efficient Accelerators and
Reconfigurable Technologies (HEART2014), Sendai, Japan, June 911, 201
Lorenz-Mie theory for 2D scattering and resonance calculations
This PhD tutorial is concerned with a description of the two-dimensional
generalized Lorenz-Mie theory (2D-GLMT), a well-established numerical method
used to compute the interaction of light with arrays of cylindrical scatterers.
This theory is based on the method of separation of variables and the
application of an addition theorem for cylindrical functions. The purpose of
this tutorial is to assemble the practical tools necessary to implement the
2D-GLMT method for the computation of scattering by passive scatterers or of
resonances in optically active media. The first part contains a derivation of
the vector and scalar Helmholtz equations for 2D geometries, starting from
Maxwell's equations. Optically active media are included in 2D-GLMT using a
recent stationary formulation of the Maxwell-Bloch equations called
steady-state ab initio laser theory (SALT), which introduces new classes of
solutions useful for resonance computations. Following these preliminaries, a
detailed description of 2D-GLMT is presented. The emphasis is placed on the
derivation of beam-shape coefficients for scattering computations, as well as
the computation of resonant modes using a combination of 2D-GLMT and SALT. The
final section contains several numerical examples illustrating the full
potential of 2D-GLMT for scattering and resonance computations. These examples,
drawn from the literature, include the design of integrated polarization
filters and the computation of optical modes of photonic crystal cavities and
random lasers.Comment: This is an author-created, un-copyedited version of an article
published in Journal of Optics. IOP Publishing Ltd is not responsible for any
errors or omissions in this version of the manuscript or any version derived
from i
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